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Diffstat (limited to 'Documentation/DocBook')
201 files changed, 71232 insertions, 0 deletions
diff --git a/Documentation/DocBook/80211.tmpl b/Documentation/DocBook/80211.tmpl new file mode 100644 index 00000000..c5ac6929 --- /dev/null +++ b/Documentation/DocBook/80211.tmpl @@ -0,0 +1,583 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE set PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> +<set> + <setinfo> + <title>The 802.11 subsystems – for kernel developers</title> + <subtitle> + Explaining wireless 802.11 networking in the Linux kernel + </subtitle> + + <copyright> + <year>2007-2009</year> + <holder>Johannes Berg</holder> + </copyright> + + <authorgroup> + <author> + <firstname>Johannes</firstname> + <surname>Berg</surname> + <affiliation> + <address><email>johannes@sipsolutions.net</email></address> + </affiliation> + </author> + </authorgroup> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + <para> + This documentation is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + <para> + You should have received a copy of the GNU General Public + License along with this documentation; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + + <abstract> + <para> + These books attempt to give a description of the + various subsystems that play a role in 802.11 wireless + networking in Linux. Since these books are for kernel + developers they attempts to document the structures + and functions used in the kernel as well as giving a + higher-level overview. + </para> + <para> + The reader is expected to be familiar with the 802.11 + standard as published by the IEEE in 802.11-2007 (or + possibly later versions). References to this standard + will be given as "802.11-2007 8.1.5". + </para> + </abstract> + </setinfo> + <book id="cfg80211-developers-guide"> + <bookinfo> + <title>The cfg80211 subsystem</title> + + <abstract> +!Pinclude/net/cfg80211.h Introduction + </abstract> + </bookinfo> + <chapter> + <title>Device registration</title> +!Pinclude/net/cfg80211.h Device registration +!Finclude/net/cfg80211.h ieee80211_band +!Finclude/net/cfg80211.h ieee80211_channel_flags +!Finclude/net/cfg80211.h ieee80211_channel +!Finclude/net/cfg80211.h ieee80211_rate_flags +!Finclude/net/cfg80211.h ieee80211_rate +!Finclude/net/cfg80211.h ieee80211_sta_ht_cap +!Finclude/net/cfg80211.h ieee80211_supported_band +!Finclude/net/cfg80211.h cfg80211_signal_type +!Finclude/net/cfg80211.h wiphy_params_flags +!Finclude/net/cfg80211.h wiphy_flags +!Finclude/net/cfg80211.h wiphy +!Finclude/net/cfg80211.h wireless_dev +!Finclude/net/cfg80211.h wiphy_new +!Finclude/net/cfg80211.h wiphy_register +!Finclude/net/cfg80211.h wiphy_unregister +!Finclude/net/cfg80211.h wiphy_free + +!Finclude/net/cfg80211.h wiphy_name +!Finclude/net/cfg80211.h wiphy_dev +!Finclude/net/cfg80211.h wiphy_priv +!Finclude/net/cfg80211.h priv_to_wiphy +!Finclude/net/cfg80211.h set_wiphy_dev +!Finclude/net/cfg80211.h wdev_priv + </chapter> + <chapter> + <title>Actions and configuration</title> +!Pinclude/net/cfg80211.h Actions and configuration +!Finclude/net/cfg80211.h cfg80211_ops +!Finclude/net/cfg80211.h vif_params +!Finclude/net/cfg80211.h key_params +!Finclude/net/cfg80211.h survey_info_flags +!Finclude/net/cfg80211.h survey_info +!Finclude/net/cfg80211.h beacon_parameters +!Finclude/net/cfg80211.h plink_actions +!Finclude/net/cfg80211.h station_parameters +!Finclude/net/cfg80211.h station_info_flags +!Finclude/net/cfg80211.h rate_info_flags +!Finclude/net/cfg80211.h rate_info +!Finclude/net/cfg80211.h station_info +!Finclude/net/cfg80211.h monitor_flags +!Finclude/net/cfg80211.h mpath_info_flags +!Finclude/net/cfg80211.h mpath_info +!Finclude/net/cfg80211.h bss_parameters +!Finclude/net/cfg80211.h ieee80211_txq_params +!Finclude/net/cfg80211.h cfg80211_crypto_settings +!Finclude/net/cfg80211.h cfg80211_auth_request +!Finclude/net/cfg80211.h cfg80211_assoc_request +!Finclude/net/cfg80211.h cfg80211_deauth_request +!Finclude/net/cfg80211.h cfg80211_disassoc_request +!Finclude/net/cfg80211.h cfg80211_ibss_params +!Finclude/net/cfg80211.h cfg80211_connect_params +!Finclude/net/cfg80211.h cfg80211_pmksa +!Finclude/net/cfg80211.h cfg80211_send_rx_auth +!Finclude/net/cfg80211.h cfg80211_send_auth_timeout +!Finclude/net/cfg80211.h cfg80211_send_rx_assoc +!Finclude/net/cfg80211.h cfg80211_send_assoc_timeout +!Finclude/net/cfg80211.h cfg80211_send_deauth +!Finclude/net/cfg80211.h __cfg80211_send_deauth +!Finclude/net/cfg80211.h cfg80211_send_disassoc +!Finclude/net/cfg80211.h __cfg80211_send_disassoc +!Finclude/net/cfg80211.h cfg80211_ibss_joined +!Finclude/net/cfg80211.h cfg80211_connect_result +!Finclude/net/cfg80211.h cfg80211_roamed +!Finclude/net/cfg80211.h cfg80211_disconnected +!Finclude/net/cfg80211.h cfg80211_ready_on_channel +!Finclude/net/cfg80211.h cfg80211_remain_on_channel_expired +!Finclude/net/cfg80211.h cfg80211_new_sta +!Finclude/net/cfg80211.h cfg80211_rx_mgmt +!Finclude/net/cfg80211.h cfg80211_mgmt_tx_status +!Finclude/net/cfg80211.h cfg80211_cqm_rssi_notify +!Finclude/net/cfg80211.h cfg80211_cqm_pktloss_notify +!Finclude/net/cfg80211.h cfg80211_michael_mic_failure + </chapter> + <chapter> + <title>Scanning and BSS list handling</title> +!Pinclude/net/cfg80211.h Scanning and BSS list handling +!Finclude/net/cfg80211.h cfg80211_ssid +!Finclude/net/cfg80211.h cfg80211_scan_request +!Finclude/net/cfg80211.h cfg80211_scan_done +!Finclude/net/cfg80211.h cfg80211_bss +!Finclude/net/cfg80211.h cfg80211_inform_bss_frame +!Finclude/net/cfg80211.h cfg80211_inform_bss +!Finclude/net/cfg80211.h cfg80211_unlink_bss +!Finclude/net/cfg80211.h cfg80211_find_ie +!Finclude/net/cfg80211.h ieee80211_bss_get_ie + </chapter> + <chapter> + <title>Utility functions</title> +!Pinclude/net/cfg80211.h Utility functions +!Finclude/net/cfg80211.h ieee80211_channel_to_frequency +!Finclude/net/cfg80211.h ieee80211_frequency_to_channel +!Finclude/net/cfg80211.h ieee80211_get_channel +!Finclude/net/cfg80211.h ieee80211_get_response_rate +!Finclude/net/cfg80211.h ieee80211_hdrlen +!Finclude/net/cfg80211.h ieee80211_get_hdrlen_from_skb +!Finclude/net/cfg80211.h ieee80211_radiotap_iterator + </chapter> + <chapter> + <title>Data path helpers</title> +!Pinclude/net/cfg80211.h Data path helpers +!Finclude/net/cfg80211.h ieee80211_data_to_8023 +!Finclude/net/cfg80211.h ieee80211_data_from_8023 +!Finclude/net/cfg80211.h ieee80211_amsdu_to_8023s +!Finclude/net/cfg80211.h cfg80211_classify8021d + </chapter> + <chapter> + <title>Regulatory enforcement infrastructure</title> +!Pinclude/net/cfg80211.h Regulatory enforcement infrastructure +!Finclude/net/cfg80211.h regulatory_hint +!Finclude/net/cfg80211.h wiphy_apply_custom_regulatory +!Finclude/net/cfg80211.h freq_reg_info + </chapter> + <chapter> + <title>RFkill integration</title> +!Pinclude/net/cfg80211.h RFkill integration +!Finclude/net/cfg80211.h wiphy_rfkill_set_hw_state +!Finclude/net/cfg80211.h wiphy_rfkill_start_polling +!Finclude/net/cfg80211.h wiphy_rfkill_stop_polling + </chapter> + <chapter> + <title>Test mode</title> +!Pinclude/net/cfg80211.h Test mode +!Finclude/net/cfg80211.h cfg80211_testmode_alloc_reply_skb +!Finclude/net/cfg80211.h cfg80211_testmode_reply +!Finclude/net/cfg80211.h cfg80211_testmode_alloc_event_skb +!Finclude/net/cfg80211.h cfg80211_testmode_event + </chapter> + </book> + <book id="mac80211-developers-guide"> + <bookinfo> + <title>The mac80211 subsystem</title> + <abstract> +!Pinclude/net/mac80211.h Introduction +!Pinclude/net/mac80211.h Warning + </abstract> + </bookinfo> + + <toc></toc> + + <!-- + Generally, this document shall be ordered by increasing complexity. + It is important to note that readers should be able to read only + the first few sections to get a working driver and only advanced + usage should require reading the full document. + --> + + <part> + <title>The basic mac80211 driver interface</title> + <partintro> + <para> + You should read and understand the information contained + within this part of the book while implementing a driver. + In some chapters, advanced usage is noted, that may be + skipped at first. + </para> + <para> + This part of the book only covers station and monitor mode + functionality, additional information required to implement + the other modes is covered in the second part of the book. + </para> + </partintro> + + <chapter id="basics"> + <title>Basic hardware handling</title> + <para>TBD</para> + <para> + This chapter shall contain information on getting a hw + struct allocated and registered with mac80211. + </para> + <para> + Since it is required to allocate rates/modes before registering + a hw struct, this chapter shall also contain information on setting + up the rate/mode structs. + </para> + <para> + Additionally, some discussion about the callbacks and + the general programming model should be in here, including + the definition of ieee80211_ops which will be referred to + a lot. + </para> + <para> + Finally, a discussion of hardware capabilities should be done + with references to other parts of the book. + </para> + <!-- intentionally multiple !F lines to get proper order --> +!Finclude/net/mac80211.h ieee80211_hw +!Finclude/net/mac80211.h ieee80211_hw_flags +!Finclude/net/mac80211.h SET_IEEE80211_DEV +!Finclude/net/mac80211.h SET_IEEE80211_PERM_ADDR +!Finclude/net/mac80211.h ieee80211_ops +!Finclude/net/mac80211.h ieee80211_alloc_hw +!Finclude/net/mac80211.h ieee80211_register_hw +!Finclude/net/mac80211.h ieee80211_unregister_hw +!Finclude/net/mac80211.h ieee80211_free_hw + </chapter> + + <chapter id="phy-handling"> + <title>PHY configuration</title> + <para>TBD</para> + <para> + This chapter should describe PHY handling including + start/stop callbacks and the various structures used. + </para> +!Finclude/net/mac80211.h ieee80211_conf +!Finclude/net/mac80211.h ieee80211_conf_flags + </chapter> + + <chapter id="iface-handling"> + <title>Virtual interfaces</title> + <para>TBD</para> + <para> + This chapter should describe virtual interface basics + that are relevant to the driver (VLANs, MGMT etc are not.) + It should explain the use of the add_iface/remove_iface + callbacks as well as the interface configuration callbacks. + </para> + <para>Things related to AP mode should be discussed there.</para> + <para> + Things related to supporting multiple interfaces should be + in the appropriate chapter, a BIG FAT note should be here about + this though and the recommendation to allow only a single + interface in STA mode at first! + </para> +!Finclude/net/mac80211.h ieee80211_vif + </chapter> + + <chapter id="rx-tx"> + <title>Receive and transmit processing</title> + <sect1> + <title>what should be here</title> + <para>TBD</para> + <para> + This should describe the receive and transmit + paths in mac80211/the drivers as well as + transmit status handling. + </para> + </sect1> + <sect1> + <title>Frame format</title> +!Pinclude/net/mac80211.h Frame format + </sect1> + <sect1> + <title>Packet alignment</title> +!Pnet/mac80211/rx.c Packet alignment + </sect1> + <sect1> + <title>Calling into mac80211 from interrupts</title> +!Pinclude/net/mac80211.h Calling mac80211 from interrupts + </sect1> + <sect1> + <title>functions/definitions</title> +!Finclude/net/mac80211.h ieee80211_rx_status +!Finclude/net/mac80211.h mac80211_rx_flags +!Finclude/net/mac80211.h mac80211_tx_control_flags +!Finclude/net/mac80211.h mac80211_rate_control_flags +!Finclude/net/mac80211.h ieee80211_tx_rate +!Finclude/net/mac80211.h ieee80211_tx_info +!Finclude/net/mac80211.h ieee80211_tx_info_clear_status +!Finclude/net/mac80211.h ieee80211_rx +!Finclude/net/mac80211.h ieee80211_rx_ni +!Finclude/net/mac80211.h ieee80211_rx_irqsafe +!Finclude/net/mac80211.h ieee80211_tx_status +!Finclude/net/mac80211.h ieee80211_tx_status_ni +!Finclude/net/mac80211.h ieee80211_tx_status_irqsafe +!Finclude/net/mac80211.h ieee80211_rts_get +!Finclude/net/mac80211.h ieee80211_rts_duration +!Finclude/net/mac80211.h ieee80211_ctstoself_get +!Finclude/net/mac80211.h ieee80211_ctstoself_duration +!Finclude/net/mac80211.h ieee80211_generic_frame_duration +!Finclude/net/mac80211.h ieee80211_wake_queue +!Finclude/net/mac80211.h ieee80211_stop_queue +!Finclude/net/mac80211.h ieee80211_wake_queues +!Finclude/net/mac80211.h ieee80211_stop_queues +!Finclude/net/mac80211.h ieee80211_queue_stopped + </sect1> + </chapter> + + <chapter id="filters"> + <title>Frame filtering</title> +!Pinclude/net/mac80211.h Frame filtering +!Finclude/net/mac80211.h ieee80211_filter_flags + </chapter> + + <chapter id="workqueue"> + <title>The mac80211 workqueue</title> +!Pinclude/net/mac80211.h mac80211 workqueue +!Finclude/net/mac80211.h ieee80211_queue_work +!Finclude/net/mac80211.h ieee80211_queue_delayed_work + </chapter> + </part> + + <part id="advanced"> + <title>Advanced driver interface</title> + <partintro> + <para> + Information contained within this part of the book is + of interest only for advanced interaction of mac80211 + with drivers to exploit more hardware capabilities and + improve performance. + </para> + </partintro> + + <chapter id="led-support"> + <title>LED support</title> + <para> + Mac80211 supports various ways of blinking LEDs. Wherever possible, + device LEDs should be exposed as LED class devices and hooked up to + the appropriate trigger, which will then be triggered appropriately + by mac80211. + </para> +!Finclude/net/mac80211.h ieee80211_get_tx_led_name +!Finclude/net/mac80211.h ieee80211_get_rx_led_name +!Finclude/net/mac80211.h ieee80211_get_assoc_led_name +!Finclude/net/mac80211.h ieee80211_get_radio_led_name +!Finclude/net/mac80211.h ieee80211_tpt_blink +!Finclude/net/mac80211.h ieee80211_tpt_led_trigger_flags +!Finclude/net/mac80211.h ieee80211_create_tpt_led_trigger + </chapter> + + <chapter id="hardware-crypto-offload"> + <title>Hardware crypto acceleration</title> +!Pinclude/net/mac80211.h Hardware crypto acceleration + <!-- intentionally multiple !F lines to get proper order --> +!Finclude/net/mac80211.h set_key_cmd +!Finclude/net/mac80211.h ieee80211_key_conf +!Finclude/net/mac80211.h ieee80211_key_flags +!Finclude/net/mac80211.h ieee80211_get_tkip_p1k +!Finclude/net/mac80211.h ieee80211_get_tkip_p1k_iv +!Finclude/net/mac80211.h ieee80211_get_tkip_p2k +!Finclude/net/mac80211.h ieee80211_key_removed + </chapter> + + <chapter id="powersave"> + <title>Powersave support</title> +!Pinclude/net/mac80211.h Powersave support + </chapter> + + <chapter id="beacon-filter"> + <title>Beacon filter support</title> +!Pinclude/net/mac80211.h Beacon filter support +!Finclude/net/mac80211.h ieee80211_beacon_loss + </chapter> + + <chapter id="qos"> + <title>Multiple queues and QoS support</title> + <para>TBD</para> +!Finclude/net/mac80211.h ieee80211_tx_queue_params + </chapter> + + <chapter id="AP"> + <title>Access point mode support</title> + <para>TBD</para> + <para>Some parts of the if_conf should be discussed here instead</para> + <para> + Insert notes about VLAN interfaces with hw crypto here or + in the hw crypto chapter. + </para> + <section id="ps-client"> + <title>support for powersaving clients</title> +!Pinclude/net/mac80211.h AP support for powersaving clients + </section> +!Finclude/net/mac80211.h ieee80211_get_buffered_bc +!Finclude/net/mac80211.h ieee80211_beacon_get +!Finclude/net/mac80211.h ieee80211_sta_eosp_irqsafe +!Finclude/net/mac80211.h ieee80211_frame_release_type +!Finclude/net/mac80211.h ieee80211_sta_ps_transition +!Finclude/net/mac80211.h ieee80211_sta_ps_transition_ni +!Finclude/net/mac80211.h ieee80211_sta_set_buffered +!Finclude/net/mac80211.h ieee80211_sta_block_awake + </chapter> + + <chapter id="multi-iface"> + <title>Supporting multiple virtual interfaces</title> + <para>TBD</para> + <para> + Note: WDS with identical MAC address should almost always be OK + </para> + <para> + Insert notes about having multiple virtual interfaces with + different MAC addresses here, note which configurations are + supported by mac80211, add notes about supporting hw crypto + with it. + </para> +!Finclude/net/mac80211.h ieee80211_iterate_active_interfaces +!Finclude/net/mac80211.h ieee80211_iterate_active_interfaces_atomic + </chapter> + + <chapter id="station-handling"> + <title>Station handling</title> + <para>TODO</para> +!Finclude/net/mac80211.h ieee80211_sta +!Finclude/net/mac80211.h sta_notify_cmd +!Finclude/net/mac80211.h ieee80211_find_sta +!Finclude/net/mac80211.h ieee80211_find_sta_by_ifaddr + </chapter> + + <chapter id="hardware-scan-offload"> + <title>Hardware scan offload</title> + <para>TBD</para> +!Finclude/net/mac80211.h ieee80211_scan_completed + </chapter> + + <chapter id="aggregation"> + <title>Aggregation</title> + <sect1> + <title>TX A-MPDU aggregation</title> +!Pnet/mac80211/agg-tx.c TX A-MPDU aggregation +!Cnet/mac80211/agg-tx.c + </sect1> + <sect1> + <title>RX A-MPDU aggregation</title> +!Pnet/mac80211/agg-rx.c RX A-MPDU aggregation +!Cnet/mac80211/agg-rx.c + </sect1> +!Finclude/net/mac80211.h ieee80211_ampdu_mlme_action + </chapter> + + <chapter id="smps"> + <title>Spatial Multiplexing Powersave (SMPS)</title> +!Pinclude/net/mac80211.h Spatial multiplexing power save +!Finclude/net/mac80211.h ieee80211_request_smps +!Finclude/net/mac80211.h ieee80211_smps_mode + </chapter> + </part> + + <part id="rate-control"> + <title>Rate control interface</title> + <partintro> + <para>TBD</para> + <para> + This part of the book describes the rate control algorithm + interface and how it relates to mac80211 and drivers. + </para> + </partintro> + <chapter id="ratecontrol-api"> + <title>Rate Control API</title> + <para>TBD</para> +!Finclude/net/mac80211.h ieee80211_start_tx_ba_session +!Finclude/net/mac80211.h ieee80211_start_tx_ba_cb_irqsafe +!Finclude/net/mac80211.h ieee80211_stop_tx_ba_session +!Finclude/net/mac80211.h ieee80211_stop_tx_ba_cb_irqsafe +!Finclude/net/mac80211.h rate_control_changed +!Finclude/net/mac80211.h ieee80211_tx_rate_control +!Finclude/net/mac80211.h rate_control_send_low + </chapter> + </part> + + <part id="internal"> + <title>Internals</title> + <partintro> + <para>TBD</para> + <para> + This part of the book describes mac80211 internals. + </para> + </partintro> + + <chapter id="key-handling"> + <title>Key handling</title> + <sect1> + <title>Key handling basics</title> +!Pnet/mac80211/key.c Key handling basics + </sect1> + <sect1> + <title>MORE TBD</title> + <para>TBD</para> + </sect1> + </chapter> + + <chapter id="rx-processing"> + <title>Receive processing</title> + <para>TBD</para> + </chapter> + + <chapter id="tx-processing"> + <title>Transmit processing</title> + <para>TBD</para> + </chapter> + + <chapter id="sta-info"> + <title>Station info handling</title> + <sect1> + <title>Programming information</title> +!Fnet/mac80211/sta_info.h sta_info +!Fnet/mac80211/sta_info.h ieee80211_sta_info_flags + </sect1> + <sect1> + <title>STA information lifetime rules</title> +!Pnet/mac80211/sta_info.c STA information lifetime rules + </sect1> + </chapter> + + <chapter id="aggregation-internals"> + <title>Aggregation</title> +!Fnet/mac80211/sta_info.h sta_ampdu_mlme +!Fnet/mac80211/sta_info.h tid_ampdu_tx +!Fnet/mac80211/sta_info.h tid_ampdu_rx + </chapter> + + <chapter id="synchronisation"> + <title>Synchronisation</title> + <para>TBD</para> + <para>Locking, lots of RCU</para> + </chapter> + </part> + </book> +</set> diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile new file mode 100644 index 00000000..66725a3d --- /dev/null +++ b/Documentation/DocBook/Makefile @@ -0,0 +1,241 @@ +### +# This makefile is used to generate the kernel documentation, +# primarily based on in-line comments in various source files. +# See Documentation/kernel-doc-nano-HOWTO.txt for instruction in how +# to document the SRC - and how to read it. +# To add a new book the only step required is to add the book to the +# list of DOCBOOKS. + +DOCBOOKS := z8530book.xml mcabook.xml device-drivers.xml \ + kernel-hacking.xml kernel-locking.xml deviceiobook.xml \ + writing_usb_driver.xml networking.xml \ + kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ + gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \ + genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \ + 80211.xml debugobjects.xml sh.xml regulator.xml \ + alsa-driver-api.xml writing-an-alsa-driver.xml \ + tracepoint.xml drm.xml media_api.xml + +include $(srctree)/Documentation/DocBook/media/Makefile + +### +# The build process is as follows (targets): +# (xmldocs) [by docproc] +# file.tmpl --> file.xml +--> file.ps (psdocs) [by db2ps or xmlto] +# +--> file.pdf (pdfdocs) [by db2pdf or xmlto] +# +--> DIR=file (htmldocs) [by xmlto] +# +--> man/ (mandocs) [by xmlto] + + +# for PDF and PS output you can choose between xmlto and docbook-utils tools +PDF_METHOD = $(prefer-db2x) +PS_METHOD = $(prefer-db2x) + + +### +# The targets that may be used. +PHONY += xmldocs sgmldocs psdocs pdfdocs htmldocs mandocs installmandocs cleandocs + +BOOKS := $(addprefix $(obj)/,$(DOCBOOKS)) +xmldocs: $(BOOKS) +sgmldocs: xmldocs + +PS := $(patsubst %.xml, %.ps, $(BOOKS)) +psdocs: $(PS) + +PDF := $(patsubst %.xml, %.pdf, $(BOOKS)) +pdfdocs: $(PDF) + +HTML := $(sort $(patsubst %.xml, %.html, $(BOOKS))) +htmldocs: $(HTML) + $(call build_main_index) + $(call build_images) + $(call install_media_images) + +MAN := $(patsubst %.xml, %.9, $(BOOKS)) +mandocs: $(MAN) + +installmandocs: mandocs + mkdir -p /usr/local/man/man9/ + install Documentation/DocBook/man/*.9.gz /usr/local/man/man9/ + +### +#External programs used +KERNELDOC = $(srctree)/scripts/kernel-doc +DOCPROC = $(objtree)/scripts/docproc + +XMLTOFLAGS = -m $(srctree)/Documentation/DocBook/stylesheet.xsl +XMLTOFLAGS += --skip-validation + +### +# DOCPROC is used for two purposes: +# 1) To generate a dependency list for a .tmpl file +# 2) To preprocess a .tmpl file and call kernel-doc with +# appropriate parameters. +# The following rules are used to generate the .xml documentation +# required to generate the final targets. (ps, pdf, html). +quiet_cmd_docproc = DOCPROC $@ + cmd_docproc = SRCTREE=$(srctree)/ $(DOCPROC) doc $< >$@ +define rule_docproc + set -e; \ + $(if $($(quiet)cmd_$(1)),echo ' $($(quiet)cmd_$(1))';) \ + $(cmd_$(1)); \ + ( \ + echo 'cmd_$@ := $(cmd_$(1))'; \ + echo $@: `SRCTREE=$(srctree) $(DOCPROC) depend $<`; \ + ) > $(dir $@).$(notdir $@).cmd +endef + +%.xml: %.tmpl FORCE + $(call if_changed_rule,docproc) + +### +#Read in all saved dependency files +cmd_files := $(wildcard $(foreach f,$(BOOKS),$(dir $(f)).$(notdir $(f)).cmd)) + +ifneq ($(cmd_files),) + include $(cmd_files) +endif + +### +# Changes in kernel-doc force a rebuild of all documentation +$(BOOKS): $(KERNELDOC) + +# Tell kbuild to always build the programs +always := $(hostprogs-y) + +notfoundtemplate = echo "*** You have to install docbook-utils or xmlto ***"; \ + exit 1 +db2xtemplate = db2TYPE -o $(dir $@) $< +xmltotemplate = xmlto TYPE $(XMLTOFLAGS) -o $(dir $@) $< + +# determine which methods are available +ifeq ($(shell which db2ps >/dev/null 2>&1 && echo found),found) + use-db2x = db2x + prefer-db2x = db2x +else + use-db2x = notfound + prefer-db2x = $(use-xmlto) +endif +ifeq ($(shell which xmlto >/dev/null 2>&1 && echo found),found) + use-xmlto = xmlto + prefer-xmlto = xmlto +else + use-xmlto = notfound + prefer-xmlto = $(use-db2x) +endif + +# the commands, generated from the chosen template +quiet_cmd_db2ps = PS $@ + cmd_db2ps = $(subst TYPE,ps, $($(PS_METHOD)template)) +%.ps : %.xml + $(call cmd,db2ps) + +quiet_cmd_db2pdf = PDF $@ + cmd_db2pdf = $(subst TYPE,pdf, $($(PDF_METHOD)template)) +%.pdf : %.xml + $(call cmd,db2pdf) + + +index = index.html +main_idx = Documentation/DocBook/$(index) +build_main_index = rm -rf $(main_idx); \ + echo '<h1>Linux Kernel HTML Documentation</h1>' >> $(main_idx) && \ + echo '<h2>Kernel Version: $(KERNELVERSION)</h2>' >> $(main_idx) && \ + cat $(HTML) >> $(main_idx) + +quiet_cmd_db2html = HTML $@ + cmd_db2html = xmlto xhtml $(XMLTOFLAGS) -o $(patsubst %.html,%,$@) $< && \ + echo '<a HREF="$(patsubst %.html,%,$(notdir $@))/index.html"> \ + $(patsubst %.html,%,$(notdir $@))</a><p>' > $@ + +%.html: %.xml + @(which xmlto > /dev/null 2>&1) || \ + (echo "*** You need to install xmlto ***"; \ + exit 1) + @rm -rf $@ $(patsubst %.html,%,$@) + $(call cmd,db2html) + @if [ ! -z "$(PNG-$(basename $(notdir $@)))" ]; then \ + cp $(PNG-$(basename $(notdir $@))) $(patsubst %.html,%,$@); fi + +quiet_cmd_db2man = MAN $@ + cmd_db2man = if grep -q refentry $<; then xmlto man $(XMLTOFLAGS) -o $(obj)/man $< ; gzip -f $(obj)/man/*.9; fi +%.9 : %.xml + @(which xmlto > /dev/null 2>&1) || \ + (echo "*** You need to install xmlto ***"; \ + exit 1) + $(Q)mkdir -p $(obj)/man + $(call cmd,db2man) + @touch $@ + +### +# Rules to generate postscripts and PNG images from .fig format files +quiet_cmd_fig2eps = FIG2EPS $@ + cmd_fig2eps = fig2dev -Leps $< $@ + +%.eps: %.fig + @(which fig2dev > /dev/null 2>&1) || \ + (echo "*** You need to install transfig ***"; \ + exit 1) + $(call cmd,fig2eps) + +quiet_cmd_fig2png = FIG2PNG $@ + cmd_fig2png = fig2dev -Lpng $< $@ + +%.png: %.fig + @(which fig2dev > /dev/null 2>&1) || \ + (echo "*** You need to install transfig ***"; \ + exit 1) + $(call cmd,fig2png) + +### +# Rule to convert a .c file to inline XML documentation + gen_xml = : + quiet_gen_xml = echo ' GEN $@' +silent_gen_xml = : +%.xml: %.c + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>"; \ + expand --tabs=8 < $< | \ + sed -e "s/&/\\&/g" \ + -e "s/</\\</g" \ + -e "s/>/\\>/g"; \ + echo "</programlisting>") > $@ + +### +# Help targets as used by the top-level makefile +dochelp: + @echo ' Linux kernel internal documentation in different formats:' + @echo ' htmldocs - HTML' + @echo ' pdfdocs - PDF' + @echo ' psdocs - Postscript' + @echo ' xmldocs - XML DocBook' + @echo ' mandocs - man pages' + @echo ' installmandocs - install man pages generated by mandocs' + @echo ' cleandocs - clean all generated DocBook files' + +### +# Temporary files left by various tools +clean-files := $(DOCBOOKS) \ + $(patsubst %.xml, %.dvi, $(DOCBOOKS)) \ + $(patsubst %.xml, %.aux, $(DOCBOOKS)) \ + $(patsubst %.xml, %.tex, $(DOCBOOKS)) \ + $(patsubst %.xml, %.log, $(DOCBOOKS)) \ + $(patsubst %.xml, %.out, $(DOCBOOKS)) \ + $(patsubst %.xml, %.ps, $(DOCBOOKS)) \ + $(patsubst %.xml, %.pdf, $(DOCBOOKS)) \ + $(patsubst %.xml, %.html, $(DOCBOOKS)) \ + $(patsubst %.xml, %.9, $(DOCBOOKS)) \ + $(index) + +clean-dirs := $(patsubst %.xml,%,$(DOCBOOKS)) man + +cleandocs: cleanmediadocs + $(Q)rm -f $(call objectify, $(clean-files)) + $(Q)rm -rf $(call objectify, $(clean-dirs)) + +# Declare the contents of the .PHONY variable as phony. We keep that +# information in a variable se we can use it in if_changed and friends. + +.PHONY: $(PHONY) diff --git a/Documentation/DocBook/alsa-driver-api.tmpl b/Documentation/DocBook/alsa-driver-api.tmpl new file mode 100644 index 00000000..0230a96f --- /dev/null +++ b/Documentation/DocBook/alsa-driver-api.tmpl @@ -0,0 +1,109 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<!-- ****************************************************** --> +<!-- Header --> +<!-- ****************************************************** --> +<book id="ALSA-Driver-API"> + <bookinfo> + <title>The ALSA Driver API</title> + + <legalnotice> + <para> + This document is free; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + </para> + + <para> + This document is distributed in the hope that it will be useful, + but <emphasis>WITHOUT ANY WARRANTY</emphasis>; without even the + implied warranty of <emphasis>MERCHANTABILITY or FITNESS FOR A + PARTICULAR PURPOSE</emphasis>. See the GNU General Public License + for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + </legalnotice> + + </bookinfo> + +<toc></toc> + + <chapter><title>Management of Cards and Devices</title> + <sect1><title>Card Management</title> +!Esound/core/init.c + </sect1> + <sect1><title>Device Components</title> +!Esound/core/device.c + </sect1> + <sect1><title>Module requests and Device File Entries</title> +!Esound/core/sound.c + </sect1> + <sect1><title>Memory Management Helpers</title> +!Esound/core/memory.c +!Esound/core/memalloc.c + </sect1> + </chapter> + <chapter><title>PCM API</title> + <sect1><title>PCM Core</title> +!Esound/core/pcm.c +!Esound/core/pcm_lib.c +!Esound/core/pcm_native.c + </sect1> + <sect1><title>PCM Format Helpers</title> +!Esound/core/pcm_misc.c + </sect1> + <sect1><title>PCM Memory Management</title> +!Esound/core/pcm_memory.c + </sect1> + </chapter> + <chapter><title>Control/Mixer API</title> + <sect1><title>General Control Interface</title> +!Esound/core/control.c + </sect1> + <sect1><title>AC97 Codec API</title> +!Esound/pci/ac97/ac97_codec.c +!Esound/pci/ac97/ac97_pcm.c + </sect1> + <sect1><title>Virtual Master Control API</title> +!Esound/core/vmaster.c +!Iinclude/sound/control.h + </sect1> + </chapter> + <chapter><title>MIDI API</title> + <sect1><title>Raw MIDI API</title> +!Esound/core/rawmidi.c + </sect1> + <sect1><title>MPU401-UART API</title> +!Esound/drivers/mpu401/mpu401_uart.c + </sect1> + </chapter> + <chapter><title>Proc Info API</title> + <sect1><title>Proc Info Interface</title> +!Esound/core/info.c + </sect1> + </chapter> + <chapter><title>Miscellaneous Functions</title> + <sect1><title>Hardware-Dependent Devices API</title> +!Esound/core/hwdep.c + </sect1> + <sect1><title>Jack Abstraction Layer API</title> +!Esound/core/jack.c + </sect1> + <sect1><title>ISA DMA Helpers</title> +!Esound/core/isadma.c + </sect1> + <sect1><title>Other Helper Macros</title> +!Iinclude/sound/core.h + </sect1> + </chapter> + +</book> diff --git a/Documentation/DocBook/debugobjects.tmpl b/Documentation/DocBook/debugobjects.tmpl new file mode 100644 index 00000000..24979f69 --- /dev/null +++ b/Documentation/DocBook/debugobjects.tmpl @@ -0,0 +1,441 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="debug-objects-guide"> + <bookinfo> + <title>Debug objects life time</title> + + <authorgroup> + <author> + <firstname>Thomas</firstname> + <surname>Gleixner</surname> + <affiliation> + <address> + <email>tglx@linutronix.de</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2008</year> + <holder>Thomas Gleixner</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + debugobjects is a generic infrastructure to track the life time + of kernel objects and validate the operations on those. + </para> + <para> + debugobjects is useful to check for the following error patterns: + <itemizedlist> + <listitem><para>Activation of uninitialized objects</para></listitem> + <listitem><para>Initialization of active objects</para></listitem> + <listitem><para>Usage of freed/destroyed objects</para></listitem> + </itemizedlist> + </para> + <para> + debugobjects is not changing the data structure of the real + object so it can be compiled in with a minimal runtime impact + and enabled on demand with a kernel command line option. + </para> + </chapter> + + <chapter id="howto"> + <title>Howto use debugobjects</title> + <para> + A kernel subsystem needs to provide a data structure which + describes the object type and add calls into the debug code at + appropriate places. The data structure to describe the object + type needs at minimum the name of the object type. Optional + functions can and should be provided to fixup detected problems + so the kernel can continue to work and the debug information can + be retrieved from a live system instead of hard core debugging + with serial consoles and stack trace transcripts from the + monitor. + </para> + <para> + The debug calls provided by debugobjects are: + <itemizedlist> + <listitem><para>debug_object_init</para></listitem> + <listitem><para>debug_object_init_on_stack</para></listitem> + <listitem><para>debug_object_activate</para></listitem> + <listitem><para>debug_object_deactivate</para></listitem> + <listitem><para>debug_object_destroy</para></listitem> + <listitem><para>debug_object_free</para></listitem> + <listitem><para>debug_object_assert_init</para></listitem> + </itemizedlist> + Each of these functions takes the address of the real object and + a pointer to the object type specific debug description + structure. + </para> + <para> + Each detected error is reported in the statistics and a limited + number of errors are printk'ed including a full stack trace. + </para> + <para> + The statistics are available via /sys/kernel/debug/debug_objects/stats. + They provide information about the number of warnings and the + number of successful fixups along with information about the + usage of the internal tracking objects and the state of the + internal tracking objects pool. + </para> + </chapter> + <chapter id="debugfunctions"> + <title>Debug functions</title> + <sect1 id="prototypes"> + <title>Debug object function reference</title> +!Elib/debugobjects.c + </sect1> + <sect1 id="debug_object_init"> + <title>debug_object_init</title> + <para> + This function is called whenever the initialization function + of a real object is called. + </para> + <para> + When the real object is already tracked by debugobjects it is + checked, whether the object can be initialized. Initializing + is not allowed for active and destroyed objects. When + debugobjects detects an error, then it calls the fixup_init + function of the object type description structure if provided + by the caller. The fixup function can correct the problem + before the real initialization of the object happens. E.g. it + can deactivate an active object in order to prevent damage to + the subsystem. + </para> + <para> + When the real object is not yet tracked by debugobjects, + debugobjects allocates a tracker object for the real object + and sets the tracker object state to ODEBUG_STATE_INIT. It + verifies that the object is not on the callers stack. If it is + on the callers stack then a limited number of warnings + including a full stack trace is printk'ed. The calling code + must use debug_object_init_on_stack() and remove the object + before leaving the function which allocated it. See next + section. + </para> + </sect1> + + <sect1 id="debug_object_init_on_stack"> + <title>debug_object_init_on_stack</title> + <para> + This function is called whenever the initialization function + of a real object which resides on the stack is called. + </para> + <para> + When the real object is already tracked by debugobjects it is + checked, whether the object can be initialized. Initializing + is not allowed for active and destroyed objects. When + debugobjects detects an error, then it calls the fixup_init + function of the object type description structure if provided + by the caller. The fixup function can correct the problem + before the real initialization of the object happens. E.g. it + can deactivate an active object in order to prevent damage to + the subsystem. + </para> + <para> + When the real object is not yet tracked by debugobjects + debugobjects allocates a tracker object for the real object + and sets the tracker object state to ODEBUG_STATE_INIT. It + verifies that the object is on the callers stack. + </para> + <para> + An object which is on the stack must be removed from the + tracker by calling debug_object_free() before the function + which allocates the object returns. Otherwise we keep track of + stale objects. + </para> + </sect1> + + <sect1 id="debug_object_activate"> + <title>debug_object_activate</title> + <para> + This function is called whenever the activation function of a + real object is called. + </para> + <para> + When the real object is already tracked by debugobjects it is + checked, whether the object can be activated. Activating is + not allowed for active and destroyed objects. When + debugobjects detects an error, then it calls the + fixup_activate function of the object type description + structure if provided by the caller. The fixup function can + correct the problem before the real activation of the object + happens. E.g. it can deactivate an active object in order to + prevent damage to the subsystem. + </para> + <para> + When the real object is not yet tracked by debugobjects then + the fixup_activate function is called if available. This is + necessary to allow the legitimate activation of statically + allocated and initialized objects. The fixup function checks + whether the object is valid and calls the debug_objects_init() + function to initialize the tracking of this object. + </para> + <para> + When the activation is legitimate, then the state of the + associated tracker object is set to ODEBUG_STATE_ACTIVE. + </para> + </sect1> + + <sect1 id="debug_object_deactivate"> + <title>debug_object_deactivate</title> + <para> + This function is called whenever the deactivation function of + a real object is called. + </para> + <para> + When the real object is tracked by debugobjects it is checked, + whether the object can be deactivated. Deactivating is not + allowed for untracked or destroyed objects. + </para> + <para> + When the deactivation is legitimate, then the state of the + associated tracker object is set to ODEBUG_STATE_INACTIVE. + </para> + </sect1> + + <sect1 id="debug_object_destroy"> + <title>debug_object_destroy</title> + <para> + This function is called to mark an object destroyed. This is + useful to prevent the usage of invalid objects, which are + still available in memory: either statically allocated objects + or objects which are freed later. + </para> + <para> + When the real object is tracked by debugobjects it is checked, + whether the object can be destroyed. Destruction is not + allowed for active and destroyed objects. When debugobjects + detects an error, then it calls the fixup_destroy function of + the object type description structure if provided by the + caller. The fixup function can correct the problem before the + real destruction of the object happens. E.g. it can deactivate + an active object in order to prevent damage to the subsystem. + </para> + <para> + When the destruction is legitimate, then the state of the + associated tracker object is set to ODEBUG_STATE_DESTROYED. + </para> + </sect1> + + <sect1 id="debug_object_free"> + <title>debug_object_free</title> + <para> + This function is called before an object is freed. + </para> + <para> + When the real object is tracked by debugobjects it is checked, + whether the object can be freed. Free is not allowed for + active objects. When debugobjects detects an error, then it + calls the fixup_free function of the object type description + structure if provided by the caller. The fixup function can + correct the problem before the real free of the object + happens. E.g. it can deactivate an active object in order to + prevent damage to the subsystem. + </para> + <para> + Note that debug_object_free removes the object from the + tracker. Later usage of the object is detected by the other + debug checks. + </para> + </sect1> + + <sect1 id="debug_object_assert_init"> + <title>debug_object_assert_init</title> + <para> + This function is called to assert that an object has been + initialized. + </para> + <para> + When the real object is not tracked by debugobjects, it calls + fixup_assert_init of the object type description structure + provided by the caller, with the hardcoded object state + ODEBUG_NOT_AVAILABLE. The fixup function can correct the problem + by calling debug_object_init and other specific initializing + functions. + </para> + <para> + When the real object is already tracked by debugobjects it is + ignored. + </para> + </sect1> + </chapter> + <chapter id="fixupfunctions"> + <title>Fixup functions</title> + <sect1 id="debug_obj_descr"> + <title>Debug object type description structure</title> +!Iinclude/linux/debugobjects.h + </sect1> + <sect1 id="fixup_init"> + <title>fixup_init</title> + <para> + This function is called from the debug code whenever a problem + in debug_object_init is detected. The function takes the + address of the object and the state which is currently + recorded in the tracker. + </para> + <para> + Called from debug_object_init when the object state is: + <itemizedlist> + <listitem><para>ODEBUG_STATE_ACTIVE</para></listitem> + </itemizedlist> + </para> + <para> + The function returns 1 when the fixup was successful, + otherwise 0. The return value is used to update the + statistics. + </para> + <para> + Note, that the function needs to call the debug_object_init() + function again, after the damage has been repaired in order to + keep the state consistent. + </para> + </sect1> + + <sect1 id="fixup_activate"> + <title>fixup_activate</title> + <para> + This function is called from the debug code whenever a problem + in debug_object_activate is detected. + </para> + <para> + Called from debug_object_activate when the object state is: + <itemizedlist> + <listitem><para>ODEBUG_STATE_NOTAVAILABLE</para></listitem> + <listitem><para>ODEBUG_STATE_ACTIVE</para></listitem> + </itemizedlist> + </para> + <para> + The function returns 1 when the fixup was successful, + otherwise 0. The return value is used to update the + statistics. + </para> + <para> + Note that the function needs to call the debug_object_activate() + function again after the damage has been repaired in order to + keep the state consistent. + </para> + <para> + The activation of statically initialized objects is a special + case. When debug_object_activate() has no tracked object for + this object address then fixup_activate() is called with + object state ODEBUG_STATE_NOTAVAILABLE. The fixup function + needs to check whether this is a legitimate case of a + statically initialized object or not. In case it is it calls + debug_object_init() and debug_object_activate() to make the + object known to the tracker and marked active. In this case + the function should return 0 because this is not a real fixup. + </para> + </sect1> + + <sect1 id="fixup_destroy"> + <title>fixup_destroy</title> + <para> + This function is called from the debug code whenever a problem + in debug_object_destroy is detected. + </para> + <para> + Called from debug_object_destroy when the object state is: + <itemizedlist> + <listitem><para>ODEBUG_STATE_ACTIVE</para></listitem> + </itemizedlist> + </para> + <para> + The function returns 1 when the fixup was successful, + otherwise 0. The return value is used to update the + statistics. + </para> + </sect1> + <sect1 id="fixup_free"> + <title>fixup_free</title> + <para> + This function is called from the debug code whenever a problem + in debug_object_free is detected. Further it can be called + from the debug checks in kfree/vfree, when an active object is + detected from the debug_check_no_obj_freed() sanity checks. + </para> + <para> + Called from debug_object_free() or debug_check_no_obj_freed() + when the object state is: + <itemizedlist> + <listitem><para>ODEBUG_STATE_ACTIVE</para></listitem> + </itemizedlist> + </para> + <para> + The function returns 1 when the fixup was successful, + otherwise 0. The return value is used to update the + statistics. + </para> + </sect1> + <sect1 id="fixup_assert_init"> + <title>fixup_assert_init</title> + <para> + This function is called from the debug code whenever a problem + in debug_object_assert_init is detected. + </para> + <para> + Called from debug_object_assert_init() with a hardcoded state + ODEBUG_STATE_NOTAVAILABLE when the object is not found in the + debug bucket. + </para> + <para> + The function returns 1 when the fixup was successful, + otherwise 0. The return value is used to update the + statistics. + </para> + <para> + Note, this function should make sure debug_object_init() is + called before returning. + </para> + <para> + The handling of statically initialized objects is a special + case. The fixup function should check if this is a legitimate + case of a statically initialized object or not. In this case only + debug_object_init() should be called to make the object known to + the tracker. Then the function should return 0 because this is not + a real fixup. + </para> + </sect1> + </chapter> + <chapter id="bugs"> + <title>Known Bugs And Assumptions</title> + <para> + None (knock on wood). + </para> + </chapter> +</book> diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl new file mode 100644 index 00000000..7514dbf0 --- /dev/null +++ b/Documentation/DocBook/device-drivers.tmpl @@ -0,0 +1,466 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="LinuxDriversAPI"> + <bookinfo> + <title>Linux Device Drivers</title> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="Basics"> + <title>Driver Basics</title> + <sect1><title>Driver Entry and Exit points</title> +!Iinclude/linux/init.h + </sect1> + + <sect1><title>Atomic and pointer manipulation</title> +!Iarch/x86/include/asm/atomic.h + </sect1> + + <sect1><title>Delaying, scheduling, and timer routines</title> +!Iinclude/linux/sched.h +!Ekernel/sched/core.c +!Ikernel/sched/cpupri.c +!Ikernel/sched/fair.c +!Iinclude/linux/completion.h +!Ekernel/timer.c + </sect1> + <sect1><title>Wait queues and Wake events</title> +!Iinclude/linux/wait.h +!Ekernel/wait.c + </sect1> + <sect1><title>High-resolution timers</title> +!Iinclude/linux/ktime.h +!Iinclude/linux/hrtimer.h +!Ekernel/hrtimer.c + </sect1> + <sect1><title>Workqueues and Kevents</title> +!Ekernel/workqueue.c + </sect1> + <sect1><title>Internal Functions</title> +!Ikernel/exit.c +!Ikernel/signal.c +!Iinclude/linux/kthread.h +!Ekernel/kthread.c + </sect1> + + <sect1><title>Kernel objects manipulation</title> +<!-- +X!Iinclude/linux/kobject.h +--> +!Elib/kobject.c + </sect1> + + <sect1><title>Kernel utility functions</title> +!Iinclude/linux/kernel.h +!Ekernel/printk.c +!Ekernel/panic.c +!Ekernel/sys.c +!Ekernel/rcupdate.c + </sect1> + + <sect1><title>Device Resource Management</title> +!Edrivers/base/devres.c + </sect1> + + </chapter> + + <chapter id="devdrivers"> + <title>Device drivers infrastructure</title> + <sect1><title>The Basic Device Driver-Model Structures </title> +!Iinclude/linux/device.h + </sect1> + <sect1><title>Device Drivers Base</title> +!Idrivers/base/init.c +!Edrivers/base/driver.c +!Edrivers/base/core.c +!Edrivers/base/syscore.c +!Edrivers/base/class.c +!Idrivers/base/node.c +!Edrivers/base/firmware_class.c +!Edrivers/base/transport_class.c +<!-- Cannot be included, because + attribute_container_add_class_device_adapter + and attribute_container_classdev_to_container + exceed allowed 44 characters maximum +X!Edrivers/base/attribute_container.c +--> +!Edrivers/base/dd.c +<!-- +X!Edrivers/base/interface.c +--> +!Iinclude/linux/platform_device.h +!Edrivers/base/platform.c +!Edrivers/base/bus.c + </sect1> + <sect1><title>Device Drivers DMA Management</title> +!Edrivers/base/dma-buf.c +!Edrivers/base/dma-coherent.c +!Edrivers/base/dma-mapping.c + </sect1> + <sect1><title>Device Drivers Power Management</title> +!Edrivers/base/power/main.c + </sect1> + <sect1><title>Device Drivers ACPI Support</title> +<!-- Internal functions only +X!Edrivers/acpi/sleep/main.c +X!Edrivers/acpi/sleep/wakeup.c +X!Edrivers/acpi/motherboard.c +X!Edrivers/acpi/bus.c +--> +!Edrivers/acpi/scan.c +!Idrivers/acpi/scan.c +<!-- No correct structured comments +X!Edrivers/acpi/pci_bind.c +--> + </sect1> + <sect1><title>Device drivers PnP support</title> +!Idrivers/pnp/core.c +<!-- No correct structured comments +X!Edrivers/pnp/system.c + --> +!Edrivers/pnp/card.c +!Idrivers/pnp/driver.c +!Edrivers/pnp/manager.c +!Edrivers/pnp/support.c + </sect1> + <sect1><title>Userspace IO devices</title> +!Edrivers/uio/uio.c +!Iinclude/linux/uio_driver.h + </sect1> + </chapter> + + <chapter id="parportdev"> + <title>Parallel Port Devices</title> +!Iinclude/linux/parport.h +!Edrivers/parport/ieee1284.c +!Edrivers/parport/share.c +!Idrivers/parport/daisy.c + </chapter> + + <chapter id="message_devices"> + <title>Message-based devices</title> + <sect1><title>Fusion message devices</title> +!Edrivers/message/fusion/mptbase.c +!Idrivers/message/fusion/mptbase.c +!Edrivers/message/fusion/mptscsih.c +!Idrivers/message/fusion/mptscsih.c +!Idrivers/message/fusion/mptctl.c +!Idrivers/message/fusion/mptspi.c +!Idrivers/message/fusion/mptfc.c +!Idrivers/message/fusion/mptlan.c + </sect1> + <sect1><title>I2O message devices</title> +!Iinclude/linux/i2o.h +!Idrivers/message/i2o/core.h +!Edrivers/message/i2o/iop.c +!Idrivers/message/i2o/iop.c +!Idrivers/message/i2o/config-osm.c +!Edrivers/message/i2o/exec-osm.c +!Idrivers/message/i2o/exec-osm.c +!Idrivers/message/i2o/bus-osm.c +!Edrivers/message/i2o/device.c +!Idrivers/message/i2o/device.c +!Idrivers/message/i2o/driver.c +!Idrivers/message/i2o/pci.c +!Idrivers/message/i2o/i2o_block.c +!Idrivers/message/i2o/i2o_scsi.c +!Idrivers/message/i2o/i2o_proc.c + </sect1> + </chapter> + + <chapter id="snddev"> + <title>Sound Devices</title> +!Iinclude/sound/core.h +!Esound/sound_core.c +!Iinclude/sound/pcm.h +!Esound/core/pcm.c +!Esound/core/device.c +!Esound/core/info.c +!Esound/core/rawmidi.c +!Esound/core/sound.c +!Esound/core/memory.c +!Esound/core/pcm_memory.c +!Esound/core/init.c +!Esound/core/isadma.c +!Esound/core/control.c +!Esound/core/pcm_lib.c +!Esound/core/hwdep.c +!Esound/core/pcm_native.c +!Esound/core/memalloc.c +<!-- FIXME: Removed for now since no structured comments in source +X!Isound/sound_firmware.c +--> + </chapter> + + <chapter id="uart16x50"> + <title>16x50 UART Driver</title> +!Edrivers/tty/serial/serial_core.c +!Edrivers/tty/serial/8250/8250.c + </chapter> + + <chapter id="fbdev"> + <title>Frame Buffer Library</title> + + <para> + The frame buffer drivers depend heavily on four data structures. + These structures are declared in include/linux/fb.h. They are + fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. + The last three can be made available to and from userland. + </para> + + <para> + fb_info defines the current state of a particular video card. + Inside fb_info, there exists a fb_ops structure which is a + collection of needed functions to make fbdev and fbcon work. + fb_info is only visible to the kernel. + </para> + + <para> + fb_var_screeninfo is used to describe the features of a video card + that are user defined. With fb_var_screeninfo, things such as + depth and the resolution may be defined. + </para> + + <para> + The next structure is fb_fix_screeninfo. This defines the + properties of a card that are created when a mode is set and can't + be changed otherwise. A good example of this is the start of the + frame buffer memory. This "locks" the address of the frame buffer + memory, so that it cannot be changed or moved. + </para> + + <para> + The last structure is fb_monospecs. In the old API, there was + little importance for fb_monospecs. This allowed for forbidden things + such as setting a mode of 800x600 on a fix frequency monitor. With + the new API, fb_monospecs prevents such things, and if used + correctly, can prevent a monitor from being cooked. fb_monospecs + will not be useful until kernels 2.5.x. + </para> + + <sect1><title>Frame Buffer Memory</title> +!Edrivers/video/fbmem.c + </sect1> +<!-- + <sect1><title>Frame Buffer Console</title> +X!Edrivers/video/console/fbcon.c + </sect1> +--> + <sect1><title>Frame Buffer Colormap</title> +!Edrivers/video/fbcmap.c + </sect1> +<!-- FIXME: + drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment + out until somebody adds docs. KAO + <sect1><title>Frame Buffer Generic Functions</title> +X!Idrivers/video/fbgen.c + </sect1> +KAO --> + <sect1><title>Frame Buffer Video Mode Database</title> +!Idrivers/video/modedb.c +!Edrivers/video/modedb.c + </sect1> + <sect1><title>Frame Buffer Macintosh Video Mode Database</title> +!Edrivers/video/macmodes.c + </sect1> + <sect1><title>Frame Buffer Fonts</title> + <para> + Refer to the file drivers/video/console/fonts.c for more information. + </para> +<!-- FIXME: Removed for now since no structured comments in source +X!Idrivers/video/console/fonts.c +--> + </sect1> + </chapter> + + <chapter id="input_subsystem"> + <title>Input Subsystem</title> + <sect1><title>Input core</title> +!Iinclude/linux/input.h +!Edrivers/input/input.c +!Edrivers/input/ff-core.c +!Edrivers/input/ff-memless.c + </sect1> + <sect1><title>Multitouch Library</title> +!Iinclude/linux/input/mt.h +!Edrivers/input/input-mt.c + </sect1> + <sect1><title>Polled input devices</title> +!Iinclude/linux/input-polldev.h +!Edrivers/input/input-polldev.c + </sect1> + <sect1><title>Matrix keyboars/keypads</title> +!Iinclude/linux/input/matrix_keypad.h + </sect1> + <sect1><title>Sparse keymap support</title> +!Iinclude/linux/input/sparse-keymap.h +!Edrivers/input/sparse-keymap.c + </sect1> + </chapter> + + <chapter id="spi"> + <title>Serial Peripheral Interface (SPI)</title> + <para> + SPI is the "Serial Peripheral Interface", widely used with + embedded systems because it is a simple and efficient + interface: basically a multiplexed shift register. + Its three signal wires hold a clock (SCK, often in the range + of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and + a "Master In, Slave Out" (MISO) data line. + SPI is a full duplex protocol; for each bit shifted out the + MOSI line (one per clock) another is shifted in on the MISO line. + Those bits are assembled into words of various sizes on the + way to and from system memory. + An additional chipselect line is usually active-low (nCS); + four signals are normally used for each peripheral, plus + sometimes an interrupt. + </para> + <para> + The SPI bus facilities listed here provide a generalized + interface to declare SPI busses and devices, manage them + according to the standard Linux driver model, and perform + input/output operations. + At this time, only "master" side interfaces are supported, + where Linux talks to SPI peripherals and does not implement + such a peripheral itself. + (Interfaces to support implementing SPI slaves would + necessarily look different.) + </para> + <para> + The programming interface is structured around two kinds of driver, + and two kinds of device. + A "Controller Driver" abstracts the controller hardware, which may + be as simple as a set of GPIO pins or as complex as a pair of FIFOs + connected to dual DMA engines on the other side of the SPI shift + register (maximizing throughput). Such drivers bridge between + whatever bus they sit on (often the platform bus) and SPI, and + expose the SPI side of their device as a + <structname>struct spi_master</structname>. + SPI devices are children of that master, represented as a + <structname>struct spi_device</structname> and manufactured from + <structname>struct spi_board_info</structname> descriptors which + are usually provided by board-specific initialization code. + A <structname>struct spi_driver</structname> is called a + "Protocol Driver", and is bound to a spi_device using normal + driver model calls. + </para> + <para> + The I/O model is a set of queued messages. Protocol drivers + submit one or more <structname>struct spi_message</structname> + objects, which are processed and completed asynchronously. + (There are synchronous wrappers, however.) Messages are + built from one or more <structname>struct spi_transfer</structname> + objects, each of which wraps a full duplex SPI transfer. + A variety of protocol tweaking options are needed, because + different chips adopt very different policies for how they + use the bits transferred with SPI. + </para> +!Iinclude/linux/spi/spi.h +!Fdrivers/spi/spi.c spi_register_board_info +!Edrivers/spi/spi.c + </chapter> + + <chapter id="i2c"> + <title>I<superscript>2</superscript>C and SMBus Subsystem</title> + + <para> + I<superscript>2</superscript>C (or without fancy typography, "I2C") + is an acronym for the "Inter-IC" bus, a simple bus protocol which is + widely used where low data rate communications suffice. + Since it's also a licensed trademark, some vendors use another + name (such as "Two-Wire Interface", TWI) for the same bus. + I2C only needs two signals (SCL for clock, SDA for data), conserving + board real estate and minimizing signal quality issues. + Most I2C devices use seven bit addresses, and bus speeds of up + to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet + found wide use. + I2C is a multi-master bus; open drain signaling is used to + arbitrate between masters, as well as to handshake and to + synchronize clocks from slower clients. + </para> + + <para> + The Linux I2C programming interfaces support only the master + side of bus interactions, not the slave side. + The programming interface is structured around two kinds of driver, + and two kinds of device. + An I2C "Adapter Driver" abstracts the controller hardware; it binds + to a physical device (perhaps a PCI device or platform_device) and + exposes a <structname>struct i2c_adapter</structname> representing + each I2C bus segment it manages. + On each I2C bus segment will be I2C devices represented by a + <structname>struct i2c_client</structname>. Those devices will + be bound to a <structname>struct i2c_driver</structname>, + which should follow the standard Linux driver model. + (At this writing, a legacy model is more widely used.) + There are functions to perform various I2C protocol operations; at + this writing all such functions are usable only from task context. + </para> + + <para> + The System Management Bus (SMBus) is a sibling protocol. Most SMBus + systems are also I2C conformant. The electrical constraints are + tighter for SMBus, and it standardizes particular protocol messages + and idioms. Controllers that support I2C can also support most + SMBus operations, but SMBus controllers don't support all the protocol + options that an I2C controller will. + There are functions to perform various SMBus protocol operations, + either using I2C primitives or by issuing SMBus commands to + i2c_adapter devices which don't support those I2C operations. + </para> + +!Iinclude/linux/i2c.h +!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info +!Edrivers/i2c/i2c-core.c + </chapter> + + <chapter id="hsi"> + <title>High Speed Synchronous Serial Interface (HSI)</title> + + <para> + High Speed Synchronous Serial Interface (HSI) is a + serial interface mainly used for connecting application + engines (APE) with cellular modem engines (CMT) in cellular + handsets. + + HSI provides multiplexing for up to 16 logical channels, + low-latency and full duplex communication. + </para> + +!Iinclude/linux/hsi/hsi.h +!Edrivers/hsi/hsi.c + </chapter> + +</book> diff --git a/Documentation/DocBook/deviceiobook.tmpl b/Documentation/DocBook/deviceiobook.tmpl new file mode 100644 index 00000000..54199a0d --- /dev/null +++ b/Documentation/DocBook/deviceiobook.tmpl @@ -0,0 +1,323 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="DoingIO"> + <bookinfo> + <title>Bus-Independent Device Accesses</title> + + <authorgroup> + <author> + <firstname>Matthew</firstname> + <surname>Wilcox</surname> + <affiliation> + <address> + <email>matthew@wil.cx</email> + </address> + </affiliation> + </author> + </authorgroup> + + <authorgroup> + <author> + <firstname>Alan</firstname> + <surname>Cox</surname> + <affiliation> + <address> + <email>alan@lxorguk.ukuu.org.uk</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2001</year> + <holder>Matthew Wilcox</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + Linux provides an API which abstracts performing IO across all busses + and devices, allowing device drivers to be written independently of + bus type. + </para> + </chapter> + + <chapter id="bugs"> + <title>Known Bugs And Assumptions</title> + <para> + None. + </para> + </chapter> + + <chapter id="mmio"> + <title>Memory Mapped IO</title> + <sect1 id="getting_access_to_the_device"> + <title>Getting Access to the Device</title> + <para> + The most widely supported form of IO is memory mapped IO. + That is, a part of the CPU's address space is interpreted + not as accesses to memory, but as accesses to a device. Some + architectures define devices to be at a fixed address, but most + have some method of discovering devices. The PCI bus walk is a + good example of such a scheme. This document does not cover how + to receive such an address, but assumes you are starting with one. + Physical addresses are of type unsigned long. + </para> + + <para> + This address should not be used directly. Instead, to get an + address suitable for passing to the accessor functions described + below, you should call <function>ioremap</function>. + An address suitable for accessing the device will be returned to you. + </para> + + <para> + After you've finished using the device (say, in your module's + exit routine), call <function>iounmap</function> in order to return + the address space to the kernel. Most architectures allocate new + address space each time you call <function>ioremap</function>, and + they can run out unless you call <function>iounmap</function>. + </para> + </sect1> + + <sect1 id="accessing_the_device"> + <title>Accessing the device</title> + <para> + The part of the interface most used by drivers is reading and + writing memory-mapped registers on the device. Linux provides + interfaces to read and write 8-bit, 16-bit, 32-bit and 64-bit + quantities. Due to a historical accident, these are named byte, + word, long and quad accesses. Both read and write accesses are + supported; there is no prefetch support at this time. + </para> + + <para> + The functions are named <function>readb</function>, + <function>readw</function>, <function>readl</function>, + <function>readq</function>, <function>readb_relaxed</function>, + <function>readw_relaxed</function>, <function>readl_relaxed</function>, + <function>readq_relaxed</function>, <function>writeb</function>, + <function>writew</function>, <function>writel</function> and + <function>writeq</function>. + </para> + + <para> + Some devices (such as framebuffers) would like to use larger + transfers than 8 bytes at a time. For these devices, the + <function>memcpy_toio</function>, <function>memcpy_fromio</function> + and <function>memset_io</function> functions are provided. + Do not use memset or memcpy on IO addresses; they + are not guaranteed to copy data in order. + </para> + + <para> + The read and write functions are defined to be ordered. That is the + compiler is not permitted to reorder the I/O sequence. When the + ordering can be compiler optimised, you can use <function> + __readb</function> and friends to indicate the relaxed ordering. Use + this with care. + </para> + + <para> + While the basic functions are defined to be synchronous with respect + to each other and ordered with respect to each other the busses the + devices sit on may themselves have asynchronicity. In particular many + authors are burned by the fact that PCI bus writes are posted + asynchronously. A driver author must issue a read from the same + device to ensure that writes have occurred in the specific cases the + author cares. This kind of property cannot be hidden from driver + writers in the API. In some cases, the read used to flush the device + may be expected to fail (if the card is resetting, for example). In + that case, the read should be done from config space, which is + guaranteed to soft-fail if the card doesn't respond. + </para> + + <para> + The following is an example of flushing a write to a device when + the driver would like to ensure the write's effects are visible prior + to continuing execution. + </para> + +<programlisting> +static inline void +qla1280_disable_intrs(struct scsi_qla_host *ha) +{ + struct device_reg *reg; + + reg = ha->iobase; + /* disable risc and host interrupts */ + WRT_REG_WORD(&reg->ictrl, 0); + /* + * The following read will ensure that the above write + * has been received by the device before we return from this + * function. + */ + RD_REG_WORD(&reg->ictrl); + ha->flags.ints_enabled = 0; +} +</programlisting> + + <para> + In addition to write posting, on some large multiprocessing systems + (e.g. SGI Challenge, Origin and Altix machines) posted writes won't + be strongly ordered coming from different CPUs. Thus it's important + to properly protect parts of your driver that do memory-mapped writes + with locks and use the <function>mmiowb</function> to make sure they + arrive in the order intended. Issuing a regular <function>readX + </function> will also ensure write ordering, but should only be used + when the driver has to be sure that the write has actually arrived + at the device (not that it's simply ordered with respect to other + writes), since a full <function>readX</function> is a relatively + expensive operation. + </para> + + <para> + Generally, one should use <function>mmiowb</function> prior to + releasing a spinlock that protects regions using <function>writeb + </function> or similar functions that aren't surrounded by <function> + readb</function> calls, which will ensure ordering and flushing. The + following pseudocode illustrates what might occur if write ordering + isn't guaranteed via <function>mmiowb</function> or one of the + <function>readX</function> functions. + </para> + +<programlisting> +CPU A: spin_lock_irqsave(&dev_lock, flags) +CPU A: ... +CPU A: writel(newval, ring_ptr); +CPU A: spin_unlock_irqrestore(&dev_lock, flags) + ... +CPU B: spin_lock_irqsave(&dev_lock, flags) +CPU B: writel(newval2, ring_ptr); +CPU B: ... +CPU B: spin_unlock_irqrestore(&dev_lock, flags) +</programlisting> + + <para> + In the case above, newval2 could be written to ring_ptr before + newval. Fixing it is easy though: + </para> + +<programlisting> +CPU A: spin_lock_irqsave(&dev_lock, flags) +CPU A: ... +CPU A: writel(newval, ring_ptr); +CPU A: mmiowb(); /* ensure no other writes beat us to the device */ +CPU A: spin_unlock_irqrestore(&dev_lock, flags) + ... +CPU B: spin_lock_irqsave(&dev_lock, flags) +CPU B: writel(newval2, ring_ptr); +CPU B: ... +CPU B: mmiowb(); +CPU B: spin_unlock_irqrestore(&dev_lock, flags) +</programlisting> + + <para> + See tg3.c for a real world example of how to use <function>mmiowb + </function> + </para> + + <para> + PCI ordering rules also guarantee that PIO read responses arrive + after any outstanding DMA writes from that bus, since for some devices + the result of a <function>readb</function> call may signal to the + driver that a DMA transaction is complete. In many cases, however, + the driver may want to indicate that the next + <function>readb</function> call has no relation to any previous DMA + writes performed by the device. The driver can use + <function>readb_relaxed</function> for these cases, although only + some platforms will honor the relaxed semantics. Using the relaxed + read functions will provide significant performance benefits on + platforms that support it. The qla2xxx driver provides examples + of how to use <function>readX_relaxed</function>. In many cases, + a majority of the driver's <function>readX</function> calls can + safely be converted to <function>readX_relaxed</function> calls, since + only a few will indicate or depend on DMA completion. + </para> + </sect1> + + </chapter> + + <chapter id="port_space_accesses"> + <title>Port Space Accesses</title> + <sect1 id="port_space_explained"> + <title>Port Space Explained</title> + + <para> + Another form of IO commonly supported is Port Space. This is a + range of addresses separate to the normal memory address space. + Access to these addresses is generally not as fast as accesses + to the memory mapped addresses, and it also has a potentially + smaller address space. + </para> + + <para> + Unlike memory mapped IO, no preparation is required + to access port space. + </para> + + </sect1> + <sect1 id="accessing_port_space"> + <title>Accessing Port Space</title> + <para> + Accesses to this space are provided through a set of functions + which allow 8-bit, 16-bit and 32-bit accesses; also + known as byte, word and long. These functions are + <function>inb</function>, <function>inw</function>, + <function>inl</function>, <function>outb</function>, + <function>outw</function> and <function>outl</function>. + </para> + + <para> + Some variants are provided for these functions. Some devices + require that accesses to their ports are slowed down. This + functionality is provided by appending a <function>_p</function> + to the end of the function. There are also equivalents to memcpy. + The <function>ins</function> and <function>outs</function> + functions copy bytes, words or longs to the given port. + </para> + </sect1> + + </chapter> + + <chapter id="pubfunctions"> + <title>Public Functions Provided</title> +!Iarch/x86/include/asm/io.h +!Elib/pci_iomap.c + </chapter> + +</book> diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl new file mode 100644 index 00000000..196b8b9d --- /dev/null +++ b/Documentation/DocBook/drm.tmpl @@ -0,0 +1,868 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="drmDevelopersGuide"> + <bookinfo> + <title>Linux DRM Developer's Guide</title> + + <copyright> + <year>2008-2009</year> + <holder> + Intel Corporation (Jesse Barnes <jesse.barnes@intel.com>) + </holder> + </copyright> + + <legalnotice> + <para> + The contents of this file may be used under the terms of the GNU + General Public License version 2 (the "GPL") as distributed in + the kernel source COPYING file. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <!-- Introduction --> + + <chapter id="drmIntroduction"> + <title>Introduction</title> + <para> + The Linux DRM layer contains code intended to support the needs + of complex graphics devices, usually containing programmable + pipelines well suited to 3D graphics acceleration. Graphics + drivers in the kernel may make use of DRM functions to make + tasks like memory management, interrupt handling and DMA easier, + and provide a uniform interface to applications. + </para> + <para> + A note on versions: this guide covers features found in the DRM + tree, including the TTM memory manager, output configuration and + mode setting, and the new vblank internals, in addition to all + the regular features found in current kernels. + </para> + <para> + [Insert diagram of typical DRM stack here] + </para> + </chapter> + + <!-- Internals --> + + <chapter id="drmInternals"> + <title>DRM Internals</title> + <para> + This chapter documents DRM internals relevant to driver authors + and developers working to add support for the latest features to + existing drivers. + </para> + <para> + First, we go over some typical driver initialization + requirements, like setting up command buffers, creating an + initial output configuration, and initializing core services. + Subsequent sections cover core internals in more detail, + providing implementation notes and examples. + </para> + <para> + The DRM layer provides several services to graphics drivers, + many of them driven by the application interfaces it provides + through libdrm, the library that wraps most of the DRM ioctls. + These include vblank event handling, memory + management, output management, framebuffer management, command + submission & fencing, suspend/resume support, and DMA + services. + </para> + <para> + The core of every DRM driver is struct drm_driver. Drivers + typically statically initialize a drm_driver structure, + then pass it to drm_init() at load time. + </para> + + <!-- Internals: driver init --> + + <sect1> + <title>Driver initialization</title> + <para> + Before calling the DRM initialization routines, the driver must + first create and fill out a struct drm_driver structure. + </para> + <programlisting> + static struct drm_driver driver = { + /* Don't use MTRRs here; the Xserver or userspace app should + * deal with them for Intel hardware. + */ + .driver_features = + DRIVER_USE_AGP | DRIVER_REQUIRE_AGP | + DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_MODESET, + .load = i915_driver_load, + .unload = i915_driver_unload, + .firstopen = i915_driver_firstopen, + .lastclose = i915_driver_lastclose, + .preclose = i915_driver_preclose, + .save = i915_save, + .restore = i915_restore, + .device_is_agp = i915_driver_device_is_agp, + .get_vblank_counter = i915_get_vblank_counter, + .enable_vblank = i915_enable_vblank, + .disable_vblank = i915_disable_vblank, + .irq_preinstall = i915_driver_irq_preinstall, + .irq_postinstall = i915_driver_irq_postinstall, + .irq_uninstall = i915_driver_irq_uninstall, + .irq_handler = i915_driver_irq_handler, + .reclaim_buffers = drm_core_reclaim_buffers, + .get_map_ofs = drm_core_get_map_ofs, + .get_reg_ofs = drm_core_get_reg_ofs, + .fb_probe = intelfb_probe, + .fb_remove = intelfb_remove, + .fb_resize = intelfb_resize, + .master_create = i915_master_create, + .master_destroy = i915_master_destroy, +#if defined(CONFIG_DEBUG_FS) + .debugfs_init = i915_debugfs_init, + .debugfs_cleanup = i915_debugfs_cleanup, +#endif + .gem_init_object = i915_gem_init_object, + .gem_free_object = i915_gem_free_object, + .gem_vm_ops = &i915_gem_vm_ops, + .ioctls = i915_ioctls, + .fops = { + .owner = THIS_MODULE, + .open = drm_open, + .release = drm_release, + .ioctl = drm_ioctl, + .mmap = drm_mmap, + .poll = drm_poll, + .fasync = drm_fasync, +#ifdef CONFIG_COMPAT + .compat_ioctl = i915_compat_ioctl, +#endif + .llseek = noop_llseek, + }, + .pci_driver = { + .name = DRIVER_NAME, + .id_table = pciidlist, + .probe = probe, + .remove = __devexit_p(drm_cleanup_pci), + }, + .name = DRIVER_NAME, + .desc = DRIVER_DESC, + .date = DRIVER_DATE, + .major = DRIVER_MAJOR, + .minor = DRIVER_MINOR, + .patchlevel = DRIVER_PATCHLEVEL, + }; + </programlisting> + <para> + In the example above, taken from the i915 DRM driver, the driver + sets several flags indicating what core features it supports; + we go over the individual callbacks in later sections. Since + flags indicate which features your driver supports to the DRM + core, you need to set most of them prior to calling drm_init(). Some, + like DRIVER_MODESET can be set later based on user supplied parameters, + but that's the exception rather than the rule. + </para> + <variablelist> + <title>Driver flags</title> + <varlistentry> + <term>DRIVER_USE_AGP</term> + <listitem><para> + Driver uses AGP interface + </para></listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_REQUIRE_AGP</term> + <listitem><para> + Driver needs AGP interface to function. + </para></listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_USE_MTRR</term> + <listitem> + <para> + Driver uses MTRR interface for mapping memory. Deprecated. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_PCI_DMA</term> + <listitem><para> + Driver is capable of PCI DMA. Deprecated. + </para></listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_SG</term> + <listitem><para> + Driver can perform scatter/gather DMA. Deprecated. + </para></listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_HAVE_DMA</term> + <listitem><para>Driver supports DMA. Deprecated.</para></listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_HAVE_IRQ</term><term>DRIVER_IRQ_SHARED</term> + <listitem> + <para> + DRIVER_HAVE_IRQ indicates whether the driver has an IRQ + handler. DRIVER_IRQ_SHARED indicates whether the device & + handler support shared IRQs (note that this is required of + PCI drivers). + </para> + </listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_DMA_QUEUE</term> + <listitem> + <para> + Should be set if the driver queues DMA requests and completes them + asynchronously. Deprecated. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_FB_DMA</term> + <listitem> + <para> + Driver supports DMA to/from the framebuffer. Deprecated. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term>DRIVER_MODESET</term> + <listitem> + <para> + Driver supports mode setting interfaces. + </para> + </listitem> + </varlistentry> + </variablelist> + <para> + In this specific case, the driver requires AGP and supports + IRQs. DMA, as discussed later, is handled by device-specific ioctls + in this case. It also supports the kernel mode setting APIs, though + unlike in the actual i915 driver source, this example unconditionally + exports KMS capability. + </para> + </sect1> + + <!-- Internals: driver load --> + + <sect1> + <title>Driver load</title> + <para> + In the previous section, we saw what a typical drm_driver + structure might look like. One of the more important fields in + the structure is the hook for the load function. + </para> + <programlisting> + static struct drm_driver driver = { + ... + .load = i915_driver_load, + ... + }; + </programlisting> + <para> + The load function has many responsibilities: allocating a driver + private structure, specifying supported performance counters, + configuring the device (e.g. mapping registers & command + buffers), initializing the memory manager, and setting up the + initial output configuration. + </para> + <para> + If compatibility is a concern (e.g. with drivers converted over + to the new interfaces from the old ones), care must be taken to + prevent device initialization and control that is incompatible with + currently active userspace drivers. For instance, if user + level mode setting drivers are in use, it would be problematic + to perform output discovery & configuration at load time. + Likewise, if user-level drivers unaware of memory management are + in use, memory management and command buffer setup may need to + be omitted. These requirements are driver-specific, and care + needs to be taken to keep both old and new applications and + libraries working. The i915 driver supports the "modeset" + module parameter to control whether advanced features are + enabled at load time or in legacy fashion. + </para> + + <sect2> + <title>Driver private & performance counters</title> + <para> + The driver private hangs off the main drm_device structure and + can be used for tracking various device-specific bits of + information, like register offsets, command buffer status, + register state for suspend/resume, etc. At load time, a + driver may simply allocate one and set drm_device.dev_priv + appropriately; it should be freed and drm_device.dev_priv set + to NULL when the driver is unloaded. + </para> + <para> + The DRM supports several counters which may be used for rough + performance characterization. Note that the DRM stat counter + system is not often used by applications, and supporting + additional counters is completely optional. + </para> + <para> + These interfaces are deprecated and should not be used. If performance + monitoring is desired, the developer should investigate and + potentially enhance the kernel perf and tracing infrastructure to export + GPU related performance information for consumption by performance + monitoring tools and applications. + </para> + </sect2> + + <sect2> + <title>Configuring the device</title> + <para> + Obviously, device configuration is device-specific. + However, there are several common operations: finding a + device's PCI resources, mapping them, and potentially setting + up an IRQ handler. + </para> + <para> + Finding & mapping resources is fairly straightforward. The + DRM wrapper functions, drm_get_resource_start() and + drm_get_resource_len(), may be used to find BARs on the given + drm_device struct. Once those values have been retrieved, the + driver load function can call drm_addmap() to create a new + mapping for the BAR in question. Note that you probably want a + drm_local_map_t in your driver private structure to track any + mappings you create. +<!-- !Fdrivers/gpu/drm/drm_bufs.c drm_get_resource_* --> +<!-- !Finclude/drm/drmP.h drm_local_map_t --> + </para> + <para> + if compatibility with other operating systems isn't a concern + (DRM drivers can run under various BSD variants and OpenSolaris), + native Linux calls may be used for the above, e.g. pci_resource_* + and iomap*/iounmap. See the Linux device driver book for more + info. + </para> + <para> + Once you have a register map, you may use the DRM_READn() and + DRM_WRITEn() macros to access the registers on your device, or + use driver-specific versions to offset into your MMIO space + relative to a driver-specific base pointer (see I915_READ for + an example). + </para> + <para> + If your device supports interrupt generation, you may want to + set up an interrupt handler when the driver is loaded. This + is done using the drm_irq_install() function. If your device + supports vertical blank interrupts, it should call + drm_vblank_init() to initialize the core vblank handling code before + enabling interrupts on your device. This ensures the vblank related + structures are allocated and allows the core to handle vblank events. + </para> +<!--!Fdrivers/char/drm/drm_irq.c drm_irq_install--> + <para> + Once your interrupt handler is registered (it uses your + drm_driver.irq_handler as the actual interrupt handling + function), you can safely enable interrupts on your device, + assuming any other state your interrupt handler uses is also + initialized. + </para> + <para> + Another task that may be necessary during configuration is + mapping the video BIOS. On many devices, the VBIOS describes + device configuration, LCD panel timings (if any), and contains + flags indicating device state. Mapping the BIOS can be done + using the pci_map_rom() call, a convenience function that + takes care of mapping the actual ROM, whether it has been + shadowed into memory (typically at address 0xc0000) or exists + on the PCI device in the ROM BAR. Note that after the ROM + has been mapped and any necessary information has been extracted, + it should be unmapped; on many devices, the ROM address decoder is + shared with other BARs, so leaving it mapped could cause + undesired behavior like hangs or memory corruption. +<!--!Fdrivers/pci/rom.c pci_map_rom--> + </para> + </sect2> + + <sect2> + <title>Memory manager initialization</title> + <para> + In order to allocate command buffers, cursor memory, scanout + buffers, etc., as well as support the latest features provided + by packages like Mesa and the X.Org X server, your driver + should support a memory manager. + </para> + <para> + If your driver supports memory management (it should!), you + need to set that up at load time as well. How you initialize + it depends on which memory manager you're using: TTM or GEM. + </para> + <sect3> + <title>TTM initialization</title> + <para> + TTM (for Translation Table Manager) manages video memory and + aperture space for graphics devices. TTM supports both UMA devices + and devices with dedicated video RAM (VRAM), i.e. most discrete + graphics devices. If your device has dedicated RAM, supporting + TTM is desirable. TTM also integrates tightly with your + driver-specific buffer execution function. See the radeon + driver for examples. + </para> + <para> + The core TTM structure is the ttm_bo_driver struct. It contains + several fields with function pointers for initializing the TTM, + allocating and freeing memory, waiting for command completion + and fence synchronization, and memory migration. See the + radeon_ttm.c file for an example of usage. + </para> + <para> + The ttm_global_reference structure is made up of several fields: + </para> + <programlisting> + struct ttm_global_reference { + enum ttm_global_types global_type; + size_t size; + void *object; + int (*init) (struct ttm_global_reference *); + void (*release) (struct ttm_global_reference *); + }; + </programlisting> + <para> + There should be one global reference structure for your memory + manager as a whole, and there will be others for each object + created by the memory manager at runtime. Your global TTM should + have a type of TTM_GLOBAL_TTM_MEM. The size field for the global + object should be sizeof(struct ttm_mem_global), and the init and + release hooks should point at your driver-specific init and + release routines, which probably eventually call + ttm_mem_global_init and ttm_mem_global_release, respectively. + </para> + <para> + Once your global TTM accounting structure is set up and initialized + by calling ttm_global_item_ref() on it, + you need to create a buffer object TTM to + provide a pool for buffer object allocation by clients and the + kernel itself. The type of this object should be TTM_GLOBAL_TTM_BO, + and its size should be sizeof(struct ttm_bo_global). Again, + driver-specific init and release functions may be provided, + likely eventually calling ttm_bo_global_init() and + ttm_bo_global_release(), respectively. Also, like the previous + object, ttm_global_item_ref() is used to create an initial reference + count for the TTM, which will call your initialization function. + </para> + </sect3> + <sect3> + <title>GEM initialization</title> + <para> + GEM is an alternative to TTM, designed specifically for UMA + devices. It has simpler initialization and execution requirements + than TTM, but has no VRAM management capability. Core GEM + is initialized by calling drm_mm_init() to create + a GTT DRM MM object, which provides an address space pool for + object allocation. In a KMS configuration, the driver + needs to allocate and initialize a command ring buffer following + core GEM initialization. A UMA device usually has what is called a + "stolen" memory region, which provides space for the initial + framebuffer and large, contiguous memory regions required by the + device. This space is not typically managed by GEM, and it must + be initialized separately into its own DRM MM object. + </para> + <para> + Initialization is driver-specific. In the case of Intel + integrated graphics chips like 965GM, GEM initialization can + be done by calling the internal GEM init function, + i915_gem_do_init(). Since the 965GM is a UMA device + (i.e. it doesn't have dedicated VRAM), GEM manages + making regular RAM available for GPU operations. Memory set + aside by the BIOS (called "stolen" memory by the i915 + driver) is managed by the DRM memrange allocator; the + rest of the aperture is managed by GEM. + <programlisting> + /* Basic memrange allocator for stolen space (aka vram) */ + drm_memrange_init(&dev_priv->vram, 0, prealloc_size); + /* Let GEM Manage from end of prealloc space to end of aperture */ + i915_gem_do_init(dev, prealloc_size, agp_size); + </programlisting> +<!--!Edrivers/char/drm/drm_memrange.c--> + </para> + <para> + Once the memory manager has been set up, we may allocate the + command buffer. In the i915 case, this is also done with a + GEM function, i915_gem_init_ringbuffer(). + </para> + </sect3> + </sect2> + + <sect2> + <title>Output configuration</title> + <para> + The final initialization task is output configuration. This involves: + <itemizedlist> + <listitem> + Finding and initializing the CRTCs, encoders, and connectors + for the device. + </listitem> + <listitem> + Creating an initial configuration. + </listitem> + <listitem> + Registering a framebuffer console driver. + </listitem> + </itemizedlist> + </para> + <sect3> + <title>Output discovery and initialization</title> + <para> + Several core functions exist to create CRTCs, encoders, and + connectors, namely: drm_crtc_init(), drm_connector_init(), and + drm_encoder_init(), along with several "helper" functions to + perform common tasks. + </para> + <para> + Connectors should be registered with sysfs once they've been + detected and initialized, using the + drm_sysfs_connector_add() function. Likewise, when they're + removed from the system, they should be destroyed with + drm_sysfs_connector_remove(). + </para> + <programlisting> +<![CDATA[ +void intel_crt_init(struct drm_device *dev) +{ + struct drm_connector *connector; + struct intel_output *intel_output; + + intel_output = kzalloc(sizeof(struct intel_output), GFP_KERNEL); + if (!intel_output) + return; + + connector = &intel_output->base; + drm_connector_init(dev, &intel_output->base, + &intel_crt_connector_funcs, DRM_MODE_CONNECTOR_VGA); + + drm_encoder_init(dev, &intel_output->enc, &intel_crt_enc_funcs, + DRM_MODE_ENCODER_DAC); + + drm_mode_connector_attach_encoder(&intel_output->base, + &intel_output->enc); + + /* Set up the DDC bus. */ + intel_output->ddc_bus = intel_i2c_create(dev, GPIOA, "CRTDDC_A"); + if (!intel_output->ddc_bus) { + dev_printk(KERN_ERR, &dev->pdev->dev, "DDC bus registration " + "failed.\n"); + return; + } + + intel_output->type = INTEL_OUTPUT_ANALOG; + connector->interlace_allowed = 0; + connector->doublescan_allowed = 0; + + drm_encoder_helper_add(&intel_output->enc, &intel_crt_helper_funcs); + drm_connector_helper_add(connector, &intel_crt_connector_helper_funcs); + + drm_sysfs_connector_add(connector); +} +]]> + </programlisting> + <para> + In the example above (again, taken from the i915 driver), a + CRT connector and encoder combination is created. A device-specific + i2c bus is also created for fetching EDID data and + performing monitor detection. Once the process is complete, + the new connector is registered with sysfs to make its + properties available to applications. + </para> + <sect4> + <title>Helper functions and core functions</title> + <para> + Since many PC-class graphics devices have similar display output + designs, the DRM provides a set of helper functions to make + output management easier. The core helper routines handle + encoder re-routing and the disabling of unused functions following + mode setting. Using the helpers is optional, but recommended for + devices with PC-style architectures (i.e. a set of display planes + for feeding pixels to encoders which are in turn routed to + connectors). Devices with more complex requirements needing + finer grained management may opt to use the core callbacks + directly. + </para> + <para> + [Insert typical diagram here.] [Insert OMAP style config here.] + </para> + </sect4> + <para> + Each encoder object needs to provide: + <itemizedlist> + <listitem> + A DPMS (basically on/off) function. + </listitem> + <listitem> + A mode-fixup function (for converting requested modes into + native hardware timings). + </listitem> + <listitem> + Functions (prepare, set, and commit) for use by the core DRM + helper functions. + </listitem> + </itemizedlist> + Connector helpers need to provide functions (mode-fetch, validity, + and encoder-matching) for returning an ideal encoder for a given + connector. The core connector functions include a DPMS callback, + save/restore routines (deprecated), detection, mode probing, + property handling, and cleanup functions. + </para> +<!--!Edrivers/char/drm/drm_crtc.h--> +<!--!Edrivers/char/drm/drm_crtc.c--> +<!--!Edrivers/char/drm/drm_crtc_helper.c--> + </sect3> + </sect2> + </sect1> + + <!-- Internals: vblank handling --> + + <sect1> + <title>VBlank event handling</title> + <para> + The DRM core exposes two vertical blank related ioctls: + <variablelist> + <varlistentry> + <term>DRM_IOCTL_WAIT_VBLANK</term> + <listitem> + <para> + This takes a struct drm_wait_vblank structure as its argument, + and it is used to block or request a signal when a specified + vblank event occurs. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term>DRM_IOCTL_MODESET_CTL</term> + <listitem> + <para> + This should be called by application level drivers before and + after mode setting, since on many devices the vertical blank + counter is reset at that time. Internally, the DRM snapshots + the last vblank count when the ioctl is called with the + _DRM_PRE_MODESET command, so that the counter won't go backwards + (which is dealt with when _DRM_POST_MODESET is used). + </para> + </listitem> + </varlistentry> + </variablelist> +<!--!Edrivers/char/drm/drm_irq.c--> + </para> + <para> + To support the functions above, the DRM core provides several + helper functions for tracking vertical blank counters, and + requires drivers to provide several callbacks: + get_vblank_counter(), enable_vblank() and disable_vblank(). The + core uses get_vblank_counter() to keep the counter accurate + across interrupt disable periods. It should return the current + vertical blank event count, which is often tracked in a device + register. The enable and disable vblank callbacks should enable + and disable vertical blank interrupts, respectively. In the + absence of DRM clients waiting on vblank events, the core DRM + code uses the disable_vblank() function to disable + interrupts, which saves power. They are re-enabled again when + a client calls the vblank wait ioctl above. + </para> + <para> + A device that doesn't provide a count register may simply use an + internal atomic counter incremented on every vertical blank + interrupt (and then treat the enable_vblank() and disable_vblank() + callbacks as no-ops). + </para> + </sect1> + + <sect1> + <title>Memory management</title> + <para> + The memory manager lies at the heart of many DRM operations; it + is required to support advanced client features like OpenGL + pbuffers. The DRM currently contains two memory managers: TTM + and GEM. + </para> + + <sect2> + <title>The Translation Table Manager (TTM)</title> + <para> + TTM was developed by Tungsten Graphics, primarily by Thomas + Hellström, and is intended to be a flexible, high performance + graphics memory manager. + </para> + <para> + Drivers wishing to support TTM must fill out a drm_bo_driver + structure. + </para> + <para> + TTM design background and information belongs here. + </para> + </sect2> + + <sect2> + <title>The Graphics Execution Manager (GEM)</title> + <para> + GEM is an Intel project, authored by Eric Anholt and Keith + Packard. It provides simpler interfaces than TTM, and is well + suited for UMA devices. + </para> + <para> + GEM-enabled drivers must provide gem_init_object() and + gem_free_object() callbacks to support the core memory + allocation routines. They should also provide several driver-specific + ioctls to support command execution, pinning, buffer + read & write, mapping, and domain ownership transfers. + </para> + <para> + On a fundamental level, GEM involves several operations: + <itemizedlist> + <listitem>Memory allocation and freeing</listitem> + <listitem>Command execution</listitem> + <listitem>Aperture management at command execution time</listitem> + </itemizedlist> + Buffer object allocation is relatively + straightforward and largely provided by Linux's shmem layer, which + provides memory to back each object. When mapped into the GTT + or used in a command buffer, the backing pages for an object are + flushed to memory and marked write combined so as to be coherent + with the GPU. Likewise, if the CPU accesses an object after the GPU + has finished rendering to the object, then the object must be made + coherent with the CPU's view + of memory, usually involving GPU cache flushing of various kinds. + This core CPU<->GPU coherency management is provided by a + device-specific ioctl, which evaluates an object's current domain and + performs any necessary flushing or synchronization to put the object + into the desired coherency domain (note that the object may be busy, + i.e. an active render target; in that case, setting the domain + blocks the client and waits for rendering to complete before + performing any necessary flushing operations). + </para> + <para> + Perhaps the most important GEM function is providing a command + execution interface to clients. Client programs construct command + buffers containing references to previously allocated memory objects, + and then submit them to GEM. At that point, GEM takes care to bind + all the objects into the GTT, execute the buffer, and provide + necessary synchronization between clients accessing the same buffers. + This often involves evicting some objects from the GTT and re-binding + others (a fairly expensive operation), and providing relocation + support which hides fixed GTT offsets from clients. Clients must + take care not to submit command buffers that reference more objects + than can fit in the GTT; otherwise, GEM will reject them and no rendering + will occur. Similarly, if several objects in the buffer require + fence registers to be allocated for correct rendering (e.g. 2D blits + on pre-965 chips), care must be taken not to require more fence + registers than are available to the client. Such resource management + should be abstracted from the client in libdrm. + </para> + </sect2> + + </sect1> + + <!-- Output management --> + <sect1> + <title>Output management</title> + <para> + At the core of the DRM output management code is a set of + structures representing CRTCs, encoders, and connectors. + </para> + <para> + A CRTC is an abstraction representing a part of the chip that + contains a pointer to a scanout buffer. Therefore, the number + of CRTCs available determines how many independent scanout + buffers can be active at any given time. The CRTC structure + contains several fields to support this: a pointer to some video + memory, a display mode, and an (x, y) offset into the video + memory to support panning or configurations where one piece of + video memory spans multiple CRTCs. + </para> + <para> + An encoder takes pixel data from a CRTC and converts it to a + format suitable for any attached connectors. On some devices, + it may be possible to have a CRTC send data to more than one + encoder. In that case, both encoders would receive data from + the same scanout buffer, resulting in a "cloned" display + configuration across the connectors attached to each encoder. + </para> + <para> + A connector is the final destination for pixel data on a device, + and usually connects directly to an external display device like + a monitor or laptop panel. A connector can only be attached to + one encoder at a time. The connector is also the structure + where information about the attached display is kept, so it + contains fields for display data, EDID data, DPMS & + connection status, and information about modes supported on the + attached displays. + </para> +<!--!Edrivers/char/drm/drm_crtc.c--> + </sect1> + + <sect1> + <title>Framebuffer management</title> + <para> + Clients need to provide a framebuffer object which provides a source + of pixels for a CRTC to deliver to the encoder(s) and ultimately the + connector(s). A framebuffer is fundamentally a driver-specific memory + object, made into an opaque handle by the DRM's addfb() function. + Once a framebuffer has been created this way, it may be passed to the + KMS mode setting routines for use in a completed configuration. + </para> + </sect1> + + <sect1> + <title>Command submission & fencing</title> + <para> + This should cover a few device-specific command submission + implementations. + </para> + </sect1> + + <sect1> + <title>Suspend/resume</title> + <para> + The DRM core provides some suspend/resume code, but drivers + wanting full suspend/resume support should provide save() and + restore() functions. These are called at suspend, + hibernate, or resume time, and should perform any state save or + restore required by your device across suspend or hibernate + states. + </para> + </sect1> + + <sect1> + <title>DMA services</title> + <para> + This should cover how DMA mapping etc. is supported by the core. + These functions are deprecated and should not be used. + </para> + </sect1> + </chapter> + + <!-- External interfaces --> + + <chapter id="drmExternals"> + <title>Userland interfaces</title> + <para> + The DRM core exports several interfaces to applications, + generally intended to be used through corresponding libdrm + wrapper functions. In addition, drivers export device-specific + interfaces for use by userspace drivers & device-aware + applications through ioctls and sysfs files. + </para> + <para> + External interfaces include: memory mapping, context management, + DMA operations, AGP management, vblank control, fence + management, memory management, and output management. + </para> + <para> + Cover generic ioctls and sysfs layout here. We only need high-level + info, since man pages should cover the rest. + </para> + </chapter> + + <!-- API reference --> + + <appendix id="drmDriverApi"> + <title>DRM Driver API</title> + <para> + Include auto-generated API reference here (need to reference it + from paragraphs above too). + </para> + </appendix> + +</book> diff --git a/Documentation/DocBook/filesystems.tmpl b/Documentation/DocBook/filesystems.tmpl new file mode 100644 index 00000000..3fca32c4 --- /dev/null +++ b/Documentation/DocBook/filesystems.tmpl @@ -0,0 +1,426 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="Linux-filesystems-API"> + <bookinfo> + <title>Linux Filesystems API</title> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="vfs"> + <title>The Linux VFS</title> + <sect1 id="the_filesystem_types"><title>The Filesystem types</title> +!Iinclude/linux/fs.h + </sect1> + <sect1 id="the_directory_cache"><title>The Directory Cache</title> +!Efs/dcache.c +!Iinclude/linux/dcache.h + </sect1> + <sect1 id="inode_handling"><title>Inode Handling</title> +!Efs/inode.c +!Efs/bad_inode.c + </sect1> + <sect1 id="registration_and_superblocks"><title>Registration and Superblocks</title> +!Efs/super.c + </sect1> + <sect1 id="file_locks"><title>File Locks</title> +!Efs/locks.c +!Ifs/locks.c + </sect1> + <sect1 id="other_functions"><title>Other Functions</title> +!Efs/mpage.c +!Efs/namei.c +!Efs/buffer.c +!Efs/bio.c +!Efs/seq_file.c +!Efs/filesystems.c +!Efs/fs-writeback.c +!Efs/block_dev.c + </sect1> + </chapter> + + <chapter id="proc"> + <title>The proc filesystem</title> + + <sect1 id="sysctl_interface"><title>sysctl interface</title> +!Ekernel/sysctl.c + </sect1> + + <sect1 id="proc_filesystem_interface"><title>proc filesystem interface</title> +!Ifs/proc/base.c + </sect1> + </chapter> + + <chapter id="fs_events"> + <title>Events based on file descriptors</title> +!Efs/eventfd.c + </chapter> + + <chapter id="sysfs"> + <title>The Filesystem for Exporting Kernel Objects</title> +!Efs/sysfs/file.c +!Efs/sysfs/symlink.c +!Efs/sysfs/bin.c + </chapter> + + <chapter id="debugfs"> + <title>The debugfs filesystem</title> + + <sect1 id="debugfs_interface"><title>debugfs interface</title> +!Efs/debugfs/inode.c +!Efs/debugfs/file.c + </sect1> + </chapter> + + <chapter id="LinuxJDBAPI"> + <chapterinfo> + <title>The Linux Journalling API</title> + + <authorgroup> + <author> + <firstname>Roger</firstname> + <surname>Gammans</surname> + <affiliation> + <address> + <email>rgammans@computer-surgery.co.uk</email> + </address> + </affiliation> + </author> + </authorgroup> + + <authorgroup> + <author> + <firstname>Stephen</firstname> + <surname>Tweedie</surname> + <affiliation> + <address> + <email>sct@redhat.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2002</year> + <holder>Roger Gammans</holder> + </copyright> + </chapterinfo> + + <title>The Linux Journalling API</title> + + <sect1 id="journaling_overview"> + <title>Overview</title> + <sect2 id="journaling_details"> + <title>Details</title> +<para> +The journalling layer is easy to use. You need to +first of all create a journal_t data structure. There are +two calls to do this dependent on how you decide to allocate the physical +media on which the journal resides. The journal_init_inode() call +is for journals stored in filesystem inodes, or the journal_init_dev() +call can be use for journal stored on a raw device (in a continuous range +of blocks). A journal_t is a typedef for a struct pointer, so when +you are finally finished make sure you call journal_destroy() on it +to free up any used kernel memory. +</para> + +<para> +Once you have got your journal_t object you need to 'mount' or load the journal +file, unless of course you haven't initialised it yet - in which case you +need to call journal_create(). +</para> + +<para> +Most of the time however your journal file will already have been created, but +before you load it you must call journal_wipe() to empty the journal file. +Hang on, you say , what if the filesystem wasn't cleanly umount()'d . Well, it is the +job of the client file system to detect this and skip the call to journal_wipe(). +</para> + +<para> +In either case the next call should be to journal_load() which prepares the +journal file for use. Note that journal_wipe(..,0) calls journal_skip_recovery() +for you if it detects any outstanding transactions in the journal and similarly +journal_load() will call journal_recover() if necessary. +I would advise reading fs/ext3/super.c for examples on this stage. +[RGG: Why is the journal_wipe() call necessary - doesn't this needlessly +complicate the API. Or isn't a good idea for the journal layer to hide +dirty mounts from the client fs] +</para> + +<para> +Now you can go ahead and start modifying the underlying +filesystem. Almost. +</para> + +<para> + +You still need to actually journal your filesystem changes, this +is done by wrapping them into transactions. Additionally you +also need to wrap the modification of each of the buffers +with calls to the journal layer, so it knows what the modifications +you are actually making are. To do this use journal_start() which +returns a transaction handle. +</para> + +<para> +journal_start() +and its counterpart journal_stop(), which indicates the end of a transaction +are nestable calls, so you can reenter a transaction if necessary, +but remember you must call journal_stop() the same number of times as +journal_start() before the transaction is completed (or more accurately +leaves the update phase). Ext3/VFS makes use of this feature to simplify +quota support. +</para> + +<para> +Inside each transaction you need to wrap the modifications to the +individual buffers (blocks). Before you start to modify a buffer you +need to call journal_get_{create,write,undo}_access() as appropriate, +this allows the journalling layer to copy the unmodified data if it +needs to. After all the buffer may be part of a previously uncommitted +transaction. +At this point you are at last ready to modify a buffer, and once +you are have done so you need to call journal_dirty_{meta,}data(). +Or if you've asked for access to a buffer you now know is now longer +required to be pushed back on the device you can call journal_forget() +in much the same way as you might have used bforget() in the past. +</para> + +<para> +A journal_flush() may be called at any time to commit and checkpoint +all your transactions. +</para> + +<para> +Then at umount time , in your put_super() (2.4) or write_super() (2.5) +you can then call journal_destroy() to clean up your in-core journal object. +</para> + +<para> +Unfortunately there a couple of ways the journal layer can cause a deadlock. +The first thing to note is that each task can only have +a single outstanding transaction at any one time, remember nothing +commits until the outermost journal_stop(). This means +you must complete the transaction at the end of each file/inode/address +etc. operation you perform, so that the journalling system isn't re-entered +on another journal. Since transactions can't be nested/batched +across differing journals, and another filesystem other than +yours (say ext3) may be modified in a later syscall. +</para> + +<para> +The second case to bear in mind is that journal_start() can +block if there isn't enough space in the journal for your transaction +(based on the passed nblocks param) - when it blocks it merely(!) needs to +wait for transactions to complete and be committed from other tasks, +so essentially we are waiting for journal_stop(). So to avoid +deadlocks you must treat journal_start/stop() as if they +were semaphores and include them in your semaphore ordering rules to prevent +deadlocks. Note that journal_extend() has similar blocking behaviour to +journal_start() so you can deadlock here just as easily as on journal_start(). +</para> + +<para> +Try to reserve the right number of blocks the first time. ;-). This will +be the maximum number of blocks you are going to touch in this transaction. +I advise having a look at at least ext3_jbd.h to see the basis on which +ext3 uses to make these decisions. +</para> + +<para> +Another wriggle to watch out for is your on-disk block allocation strategy. +why? Because, if you undo a delete, you need to ensure you haven't reused any +of the freed blocks in a later transaction. One simple way of doing this +is make sure any blocks you allocate only have checkpointed transactions +listed against them. Ext3 does this in ext3_test_allocatable(). +</para> + +<para> +Lock is also providing through journal_{un,}lock_updates(), +ext3 uses this when it wants a window with a clean and stable fs for a moment. +eg. +</para> + +<programlisting> + + journal_lock_updates() //stop new stuff happening.. + journal_flush() // checkpoint everything. + ..do stuff on stable fs + journal_unlock_updates() // carry on with filesystem use. +</programlisting> + +<para> +The opportunities for abuse and DOS attacks with this should be obvious, +if you allow unprivileged userspace to trigger codepaths containing these +calls. +</para> + +<para> +A new feature of jbd since 2.5.25 is commit callbacks with the new +journal_callback_set() function you can now ask the journalling layer +to call you back when the transaction is finally committed to disk, so that +you can do some of your own management. The key to this is the journal_callback +struct, this maintains the internal callback information but you can +extend it like this:- +</para> +<programlisting> + struct myfs_callback_s { + //Data structure element required by jbd.. + struct journal_callback for_jbd; + // Stuff for myfs allocated together. + myfs_inode* i_commited; + + } +</programlisting> + +<para> +this would be useful if you needed to know when data was committed to a +particular inode. +</para> + + </sect2> + + <sect2 id="jbd_summary"> + <title>Summary</title> +<para> +Using the journal is a matter of wrapping the different context changes, +being each mount, each modification (transaction) and each changed buffer +to tell the journalling layer about them. +</para> + +<para> +Here is a some pseudo code to give you an idea of how it works, as +an example. +</para> + +<programlisting> + journal_t* my_jnrl = journal_create(); + journal_init_{dev,inode}(jnrl,...) + if (clean) journal_wipe(); + journal_load(); + + foreach(transaction) { /*transactions must be + completed before + a syscall returns to + userspace*/ + + handle_t * xct=journal_start(my_jnrl); + foreach(bh) { + journal_get_{create,write,undo}_access(xact,bh); + if ( myfs_modify(bh) ) { /* returns true + if makes changes */ + journal_dirty_{meta,}data(xact,bh); + } else { + journal_forget(bh); + } + } + journal_stop(xct); + } + journal_destroy(my_jrnl); +</programlisting> + </sect2> + + </sect1> + + <sect1 id="data_types"> + <title>Data Types</title> + <para> + The journalling layer uses typedefs to 'hide' the concrete definitions + of the structures used. As a client of the JBD layer you can + just rely on the using the pointer as a magic cookie of some sort. + + Obviously the hiding is not enforced as this is 'C'. + </para> + <sect2 id="structures"><title>Structures</title> +!Iinclude/linux/jbd.h + </sect2> + </sect1> + + <sect1 id="functions"> + <title>Functions</title> + <para> + The functions here are split into two groups those that + affect a journal as a whole, and those which are used to + manage transactions + </para> + <sect2 id="journal_level"><title>Journal Level</title> +!Efs/jbd/journal.c +!Ifs/jbd/recovery.c + </sect2> + <sect2 id="transaction_level"><title>Transasction Level</title> +!Efs/jbd/transaction.c + </sect2> + </sect1> + <sect1 id="see_also"> + <title>See also</title> + <para> + <citation> + <ulink url="http://kernel.org/pub/linux/kernel/people/sct/ext3/journal-design.ps.gz"> + Journaling the Linux ext2fs Filesystem, LinuxExpo 98, Stephen Tweedie + </ulink> + </citation> + </para> + <para> + <citation> + <ulink url="http://olstrans.sourceforge.net/release/OLS2000-ext3/OLS2000-ext3.html"> + Ext3 Journalling FileSystem, OLS 2000, Dr. Stephen Tweedie + </ulink> + </citation> + </para> + </sect1> + + </chapter> + + <chapter id="splice"> + <title>splice API</title> + <para> + splice is a method for moving blocks of data around inside the + kernel, without continually transferring them between the kernel + and user space. + </para> +!Ffs/splice.c + </chapter> + + <chapter id="pipes"> + <title>pipes API</title> + <para> + Pipe interfaces are all for in-kernel (builtin image) use. + They are not exported for use by modules. + </para> +!Iinclude/linux/pipe_fs_i.h +!Ffs/pipe.c + </chapter> + +</book> diff --git a/Documentation/DocBook/gadget.tmpl b/Documentation/DocBook/gadget.tmpl new file mode 100644 index 00000000..6ef2f007 --- /dev/null +++ b/Documentation/DocBook/gadget.tmpl @@ -0,0 +1,793 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="USB-Gadget-API"> + <bookinfo> + <title>USB Gadget API for Linux</title> + <date>20 August 2004</date> + <edition>20 August 2004</edition> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + <copyright> + <year>2003-2004</year> + <holder>David Brownell</holder> + </copyright> + + <author> + <firstname>David</firstname> + <surname>Brownell</surname> + <affiliation> + <address><email>dbrownell@users.sourceforge.net</email></address> + </affiliation> + </author> + </bookinfo> + +<toc></toc> + +<chapter id="intro"><title>Introduction</title> + +<para>This document presents a Linux-USB "Gadget" +kernel mode +API, for use within peripherals and other USB devices +that embed Linux. +It provides an overview of the API structure, +and shows how that fits into a system development project. +This is the first such API released on Linux to address +a number of important problems, including: </para> + +<itemizedlist> + <listitem><para>Supports USB 2.0, for high speed devices which + can stream data at several dozen megabytes per second. + </para></listitem> + <listitem><para>Handles devices with dozens of endpoints just as + well as ones with just two fixed-function ones. Gadget drivers + can be written so they're easy to port to new hardware. + </para></listitem> + <listitem><para>Flexible enough to expose more complex USB device + capabilities such as multiple configurations, multiple interfaces, + composite devices, + and alternate interface settings. + </para></listitem> + <listitem><para>USB "On-The-Go" (OTG) support, in conjunction + with updates to the Linux-USB host side. + </para></listitem> + <listitem><para>Sharing data structures and API models with the + Linux-USB host side API. This helps the OTG support, and + looks forward to more-symmetric frameworks (where the same + I/O model is used by both host and device side drivers). + </para></listitem> + <listitem><para>Minimalist, so it's easier to support new device + controller hardware. I/O processing doesn't imply large + demands for memory or CPU resources. + </para></listitem> +</itemizedlist> + + +<para>Most Linux developers will not be able to use this API, since they +have USB "host" hardware in a PC, workstation, or server. +Linux users with embedded systems are more likely to +have USB peripheral hardware. +To distinguish drivers running inside such hardware from the +more familiar Linux "USB device drivers", +which are host side proxies for the real USB devices, +a different term is used: +the drivers inside the peripherals are "USB gadget drivers". +In USB protocol interactions, the device driver is the master +(or "client driver") +and the gadget driver is the slave (or "function driver"). +</para> + +<para>The gadget API resembles the host side Linux-USB API in that both +use queues of request objects to package I/O buffers, and those requests +may be submitted or canceled. +They share common definitions for the standard USB +<emphasis>Chapter 9</emphasis> messages, structures, and constants. +Also, both APIs bind and unbind drivers to devices. +The APIs differ in detail, since the host side's current +URB framework exposes a number of implementation details +and assumptions that are inappropriate for a gadget API. +While the model for control transfers and configuration +management is necessarily different (one side is a hardware-neutral master, +the other is a hardware-aware slave), the endpoint I/0 API used here +should also be usable for an overhead-reduced host side API. +</para> + +</chapter> + +<chapter id="structure"><title>Structure of Gadget Drivers</title> + +<para>A system running inside a USB peripheral +normally has at least three layers inside the kernel to handle +USB protocol processing, and may have additional layers in +user space code. +The "gadget" API is used by the middle layer to interact +with the lowest level (which directly handles hardware). +</para> + +<para>In Linux, from the bottom up, these layers are: +</para> + +<variablelist> + + <varlistentry> + <term><emphasis>USB Controller Driver</emphasis></term> + + <listitem> + <para>This is the lowest software level. + It is the only layer that talks to hardware, + through registers, fifos, dma, irqs, and the like. + The <filename><linux/usb/gadget.h></filename> API abstracts + the peripheral controller endpoint hardware. + That hardware is exposed through endpoint objects, which accept + streams of IN/OUT buffers, and through callbacks that interact + with gadget drivers. + Since normal USB devices only have one upstream + port, they only have one of these drivers. + The controller driver can support any number of different + gadget drivers, but only one of them can be used at a time. + </para> + + <para>Examples of such controller hardware include + the PCI-based NetChip 2280 USB 2.0 high speed controller, + the SA-11x0 or PXA-25x UDC (found within many PDAs), + and a variety of other products. + </para> + + </listitem></varlistentry> + + <varlistentry> + <term><emphasis>Gadget Driver</emphasis></term> + + <listitem> + <para>The lower boundary of this driver implements hardware-neutral + USB functions, using calls to the controller driver. + Because such hardware varies widely in capabilities and restrictions, + and is used in embedded environments where space is at a premium, + the gadget driver is often configured at compile time + to work with endpoints supported by one particular controller. + Gadget drivers may be portable to several different controllers, + using conditional compilation. + (Recent kernels substantially simplify the work involved in + supporting new hardware, by <emphasis>autoconfiguring</emphasis> + endpoints automatically for many bulk-oriented drivers.) + Gadget driver responsibilities include: + </para> + <itemizedlist> + <listitem><para>handling setup requests (ep0 protocol responses) + possibly including class-specific functionality + </para></listitem> + <listitem><para>returning configuration and string descriptors + </para></listitem> + <listitem><para>(re)setting configurations and interface + altsettings, including enabling and configuring endpoints + </para></listitem> + <listitem><para>handling life cycle events, such as managing + bindings to hardware, + USB suspend/resume, remote wakeup, + and disconnection from the USB host. + </para></listitem> + <listitem><para>managing IN and OUT transfers on all currently + enabled endpoints + </para></listitem> + </itemizedlist> + + <para> + Such drivers may be modules of proprietary code, although + that approach is discouraged in the Linux community. + </para> + </listitem></varlistentry> + + <varlistentry> + <term><emphasis>Upper Level</emphasis></term> + + <listitem> + <para>Most gadget drivers have an upper boundary that connects + to some Linux driver or framework in Linux. + Through that boundary flows the data which the gadget driver + produces and/or consumes through protocol transfers over USB. + Examples include: + </para> + <itemizedlist> + <listitem><para>user mode code, using generic (gadgetfs) + or application specific files in + <filename>/dev</filename> + </para></listitem> + <listitem><para>networking subsystem (for network gadgets, + like the CDC Ethernet Model gadget driver) + </para></listitem> + <listitem><para>data capture drivers, perhaps video4Linux or + a scanner driver; or test and measurement hardware. + </para></listitem> + <listitem><para>input subsystem (for HID gadgets) + </para></listitem> + <listitem><para>sound subsystem (for audio gadgets) + </para></listitem> + <listitem><para>file system (for PTP gadgets) + </para></listitem> + <listitem><para>block i/o subsystem (for usb-storage gadgets) + </para></listitem> + <listitem><para>... and more </para></listitem> + </itemizedlist> + </listitem></varlistentry> + + <varlistentry> + <term><emphasis>Additional Layers</emphasis></term> + + <listitem> + <para>Other layers may exist. + These could include kernel layers, such as network protocol stacks, + as well as user mode applications building on standard POSIX + system call APIs such as + <emphasis>open()</emphasis>, <emphasis>close()</emphasis>, + <emphasis>read()</emphasis> and <emphasis>write()</emphasis>. + On newer systems, POSIX Async I/O calls may be an option. + Such user mode code will not necessarily be subject to + the GNU General Public License (GPL). + </para> + </listitem></varlistentry> + + +</variablelist> + +<para>OTG-capable systems will also need to include a standard Linux-USB +host side stack, +with <emphasis>usbcore</emphasis>, +one or more <emphasis>Host Controller Drivers</emphasis> (HCDs), +<emphasis>USB Device Drivers</emphasis> to support +the OTG "Targeted Peripheral List", +and so forth. +There will also be an <emphasis>OTG Controller Driver</emphasis>, +which is visible to gadget and device driver developers only indirectly. +That helps the host and device side USB controllers implement the +two new OTG protocols (HNP and SRP). +Roles switch (host to peripheral, or vice versa) using HNP +during USB suspend processing, and SRP can be viewed as a +more battery-friendly kind of device wakeup protocol. +</para> + +<para>Over time, reusable utilities are evolving to help make some +gadget driver tasks simpler. +For example, building configuration descriptors from vectors of +descriptors for the configurations interfaces and endpoints is +now automated, and many drivers now use autoconfiguration to +choose hardware endpoints and initialize their descriptors. + +A potential example of particular interest +is code implementing standard USB-IF protocols for +HID, networking, storage, or audio classes. +Some developers are interested in KDB or KGDB hooks, to let +target hardware be remotely debugged. +Most such USB protocol code doesn't need to be hardware-specific, +any more than network protocols like X11, HTTP, or NFS are. +Such gadget-side interface drivers should eventually be combined, +to implement composite devices. +</para> + +</chapter> + + +<chapter id="api"><title>Kernel Mode Gadget API</title> + +<para>Gadget drivers declare themselves through a +<emphasis>struct usb_gadget_driver</emphasis>, which is responsible for +most parts of enumeration for a <emphasis>struct usb_gadget</emphasis>. +The response to a set_configuration usually involves +enabling one or more of the <emphasis>struct usb_ep</emphasis> objects +exposed by the gadget, and submitting one or more +<emphasis>struct usb_request</emphasis> buffers to transfer data. +Understand those four data types, and their operations, and +you will understand how this API works. +</para> + +<note><title>Incomplete Data Type Descriptions</title> + +<para>This documentation was prepared using the standard Linux +kernel <filename>docproc</filename> tool, which turns text +and in-code comments into SGML DocBook and then into usable +formats such as HTML or PDF. +Other than the "Chapter 9" data types, most of the significant +data types and functions are described here. +</para> + +<para>However, docproc does not understand all the C constructs +that are used, so some relevant information is likely omitted from +what you are reading. +One example of such information is endpoint autoconfiguration. +You'll have to read the header file, and use example source +code (such as that for "Gadget Zero"), to fully understand the API. +</para> + +<para>The part of the API implementing some basic +driver capabilities is specific to the version of the +Linux kernel that's in use. +The 2.6 kernel includes a <emphasis>driver model</emphasis> +framework that has no analogue on earlier kernels; +so those parts of the gadget API are not fully portable. +(They are implemented on 2.4 kernels, but in a different way.) +The driver model state is another part of this API that is +ignored by the kerneldoc tools. +</para> +</note> + +<para>The core API does not expose +every possible hardware feature, only the most widely available ones. +There are significant hardware features, such as device-to-device DMA +(without temporary storage in a memory buffer) +that would be added using hardware-specific APIs. +</para> + +<para>This API allows drivers to use conditional compilation to handle +endpoint capabilities of different hardware, but doesn't require that. +Hardware tends to have arbitrary restrictions, relating to +transfer types, addressing, packet sizes, buffering, and availability. +As a rule, such differences only matter for "endpoint zero" logic +that handles device configuration and management. +The API supports limited run-time +detection of capabilities, through naming conventions for endpoints. +Many drivers will be able to at least partially autoconfigure +themselves. +In particular, driver init sections will often have endpoint +autoconfiguration logic that scans the hardware's list of endpoints +to find ones matching the driver requirements +(relying on those conventions), to eliminate some of the most +common reasons for conditional compilation. +</para> + +<para>Like the Linux-USB host side API, this API exposes +the "chunky" nature of USB messages: I/O requests are in terms +of one or more "packets", and packet boundaries are visible to drivers. +Compared to RS-232 serial protocols, USB resembles +synchronous protocols like HDLC +(N bytes per frame, multipoint addressing, host as the primary +station and devices as secondary stations) +more than asynchronous ones +(tty style: 8 data bits per frame, no parity, one stop bit). +So for example the controller drivers won't buffer +two single byte writes into a single two-byte USB IN packet, +although gadget drivers may do so when they implement +protocols where packet boundaries (and "short packets") +are not significant. +</para> + +<sect1 id="lifecycle"><title>Driver Life Cycle</title> + +<para>Gadget drivers make endpoint I/O requests to hardware without +needing to know many details of the hardware, but driver +setup/configuration code needs to handle some differences. +Use the API like this: +</para> + +<orderedlist numeration='arabic'> + +<listitem><para>Register a driver for the particular device side +usb controller hardware, +such as the net2280 on PCI (USB 2.0), +sa11x0 or pxa25x as found in Linux PDAs, +and so on. +At this point the device is logically in the USB ch9 initial state +("attached"), drawing no power and not usable +(since it does not yet support enumeration). +Any host should not see the device, since it's not +activated the data line pullup used by the host to +detect a device, even if VBUS power is available. +</para></listitem> + +<listitem><para>Register a gadget driver that implements some higher level +device function. That will then bind() to a usb_gadget, which +activates the data line pullup sometime after detecting VBUS. +</para></listitem> + +<listitem><para>The hardware driver can now start enumerating. +The steps it handles are to accept USB power and set_address requests. +Other steps are handled by the gadget driver. +If the gadget driver module is unloaded before the host starts to +enumerate, steps before step 7 are skipped. +</para></listitem> + +<listitem><para>The gadget driver's setup() call returns usb descriptors, +based both on what the bus interface hardware provides and on the +functionality being implemented. +That can involve alternate settings or configurations, +unless the hardware prevents such operation. +For OTG devices, each configuration descriptor includes +an OTG descriptor. +</para></listitem> + +<listitem><para>The gadget driver handles the last step of enumeration, +when the USB host issues a set_configuration call. +It enables all endpoints used in that configuration, +with all interfaces in their default settings. +That involves using a list of the hardware's endpoints, enabling each +endpoint according to its descriptor. +It may also involve using <function>usb_gadget_vbus_draw</function> +to let more power be drawn from VBUS, as allowed by that configuration. +For OTG devices, setting a configuration may also involve reporting +HNP capabilities through a user interface. +</para></listitem> + +<listitem><para>Do real work and perform data transfers, possibly involving +changes to interface settings or switching to new configurations, until the +device is disconnect()ed from the host. +Queue any number of transfer requests to each endpoint. +It may be suspended and resumed several times before being disconnected. +On disconnect, the drivers go back to step 3 (above). +</para></listitem> + +<listitem><para>When the gadget driver module is being unloaded, +the driver unbind() callback is issued. That lets the controller +driver be unloaded. +</para></listitem> + +</orderedlist> + +<para>Drivers will normally be arranged so that just loading the +gadget driver module (or statically linking it into a Linux kernel) +allows the peripheral device to be enumerated, but some drivers +will defer enumeration until some higher level component (like +a user mode daemon) enables it. +Note that at this lowest level there are no policies about how +ep0 configuration logic is implemented, +except that it should obey USB specifications. +Such issues are in the domain of gadget drivers, +including knowing about implementation constraints +imposed by some USB controllers +or understanding that composite devices might happen to +be built by integrating reusable components. +</para> + +<para>Note that the lifecycle above can be slightly different +for OTG devices. +Other than providing an additional OTG descriptor in each +configuration, only the HNP-related differences are particularly +visible to driver code. +They involve reporting requirements during the SET_CONFIGURATION +request, and the option to invoke HNP during some suspend callbacks. +Also, SRP changes the semantics of +<function>usb_gadget_wakeup</function> +slightly. +</para> + +</sect1> + +<sect1 id="ch9"><title>USB 2.0 Chapter 9 Types and Constants</title> + +<para>Gadget drivers +rely on common USB structures and constants +defined in the +<filename><linux/usb/ch9.h></filename> +header file, which is standard in Linux 2.6 kernels. +These are the same types and constants used by host +side drivers (and usbcore). +</para> + +!Iinclude/linux/usb/ch9.h +</sect1> + +<sect1 id="core"><title>Core Objects and Methods</title> + +<para>These are declared in +<filename><linux/usb/gadget.h></filename>, +and are used by gadget drivers to interact with +USB peripheral controller drivers. +</para> + + <!-- yeech, this is ugly in nsgmls PDF output. + + the PDF bookmark and refentry output nesting is wrong, + and the member/argument documentation indents ugly. + + plus something (docproc?) adds whitespace before the + descriptive paragraph text, so it can't line up right + unless the explanations are trivial. + --> + +!Iinclude/linux/usb/gadget.h +</sect1> + +<sect1 id="utils"><title>Optional Utilities</title> + +<para>The core API is sufficient for writing a USB Gadget Driver, +but some optional utilities are provided to simplify common tasks. +These utilities include endpoint autoconfiguration. +</para> + +!Edrivers/usb/gadget/usbstring.c +!Edrivers/usb/gadget/config.c +<!-- !Edrivers/usb/gadget/epautoconf.c --> +</sect1> + +<sect1 id="composite"><title>Composite Device Framework</title> + +<para>The core API is sufficient for writing drivers for composite +USB devices (with more than one function in a given configuration), +and also multi-configuration devices (also more than one function, +but not necessarily sharing a given configuration). +There is however an optional framework which makes it easier to +reuse and combine functions. +</para> + +<para>Devices using this framework provide a <emphasis>struct +usb_composite_driver</emphasis>, which in turn provides one or +more <emphasis>struct usb_configuration</emphasis> instances. +Each such configuration includes at least one +<emphasis>struct usb_function</emphasis>, which packages a user +visible role such as "network link" or "mass storage device". +Management functions may also exist, such as "Device Firmware +Upgrade". +</para> + +!Iinclude/linux/usb/composite.h +!Edrivers/usb/gadget/composite.c + +</sect1> + +<sect1 id="functions"><title>Composite Device Functions</title> + +<para>At this writing, a few of the current gadget drivers have +been converted to this framework. +Near-term plans include converting all of them, except for "gadgetfs". +</para> + +!Edrivers/usb/gadget/f_acm.c +!Edrivers/usb/gadget/f_ecm.c +!Edrivers/usb/gadget/f_subset.c +!Edrivers/usb/gadget/f_obex.c +!Edrivers/usb/gadget/f_serial.c + +</sect1> + + +</chapter> + +<chapter id="controllers"><title>Peripheral Controller Drivers</title> + +<para>The first hardware supporting this API was the NetChip 2280 +controller, which supports USB 2.0 high speed and is based on PCI. +This is the <filename>net2280</filename> driver module. +The driver supports Linux kernel versions 2.4 and 2.6; +contact NetChip Technologies for development boards and product +information. +</para> + +<para>Other hardware working in the "gadget" framework includes: +Intel's PXA 25x and IXP42x series processors +(<filename>pxa2xx_udc</filename>), +Toshiba TC86c001 "Goku-S" (<filename>goku_udc</filename>), +Renesas SH7705/7727 (<filename>sh_udc</filename>), +MediaQ 11xx (<filename>mq11xx_udc</filename>), +Hynix HMS30C7202 (<filename>h7202_udc</filename>), +National 9303/4 (<filename>n9604_udc</filename>), +Texas Instruments OMAP (<filename>omap_udc</filename>), +Sharp LH7A40x (<filename>lh7a40x_udc</filename>), +and more. +Most of those are full speed controllers. +</para> + +<para>At this writing, there are people at work on drivers in +this framework for several other USB device controllers, +with plans to make many of them be widely available. +</para> + +<!-- !Edrivers/usb/gadget/net2280.c --> + +<para>A partial USB simulator, +the <filename>dummy_hcd</filename> driver, is available. +It can act like a net2280, a pxa25x, or an sa11x0 in terms +of available endpoints and device speeds; and it simulates +control, bulk, and to some extent interrupt transfers. +That lets you develop some parts of a gadget driver on a normal PC, +without any special hardware, and perhaps with the assistance +of tools such as GDB running with User Mode Linux. +At least one person has expressed interest in adapting that +approach, hooking it up to a simulator for a microcontroller. +Such simulators can help debug subsystems where the runtime hardware +is unfriendly to software development, or is not yet available. +</para> + +<para>Support for other controllers is expected to be developed +and contributed +over time, as this driver framework evolves. +</para> + +</chapter> + +<chapter id="gadget"><title>Gadget Drivers</title> + +<para>In addition to <emphasis>Gadget Zero</emphasis> +(used primarily for testing and development with drivers +for usb controller hardware), other gadget drivers exist. +</para> + +<para>There's an <emphasis>ethernet</emphasis> gadget +driver, which implements one of the most useful +<emphasis>Communications Device Class</emphasis> (CDC) models. +One of the standards for cable modem interoperability even +specifies the use of this ethernet model as one of two +mandatory options. +Gadgets using this code look to a USB host as if they're +an Ethernet adapter. +It provides access to a network where the gadget's CPU is one host, +which could easily be bridging, routing, or firewalling +access to other networks. +Since some hardware can't fully implement the CDC Ethernet +requirements, this driver also implements a "good parts only" +subset of CDC Ethernet. +(That subset doesn't advertise itself as CDC Ethernet, +to avoid creating problems.) +</para> + +<para>Support for Microsoft's <emphasis>RNDIS</emphasis> +protocol has been contributed by Pengutronix and Auerswald GmbH. +This is like CDC Ethernet, but it runs on more slightly USB hardware +(but less than the CDC subset). +However, its main claim to fame is being able to connect directly to +recent versions of Windows, using drivers that Microsoft bundles +and supports, making it much simpler to network with Windows. +</para> + +<para>There is also support for user mode gadget drivers, +using <emphasis>gadgetfs</emphasis>. +This provides a <emphasis>User Mode API</emphasis> that presents +each endpoint as a single file descriptor. I/O is done using +normal <emphasis>read()</emphasis> and <emphasis>read()</emphasis> calls. +Familiar tools like GDB and pthreads can be used to +develop and debug user mode drivers, so that once a robust +controller driver is available many applications for it +won't require new kernel mode software. +Linux 2.6 <emphasis>Async I/O (AIO)</emphasis> +support is available, so that user mode software +can stream data with only slightly more overhead +than a kernel driver. +</para> + +<para>There's a USB Mass Storage class driver, which provides +a different solution for interoperability with systems such +as MS-Windows and MacOS. +That <emphasis>File-backed Storage</emphasis> driver uses a +file or block device as backing store for a drive, +like the <filename>loop</filename> driver. +The USB host uses the BBB, CB, or CBI versions of the mass +storage class specification, using transparent SCSI commands +to access the data from the backing store. +</para> + +<para>There's a "serial line" driver, useful for TTY style +operation over USB. +The latest version of that driver supports CDC ACM style +operation, like a USB modem, and so on most hardware it can +interoperate easily with MS-Windows. +One interesting use of that driver is in boot firmware (like a BIOS), +which can sometimes use that model with very small systems without +real serial lines. +</para> + +<para>Support for other kinds of gadget is expected to +be developed and contributed +over time, as this driver framework evolves. +</para> + +</chapter> + +<chapter id="otg"><title>USB On-The-GO (OTG)</title> + +<para>USB OTG support on Linux 2.6 was initially developed +by Texas Instruments for +<ulink url="http://www.omap.com">OMAP</ulink> 16xx and 17xx +series processors. +Other OTG systems should work in similar ways, but the +hardware level details could be very different. +</para> + +<para>Systems need specialized hardware support to implement OTG, +notably including a special <emphasis>Mini-AB</emphasis> jack +and associated transciever to support <emphasis>Dual-Role</emphasis> +operation: +they can act either as a host, using the standard +Linux-USB host side driver stack, +or as a peripheral, using this "gadget" framework. +To do that, the system software relies on small additions +to those programming interfaces, +and on a new internal component (here called an "OTG Controller") +affecting which driver stack connects to the OTG port. +In each role, the system can re-use the existing pool of +hardware-neutral drivers, layered on top of the controller +driver interfaces (<emphasis>usb_bus</emphasis> or +<emphasis>usb_gadget</emphasis>). +Such drivers need at most minor changes, and most of the calls +added to support OTG can also benefit non-OTG products. +</para> + +<itemizedlist> + <listitem><para>Gadget drivers test the <emphasis>is_otg</emphasis> + flag, and use it to determine whether or not to include + an OTG descriptor in each of their configurations. + </para></listitem> + <listitem><para>Gadget drivers may need changes to support the + two new OTG protocols, exposed in new gadget attributes + such as <emphasis>b_hnp_enable</emphasis> flag. + HNP support should be reported through a user interface + (two LEDs could suffice), and is triggered in some cases + when the host suspends the peripheral. + SRP support can be user-initiated just like remote wakeup, + probably by pressing the same button. + </para></listitem> + <listitem><para>On the host side, USB device drivers need + to be taught to trigger HNP at appropriate moments, using + <function>usb_suspend_device()</function>. + That also conserves battery power, which is useful even + for non-OTG configurations. + </para></listitem> + <listitem><para>Also on the host side, a driver must support the + OTG "Targeted Peripheral List". That's just a whitelist, + used to reject peripherals not supported with a given + Linux OTG host. + <emphasis>This whitelist is product-specific; + each product must modify <filename>otg_whitelist.h</filename> + to match its interoperability specification. + </emphasis> + </para> + <para>Non-OTG Linux hosts, like PCs and workstations, + normally have some solution for adding drivers, so that + peripherals that aren't recognized can eventually be supported. + That approach is unreasonable for consumer products that may + never have their firmware upgraded, and where it's usually + unrealistic to expect traditional PC/workstation/server kinds + of support model to work. + For example, it's often impractical to change device firmware + once the product has been distributed, so driver bugs can't + normally be fixed if they're found after shipment. + </para></listitem> +</itemizedlist> + +<para> +Additional changes are needed below those hardware-neutral +<emphasis>usb_bus</emphasis> and <emphasis>usb_gadget</emphasis> +driver interfaces; those aren't discussed here in any detail. +Those affect the hardware-specific code for each USB Host or Peripheral +controller, and how the HCD initializes (since OTG can be active only +on a single port). +They also involve what may be called an <emphasis>OTG Controller +Driver</emphasis>, managing the OTG transceiver and the OTG state +machine logic as well as much of the root hub behavior for the +OTG port. +The OTG controller driver needs to activate and deactivate USB +controllers depending on the relevant device role. +Some related changes were needed inside usbcore, so that it +can identify OTG-capable devices and respond appropriately +to HNP or SRP protocols. +</para> + +</chapter> + +</book> +<!-- + vim:syntax=sgml:sw=4 +--> diff --git a/Documentation/DocBook/genericirq.tmpl b/Documentation/DocBook/genericirq.tmpl new file mode 100644 index 00000000..b3422341 --- /dev/null +++ b/Documentation/DocBook/genericirq.tmpl @@ -0,0 +1,507 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="Generic-IRQ-Guide"> + <bookinfo> + <title>Linux generic IRQ handling</title> + + <authorgroup> + <author> + <firstname>Thomas</firstname> + <surname>Gleixner</surname> + <affiliation> + <address> + <email>tglx@linutronix.de</email> + </address> + </affiliation> + </author> + <author> + <firstname>Ingo</firstname> + <surname>Molnar</surname> + <affiliation> + <address> + <email>mingo@elte.hu</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2005-2010</year> + <holder>Thomas Gleixner</holder> + </copyright> + <copyright> + <year>2005-2006</year> + <holder>Ingo Molnar</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + The generic interrupt handling layer is designed to provide a + complete abstraction of interrupt handling for device drivers. + It is able to handle all the different types of interrupt controller + hardware. Device drivers use generic API functions to request, enable, + disable and free interrupts. The drivers do not have to know anything + about interrupt hardware details, so they can be used on different + platforms without code changes. + </para> + <para> + This documentation is provided to developers who want to implement + an interrupt subsystem based for their architecture, with the help + of the generic IRQ handling layer. + </para> + </chapter> + + <chapter id="rationale"> + <title>Rationale</title> + <para> + The original implementation of interrupt handling in Linux is using + the __do_IRQ() super-handler, which is able to deal with every + type of interrupt logic. + </para> + <para> + Originally, Russell King identified different types of handlers to + build a quite universal set for the ARM interrupt handler + implementation in Linux 2.5/2.6. He distinguished between: + <itemizedlist> + <listitem><para>Level type</para></listitem> + <listitem><para>Edge type</para></listitem> + <listitem><para>Simple type</para></listitem> + </itemizedlist> + During the implementation we identified another type: + <itemizedlist> + <listitem><para>Fast EOI type</para></listitem> + </itemizedlist> + In the SMP world of the __do_IRQ() super-handler another type + was identified: + <itemizedlist> + <listitem><para>Per CPU type</para></listitem> + </itemizedlist> + </para> + <para> + This split implementation of highlevel IRQ handlers allows us to + optimize the flow of the interrupt handling for each specific + interrupt type. This reduces complexity in that particular codepath + and allows the optimized handling of a given type. + </para> + <para> + The original general IRQ implementation used hw_interrupt_type + structures and their ->ack(), ->end() [etc.] callbacks to + differentiate the flow control in the super-handler. This leads to + a mix of flow logic and lowlevel hardware logic, and it also leads + to unnecessary code duplication: for example in i386, there is a + ioapic_level_irq and a ioapic_edge_irq irq-type which share many + of the lowlevel details but have different flow handling. + </para> + <para> + A more natural abstraction is the clean separation of the + 'irq flow' and the 'chip details'. + </para> + <para> + Analysing a couple of architecture's IRQ subsystem implementations + reveals that most of them can use a generic set of 'irq flow' + methods and only need to add the chip level specific code. + The separation is also valuable for (sub)architectures + which need specific quirks in the irq flow itself but not in the + chip-details - and thus provides a more transparent IRQ subsystem + design. + </para> + <para> + Each interrupt descriptor is assigned its own highlevel flow + handler, which is normally one of the generic + implementations. (This highlevel flow handler implementation also + makes it simple to provide demultiplexing handlers which can be + found in embedded platforms on various architectures.) + </para> + <para> + The separation makes the generic interrupt handling layer more + flexible and extensible. For example, an (sub)architecture can + use a generic irq-flow implementation for 'level type' interrupts + and add a (sub)architecture specific 'edge type' implementation. + </para> + <para> + To make the transition to the new model easier and prevent the + breakage of existing implementations, the __do_IRQ() super-handler + is still available. This leads to a kind of duality for the time + being. Over time the new model should be used in more and more + architectures, as it enables smaller and cleaner IRQ subsystems. + It's deprecated for three years now and about to be removed. + </para> + </chapter> + <chapter id="bugs"> + <title>Known Bugs And Assumptions</title> + <para> + None (knock on wood). + </para> + </chapter> + + <chapter id="Abstraction"> + <title>Abstraction layers</title> + <para> + There are three main levels of abstraction in the interrupt code: + <orderedlist> + <listitem><para>Highlevel driver API</para></listitem> + <listitem><para>Highlevel IRQ flow handlers</para></listitem> + <listitem><para>Chiplevel hardware encapsulation</para></listitem> + </orderedlist> + </para> + <sect1 id="Interrupt_control_flow"> + <title>Interrupt control flow</title> + <para> + Each interrupt is described by an interrupt descriptor structure + irq_desc. The interrupt is referenced by an 'unsigned int' numeric + value which selects the corresponding interrupt decription structure + in the descriptor structures array. + The descriptor structure contains status information and pointers + to the interrupt flow method and the interrupt chip structure + which are assigned to this interrupt. + </para> + <para> + Whenever an interrupt triggers, the lowlevel arch code calls into + the generic interrupt code by calling desc->handle_irq(). + This highlevel IRQ handling function only uses desc->irq_data.chip + primitives referenced by the assigned chip descriptor structure. + </para> + </sect1> + <sect1 id="Highlevel_Driver_API"> + <title>Highlevel Driver API</title> + <para> + The highlevel Driver API consists of following functions: + <itemizedlist> + <listitem><para>request_irq()</para></listitem> + <listitem><para>free_irq()</para></listitem> + <listitem><para>disable_irq()</para></listitem> + <listitem><para>enable_irq()</para></listitem> + <listitem><para>disable_irq_nosync() (SMP only)</para></listitem> + <listitem><para>synchronize_irq() (SMP only)</para></listitem> + <listitem><para>irq_set_irq_type()</para></listitem> + <listitem><para>irq_set_irq_wake()</para></listitem> + <listitem><para>irq_set_handler_data()</para></listitem> + <listitem><para>irq_set_chip()</para></listitem> + <listitem><para>irq_set_chip_data()</para></listitem> + </itemizedlist> + See the autogenerated function documentation for details. + </para> + </sect1> + <sect1 id="Highlevel_IRQ_flow_handlers"> + <title>Highlevel IRQ flow handlers</title> + <para> + The generic layer provides a set of pre-defined irq-flow methods: + <itemizedlist> + <listitem><para>handle_level_irq</para></listitem> + <listitem><para>handle_edge_irq</para></listitem> + <listitem><para>handle_fasteoi_irq</para></listitem> + <listitem><para>handle_simple_irq</para></listitem> + <listitem><para>handle_percpu_irq</para></listitem> + <listitem><para>handle_edge_eoi_irq</para></listitem> + <listitem><para>handle_bad_irq</para></listitem> + </itemizedlist> + The interrupt flow handlers (either predefined or architecture + specific) are assigned to specific interrupts by the architecture + either during bootup or during device initialization. + </para> + <sect2 id="Default_flow_implementations"> + <title>Default flow implementations</title> + <sect3 id="Helper_functions"> + <title>Helper functions</title> + <para> + The helper functions call the chip primitives and + are used by the default flow implementations. + The following helper functions are implemented (simplified excerpt): + <programlisting> +default_enable(struct irq_data *data) +{ + desc->irq_data.chip->irq_unmask(data); +} + +default_disable(struct irq_data *data) +{ + if (!delay_disable(data)) + desc->irq_data.chip->irq_mask(data); +} + +default_ack(struct irq_data *data) +{ + chip->irq_ack(data); +} + +default_mask_ack(struct irq_data *data) +{ + if (chip->irq_mask_ack) { + chip->irq_mask_ack(data); + } else { + chip->irq_mask(data); + chip->irq_ack(data); + } +} + +noop(struct irq_data *data)) +{ +} + + </programlisting> + </para> + </sect3> + </sect2> + <sect2 id="Default_flow_handler_implementations"> + <title>Default flow handler implementations</title> + <sect3 id="Default_Level_IRQ_flow_handler"> + <title>Default Level IRQ flow handler</title> + <para> + handle_level_irq provides a generic implementation + for level-triggered interrupts. + </para> + <para> + The following control flow is implemented (simplified excerpt): + <programlisting> +desc->irq_data.chip->irq_mask_ack(); +handle_irq_event(desc->action); +desc->irq_data.chip->irq_unmask(); + </programlisting> + </para> + </sect3> + <sect3 id="Default_FASTEOI_IRQ_flow_handler"> + <title>Default Fast EOI IRQ flow handler</title> + <para> + handle_fasteoi_irq provides a generic implementation + for interrupts, which only need an EOI at the end of + the handler + </para> + <para> + The following control flow is implemented (simplified excerpt): + <programlisting> +handle_irq_event(desc->action); +desc->irq_data.chip->irq_eoi(); + </programlisting> + </para> + </sect3> + <sect3 id="Default_Edge_IRQ_flow_handler"> + <title>Default Edge IRQ flow handler</title> + <para> + handle_edge_irq provides a generic implementation + for edge-triggered interrupts. + </para> + <para> + The following control flow is implemented (simplified excerpt): + <programlisting> +if (desc->status & running) { + desc->irq_data.chip->irq_mask_ack(); + desc->status |= pending | masked; + return; +} +desc->irq_data.chip->irq_ack(); +desc->status |= running; +do { + if (desc->status & masked) + desc->irq_data.chip->irq_unmask(); + desc->status &= ~pending; + handle_irq_event(desc->action); +} while (status & pending); +desc->status &= ~running; + </programlisting> + </para> + </sect3> + <sect3 id="Default_simple_IRQ_flow_handler"> + <title>Default simple IRQ flow handler</title> + <para> + handle_simple_irq provides a generic implementation + for simple interrupts. + </para> + <para> + Note: The simple flow handler does not call any + handler/chip primitives. + </para> + <para> + The following control flow is implemented (simplified excerpt): + <programlisting> +handle_irq_event(desc->action); + </programlisting> + </para> + </sect3> + <sect3 id="Default_per_CPU_flow_handler"> + <title>Default per CPU flow handler</title> + <para> + handle_percpu_irq provides a generic implementation + for per CPU interrupts. + </para> + <para> + Per CPU interrupts are only available on SMP and + the handler provides a simplified version without + locking. + </para> + <para> + The following control flow is implemented (simplified excerpt): + <programlisting> +if (desc->irq_data.chip->irq_ack) + desc->irq_data.chip->irq_ack(); +handle_irq_event(desc->action); +if (desc->irq_data.chip->irq_eoi) + desc->irq_data.chip->irq_eoi(); + </programlisting> + </para> + </sect3> + <sect3 id="EOI_Edge_IRQ_flow_handler"> + <title>EOI Edge IRQ flow handler</title> + <para> + handle_edge_eoi_irq provides an abnomination of the edge + handler which is solely used to tame a badly wreckaged + irq controller on powerpc/cell. + </para> + </sect3> + <sect3 id="BAD_IRQ_flow_handler"> + <title>Bad IRQ flow handler</title> + <para> + handle_bad_irq is used for spurious interrupts which + have no real handler assigned.. + </para> + </sect3> + </sect2> + <sect2 id="Quirks_and_optimizations"> + <title>Quirks and optimizations</title> + <para> + The generic functions are intended for 'clean' architectures and chips, + which have no platform-specific IRQ handling quirks. If an architecture + needs to implement quirks on the 'flow' level then it can do so by + overriding the highlevel irq-flow handler. + </para> + </sect2> + <sect2 id="Delayed_interrupt_disable"> + <title>Delayed interrupt disable</title> + <para> + This per interrupt selectable feature, which was introduced by Russell + King in the ARM interrupt implementation, does not mask an interrupt + at the hardware level when disable_irq() is called. The interrupt is + kept enabled and is masked in the flow handler when an interrupt event + happens. This prevents losing edge interrupts on hardware which does + not store an edge interrupt event while the interrupt is disabled at + the hardware level. When an interrupt arrives while the IRQ_DISABLED + flag is set, then the interrupt is masked at the hardware level and + the IRQ_PENDING bit is set. When the interrupt is re-enabled by + enable_irq() the pending bit is checked and if it is set, the + interrupt is resent either via hardware or by a software resend + mechanism. (It's necessary to enable CONFIG_HARDIRQS_SW_RESEND when + you want to use the delayed interrupt disable feature and your + hardware is not capable of retriggering an interrupt.) + The delayed interrupt disable is not configurable. + </para> + </sect2> + </sect1> + <sect1 id="Chiplevel_hardware_encapsulation"> + <title>Chiplevel hardware encapsulation</title> + <para> + The chip level hardware descriptor structure irq_chip + contains all the direct chip relevant functions, which + can be utilized by the irq flow implementations. + <itemizedlist> + <listitem><para>irq_ack()</para></listitem> + <listitem><para>irq_mask_ack() - Optional, recommended for performance</para></listitem> + <listitem><para>irq_mask()</para></listitem> + <listitem><para>irq_unmask()</para></listitem> + <listitem><para>irq_eoi() - Optional, required for eoi flow handlers</para></listitem> + <listitem><para>irq_retrigger() - Optional</para></listitem> + <listitem><para>irq_set_type() - Optional</para></listitem> + <listitem><para>irq_set_wake() - Optional</para></listitem> + </itemizedlist> + These primitives are strictly intended to mean what they say: ack means + ACK, masking means masking of an IRQ line, etc. It is up to the flow + handler(s) to use these basic units of lowlevel functionality. + </para> + </sect1> + </chapter> + + <chapter id="doirq"> + <title>__do_IRQ entry point</title> + <para> + The original implementation __do_IRQ() was an alternative entry + point for all types of interrupts. It not longer exists. + </para> + <para> + This handler turned out to be not suitable for all + interrupt hardware and was therefore reimplemented with split + functionality for edge/level/simple/percpu interrupts. This is not + only a functional optimization. It also shortens code paths for + interrupts. + </para> + </chapter> + + <chapter id="locking"> + <title>Locking on SMP</title> + <para> + The locking of chip registers is up to the architecture that + defines the chip primitives. The per-irq structure is + protected via desc->lock, by the generic layer. + </para> + </chapter> + <chapter id="structs"> + <title>Structures</title> + <para> + This chapter contains the autogenerated documentation of the structures which are + used in the generic IRQ layer. + </para> +!Iinclude/linux/irq.h +!Iinclude/linux/interrupt.h + </chapter> + + <chapter id="pubfunctions"> + <title>Public Functions Provided</title> + <para> + This chapter contains the autogenerated documentation of the kernel API functions + which are exported. + </para> +!Ekernel/irq/manage.c +!Ekernel/irq/chip.c + </chapter> + + <chapter id="intfunctions"> + <title>Internal Functions Provided</title> + <para> + This chapter contains the autogenerated documentation of the internal functions. + </para> +!Ikernel/irq/irqdesc.c +!Ikernel/irq/handle.c +!Ikernel/irq/chip.c + </chapter> + + <chapter id="credits"> + <title>Credits</title> + <para> + The following people have contributed to this document: + <orderedlist> + <listitem><para>Thomas Gleixner<email>tglx@linutronix.de</email></para></listitem> + <listitem><para>Ingo Molnar<email>mingo@elte.hu</email></para></listitem> + </orderedlist> + </para> + </chapter> +</book> diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl new file mode 100644 index 00000000..7160652a --- /dev/null +++ b/Documentation/DocBook/kernel-api.tmpl @@ -0,0 +1,340 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="LinuxKernelAPI"> + <bookinfo> + <title>The Linux Kernel API</title> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="adt"> + <title>Data Types</title> + <sect1><title>Doubly Linked Lists</title> +!Iinclude/linux/list.h + </sect1> + </chapter> + + <chapter id="libc"> + <title>Basic C Library Functions</title> + + <para> + When writing drivers, you cannot in general use routines which are + from the C Library. Some of the functions have been found generally + useful and they are listed below. The behaviour of these functions + may vary slightly from those defined by ANSI, and these deviations + are noted in the text. + </para> + + <sect1><title>String Conversions</title> +!Elib/vsprintf.c + </sect1> + <sect1><title>String Manipulation</title> +<!-- All functions are exported at now +X!Ilib/string.c + --> +!Elib/string.c + </sect1> + <sect1><title>Bit Operations</title> +!Iarch/x86/include/asm/bitops.h + </sect1> + </chapter> + + <chapter id="kernel-lib"> + <title>Basic Kernel Library Functions</title> + + <para> + The Linux kernel provides more basic utility functions. + </para> + + <sect1><title>Bitmap Operations</title> +!Elib/bitmap.c +!Ilib/bitmap.c + </sect1> + + <sect1><title>Command-line Parsing</title> +!Elib/cmdline.c + </sect1> + + <sect1 id="crc"><title>CRC Functions</title> +!Elib/crc7.c +!Elib/crc16.c +!Elib/crc-itu-t.c +!Elib/crc32.c +!Elib/crc-ccitt.c + </sect1> + + <sect1 id="idr"><title>idr/ida Functions</title> +!Pinclude/linux/idr.h idr sync +!Plib/idr.c IDA description +!Elib/idr.c + </sect1> + </chapter> + + <chapter id="mm"> + <title>Memory Management in Linux</title> + <sect1><title>The Slab Cache</title> +!Iinclude/linux/slab.h +!Emm/slab.c + </sect1> + <sect1><title>User Space Memory Access</title> +!Iarch/x86/include/asm/uaccess_32.h +!Earch/x86/lib/usercopy_32.c + </sect1> + <sect1><title>More Memory Management Functions</title> +!Emm/readahead.c +!Emm/filemap.c +!Emm/memory.c +!Emm/vmalloc.c +!Imm/page_alloc.c +!Emm/mempool.c +!Emm/dmapool.c +!Emm/page-writeback.c +!Emm/truncate.c + </sect1> + </chapter> + + + <chapter id="ipc"> + <title>Kernel IPC facilities</title> + + <sect1><title>IPC utilities</title> +!Iipc/util.c + </sect1> + </chapter> + + <chapter id="kfifo"> + <title>FIFO Buffer</title> + <sect1><title>kfifo interface</title> +!Iinclude/linux/kfifo.h + </sect1> + </chapter> + + <chapter id="relayfs"> + <title>relay interface support</title> + + <para> + Relay interface support + is designed to provide an efficient mechanism for tools and + facilities to relay large amounts of data from kernel space to + user space. + </para> + + <sect1><title>relay interface</title> +!Ekernel/relay.c +!Ikernel/relay.c + </sect1> + </chapter> + + <chapter id="modload"> + <title>Module Support</title> + <sect1><title>Module Loading</title> +!Ekernel/kmod.c + </sect1> + <sect1><title>Inter Module support</title> + <para> + Refer to the file kernel/module.c for more information. + </para> +<!-- FIXME: Removed for now since no structured comments in source +X!Ekernel/module.c +--> + </sect1> + </chapter> + + <chapter id="hardware"> + <title>Hardware Interfaces</title> + <sect1><title>Interrupt Handling</title> +!Ekernel/irq/manage.c + </sect1> + + <sect1><title>DMA Channels</title> +!Ekernel/dma.c + </sect1> + + <sect1><title>Resources Management</title> +!Ikernel/resource.c +!Ekernel/resource.c + </sect1> + + <sect1><title>MTRR Handling</title> +!Earch/x86/kernel/cpu/mtrr/main.c + </sect1> + + <sect1><title>PCI Support Library</title> +!Edrivers/pci/pci.c +!Edrivers/pci/pci-driver.c +!Edrivers/pci/remove.c +!Edrivers/pci/search.c +!Edrivers/pci/msi.c +!Edrivers/pci/bus.c +!Edrivers/pci/access.c +!Edrivers/pci/irq.c +!Edrivers/pci/htirq.c +<!-- FIXME: Removed for now since no structured comments in source +X!Edrivers/pci/hotplug.c +--> +!Edrivers/pci/probe.c +!Edrivers/pci/slot.c +!Edrivers/pci/rom.c +!Edrivers/pci/iov.c +!Idrivers/pci/pci-sysfs.c + </sect1> + <sect1><title>PCI Hotplug Support Library</title> +!Edrivers/pci/hotplug/pci_hotplug_core.c + </sect1> + <sect1><title>MCA Architecture</title> + <sect2><title>MCA Device Functions</title> + <para> + Refer to the file arch/x86/kernel/mca_32.c for more information. + </para> +<!-- FIXME: Removed for now since no structured comments in source +X!Earch/x86/kernel/mca_32.c +--> + </sect2> + <sect2><title>MCA Bus DMA</title> +!Iarch/x86/include/asm/mca_dma.h + </sect2> + </sect1> + </chapter> + + <chapter id="firmware"> + <title>Firmware Interfaces</title> + <sect1><title>DMI Interfaces</title> +!Edrivers/firmware/dmi_scan.c + </sect1> + <sect1><title>EDD Interfaces</title> +!Idrivers/firmware/edd.c + </sect1> + </chapter> + + <chapter id="security"> + <title>Security Framework</title> +!Isecurity/security.c +!Esecurity/inode.c + </chapter> + + <chapter id="audit"> + <title>Audit Interfaces</title> +!Ekernel/audit.c +!Ikernel/auditsc.c +!Ikernel/auditfilter.c + </chapter> + + <chapter id="accounting"> + <title>Accounting Framework</title> +!Ikernel/acct.c + </chapter> + + <chapter id="blkdev"> + <title>Block Devices</title> +!Eblock/blk-core.c +!Iblock/blk-core.c +!Eblock/blk-map.c +!Iblock/blk-sysfs.c +!Eblock/blk-settings.c +!Eblock/blk-exec.c +!Eblock/blk-flush.c +!Eblock/blk-lib.c +!Eblock/blk-tag.c +!Iblock/blk-tag.c +!Eblock/blk-integrity.c +!Ikernel/trace/blktrace.c +!Iblock/genhd.c +!Eblock/genhd.c + </chapter> + + <chapter id="chrdev"> + <title>Char devices</title> +!Efs/char_dev.c + </chapter> + + <chapter id="miscdev"> + <title>Miscellaneous Devices</title> +!Edrivers/char/misc.c + </chapter> + + <chapter id="clk"> + <title>Clock Framework</title> + + <para> + The clock framework defines programming interfaces to support + software management of the system clock tree. + This framework is widely used with System-On-Chip (SOC) platforms + to support power management and various devices which may need + custom clock rates. + Note that these "clocks" don't relate to timekeeping or real + time clocks (RTCs), each of which have separate frameworks. + These <structname>struct clk</structname> instances may be used + to manage for example a 96 MHz signal that is used to shift bits + into and out of peripherals or busses, or otherwise trigger + synchronous state machine transitions in system hardware. + </para> + + <para> + Power management is supported by explicit software clock gating: + unused clocks are disabled, so the system doesn't waste power + changing the state of transistors that aren't in active use. + On some systems this may be backed by hardware clock gating, + where clocks are gated without being disabled in software. + Sections of chips that are powered but not clocked may be able + to retain their last state. + This low power state is often called a <emphasis>retention + mode</emphasis>. + This mode still incurs leakage currents, especially with finer + circuit geometries, but for CMOS circuits power is mostly used + by clocked state changes. + </para> + + <para> + Power-aware drivers only enable their clocks when the device + they manage is in active use. Also, system sleep states often + differ according to which clock domains are active: while a + "standby" state may allow wakeup from several active domains, a + "mem" (suspend-to-RAM) state may require a more wholesale shutdown + of clocks derived from higher speed PLLs and oscillators, limiting + the number of possible wakeup event sources. A driver's suspend + method may need to be aware of system-specific clock constraints + on the target sleep state. + </para> + + <para> + Some platforms support programmable clock generators. These + can be used by external chips of various kinds, such as other + CPUs, multimedia codecs, and devices with strict requirements + for interface clocking. + </para> + +!Iinclude/linux/clk.h + </chapter> + +</book> diff --git a/Documentation/DocBook/kernel-hacking.tmpl b/Documentation/DocBook/kernel-hacking.tmpl new file mode 100644 index 00000000..07a9c48d --- /dev/null +++ b/Documentation/DocBook/kernel-hacking.tmpl @@ -0,0 +1,1327 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="lk-hacking-guide"> + <bookinfo> + <title>Unreliable Guide To Hacking The Linux Kernel</title> + + <authorgroup> + <author> + <firstname>Rusty</firstname> + <surname>Russell</surname> + <affiliation> + <address> + <email>rusty@rustcorp.com.au</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2005</year> + <holder>Rusty Russell</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + + <releaseinfo> + This is the first release of this document as part of the kernel tarball. + </releaseinfo> + + </bookinfo> + + <toc></toc> + + <chapter id="introduction"> + <title>Introduction</title> + <para> + Welcome, gentle reader, to Rusty's Remarkably Unreliable Guide to Linux + Kernel Hacking. This document describes the common routines and + general requirements for kernel code: its goal is to serve as a + primer for Linux kernel development for experienced C + programmers. I avoid implementation details: that's what the + code is for, and I ignore whole tracts of useful routines. + </para> + <para> + Before you read this, please understand that I never wanted to + write this document, being grossly under-qualified, but I always + wanted to read it, and this was the only way. I hope it will + grow into a compendium of best practice, common starting points + and random information. + </para> + </chapter> + + <chapter id="basic-players"> + <title>The Players</title> + + <para> + At any time each of the CPUs in a system can be: + </para> + + <itemizedlist> + <listitem> + <para> + not associated with any process, serving a hardware interrupt; + </para> + </listitem> + + <listitem> + <para> + not associated with any process, serving a softirq or tasklet; + </para> + </listitem> + + <listitem> + <para> + running in kernel space, associated with a process (user context); + </para> + </listitem> + + <listitem> + <para> + running a process in user space. + </para> + </listitem> + </itemizedlist> + + <para> + There is an ordering between these. The bottom two can preempt + each other, but above that is a strict hierarchy: each can only be + preempted by the ones above it. For example, while a softirq is + running on a CPU, no other softirq will preempt it, but a hardware + interrupt can. However, any other CPUs in the system execute + independently. + </para> + + <para> + We'll see a number of ways that the user context can block + interrupts, to become truly non-preemptable. + </para> + + <sect1 id="basics-usercontext"> + <title>User Context</title> + + <para> + User context is when you are coming in from a system call or other + trap: like userspace, you can be preempted by more important tasks + and by interrupts. You can sleep, by calling + <function>schedule()</function>. + </para> + + <note> + <para> + You are always in user context on module load and unload, + and on operations on the block device layer. + </para> + </note> + + <para> + In user context, the <varname>current</varname> pointer (indicating + the task we are currently executing) is valid, and + <function>in_interrupt()</function> + (<filename>include/linux/interrupt.h</filename>) is <returnvalue>false + </returnvalue>. + </para> + + <caution> + <para> + Beware that if you have preemption or softirqs disabled + (see below), <function>in_interrupt()</function> will return a + false positive. + </para> + </caution> + </sect1> + + <sect1 id="basics-hardirqs"> + <title>Hardware Interrupts (Hard IRQs)</title> + + <para> + Timer ticks, <hardware>network cards</hardware> and + <hardware>keyboard</hardware> are examples of real + hardware which produce interrupts at any time. The kernel runs + interrupt handlers, which services the hardware. The kernel + guarantees that this handler is never re-entered: if the same + interrupt arrives, it is queued (or dropped). Because it + disables interrupts, this handler has to be fast: frequently it + simply acknowledges the interrupt, marks a 'software interrupt' + for execution and exits. + </para> + + <para> + You can tell you are in a hardware interrupt, because + <function>in_irq()</function> returns <returnvalue>true</returnvalue>. + </para> + <caution> + <para> + Beware that this will return a false positive if interrupts are disabled + (see below). + </para> + </caution> + </sect1> + + <sect1 id="basics-softirqs"> + <title>Software Interrupt Context: Softirqs and Tasklets</title> + + <para> + Whenever a system call is about to return to userspace, or a + hardware interrupt handler exits, any 'software interrupts' + which are marked pending (usually by hardware interrupts) are + run (<filename>kernel/softirq.c</filename>). + </para> + + <para> + Much of the real interrupt handling work is done here. Early in + the transition to <acronym>SMP</acronym>, there were only 'bottom + halves' (BHs), which didn't take advantage of multiple CPUs. Shortly + after we switched from wind-up computers made of match-sticks and snot, + we abandoned this limitation and switched to 'softirqs'. + </para> + + <para> + <filename class="headerfile">include/linux/interrupt.h</filename> lists the + different softirqs. A very important softirq is the + timer softirq (<filename + class="headerfile">include/linux/timer.h</filename>): you can + register to have it call functions for you in a given length of + time. + </para> + + <para> + Softirqs are often a pain to deal with, since the same softirq + will run simultaneously on more than one CPU. For this reason, + tasklets (<filename + class="headerfile">include/linux/interrupt.h</filename>) are more + often used: they are dynamically-registrable (meaning you can have + as many as you want), and they also guarantee that any tasklet + will only run on one CPU at any time, although different tasklets + can run simultaneously. + </para> + <caution> + <para> + The name 'tasklet' is misleading: they have nothing to do with 'tasks', + and probably more to do with some bad vodka Alexey Kuznetsov had at the + time. + </para> + </caution> + + <para> + You can tell you are in a softirq (or tasklet) + using the <function>in_softirq()</function> macro + (<filename class="headerfile">include/linux/interrupt.h</filename>). + </para> + <caution> + <para> + Beware that this will return a false positive if a bh lock (see below) + is held. + </para> + </caution> + </sect1> + </chapter> + + <chapter id="basic-rules"> + <title>Some Basic Rules</title> + + <variablelist> + <varlistentry> + <term>No memory protection</term> + <listitem> + <para> + If you corrupt memory, whether in user context or + interrupt context, the whole machine will crash. Are you + sure you can't do what you want in userspace? + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>No floating point or <acronym>MMX</acronym></term> + <listitem> + <para> + The <acronym>FPU</acronym> context is not saved; even in user + context the <acronym>FPU</acronym> state probably won't + correspond with the current process: you would mess with some + user process' <acronym>FPU</acronym> state. If you really want + to do this, you would have to explicitly save/restore the full + <acronym>FPU</acronym> state (and avoid context switches). It + is generally a bad idea; use fixed point arithmetic first. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>A rigid stack limit</term> + <listitem> + <para> + Depending on configuration options the kernel stack is about 3K to 6K for most 32-bit architectures: it's + about 14K on most 64-bit archs, and often shared with interrupts + so you can't use it all. Avoid deep recursion and huge local + arrays on the stack (allocate them dynamically instead). + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>The Linux kernel is portable</term> + <listitem> + <para> + Let's keep it that way. Your code should be 64-bit clean, + and endian-independent. You should also minimize CPU + specific stuff, e.g. inline assembly should be cleanly + encapsulated and minimized to ease porting. Generally it + should be restricted to the architecture-dependent part of + the kernel tree. + </para> + </listitem> + </varlistentry> + </variablelist> + </chapter> + + <chapter id="ioctls"> + <title>ioctls: Not writing a new system call</title> + + <para> + A system call generally looks like this + </para> + + <programlisting> +asmlinkage long sys_mycall(int arg) +{ + return 0; +} + </programlisting> + + <para> + First, in most cases you don't want to create a new system call. + You create a character device and implement an appropriate ioctl + for it. This is much more flexible than system calls, doesn't have + to be entered in every architecture's + <filename class="headerfile">include/asm/unistd.h</filename> and + <filename>arch/kernel/entry.S</filename> file, and is much more + likely to be accepted by Linus. + </para> + + <para> + If all your routine does is read or write some parameter, consider + implementing a <function>sysfs</function> interface instead. + </para> + + <para> + Inside the ioctl you're in user context to a process. When a + error occurs you return a negated errno (see + <filename class="headerfile">include/linux/errno.h</filename>), + otherwise you return <returnvalue>0</returnvalue>. + </para> + + <para> + After you slept you should check if a signal occurred: the + Unix/Linux way of handling signals is to temporarily exit the + system call with the <constant>-ERESTARTSYS</constant> error. The + system call entry code will switch back to user context, process + the signal handler and then your system call will be restarted + (unless the user disabled that). So you should be prepared to + process the restart, e.g. if you're in the middle of manipulating + some data structure. + </para> + + <programlisting> +if (signal_pending(current)) + return -ERESTARTSYS; + </programlisting> + + <para> + If you're doing longer computations: first think userspace. If you + <emphasis>really</emphasis> want to do it in kernel you should + regularly check if you need to give up the CPU (remember there is + cooperative multitasking per CPU). Idiom: + </para> + + <programlisting> +cond_resched(); /* Will sleep */ + </programlisting> + + <para> + A short note on interface design: the UNIX system call motto is + "Provide mechanism not policy". + </para> + </chapter> + + <chapter id="deadlock-recipes"> + <title>Recipes for Deadlock</title> + + <para> + You cannot call any routines which may sleep, unless: + </para> + <itemizedlist> + <listitem> + <para> + You are in user context. + </para> + </listitem> + + <listitem> + <para> + You do not own any spinlocks. + </para> + </listitem> + + <listitem> + <para> + You have interrupts enabled (actually, Andi Kleen says + that the scheduling code will enable them for you, but + that's probably not what you wanted). + </para> + </listitem> + </itemizedlist> + + <para> + Note that some functions may sleep implicitly: common ones are + the user space access functions (*_user) and memory allocation + functions without <symbol>GFP_ATOMIC</symbol>. + </para> + + <para> + You should always compile your kernel + <symbol>CONFIG_DEBUG_ATOMIC_SLEEP</symbol> on, and it will warn + you if you break these rules. If you <emphasis>do</emphasis> break + the rules, you will eventually lock up your box. + </para> + + <para> + Really. + </para> + </chapter> + + <chapter id="common-routines"> + <title>Common Routines</title> + + <sect1 id="routines-printk"> + <title> + <function>printk()</function> + <filename class="headerfile">include/linux/kernel.h</filename> + </title> + + <para> + <function>printk()</function> feeds kernel messages to the + console, dmesg, and the syslog daemon. It is useful for debugging + and reporting errors, and can be used inside interrupt context, + but use with caution: a machine which has its console flooded with + printk messages is unusable. It uses a format string mostly + compatible with ANSI C printf, and C string concatenation to give + it a first "priority" argument: + </para> + + <programlisting> +printk(KERN_INFO "i = %u\n", i); + </programlisting> + + <para> + See <filename class="headerfile">include/linux/kernel.h</filename>; + for other KERN_ values; these are interpreted by syslog as the + level. Special case: for printing an IP address use + </para> + + <programlisting> +__be32 ipaddress; +printk(KERN_INFO "my ip: %pI4\n", &ipaddress); + </programlisting> + + <para> + <function>printk()</function> internally uses a 1K buffer and does + not catch overruns. Make sure that will be enough. + </para> + + <note> + <para> + You will know when you are a real kernel hacker + when you start typoing printf as printk in your user programs :) + </para> + </note> + + <!--- From the Lions book reader department --> + + <note> + <para> + Another sidenote: the original Unix Version 6 sources had a + comment on top of its printf function: "Printf should not be + used for chit-chat". You should follow that advice. + </para> + </note> + </sect1> + + <sect1 id="routines-copy"> + <title> + <function>copy_[to/from]_user()</function> + / + <function>get_user()</function> + / + <function>put_user()</function> + <filename class="headerfile">include/asm/uaccess.h</filename> + </title> + + <para> + <emphasis>[SLEEPS]</emphasis> + </para> + + <para> + <function>put_user()</function> and <function>get_user()</function> + are used to get and put single values (such as an int, char, or + long) from and to userspace. A pointer into userspace should + never be simply dereferenced: data should be copied using these + routines. Both return <constant>-EFAULT</constant> or 0. + </para> + <para> + <function>copy_to_user()</function> and + <function>copy_from_user()</function> are more general: they copy + an arbitrary amount of data to and from userspace. + <caution> + <para> + Unlike <function>put_user()</function> and + <function>get_user()</function>, they return the amount of + uncopied data (ie. <returnvalue>0</returnvalue> still means + success). + </para> + </caution> + [Yes, this moronic interface makes me cringe. The flamewar comes up every year or so. --RR.] + </para> + <para> + The functions may sleep implicitly. This should never be called + outside user context (it makes no sense), with interrupts + disabled, or a spinlock held. + </para> + </sect1> + + <sect1 id="routines-kmalloc"> + <title><function>kmalloc()</function>/<function>kfree()</function> + <filename class="headerfile">include/linux/slab.h</filename></title> + + <para> + <emphasis>[MAY SLEEP: SEE BELOW]</emphasis> + </para> + + <para> + These routines are used to dynamically request pointer-aligned + chunks of memory, like malloc and free do in userspace, but + <function>kmalloc()</function> takes an extra flag word. + Important values: + </para> + + <variablelist> + <varlistentry> + <term> + <constant> + GFP_KERNEL + </constant> + </term> + <listitem> + <para> + May sleep and swap to free memory. Only allowed in user + context, but is the most reliable way to allocate memory. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <constant> + GFP_ATOMIC + </constant> + </term> + <listitem> + <para> + Don't sleep. Less reliable than <constant>GFP_KERNEL</constant>, + but may be called from interrupt context. You should + <emphasis>really</emphasis> have a good out-of-memory + error-handling strategy. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <constant> + GFP_DMA + </constant> + </term> + <listitem> + <para> + Allocate ISA DMA lower than 16MB. If you don't know what that + is you don't need it. Very unreliable. + </para> + </listitem> + </varlistentry> + </variablelist> + + <para> + If you see a <errorname>sleeping function called from invalid + context</errorname> warning message, then maybe you called a + sleeping allocation function from interrupt context without + <constant>GFP_ATOMIC</constant>. You should really fix that. + Run, don't walk. + </para> + + <para> + If you are allocating at least <constant>PAGE_SIZE</constant> + (<filename class="headerfile">include/asm/page.h</filename>) bytes, + consider using <function>__get_free_pages()</function> + + (<filename class="headerfile">include/linux/mm.h</filename>). It + takes an order argument (0 for page sized, 1 for double page, 2 + for four pages etc.) and the same memory priority flag word as + above. + </para> + + <para> + If you are allocating more than a page worth of bytes you can use + <function>vmalloc()</function>. It'll allocate virtual memory in + the kernel map. This block is not contiguous in physical memory, + but the <acronym>MMU</acronym> makes it look like it is for you + (so it'll only look contiguous to the CPUs, not to external device + drivers). If you really need large physically contiguous memory + for some weird device, you have a problem: it is poorly supported + in Linux because after some time memory fragmentation in a running + kernel makes it hard. The best way is to allocate the block early + in the boot process via the <function>alloc_bootmem()</function> + routine. + </para> + + <para> + Before inventing your own cache of often-used objects consider + using a slab cache in + <filename class="headerfile">include/linux/slab.h</filename> + </para> + </sect1> + + <sect1 id="routines-current"> + <title><function>current</function> + <filename class="headerfile">include/asm/current.h</filename></title> + + <para> + This global variable (really a macro) contains a pointer to + the current task structure, so is only valid in user context. + For example, when a process makes a system call, this will + point to the task structure of the calling process. It is + <emphasis>not NULL</emphasis> in interrupt context. + </para> + </sect1> + + <sect1 id="routines-udelay"> + <title><function>mdelay()</function>/<function>udelay()</function> + <filename class="headerfile">include/asm/delay.h</filename> + <filename class="headerfile">include/linux/delay.h</filename> + </title> + + <para> + The <function>udelay()</function> and <function>ndelay()</function> functions can be used for small pauses. + Do not use large values with them as you risk + overflow - the helper function <function>mdelay()</function> is useful + here, or consider <function>msleep()</function>. + </para> + </sect1> + + <sect1 id="routines-endian"> + <title><function>cpu_to_be32()</function>/<function>be32_to_cpu()</function>/<function>cpu_to_le32()</function>/<function>le32_to_cpu()</function> + <filename class="headerfile">include/asm/byteorder.h</filename> + </title> + + <para> + The <function>cpu_to_be32()</function> family (where the "32" can + be replaced by 64 or 16, and the "be" can be replaced by "le") are + the general way to do endian conversions in the kernel: they + return the converted value. All variations supply the reverse as + well: <function>be32_to_cpu()</function>, etc. + </para> + + <para> + There are two major variations of these functions: the pointer + variation, such as <function>cpu_to_be32p()</function>, which take + a pointer to the given type, and return the converted value. The + other variation is the "in-situ" family, such as + <function>cpu_to_be32s()</function>, which convert value referred + to by the pointer, and return void. + </para> + </sect1> + + <sect1 id="routines-local-irqs"> + <title><function>local_irq_save()</function>/<function>local_irq_restore()</function> + <filename class="headerfile">include/asm/system.h</filename> + </title> + + <para> + These routines disable hard interrupts on the local CPU, and + restore them. They are reentrant; saving the previous state in + their one <varname>unsigned long flags</varname> argument. If you + know that interrupts are enabled, you can simply use + <function>local_irq_disable()</function> and + <function>local_irq_enable()</function>. + </para> + </sect1> + + <sect1 id="routines-softirqs"> + <title><function>local_bh_disable()</function>/<function>local_bh_enable()</function> + <filename class="headerfile">include/linux/interrupt.h</filename></title> + + <para> + These routines disable soft interrupts on the local CPU, and + restore them. They are reentrant; if soft interrupts were + disabled before, they will still be disabled after this pair + of functions has been called. They prevent softirqs and tasklets + from running on the current CPU. + </para> + </sect1> + + <sect1 id="routines-processorids"> + <title><function>smp_processor_id</function>() + <filename class="headerfile">include/asm/smp.h</filename></title> + + <para> + <function>get_cpu()</function> disables preemption (so you won't + suddenly get moved to another CPU) and returns the current + processor number, between 0 and <symbol>NR_CPUS</symbol>. Note + that the CPU numbers are not necessarily continuous. You return + it again with <function>put_cpu()</function> when you are done. + </para> + <para> + If you know you cannot be preempted by another task (ie. you are + in interrupt context, or have preemption disabled) you can use + smp_processor_id(). + </para> + </sect1> + + <sect1 id="routines-init"> + <title><type>__init</type>/<type>__exit</type>/<type>__initdata</type> + <filename class="headerfile">include/linux/init.h</filename></title> + + <para> + After boot, the kernel frees up a special section; functions + marked with <type>__init</type> and data structures marked with + <type>__initdata</type> are dropped after boot is complete: similarly + modules discard this memory after initialization. <type>__exit</type> + is used to declare a function which is only required on exit: the + function will be dropped if this file is not compiled as a module. + See the header file for use. Note that it makes no sense for a function + marked with <type>__init</type> to be exported to modules with + <function>EXPORT_SYMBOL()</function> - this will break. + </para> + + </sect1> + + <sect1 id="routines-init-again"> + <title><function>__initcall()</function>/<function>module_init()</function> + <filename class="headerfile">include/linux/init.h</filename></title> + <para> + Many parts of the kernel are well served as a module + (dynamically-loadable parts of the kernel). Using the + <function>module_init()</function> and + <function>module_exit()</function> macros it is easy to write code + without #ifdefs which can operate both as a module or built into + the kernel. + </para> + + <para> + The <function>module_init()</function> macro defines which + function is to be called at module insertion time (if the file is + compiled as a module), or at boot time: if the file is not + compiled as a module the <function>module_init()</function> macro + becomes equivalent to <function>__initcall()</function>, which + through linker magic ensures that the function is called on boot. + </para> + + <para> + The function can return a negative error number to cause + module loading to fail (unfortunately, this has no effect if + the module is compiled into the kernel). This function is + called in user context with interrupts enabled, so it can sleep. + </para> + </sect1> + + <sect1 id="routines-moduleexit"> + <title> <function>module_exit()</function> + <filename class="headerfile">include/linux/init.h</filename> </title> + + <para> + This macro defines the function to be called at module removal + time (or never, in the case of the file compiled into the + kernel). It will only be called if the module usage count has + reached zero. This function can also sleep, but cannot fail: + everything must be cleaned up by the time it returns. + </para> + + <para> + Note that this macro is optional: if it is not present, your + module will not be removable (except for 'rmmod -f'). + </para> + </sect1> + + <sect1 id="routines-module-use-counters"> + <title> <function>try_module_get()</function>/<function>module_put()</function> + <filename class="headerfile">include/linux/module.h</filename></title> + + <para> + These manipulate the module usage count, to protect against + removal (a module also can't be removed if another module uses one + of its exported symbols: see below). Before calling into module + code, you should call <function>try_module_get()</function> on + that module: if it fails, then the module is being removed and you + should act as if it wasn't there. Otherwise, you can safely enter + the module, and call <function>module_put()</function> when you're + finished. + </para> + + <para> + Most registerable structures have an + <structfield>owner</structfield> field, such as in the + <structname>file_operations</structname> structure. Set this field + to the macro <symbol>THIS_MODULE</symbol>. + </para> + </sect1> + + <!-- add info on new-style module refcounting here --> + </chapter> + + <chapter id="queues"> + <title>Wait Queues + <filename class="headerfile">include/linux/wait.h</filename> + </title> + <para> + <emphasis>[SLEEPS]</emphasis> + </para> + + <para> + A wait queue is used to wait for someone to wake you up when a + certain condition is true. They must be used carefully to ensure + there is no race condition. You declare a + <type>wait_queue_head_t</type>, and then processes which want to + wait for that condition declare a <type>wait_queue_t</type> + referring to themselves, and place that in the queue. + </para> + + <sect1 id="queue-declaring"> + <title>Declaring</title> + + <para> + You declare a <type>wait_queue_head_t</type> using the + <function>DECLARE_WAIT_QUEUE_HEAD()</function> macro, or using the + <function>init_waitqueue_head()</function> routine in your + initialization code. + </para> + </sect1> + + <sect1 id="queue-waitqueue"> + <title>Queuing</title> + + <para> + Placing yourself in the waitqueue is fairly complex, because you + must put yourself in the queue before checking the condition. + There is a macro to do this: + <function>wait_event_interruptible()</function> + + <filename class="headerfile">include/linux/wait.h</filename> The + first argument is the wait queue head, and the second is an + expression which is evaluated; the macro returns + <returnvalue>0</returnvalue> when this expression is true, or + <returnvalue>-ERESTARTSYS</returnvalue> if a signal is received. + The <function>wait_event()</function> version ignores signals. + </para> + <para> + Do not use the <function>sleep_on()</function> function family - + it is very easy to accidentally introduce races; almost certainly + one of the <function>wait_event()</function> family will do, or a + loop around <function>schedule_timeout()</function>. If you choose + to loop around <function>schedule_timeout()</function> remember + you must set the task state (with + <function>set_current_state()</function>) on each iteration to avoid + busy-looping. + </para> + + </sect1> + + <sect1 id="queue-waking"> + <title>Waking Up Queued Tasks</title> + + <para> + Call <function>wake_up()</function> + + <filename class="headerfile">include/linux/wait.h</filename>;, + which will wake up every process in the queue. The exception is + if one has <constant>TASK_EXCLUSIVE</constant> set, in which case + the remainder of the queue will not be woken. There are other variants + of this basic function available in the same header. + </para> + </sect1> + </chapter> + + <chapter id="atomic-ops"> + <title>Atomic Operations</title> + + <para> + Certain operations are guaranteed atomic on all platforms. The + first class of operations work on <type>atomic_t</type> + + <filename class="headerfile">include/asm/atomic.h</filename>; this + contains a signed integer (at least 32 bits long), and you must use + these functions to manipulate or read atomic_t variables. + <function>atomic_read()</function> and + <function>atomic_set()</function> get and set the counter, + <function>atomic_add()</function>, + <function>atomic_sub()</function>, + <function>atomic_inc()</function>, + <function>atomic_dec()</function>, and + <function>atomic_dec_and_test()</function> (returns + <returnvalue>true</returnvalue> if it was decremented to zero). + </para> + + <para> + Yes. It returns <returnvalue>true</returnvalue> (i.e. != 0) if the + atomic variable is zero. + </para> + + <para> + Note that these functions are slower than normal arithmetic, and + so should not be used unnecessarily. + </para> + + <para> + The second class of atomic operations is atomic bit operations on an + <type>unsigned long</type>, defined in + + <filename class="headerfile">include/linux/bitops.h</filename>. These + operations generally take a pointer to the bit pattern, and a bit + number: 0 is the least significant bit. + <function>set_bit()</function>, <function>clear_bit()</function> + and <function>change_bit()</function> set, clear, and flip the + given bit. <function>test_and_set_bit()</function>, + <function>test_and_clear_bit()</function> and + <function>test_and_change_bit()</function> do the same thing, + except return true if the bit was previously set; these are + particularly useful for atomically setting flags. + </para> + + <para> + It is possible to call these operations with bit indices greater + than BITS_PER_LONG. The resulting behavior is strange on big-endian + platforms though so it is a good idea not to do this. + </para> + </chapter> + + <chapter id="symbols"> + <title>Symbols</title> + + <para> + Within the kernel proper, the normal linking rules apply + (ie. unless a symbol is declared to be file scope with the + <type>static</type> keyword, it can be used anywhere in the + kernel). However, for modules, a special exported symbol table is + kept which limits the entry points to the kernel proper. Modules + can also export symbols. + </para> + + <sect1 id="sym-exportsymbols"> + <title><function>EXPORT_SYMBOL()</function> + <filename class="headerfile">include/linux/module.h</filename></title> + + <para> + This is the classic method of exporting a symbol: dynamically + loaded modules will be able to use the symbol as normal. + </para> + </sect1> + + <sect1 id="sym-exportsymbols-gpl"> + <title><function>EXPORT_SYMBOL_GPL()</function> + <filename class="headerfile">include/linux/module.h</filename></title> + + <para> + Similar to <function>EXPORT_SYMBOL()</function> except that the + symbols exported by <function>EXPORT_SYMBOL_GPL()</function> can + only be seen by modules with a + <function>MODULE_LICENSE()</function> that specifies a GPL + compatible license. It implies that the function is considered + an internal implementation issue, and not really an interface. + </para> + </sect1> + </chapter> + + <chapter id="conventions"> + <title>Routines and Conventions</title> + + <sect1 id="conventions-doublelinkedlist"> + <title>Double-linked lists + <filename class="headerfile">include/linux/list.h</filename></title> + + <para> + There used to be three sets of linked-list routines in the kernel + headers, but this one is the winner. If you don't have some + particular pressing need for a single list, it's a good choice. + </para> + + <para> + In particular, <function>list_for_each_entry</function> is useful. + </para> + </sect1> + + <sect1 id="convention-returns"> + <title>Return Conventions</title> + + <para> + For code called in user context, it's very common to defy C + convention, and return <returnvalue>0</returnvalue> for success, + and a negative error number + (eg. <returnvalue>-EFAULT</returnvalue>) for failure. This can be + unintuitive at first, but it's fairly widespread in the kernel. + </para> + + <para> + Using <function>ERR_PTR()</function> + + <filename class="headerfile">include/linux/err.h</filename>; to + encode a negative error number into a pointer, and + <function>IS_ERR()</function> and <function>PTR_ERR()</function> + to get it back out again: avoids a separate pointer parameter for + the error number. Icky, but in a good way. + </para> + </sect1> + + <sect1 id="conventions-borkedcompile"> + <title>Breaking Compilation</title> + + <para> + Linus and the other developers sometimes change function or + structure names in development kernels; this is not done just to + keep everyone on their toes: it reflects a fundamental change + (eg. can no longer be called with interrupts on, or does extra + checks, or doesn't do checks which were caught before). Usually + this is accompanied by a fairly complete note to the linux-kernel + mailing list; search the archive. Simply doing a global replace + on the file usually makes things <emphasis>worse</emphasis>. + </para> + </sect1> + + <sect1 id="conventions-initialising"> + <title>Initializing structure members</title> + + <para> + The preferred method of initializing structures is to use + designated initialisers, as defined by ISO C99, eg: + </para> + <programlisting> +static struct block_device_operations opt_fops = { + .open = opt_open, + .release = opt_release, + .ioctl = opt_ioctl, + .check_media_change = opt_media_change, +}; + </programlisting> + <para> + This makes it easy to grep for, and makes it clear which + structure fields are set. You should do this because it looks + cool. + </para> + </sect1> + + <sect1 id="conventions-gnu-extns"> + <title>GNU Extensions</title> + + <para> + GNU Extensions are explicitly allowed in the Linux kernel. + Note that some of the more complex ones are not very well + supported, due to lack of general use, but the following are + considered standard (see the GCC info page section "C + Extensions" for more details - Yes, really the info page, the + man page is only a short summary of the stuff in info). + </para> + <itemizedlist> + <listitem> + <para> + Inline functions + </para> + </listitem> + <listitem> + <para> + Statement expressions (ie. the ({ and }) constructs). + </para> + </listitem> + <listitem> + <para> + Declaring attributes of a function / variable / type + (__attribute__) + </para> + </listitem> + <listitem> + <para> + typeof + </para> + </listitem> + <listitem> + <para> + Zero length arrays + </para> + </listitem> + <listitem> + <para> + Macro varargs + </para> + </listitem> + <listitem> + <para> + Arithmetic on void pointers + </para> + </listitem> + <listitem> + <para> + Non-Constant initializers + </para> + </listitem> + <listitem> + <para> + Assembler Instructions (not outside arch/ and include/asm/) + </para> + </listitem> + <listitem> + <para> + Function names as strings (__func__). + </para> + </listitem> + <listitem> + <para> + __builtin_constant_p() + </para> + </listitem> + </itemizedlist> + + <para> + Be wary when using long long in the kernel, the code gcc generates for + it is horrible and worse: division and multiplication does not work + on i386 because the GCC runtime functions for it are missing from + the kernel environment. + </para> + + <!-- FIXME: add a note about ANSI aliasing cleanness --> + </sect1> + + <sect1 id="conventions-cplusplus"> + <title>C++</title> + + <para> + Using C++ in the kernel is usually a bad idea, because the + kernel does not provide the necessary runtime environment + and the include files are not tested for it. It is still + possible, but not recommended. If you really want to do + this, forget about exceptions at least. + </para> + </sect1> + + <sect1 id="conventions-ifdef"> + <title>#if</title> + + <para> + It is generally considered cleaner to use macros in header files + (or at the top of .c files) to abstract away functions rather than + using `#if' pre-processor statements throughout the source code. + </para> + </sect1> + </chapter> + + <chapter id="submitting"> + <title>Putting Your Stuff in the Kernel</title> + + <para> + In order to get your stuff into shape for official inclusion, or + even to make a neat patch, there's administrative work to be + done: + </para> + <itemizedlist> + <listitem> + <para> + Figure out whose pond you've been pissing in. Look at the top of + the source files, inside the <filename>MAINTAINERS</filename> + file, and last of all in the <filename>CREDITS</filename> file. + You should coordinate with this person to make sure you're not + duplicating effort, or trying something that's already been + rejected. + </para> + + <para> + Make sure you put your name and EMail address at the top of + any files you create or mangle significantly. This is the + first place people will look when they find a bug, or when + <emphasis>they</emphasis> want to make a change. + </para> + </listitem> + + <listitem> + <para> + Usually you want a configuration option for your kernel hack. + Edit <filename>Kconfig</filename> in the appropriate directory. + The Config language is simple to use by cut and paste, and there's + complete documentation in + <filename>Documentation/kbuild/kconfig-language.txt</filename>. + </para> + + <para> + You may well want to make your CONFIG option only visible if + <symbol>CONFIG_EXPERIMENTAL</symbol> is enabled: this serves as a + warning to users. There many other fancy things you can do: see + the various <filename>Kconfig</filename> files for ideas. + </para> + + <para> + In your description of the option, make sure you address both the + expert user and the user who knows nothing about your feature. Mention + incompatibilities and issues here. <emphasis> Definitely + </emphasis> end your description with <quote> if in doubt, say N + </quote> (or, occasionally, `Y'); this is for people who have no + idea what you are talking about. + </para> + </listitem> + + <listitem> + <para> + Edit the <filename>Makefile</filename>: the CONFIG variables are + exported here so you can usually just add a "obj-$(CONFIG_xxx) += + xxx.o" line. The syntax is documented in + <filename>Documentation/kbuild/makefiles.txt</filename>. + </para> + </listitem> + + <listitem> + <para> + Put yourself in <filename>CREDITS</filename> if you've done + something noteworthy, usually beyond a single file (your name + should be at the top of the source files anyway). + <filename>MAINTAINERS</filename> means you want to be consulted + when changes are made to a subsystem, and hear about bugs; it + implies a more-than-passing commitment to some part of the code. + </para> + </listitem> + + <listitem> + <para> + Finally, don't forget to read <filename>Documentation/SubmittingPatches</filename> + and possibly <filename>Documentation/SubmittingDrivers</filename>. + </para> + </listitem> + </itemizedlist> + </chapter> + + <chapter id="cantrips"> + <title>Kernel Cantrips</title> + + <para> + Some favorites from browsing the source. Feel free to add to this + list. + </para> + + <para> + <filename>arch/x86/include/asm/delay.h:</filename> + </para> + <programlisting> +#define ndelay(n) (__builtin_constant_p(n) ? \ + ((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \ + __ndelay(n)) + </programlisting> + + <para> + <filename>include/linux/fs.h</filename>: + </para> + <programlisting> +/* + * Kernel pointers have redundant information, so we can use a + * scheme where we can return either an error code or a dentry + * pointer with the same return value. + * + * This should be a per-architecture thing, to allow different + * error and pointer decisions. + */ + #define ERR_PTR(err) ((void *)((long)(err))) + #define PTR_ERR(ptr) ((long)(ptr)) + #define IS_ERR(ptr) ((unsigned long)(ptr) > (unsigned long)(-1000)) +</programlisting> + + <para> + <filename>arch/x86/include/asm/uaccess_32.h:</filename> + </para> + + <programlisting> +#define copy_to_user(to,from,n) \ + (__builtin_constant_p(n) ? \ + __constant_copy_to_user((to),(from),(n)) : \ + __generic_copy_to_user((to),(from),(n))) + </programlisting> + + <para> + <filename>arch/sparc/kernel/head.S:</filename> + </para> + + <programlisting> +/* + * Sun people can't spell worth damn. "compatability" indeed. + * At least we *know* we can't spell, and use a spell-checker. + */ + +/* Uh, actually Linus it is I who cannot spell. Too much murky + * Sparc assembly will do this to ya. + */ +C_LABEL(cputypvar): + .asciz "compatability" + +/* Tested on SS-5, SS-10. Probably someone at Sun applied a spell-checker. */ + .align 4 +C_LABEL(cputypvar_sun4m): + .asciz "compatible" + </programlisting> + + <para> + <filename>arch/sparc/lib/checksum.S:</filename> + </para> + + <programlisting> + /* Sun, you just can't beat me, you just can't. Stop trying, + * give up. I'm serious, I am going to kick the living shit + * out of you, game over, lights out. + */ + </programlisting> + </chapter> + + <chapter id="credits"> + <title>Thanks</title> + + <para> + Thanks to Andi Kleen for the idea, answering my questions, fixing + my mistakes, filling content, etc. Philipp Rumpf for more spelling + and clarity fixes, and some excellent non-obvious points. Werner + Almesberger for giving me a great summary of + <function>disable_irq()</function>, and Jes Sorensen and Andrea + Arcangeli added caveats. Michael Elizabeth Chastain for checking + and adding to the Configure section. <!-- Rusty insisted on this + bit; I didn't do it! --> Telsa Gwynne for teaching me DocBook. + </para> + </chapter> +</book> + diff --git a/Documentation/DocBook/kernel-locking.tmpl b/Documentation/DocBook/kernel-locking.tmpl new file mode 100644 index 00000000..67e7ab41 --- /dev/null +++ b/Documentation/DocBook/kernel-locking.tmpl @@ -0,0 +1,2146 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="LKLockingGuide"> + <bookinfo> + <title>Unreliable Guide To Locking</title> + + <authorgroup> + <author> + <firstname>Rusty</firstname> + <surname>Russell</surname> + <affiliation> + <address> + <email>rusty@rustcorp.com.au</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2003</year> + <holder>Rusty Russell</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + + <toc></toc> + <chapter id="intro"> + <title>Introduction</title> + <para> + Welcome, to Rusty's Remarkably Unreliable Guide to Kernel + Locking issues. This document describes the locking systems in + the Linux Kernel in 2.6. + </para> + <para> + With the wide availability of HyperThreading, and <firstterm + linkend="gloss-preemption">preemption </firstterm> in the Linux + Kernel, everyone hacking on the kernel needs to know the + fundamentals of concurrency and locking for + <firstterm linkend="gloss-smp"><acronym>SMP</acronym></firstterm>. + </para> + </chapter> + + <chapter id="races"> + <title>The Problem With Concurrency</title> + <para> + (Skip this if you know what a Race Condition is). + </para> + <para> + In a normal program, you can increment a counter like so: + </para> + <programlisting> + very_important_count++; + </programlisting> + + <para> + This is what they would expect to happen: + </para> + + <table> + <title>Expected Results</title> + + <tgroup cols="2" align="left"> + + <thead> + <row> + <entry>Instance 1</entry> + <entry>Instance 2</entry> + </row> + </thead> + + <tbody> + <row> + <entry>read very_important_count (5)</entry> + <entry></entry> + </row> + <row> + <entry>add 1 (6)</entry> + <entry></entry> + </row> + <row> + <entry>write very_important_count (6)</entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>read very_important_count (6)</entry> + </row> + <row> + <entry></entry> + <entry>add 1 (7)</entry> + </row> + <row> + <entry></entry> + <entry>write very_important_count (7)</entry> + </row> + </tbody> + + </tgroup> + </table> + + <para> + This is what might happen: + </para> + + <table> + <title>Possible Results</title> + + <tgroup cols="2" align="left"> + <thead> + <row> + <entry>Instance 1</entry> + <entry>Instance 2</entry> + </row> + </thead> + + <tbody> + <row> + <entry>read very_important_count (5)</entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>read very_important_count (5)</entry> + </row> + <row> + <entry>add 1 (6)</entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>add 1 (6)</entry> + </row> + <row> + <entry>write very_important_count (6)</entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>write very_important_count (6)</entry> + </row> + </tbody> + </tgroup> + </table> + + <sect1 id="race-condition"> + <title>Race Conditions and Critical Regions</title> + <para> + This overlap, where the result depends on the + relative timing of multiple tasks, is called a <firstterm>race condition</firstterm>. + The piece of code containing the concurrency issue is called a + <firstterm>critical region</firstterm>. And especially since Linux starting running + on SMP machines, they became one of the major issues in kernel + design and implementation. + </para> + <para> + Preemption can have the same effect, even if there is only one + CPU: by preempting one task during the critical region, we have + exactly the same race condition. In this case the thread which + preempts might run the critical region itself. + </para> + <para> + The solution is to recognize when these simultaneous accesses + occur, and use locks to make sure that only one instance can + enter the critical region at any time. There are many + friendly primitives in the Linux kernel to help you do this. + And then there are the unfriendly primitives, but I'll pretend + they don't exist. + </para> + </sect1> + </chapter> + + <chapter id="locks"> + <title>Locking in the Linux Kernel</title> + + <para> + If I could give you one piece of advice: never sleep with anyone + crazier than yourself. But if I had to give you advice on + locking: <emphasis>keep it simple</emphasis>. + </para> + + <para> + Be reluctant to introduce new locks. + </para> + + <para> + Strangely enough, this last one is the exact reverse of my advice when + you <emphasis>have</emphasis> slept with someone crazier than yourself. + And you should think about getting a big dog. + </para> + + <sect1 id="lock-intro"> + <title>Two Main Types of Kernel Locks: Spinlocks and Mutexes</title> + + <para> + There are two main types of kernel locks. The fundamental type + is the spinlock + (<filename class="headerfile">include/asm/spinlock.h</filename>), + which is a very simple single-holder lock: if you can't get the + spinlock, you keep trying (spinning) until you can. Spinlocks are + very small and fast, and can be used anywhere. + </para> + <para> + The second type is a mutex + (<filename class="headerfile">include/linux/mutex.h</filename>): it + is like a spinlock, but you may block holding a mutex. + If you can't lock a mutex, your task will suspend itself, and be woken + up when the mutex is released. This means the CPU can do something + else while you are waiting. There are many cases when you simply + can't sleep (see <xref linkend="sleeping-things"/>), and so have to + use a spinlock instead. + </para> + <para> + Neither type of lock is recursive: see + <xref linkend="deadlock"/>. + </para> + </sect1> + + <sect1 id="uniprocessor"> + <title>Locks and Uniprocessor Kernels</title> + + <para> + For kernels compiled without <symbol>CONFIG_SMP</symbol>, and + without <symbol>CONFIG_PREEMPT</symbol> spinlocks do not exist at + all. This is an excellent design decision: when no-one else can + run at the same time, there is no reason to have a lock. + </para> + + <para> + If the kernel is compiled without <symbol>CONFIG_SMP</symbol>, + but <symbol>CONFIG_PREEMPT</symbol> is set, then spinlocks + simply disable preemption, which is sufficient to prevent any + races. For most purposes, we can think of preemption as + equivalent to SMP, and not worry about it separately. + </para> + + <para> + You should always test your locking code with <symbol>CONFIG_SMP</symbol> + and <symbol>CONFIG_PREEMPT</symbol> enabled, even if you don't have an SMP test box, because it + will still catch some kinds of locking bugs. + </para> + + <para> + Mutexes still exist, because they are required for + synchronization between <firstterm linkend="gloss-usercontext">user + contexts</firstterm>, as we will see below. + </para> + </sect1> + + <sect1 id="usercontextlocking"> + <title>Locking Only In User Context</title> + + <para> + If you have a data structure which is only ever accessed from + user context, then you can use a simple mutex + (<filename>include/linux/mutex.h</filename>) to protect it. This + is the most trivial case: you initialize the mutex. Then you can + call <function>mutex_lock_interruptible()</function> to grab the mutex, + and <function>mutex_unlock()</function> to release it. There is also a + <function>mutex_lock()</function>, which should be avoided, because it + will not return if a signal is received. + </para> + + <para> + Example: <filename>net/netfilter/nf_sockopt.c</filename> allows + registration of new <function>setsockopt()</function> and + <function>getsockopt()</function> calls, with + <function>nf_register_sockopt()</function>. Registration and + de-registration are only done on module load and unload (and boot + time, where there is no concurrency), and the list of registrations + is only consulted for an unknown <function>setsockopt()</function> + or <function>getsockopt()</function> system call. The + <varname>nf_sockopt_mutex</varname> is perfect to protect this, + especially since the setsockopt and getsockopt calls may well + sleep. + </para> + </sect1> + + <sect1 id="lock-user-bh"> + <title>Locking Between User Context and Softirqs</title> + + <para> + If a <firstterm linkend="gloss-softirq">softirq</firstterm> shares + data with user context, you have two problems. Firstly, the current + user context can be interrupted by a softirq, and secondly, the + critical region could be entered from another CPU. This is where + <function>spin_lock_bh()</function> + (<filename class="headerfile">include/linux/spinlock.h</filename>) is + used. It disables softirqs on that CPU, then grabs the lock. + <function>spin_unlock_bh()</function> does the reverse. (The + '_bh' suffix is a historical reference to "Bottom Halves", the + old name for software interrupts. It should really be + called spin_lock_softirq()' in a perfect world). + </para> + + <para> + Note that you can also use <function>spin_lock_irq()</function> + or <function>spin_lock_irqsave()</function> here, which stop + hardware interrupts as well: see <xref linkend="hardirq-context"/>. + </para> + + <para> + This works perfectly for <firstterm linkend="gloss-up"><acronym>UP + </acronym></firstterm> as well: the spin lock vanishes, and this macro + simply becomes <function>local_bh_disable()</function> + (<filename class="headerfile">include/linux/interrupt.h</filename>), which + protects you from the softirq being run. + </para> + </sect1> + + <sect1 id="lock-user-tasklet"> + <title>Locking Between User Context and Tasklets</title> + + <para> + This is exactly the same as above, because <firstterm + linkend="gloss-tasklet">tasklets</firstterm> are actually run + from a softirq. + </para> + </sect1> + + <sect1 id="lock-user-timers"> + <title>Locking Between User Context and Timers</title> + + <para> + This, too, is exactly the same as above, because <firstterm + linkend="gloss-timers">timers</firstterm> are actually run from + a softirq. From a locking point of view, tasklets and timers + are identical. + </para> + </sect1> + + <sect1 id="lock-tasklets"> + <title>Locking Between Tasklets/Timers</title> + + <para> + Sometimes a tasklet or timer might want to share data with + another tasklet or timer. + </para> + + <sect2 id="lock-tasklets-same"> + <title>The Same Tasklet/Timer</title> + <para> + Since a tasklet is never run on two CPUs at once, you don't + need to worry about your tasklet being reentrant (running + twice at once), even on SMP. + </para> + </sect2> + + <sect2 id="lock-tasklets-different"> + <title>Different Tasklets/Timers</title> + <para> + If another tasklet/timer wants + to share data with your tasklet or timer , you will both need to use + <function>spin_lock()</function> and + <function>spin_unlock()</function> calls. + <function>spin_lock_bh()</function> is + unnecessary here, as you are already in a tasklet, and + none will be run on the same CPU. + </para> + </sect2> + </sect1> + + <sect1 id="lock-softirqs"> + <title>Locking Between Softirqs</title> + + <para> + Often a softirq might + want to share data with itself or a tasklet/timer. + </para> + + <sect2 id="lock-softirqs-same"> + <title>The Same Softirq</title> + + <para> + The same softirq can run on the other CPUs: you can use a + per-CPU array (see <xref linkend="per-cpu"/>) for better + performance. If you're going so far as to use a softirq, + you probably care about scalable performance enough + to justify the extra complexity. + </para> + + <para> + You'll need to use <function>spin_lock()</function> and + <function>spin_unlock()</function> for shared data. + </para> + </sect2> + + <sect2 id="lock-softirqs-different"> + <title>Different Softirqs</title> + + <para> + You'll need to use <function>spin_lock()</function> and + <function>spin_unlock()</function> for shared data, whether it + be a timer, tasklet, different softirq or the same or another + softirq: any of them could be running on a different CPU. + </para> + </sect2> + </sect1> + </chapter> + + <chapter id="hardirq-context"> + <title>Hard IRQ Context</title> + + <para> + Hardware interrupts usually communicate with a + tasklet or softirq. Frequently this involves putting work in a + queue, which the softirq will take out. + </para> + + <sect1 id="hardirq-softirq"> + <title>Locking Between Hard IRQ and Softirqs/Tasklets</title> + + <para> + If a hardware irq handler shares data with a softirq, you have + two concerns. Firstly, the softirq processing can be + interrupted by a hardware interrupt, and secondly, the + critical region could be entered by a hardware interrupt on + another CPU. This is where <function>spin_lock_irq()</function> is + used. It is defined to disable interrupts on that cpu, then grab + the lock. <function>spin_unlock_irq()</function> does the reverse. + </para> + + <para> + The irq handler does not to use + <function>spin_lock_irq()</function>, because the softirq cannot + run while the irq handler is running: it can use + <function>spin_lock()</function>, which is slightly faster. The + only exception would be if a different hardware irq handler uses + the same lock: <function>spin_lock_irq()</function> will stop + that from interrupting us. + </para> + + <para> + This works perfectly for UP as well: the spin lock vanishes, + and this macro simply becomes <function>local_irq_disable()</function> + (<filename class="headerfile">include/asm/smp.h</filename>), which + protects you from the softirq/tasklet/BH being run. + </para> + + <para> + <function>spin_lock_irqsave()</function> + (<filename>include/linux/spinlock.h</filename>) is a variant + which saves whether interrupts were on or off in a flags word, + which is passed to <function>spin_unlock_irqrestore()</function>. This + means that the same code can be used inside an hard irq handler (where + interrupts are already off) and in softirqs (where the irq + disabling is required). + </para> + + <para> + Note that softirqs (and hence tasklets and timers) are run on + return from hardware interrupts, so + <function>spin_lock_irq()</function> also stops these. In that + sense, <function>spin_lock_irqsave()</function> is the most + general and powerful locking function. + </para> + + </sect1> + <sect1 id="hardirq-hardirq"> + <title>Locking Between Two Hard IRQ Handlers</title> + <para> + It is rare to have to share data between two IRQ handlers, but + if you do, <function>spin_lock_irqsave()</function> should be + used: it is architecture-specific whether all interrupts are + disabled inside irq handlers themselves. + </para> + </sect1> + + </chapter> + + <chapter id="cheatsheet"> + <title>Cheat Sheet For Locking</title> + <para> + Pete Zaitcev gives the following summary: + </para> + <itemizedlist> + <listitem> + <para> + If you are in a process context (any syscall) and want to + lock other process out, use a mutex. You can take a mutex + and sleep (<function>copy_from_user*(</function> or + <function>kmalloc(x,GFP_KERNEL)</function>). + </para> + </listitem> + <listitem> + <para> + Otherwise (== data can be touched in an interrupt), use + <function>spin_lock_irqsave()</function> and + <function>spin_unlock_irqrestore()</function>. + </para> + </listitem> + <listitem> + <para> + Avoid holding spinlock for more than 5 lines of code and + across any function call (except accessors like + <function>readb</function>). + </para> + </listitem> + </itemizedlist> + + <sect1 id="minimum-lock-reqirements"> + <title>Table of Minimum Requirements</title> + + <para> The following table lists the <emphasis>minimum</emphasis> + locking requirements between various contexts. In some cases, + the same context can only be running on one CPU at a time, so + no locking is required for that context (eg. a particular + thread can only run on one CPU at a time, but if it needs + shares data with another thread, locking is required). + </para> + <para> + Remember the advice above: you can always use + <function>spin_lock_irqsave()</function>, which is a superset + of all other spinlock primitives. + </para> + + <table> +<title>Table of Locking Requirements</title> +<tgroup cols="11"> +<tbody> + +<row> +<entry></entry> +<entry>IRQ Handler A</entry> +<entry>IRQ Handler B</entry> +<entry>Softirq A</entry> +<entry>Softirq B</entry> +<entry>Tasklet A</entry> +<entry>Tasklet B</entry> +<entry>Timer A</entry> +<entry>Timer B</entry> +<entry>User Context A</entry> +<entry>User Context B</entry> +</row> + +<row> +<entry>IRQ Handler A</entry> +<entry>None</entry> +</row> + +<row> +<entry>IRQ Handler B</entry> +<entry>SLIS</entry> +<entry>None</entry> +</row> + +<row> +<entry>Softirq A</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SL</entry> +</row> + +<row> +<entry>Softirq B</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SL</entry> +<entry>SL</entry> +</row> + +<row> +<entry>Tasklet A</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>None</entry> +</row> + +<row> +<entry>Tasklet B</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>None</entry> +</row> + +<row> +<entry>Timer A</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>None</entry> +</row> + +<row> +<entry>Timer B</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>SL</entry> +<entry>None</entry> +</row> + +<row> +<entry>User Context A</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>None</entry> +</row> + +<row> +<entry>User Context B</entry> +<entry>SLI</entry> +<entry>SLI</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>SLBH</entry> +<entry>MLI</entry> +<entry>None</entry> +</row> + +</tbody> +</tgroup> +</table> + + <table> +<title>Legend for Locking Requirements Table</title> +<tgroup cols="2"> +<tbody> + +<row> +<entry>SLIS</entry> +<entry>spin_lock_irqsave</entry> +</row> +<row> +<entry>SLI</entry> +<entry>spin_lock_irq</entry> +</row> +<row> +<entry>SL</entry> +<entry>spin_lock</entry> +</row> +<row> +<entry>SLBH</entry> +<entry>spin_lock_bh</entry> +</row> +<row> +<entry>MLI</entry> +<entry>mutex_lock_interruptible</entry> +</row> + +</tbody> +</tgroup> +</table> + +</sect1> +</chapter> + +<chapter id="trylock-functions"> + <title>The trylock Functions</title> + <para> + There are functions that try to acquire a lock only once and immediately + return a value telling about success or failure to acquire the lock. + They can be used if you need no access to the data protected with the lock + when some other thread is holding the lock. You should acquire the lock + later if you then need access to the data protected with the lock. + </para> + + <para> + <function>spin_trylock()</function> does not spin but returns non-zero if + it acquires the spinlock on the first try or 0 if not. This function can + be used in all contexts like <function>spin_lock</function>: you must have + disabled the contexts that might interrupt you and acquire the spin lock. + </para> + + <para> + <function>mutex_trylock()</function> does not suspend your task + but returns non-zero if it could lock the mutex on the first try + or 0 if not. This function cannot be safely used in hardware or software + interrupt contexts despite not sleeping. + </para> +</chapter> + + <chapter id="Examples"> + <title>Common Examples</title> + <para> +Let's step through a simple example: a cache of number to name +mappings. The cache keeps a count of how often each of the objects is +used, and when it gets full, throws out the least used one. + + </para> + + <sect1 id="examples-usercontext"> + <title>All In User Context</title> + <para> +For our first example, we assume that all operations are in user +context (ie. from system calls), so we can sleep. This means we can +use a mutex to protect the cache and all the objects within +it. Here's the code: + </para> + + <programlisting> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/mutex.h> +#include <asm/errno.h> + +struct object +{ + struct list_head list; + int id; + char name[32]; + int popularity; +}; + +/* Protects the cache, cache_num, and the objects within it */ +static DEFINE_MUTEX(cache_lock); +static LIST_HEAD(cache); +static unsigned int cache_num = 0; +#define MAX_CACHE_SIZE 10 + +/* Must be holding cache_lock */ +static struct object *__cache_find(int id) +{ + struct object *i; + + list_for_each_entry(i, &cache, list) + if (i->id == id) { + i->popularity++; + return i; + } + return NULL; +} + +/* Must be holding cache_lock */ +static void __cache_delete(struct object *obj) +{ + BUG_ON(!obj); + list_del(&obj->list); + kfree(obj); + cache_num--; +} + +/* Must be holding cache_lock */ +static void __cache_add(struct object *obj) +{ + list_add(&obj->list, &cache); + if (++cache_num > MAX_CACHE_SIZE) { + struct object *i, *outcast = NULL; + list_for_each_entry(i, &cache, list) { + if (!outcast || i->popularity < outcast->popularity) + outcast = i; + } + __cache_delete(outcast); + } +} + +int cache_add(int id, const char *name) +{ + struct object *obj; + + if ((obj = kmalloc(sizeof(*obj), GFP_KERNEL)) == NULL) + return -ENOMEM; + + strlcpy(obj->name, name, sizeof(obj->name)); + obj->id = id; + obj->popularity = 0; + + mutex_lock(&cache_lock); + __cache_add(obj); + mutex_unlock(&cache_lock); + return 0; +} + +void cache_delete(int id) +{ + mutex_lock(&cache_lock); + __cache_delete(__cache_find(id)); + mutex_unlock(&cache_lock); +} + +int cache_find(int id, char *name) +{ + struct object *obj; + int ret = -ENOENT; + + mutex_lock(&cache_lock); + obj = __cache_find(id); + if (obj) { + ret = 0; + strcpy(name, obj->name); + } + mutex_unlock(&cache_lock); + return ret; +} +</programlisting> + + <para> +Note that we always make sure we have the cache_lock when we add, +delete, or look up the cache: both the cache infrastructure itself and +the contents of the objects are protected by the lock. In this case +it's easy, since we copy the data for the user, and never let them +access the objects directly. + </para> + <para> +There is a slight (and common) optimization here: in +<function>cache_add</function> we set up the fields of the object +before grabbing the lock. This is safe, as no-one else can access it +until we put it in cache. + </para> + </sect1> + + <sect1 id="examples-interrupt"> + <title>Accessing From Interrupt Context</title> + <para> +Now consider the case where <function>cache_find</function> can be +called from interrupt context: either a hardware interrupt or a +softirq. An example would be a timer which deletes object from the +cache. + </para> + <para> +The change is shown below, in standard patch format: the +<symbol>-</symbol> are lines which are taken away, and the +<symbol>+</symbol> are lines which are added. + </para> +<programlisting> +--- cache.c.usercontext 2003-12-09 13:58:54.000000000 +1100 ++++ cache.c.interrupt 2003-12-09 14:07:49.000000000 +1100 +@@ -12,7 +12,7 @@ + int popularity; + }; + +-static DEFINE_MUTEX(cache_lock); ++static DEFINE_SPINLOCK(cache_lock); + static LIST_HEAD(cache); + static unsigned int cache_num = 0; + #define MAX_CACHE_SIZE 10 +@@ -55,6 +55,7 @@ + int cache_add(int id, const char *name) + { + struct object *obj; ++ unsigned long flags; + + if ((obj = kmalloc(sizeof(*obj), GFP_KERNEL)) == NULL) + return -ENOMEM; +@@ -63,30 +64,33 @@ + obj->id = id; + obj->popularity = 0; + +- mutex_lock(&cache_lock); ++ spin_lock_irqsave(&cache_lock, flags); + __cache_add(obj); +- mutex_unlock(&cache_lock); ++ spin_unlock_irqrestore(&cache_lock, flags); + return 0; + } + + void cache_delete(int id) + { +- mutex_lock(&cache_lock); ++ unsigned long flags; ++ ++ spin_lock_irqsave(&cache_lock, flags); + __cache_delete(__cache_find(id)); +- mutex_unlock(&cache_lock); ++ spin_unlock_irqrestore(&cache_lock, flags); + } + + int cache_find(int id, char *name) + { + struct object *obj; + int ret = -ENOENT; ++ unsigned long flags; + +- mutex_lock(&cache_lock); ++ spin_lock_irqsave(&cache_lock, flags); + obj = __cache_find(id); + if (obj) { + ret = 0; + strcpy(name, obj->name); + } +- mutex_unlock(&cache_lock); ++ spin_unlock_irqrestore(&cache_lock, flags); + return ret; + } +</programlisting> + + <para> +Note that the <function>spin_lock_irqsave</function> will turn off +interrupts if they are on, otherwise does nothing (if we are already +in an interrupt handler), hence these functions are safe to call from +any context. + </para> + <para> +Unfortunately, <function>cache_add</function> calls +<function>kmalloc</function> with the <symbol>GFP_KERNEL</symbol> +flag, which is only legal in user context. I have assumed that +<function>cache_add</function> is still only called in user context, +otherwise this should become a parameter to +<function>cache_add</function>. + </para> + </sect1> + <sect1 id="examples-refcnt"> + <title>Exposing Objects Outside This File</title> + <para> +If our objects contained more information, it might not be sufficient +to copy the information in and out: other parts of the code might want +to keep pointers to these objects, for example, rather than looking up +the id every time. This produces two problems. + </para> + <para> +The first problem is that we use the <symbol>cache_lock</symbol> to +protect objects: we'd need to make this non-static so the rest of the +code can use it. This makes locking trickier, as it is no longer all +in one place. + </para> + <para> +The second problem is the lifetime problem: if another structure keeps +a pointer to an object, it presumably expects that pointer to remain +valid. Unfortunately, this is only guaranteed while you hold the +lock, otherwise someone might call <function>cache_delete</function> +and even worse, add another object, re-using the same address. + </para> + <para> +As there is only one lock, you can't hold it forever: no-one else would +get any work done. + </para> + <para> +The solution to this problem is to use a reference count: everyone who +has a pointer to the object increases it when they first get the +object, and drops the reference count when they're finished with it. +Whoever drops it to zero knows it is unused, and can actually delete it. + </para> + <para> +Here is the code: + </para> + +<programlisting> +--- cache.c.interrupt 2003-12-09 14:25:43.000000000 +1100 ++++ cache.c.refcnt 2003-12-09 14:33:05.000000000 +1100 +@@ -7,6 +7,7 @@ + struct object + { + struct list_head list; ++ unsigned int refcnt; + int id; + char name[32]; + int popularity; +@@ -17,6 +18,35 @@ + static unsigned int cache_num = 0; + #define MAX_CACHE_SIZE 10 + ++static void __object_put(struct object *obj) ++{ ++ if (--obj->refcnt == 0) ++ kfree(obj); ++} ++ ++static void __object_get(struct object *obj) ++{ ++ obj->refcnt++; ++} ++ ++void object_put(struct object *obj) ++{ ++ unsigned long flags; ++ ++ spin_lock_irqsave(&cache_lock, flags); ++ __object_put(obj); ++ spin_unlock_irqrestore(&cache_lock, flags); ++} ++ ++void object_get(struct object *obj) ++{ ++ unsigned long flags; ++ ++ spin_lock_irqsave(&cache_lock, flags); ++ __object_get(obj); ++ spin_unlock_irqrestore(&cache_lock, flags); ++} ++ + /* Must be holding cache_lock */ + static struct object *__cache_find(int id) + { +@@ -35,6 +65,7 @@ + { + BUG_ON(!obj); + list_del(&obj->list); ++ __object_put(obj); + cache_num--; + } + +@@ -63,6 +94,7 @@ + strlcpy(obj->name, name, sizeof(obj->name)); + obj->id = id; + obj->popularity = 0; ++ obj->refcnt = 1; /* The cache holds a reference */ + + spin_lock_irqsave(&cache_lock, flags); + __cache_add(obj); +@@ -79,18 +111,15 @@ + spin_unlock_irqrestore(&cache_lock, flags); + } + +-int cache_find(int id, char *name) ++struct object *cache_find(int id) + { + struct object *obj; +- int ret = -ENOENT; + unsigned long flags; + + spin_lock_irqsave(&cache_lock, flags); + obj = __cache_find(id); +- if (obj) { +- ret = 0; +- strcpy(name, obj->name); +- } ++ if (obj) ++ __object_get(obj); + spin_unlock_irqrestore(&cache_lock, flags); +- return ret; ++ return obj; + } +</programlisting> + +<para> +We encapsulate the reference counting in the standard 'get' and 'put' +functions. Now we can return the object itself from +<function>cache_find</function> which has the advantage that the user +can now sleep holding the object (eg. to +<function>copy_to_user</function> to name to userspace). +</para> +<para> +The other point to note is that I said a reference should be held for +every pointer to the object: thus the reference count is 1 when first +inserted into the cache. In some versions the framework does not hold +a reference count, but they are more complicated. +</para> + + <sect2 id="examples-refcnt-atomic"> + <title>Using Atomic Operations For The Reference Count</title> +<para> +In practice, <type>atomic_t</type> would usually be used for +<structfield>refcnt</structfield>. There are a number of atomic +operations defined in + +<filename class="headerfile">include/asm/atomic.h</filename>: these are +guaranteed to be seen atomically from all CPUs in the system, so no +lock is required. In this case, it is simpler than using spinlocks, +although for anything non-trivial using spinlocks is clearer. The +<function>atomic_inc</function> and +<function>atomic_dec_and_test</function> are used instead of the +standard increment and decrement operators, and the lock is no longer +used to protect the reference count itself. +</para> + +<programlisting> +--- cache.c.refcnt 2003-12-09 15:00:35.000000000 +1100 ++++ cache.c.refcnt-atomic 2003-12-11 15:49:42.000000000 +1100 +@@ -7,7 +7,7 @@ + struct object + { + struct list_head list; +- unsigned int refcnt; ++ atomic_t refcnt; + int id; + char name[32]; + int popularity; +@@ -18,33 +18,15 @@ + static unsigned int cache_num = 0; + #define MAX_CACHE_SIZE 10 + +-static void __object_put(struct object *obj) +-{ +- if (--obj->refcnt == 0) +- kfree(obj); +-} +- +-static void __object_get(struct object *obj) +-{ +- obj->refcnt++; +-} +- + void object_put(struct object *obj) + { +- unsigned long flags; +- +- spin_lock_irqsave(&cache_lock, flags); +- __object_put(obj); +- spin_unlock_irqrestore(&cache_lock, flags); ++ if (atomic_dec_and_test(&obj->refcnt)) ++ kfree(obj); + } + + void object_get(struct object *obj) + { +- unsigned long flags; +- +- spin_lock_irqsave(&cache_lock, flags); +- __object_get(obj); +- spin_unlock_irqrestore(&cache_lock, flags); ++ atomic_inc(&obj->refcnt); + } + + /* Must be holding cache_lock */ +@@ -65,7 +47,7 @@ + { + BUG_ON(!obj); + list_del(&obj->list); +- __object_put(obj); ++ object_put(obj); + cache_num--; + } + +@@ -94,7 +76,7 @@ + strlcpy(obj->name, name, sizeof(obj->name)); + obj->id = id; + obj->popularity = 0; +- obj->refcnt = 1; /* The cache holds a reference */ ++ atomic_set(&obj->refcnt, 1); /* The cache holds a reference */ + + spin_lock_irqsave(&cache_lock, flags); + __cache_add(obj); +@@ -119,7 +101,7 @@ + spin_lock_irqsave(&cache_lock, flags); + obj = __cache_find(id); + if (obj) +- __object_get(obj); ++ object_get(obj); + spin_unlock_irqrestore(&cache_lock, flags); + return obj; + } +</programlisting> +</sect2> +</sect1> + + <sect1 id="examples-lock-per-obj"> + <title>Protecting The Objects Themselves</title> + <para> +In these examples, we assumed that the objects (except the reference +counts) never changed once they are created. If we wanted to allow +the name to change, there are three possibilities: + </para> + <itemizedlist> + <listitem> + <para> +You can make <symbol>cache_lock</symbol> non-static, and tell people +to grab that lock before changing the name in any object. + </para> + </listitem> + <listitem> + <para> +You can provide a <function>cache_obj_rename</function> which grabs +this lock and changes the name for the caller, and tell everyone to +use that function. + </para> + </listitem> + <listitem> + <para> +You can make the <symbol>cache_lock</symbol> protect only the cache +itself, and use another lock to protect the name. + </para> + </listitem> + </itemizedlist> + + <para> +Theoretically, you can make the locks as fine-grained as one lock for +every field, for every object. In practice, the most common variants +are: +</para> + <itemizedlist> + <listitem> + <para> +One lock which protects the infrastructure (the <symbol>cache</symbol> +list in this example) and all the objects. This is what we have done +so far. + </para> + </listitem> + <listitem> + <para> +One lock which protects the infrastructure (including the list +pointers inside the objects), and one lock inside the object which +protects the rest of that object. + </para> + </listitem> + <listitem> + <para> +Multiple locks to protect the infrastructure (eg. one lock per hash +chain), possibly with a separate per-object lock. + </para> + </listitem> + </itemizedlist> + +<para> +Here is the "lock-per-object" implementation: +</para> +<programlisting> +--- cache.c.refcnt-atomic 2003-12-11 15:50:54.000000000 +1100 ++++ cache.c.perobjectlock 2003-12-11 17:15:03.000000000 +1100 +@@ -6,11 +6,17 @@ + + struct object + { ++ /* These two protected by cache_lock. */ + struct list_head list; ++ int popularity; ++ + atomic_t refcnt; ++ ++ /* Doesn't change once created. */ + int id; ++ ++ spinlock_t lock; /* Protects the name */ + char name[32]; +- int popularity; + }; + + static DEFINE_SPINLOCK(cache_lock); +@@ -77,6 +84,7 @@ + obj->id = id; + obj->popularity = 0; + atomic_set(&obj->refcnt, 1); /* The cache holds a reference */ ++ spin_lock_init(&obj->lock); + + spin_lock_irqsave(&cache_lock, flags); + __cache_add(obj); +</programlisting> + +<para> +Note that I decide that the <structfield>popularity</structfield> +count should be protected by the <symbol>cache_lock</symbol> rather +than the per-object lock: this is because it (like the +<structname>struct list_head</structname> inside the object) is +logically part of the infrastructure. This way, I don't need to grab +the lock of every object in <function>__cache_add</function> when +seeking the least popular. +</para> + +<para> +I also decided that the <structfield>id</structfield> member is +unchangeable, so I don't need to grab each object lock in +<function>__cache_find()</function> to examine the +<structfield>id</structfield>: the object lock is only used by a +caller who wants to read or write the <structfield>name</structfield> +field. +</para> + +<para> +Note also that I added a comment describing what data was protected by +which locks. This is extremely important, as it describes the runtime +behavior of the code, and can be hard to gain from just reading. And +as Alan Cox says, <quote>Lock data, not code</quote>. +</para> +</sect1> +</chapter> + + <chapter id="common-problems"> + <title>Common Problems</title> + <sect1 id="deadlock"> + <title>Deadlock: Simple and Advanced</title> + + <para> + There is a coding bug where a piece of code tries to grab a + spinlock twice: it will spin forever, waiting for the lock to + be released (spinlocks, rwlocks and mutexes are not + recursive in Linux). This is trivial to diagnose: not a + stay-up-five-nights-talk-to-fluffy-code-bunnies kind of + problem. + </para> + + <para> + For a slightly more complex case, imagine you have a region + shared by a softirq and user context. If you use a + <function>spin_lock()</function> call to protect it, it is + possible that the user context will be interrupted by the softirq + while it holds the lock, and the softirq will then spin + forever trying to get the same lock. + </para> + + <para> + Both of these are called deadlock, and as shown above, it can + occur even with a single CPU (although not on UP compiles, + since spinlocks vanish on kernel compiles with + <symbol>CONFIG_SMP</symbol>=n. You'll still get data corruption + in the second example). + </para> + + <para> + This complete lockup is easy to diagnose: on SMP boxes the + watchdog timer or compiling with <symbol>DEBUG_SPINLOCK</symbol> set + (<filename>include/linux/spinlock.h</filename>) will show this up + immediately when it happens. + </para> + + <para> + A more complex problem is the so-called 'deadly embrace', + involving two or more locks. Say you have a hash table: each + entry in the table is a spinlock, and a chain of hashed + objects. Inside a softirq handler, you sometimes want to + alter an object from one place in the hash to another: you + grab the spinlock of the old hash chain and the spinlock of + the new hash chain, and delete the object from the old one, + and insert it in the new one. + </para> + + <para> + There are two problems here. First, if your code ever + tries to move the object to the same chain, it will deadlock + with itself as it tries to lock it twice. Secondly, if the + same softirq on another CPU is trying to move another object + in the reverse direction, the following could happen: + </para> + + <table> + <title>Consequences</title> + + <tgroup cols="2" align="left"> + + <thead> + <row> + <entry>CPU 1</entry> + <entry>CPU 2</entry> + </row> + </thead> + + <tbody> + <row> + <entry>Grab lock A -> OK</entry> + <entry>Grab lock B -> OK</entry> + </row> + <row> + <entry>Grab lock B -> spin</entry> + <entry>Grab lock A -> spin</entry> + </row> + </tbody> + </tgroup> + </table> + + <para> + The two CPUs will spin forever, waiting for the other to give up + their lock. It will look, smell, and feel like a crash. + </para> + </sect1> + + <sect1 id="techs-deadlock-prevent"> + <title>Preventing Deadlock</title> + + <para> + Textbooks will tell you that if you always lock in the same + order, you will never get this kind of deadlock. Practice + will tell you that this approach doesn't scale: when I + create a new lock, I don't understand enough of the kernel + to figure out where in the 5000 lock hierarchy it will fit. + </para> + + <para> + The best locks are encapsulated: they never get exposed in + headers, and are never held around calls to non-trivial + functions outside the same file. You can read through this + code and see that it will never deadlock, because it never + tries to grab another lock while it has that one. People + using your code don't even need to know you are using a + lock. + </para> + + <para> + A classic problem here is when you provide callbacks or + hooks: if you call these with the lock held, you risk simple + deadlock, or a deadly embrace (who knows what the callback + will do?). Remember, the other programmers are out to get + you, so don't do this. + </para> + + <sect2 id="techs-deadlock-overprevent"> + <title>Overzealous Prevention Of Deadlocks</title> + + <para> + Deadlocks are problematic, but not as bad as data + corruption. Code which grabs a read lock, searches a list, + fails to find what it wants, drops the read lock, grabs a + write lock and inserts the object has a race condition. + </para> + + <para> + If you don't see why, please stay the fuck away from my code. + </para> + </sect2> + </sect1> + + <sect1 id="racing-timers"> + <title>Racing Timers: A Kernel Pastime</title> + + <para> + Timers can produce their own special problems with races. + Consider a collection of objects (list, hash, etc) where each + object has a timer which is due to destroy it. + </para> + + <para> + If you want to destroy the entire collection (say on module + removal), you might do the following: + </para> + + <programlisting> + /* THIS CODE BAD BAD BAD BAD: IF IT WAS ANY WORSE IT WOULD USE + HUNGARIAN NOTATION */ + spin_lock_bh(&list_lock); + + while (list) { + struct foo *next = list->next; + del_timer(&list->timer); + kfree(list); + list = next; + } + + spin_unlock_bh(&list_lock); + </programlisting> + + <para> + Sooner or later, this will crash on SMP, because a timer can + have just gone off before the <function>spin_lock_bh()</function>, + and it will only get the lock after we + <function>spin_unlock_bh()</function>, and then try to free + the element (which has already been freed!). + </para> + + <para> + This can be avoided by checking the result of + <function>del_timer()</function>: if it returns + <returnvalue>1</returnvalue>, the timer has been deleted. + If <returnvalue>0</returnvalue>, it means (in this + case) that it is currently running, so we can do: + </para> + + <programlisting> + retry: + spin_lock_bh(&list_lock); + + while (list) { + struct foo *next = list->next; + if (!del_timer(&list->timer)) { + /* Give timer a chance to delete this */ + spin_unlock_bh(&list_lock); + goto retry; + } + kfree(list); + list = next; + } + + spin_unlock_bh(&list_lock); + </programlisting> + + <para> + Another common problem is deleting timers which restart + themselves (by calling <function>add_timer()</function> at the end + of their timer function). Because this is a fairly common case + which is prone to races, you should use <function>del_timer_sync()</function> + (<filename class="headerfile">include/linux/timer.h</filename>) + to handle this case. It returns the number of times the timer + had to be deleted before we finally stopped it from adding itself back + in. + </para> + </sect1> + + </chapter> + + <chapter id="Efficiency"> + <title>Locking Speed</title> + + <para> +There are three main things to worry about when considering speed of +some code which does locking. First is concurrency: how many things +are going to be waiting while someone else is holding a lock. Second +is the time taken to actually acquire and release an uncontended lock. +Third is using fewer, or smarter locks. I'm assuming that the lock is +used fairly often: otherwise, you wouldn't be concerned about +efficiency. +</para> + <para> +Concurrency depends on how long the lock is usually held: you should +hold the lock for as long as needed, but no longer. In the cache +example, we always create the object without the lock held, and then +grab the lock only when we are ready to insert it in the list. +</para> + <para> +Acquisition times depend on how much damage the lock operations do to +the pipeline (pipeline stalls) and how likely it is that this CPU was +the last one to grab the lock (ie. is the lock cache-hot for this +CPU): on a machine with more CPUs, this likelihood drops fast. +Consider a 700MHz Intel Pentium III: an instruction takes about 0.7ns, +an atomic increment takes about 58ns, a lock which is cache-hot on +this CPU takes 160ns, and a cacheline transfer from another CPU takes +an additional 170 to 360ns. (These figures from Paul McKenney's +<ulink url="http://www.linuxjournal.com/article.php?sid=6993"> Linux +Journal RCU article</ulink>). +</para> + <para> +These two aims conflict: holding a lock for a short time might be done +by splitting locks into parts (such as in our final per-object-lock +example), but this increases the number of lock acquisitions, and the +results are often slower than having a single lock. This is another +reason to advocate locking simplicity. +</para> + <para> +The third concern is addressed below: there are some methods to reduce +the amount of locking which needs to be done. +</para> + + <sect1 id="efficiency-rwlocks"> + <title>Read/Write Lock Variants</title> + + <para> + Both spinlocks and mutexes have read/write variants: + <type>rwlock_t</type> and <structname>struct rw_semaphore</structname>. + These divide users into two classes: the readers and the writers. If + you are only reading the data, you can get a read lock, but to write to + the data you need the write lock. Many people can hold a read lock, + but a writer must be sole holder. + </para> + + <para> + If your code divides neatly along reader/writer lines (as our + cache code does), and the lock is held by readers for + significant lengths of time, using these locks can help. They + are slightly slower than the normal locks though, so in practice + <type>rwlock_t</type> is not usually worthwhile. + </para> + </sect1> + + <sect1 id="efficiency-read-copy-update"> + <title>Avoiding Locks: Read Copy Update</title> + + <para> + There is a special method of read/write locking called Read Copy + Update. Using RCU, the readers can avoid taking a lock + altogether: as we expect our cache to be read more often than + updated (otherwise the cache is a waste of time), it is a + candidate for this optimization. + </para> + + <para> + How do we get rid of read locks? Getting rid of read locks + means that writers may be changing the list underneath the + readers. That is actually quite simple: we can read a linked + list while an element is being added if the writer adds the + element very carefully. For example, adding + <symbol>new</symbol> to a single linked list called + <symbol>list</symbol>: + </para> + + <programlisting> + new->next = list->next; + wmb(); + list->next = new; + </programlisting> + + <para> + The <function>wmb()</function> is a write memory barrier. It + ensures that the first operation (setting the new element's + <symbol>next</symbol> pointer) is complete and will be seen by + all CPUs, before the second operation is (putting the new + element into the list). This is important, since modern + compilers and modern CPUs can both reorder instructions unless + told otherwise: we want a reader to either not see the new + element at all, or see the new element with the + <symbol>next</symbol> pointer correctly pointing at the rest of + the list. + </para> + <para> + Fortunately, there is a function to do this for standard + <structname>struct list_head</structname> lists: + <function>list_add_rcu()</function> + (<filename>include/linux/list.h</filename>). + </para> + <para> + Removing an element from the list is even simpler: we replace + the pointer to the old element with a pointer to its successor, + and readers will either see it, or skip over it. + </para> + <programlisting> + list->next = old->next; + </programlisting> + <para> + There is <function>list_del_rcu()</function> + (<filename>include/linux/list.h</filename>) which does this (the + normal version poisons the old object, which we don't want). + </para> + <para> + The reader must also be careful: some CPUs can look through the + <symbol>next</symbol> pointer to start reading the contents of + the next element early, but don't realize that the pre-fetched + contents is wrong when the <symbol>next</symbol> pointer changes + underneath them. Once again, there is a + <function>list_for_each_entry_rcu()</function> + (<filename>include/linux/list.h</filename>) to help you. Of + course, writers can just use + <function>list_for_each_entry()</function>, since there cannot + be two simultaneous writers. + </para> + <para> + Our final dilemma is this: when can we actually destroy the + removed element? Remember, a reader might be stepping through + this element in the list right now: if we free this element and + the <symbol>next</symbol> pointer changes, the reader will jump + off into garbage and crash. We need to wait until we know that + all the readers who were traversing the list when we deleted the + element are finished. We use <function>call_rcu()</function> to + register a callback which will actually destroy the object once + all pre-existing readers are finished. Alternatively, + <function>synchronize_rcu()</function> may be used to block until + all pre-existing are finished. + </para> + <para> + But how does Read Copy Update know when the readers are + finished? The method is this: firstly, the readers always + traverse the list inside + <function>rcu_read_lock()</function>/<function>rcu_read_unlock()</function> + pairs: these simply disable preemption so the reader won't go to + sleep while reading the list. + </para> + <para> + RCU then waits until every other CPU has slept at least once: + since readers cannot sleep, we know that any readers which were + traversing the list during the deletion are finished, and the + callback is triggered. The real Read Copy Update code is a + little more optimized than this, but this is the fundamental + idea. + </para> + +<programlisting> +--- cache.c.perobjectlock 2003-12-11 17:15:03.000000000 +1100 ++++ cache.c.rcupdate 2003-12-11 17:55:14.000000000 +1100 +@@ -1,15 +1,18 @@ + #include <linux/list.h> + #include <linux/slab.h> + #include <linux/string.h> ++#include <linux/rcupdate.h> + #include <linux/mutex.h> + #include <asm/errno.h> + + struct object + { +- /* These two protected by cache_lock. */ ++ /* This is protected by RCU */ + struct list_head list; + int popularity; + ++ struct rcu_head rcu; ++ + atomic_t refcnt; + + /* Doesn't change once created. */ +@@ -40,7 +43,7 @@ + { + struct object *i; + +- list_for_each_entry(i, &cache, list) { ++ list_for_each_entry_rcu(i, &cache, list) { + if (i->id == id) { + i->popularity++; + return i; +@@ -49,19 +52,25 @@ + return NULL; + } + ++/* Final discard done once we know no readers are looking. */ ++static void cache_delete_rcu(void *arg) ++{ ++ object_put(arg); ++} ++ + /* Must be holding cache_lock */ + static void __cache_delete(struct object *obj) + { + BUG_ON(!obj); +- list_del(&obj->list); +- object_put(obj); ++ list_del_rcu(&obj->list); + cache_num--; ++ call_rcu(&obj->rcu, cache_delete_rcu); + } + + /* Must be holding cache_lock */ + static void __cache_add(struct object *obj) + { +- list_add(&obj->list, &cache); ++ list_add_rcu(&obj->list, &cache); + if (++cache_num > MAX_CACHE_SIZE) { + struct object *i, *outcast = NULL; + list_for_each_entry(i, &cache, list) { +@@ -104,12 +114,11 @@ + struct object *cache_find(int id) + { + struct object *obj; +- unsigned long flags; + +- spin_lock_irqsave(&cache_lock, flags); ++ rcu_read_lock(); + obj = __cache_find(id); + if (obj) + object_get(obj); +- spin_unlock_irqrestore(&cache_lock, flags); ++ rcu_read_unlock(); + return obj; + } +</programlisting> + +<para> +Note that the reader will alter the +<structfield>popularity</structfield> member in +<function>__cache_find()</function>, and now it doesn't hold a lock. +One solution would be to make it an <type>atomic_t</type>, but for +this usage, we don't really care about races: an approximate result is +good enough, so I didn't change it. +</para> + +<para> +The result is that <function>cache_find()</function> requires no +synchronization with any other functions, so is almost as fast on SMP +as it would be on UP. +</para> + +<para> +There is a furthur optimization possible here: remember our original +cache code, where there were no reference counts and the caller simply +held the lock whenever using the object? This is still possible: if +you hold the lock, no one can delete the object, so you don't need to +get and put the reference count. +</para> + +<para> +Now, because the 'read lock' in RCU is simply disabling preemption, a +caller which always has preemption disabled between calling +<function>cache_find()</function> and +<function>object_put()</function> does not need to actually get and +put the reference count: we could expose +<function>__cache_find()</function> by making it non-static, and +such callers could simply call that. +</para> +<para> +The benefit here is that the reference count is not written to: the +object is not altered in any way, which is much faster on SMP +machines due to caching. +</para> + </sect1> + + <sect1 id="per-cpu"> + <title>Per-CPU Data</title> + + <para> + Another technique for avoiding locking which is used fairly + widely is to duplicate information for each CPU. For example, + if you wanted to keep a count of a common condition, you could + use a spin lock and a single counter. Nice and simple. + </para> + + <para> + If that was too slow (it's usually not, but if you've got a + really big machine to test on and can show that it is), you + could instead use a counter for each CPU, then none of them need + an exclusive lock. See <function>DEFINE_PER_CPU()</function>, + <function>get_cpu_var()</function> and + <function>put_cpu_var()</function> + (<filename class="headerfile">include/linux/percpu.h</filename>). + </para> + + <para> + Of particular use for simple per-cpu counters is the + <type>local_t</type> type, and the + <function>cpu_local_inc()</function> and related functions, + which are more efficient than simple code on some architectures + (<filename class="headerfile">include/asm/local.h</filename>). + </para> + + <para> + Note that there is no simple, reliable way of getting an exact + value of such a counter, without introducing more locks. This + is not a problem for some uses. + </para> + </sect1> + + <sect1 id="mostly-hardirq"> + <title>Data Which Mostly Used By An IRQ Handler</title> + + <para> + If data is always accessed from within the same IRQ handler, you + don't need a lock at all: the kernel already guarantees that the + irq handler will not run simultaneously on multiple CPUs. + </para> + <para> + Manfred Spraul points out that you can still do this, even if + the data is very occasionally accessed in user context or + softirqs/tasklets. The irq handler doesn't use a lock, and + all other accesses are done as so: + </para> + +<programlisting> + spin_lock(&lock); + disable_irq(irq); + ... + enable_irq(irq); + spin_unlock(&lock); +</programlisting> + <para> + The <function>disable_irq()</function> prevents the irq handler + from running (and waits for it to finish if it's currently + running on other CPUs). The spinlock prevents any other + accesses happening at the same time. Naturally, this is slower + than just a <function>spin_lock_irq()</function> call, so it + only makes sense if this type of access happens extremely + rarely. + </para> + </sect1> + </chapter> + + <chapter id="sleeping-things"> + <title>What Functions Are Safe To Call From Interrupts?</title> + + <para> + Many functions in the kernel sleep (ie. call schedule()) + directly or indirectly: you can never call them while holding a + spinlock, or with preemption disabled. This also means you need + to be in user context: calling them from an interrupt is illegal. + </para> + + <sect1 id="sleeping"> + <title>Some Functions Which Sleep</title> + + <para> + The most common ones are listed below, but you usually have to + read the code to find out if other calls are safe. If everyone + else who calls it can sleep, you probably need to be able to + sleep, too. In particular, registration and deregistration + functions usually expect to be called from user context, and can + sleep. + </para> + + <itemizedlist> + <listitem> + <para> + Accesses to + <firstterm linkend="gloss-userspace">userspace</firstterm>: + </para> + <itemizedlist> + <listitem> + <para> + <function>copy_from_user()</function> + </para> + </listitem> + <listitem> + <para> + <function>copy_to_user()</function> + </para> + </listitem> + <listitem> + <para> + <function>get_user()</function> + </para> + </listitem> + <listitem> + <para> + <function>put_user()</function> + </para> + </listitem> + </itemizedlist> + </listitem> + + <listitem> + <para> + <function>kmalloc(GFP_KERNEL)</function> + </para> + </listitem> + + <listitem> + <para> + <function>mutex_lock_interruptible()</function> and + <function>mutex_lock()</function> + </para> + <para> + There is a <function>mutex_trylock()</function> which does not + sleep. Still, it must not be used inside interrupt context since + its implementation is not safe for that. + <function>mutex_unlock()</function> will also never sleep. + It cannot be used in interrupt context either since a mutex + must be released by the same task that acquired it. + </para> + </listitem> + </itemizedlist> + </sect1> + + <sect1 id="dont-sleep"> + <title>Some Functions Which Don't Sleep</title> + + <para> + Some functions are safe to call from any context, or holding + almost any lock. + </para> + + <itemizedlist> + <listitem> + <para> + <function>printk()</function> + </para> + </listitem> + <listitem> + <para> + <function>kfree()</function> + </para> + </listitem> + <listitem> + <para> + <function>add_timer()</function> and <function>del_timer()</function> + </para> + </listitem> + </itemizedlist> + </sect1> + </chapter> + + <chapter id="apiref"> + <title>Mutex API reference</title> +!Iinclude/linux/mutex.h +!Ekernel/mutex.c + </chapter> + + <chapter id="references"> + <title>Further reading</title> + + <itemizedlist> + <listitem> + <para> + <filename>Documentation/spinlocks.txt</filename>: + Linus Torvalds' spinlocking tutorial in the kernel sources. + </para> + </listitem> + + <listitem> + <para> + Unix Systems for Modern Architectures: Symmetric + Multiprocessing and Caching for Kernel Programmers: + </para> + + <para> + Curt Schimmel's very good introduction to kernel level + locking (not written for Linux, but nearly everything + applies). The book is expensive, but really worth every + penny to understand SMP locking. [ISBN: 0201633388] + </para> + </listitem> + </itemizedlist> + </chapter> + + <chapter id="thanks"> + <title>Thanks</title> + + <para> + Thanks to Telsa Gwynne for DocBooking, neatening and adding + style. + </para> + + <para> + Thanks to Martin Pool, Philipp Rumpf, Stephen Rothwell, Paul + Mackerras, Ruedi Aschwanden, Alan Cox, Manfred Spraul, Tim + Waugh, Pete Zaitcev, James Morris, Robert Love, Paul McKenney, + John Ashby for proofreading, correcting, flaming, commenting. + </para> + + <para> + Thanks to the cabal for having no influence on this document. + </para> + </chapter> + + <glossary id="glossary"> + <title>Glossary</title> + + <glossentry id="gloss-preemption"> + <glossterm>preemption</glossterm> + <glossdef> + <para> + Prior to 2.5, or when <symbol>CONFIG_PREEMPT</symbol> is + unset, processes in user context inside the kernel would not + preempt each other (ie. you had that CPU until you gave it up, + except for interrupts). With the addition of + <symbol>CONFIG_PREEMPT</symbol> in 2.5.4, this changed: when + in user context, higher priority tasks can "cut in": spinlocks + were changed to disable preemption, even on UP. + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-bh"> + <glossterm>bh</glossterm> + <glossdef> + <para> + Bottom Half: for historical reasons, functions with + '_bh' in them often now refer to any software interrupt, e.g. + <function>spin_lock_bh()</function> blocks any software interrupt + on the current CPU. Bottom halves are deprecated, and will + eventually be replaced by tasklets. Only one bottom half will be + running at any time. + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-hwinterrupt"> + <glossterm>Hardware Interrupt / Hardware IRQ</glossterm> + <glossdef> + <para> + Hardware interrupt request. <function>in_irq()</function> returns + <returnvalue>true</returnvalue> in a hardware interrupt handler. + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-interruptcontext"> + <glossterm>Interrupt Context</glossterm> + <glossdef> + <para> + Not user context: processing a hardware irq or software irq. + Indicated by the <function>in_interrupt()</function> macro + returning <returnvalue>true</returnvalue>. + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-smp"> + <glossterm><acronym>SMP</acronym></glossterm> + <glossdef> + <para> + Symmetric Multi-Processor: kernels compiled for multiple-CPU + machines. (CONFIG_SMP=y). + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-softirq"> + <glossterm>Software Interrupt / softirq</glossterm> + <glossdef> + <para> + Software interrupt handler. <function>in_irq()</function> returns + <returnvalue>false</returnvalue>; <function>in_softirq()</function> + returns <returnvalue>true</returnvalue>. Tasklets and softirqs + both fall into the category of 'software interrupts'. + </para> + <para> + Strictly speaking a softirq is one of up to 32 enumerated software + interrupts which can run on multiple CPUs at once. + Sometimes used to refer to tasklets as + well (ie. all software interrupts). + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-tasklet"> + <glossterm>tasklet</glossterm> + <glossdef> + <para> + A dynamically-registrable software interrupt, + which is guaranteed to only run on one CPU at a time. + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-timers"> + <glossterm>timer</glossterm> + <glossdef> + <para> + A dynamically-registrable software interrupt, which is run at + (or close to) a given time. When running, it is just like a + tasklet (in fact, they are called from the TIMER_SOFTIRQ). + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-up"> + <glossterm><acronym>UP</acronym></glossterm> + <glossdef> + <para> + Uni-Processor: Non-SMP. (CONFIG_SMP=n). + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-usercontext"> + <glossterm>User Context</glossterm> + <glossdef> + <para> + The kernel executing on behalf of a particular process (ie. a + system call or trap) or kernel thread. You can tell which + process with the <symbol>current</symbol> macro.) Not to + be confused with userspace. Can be interrupted by software or + hardware interrupts. + </para> + </glossdef> + </glossentry> + + <glossentry id="gloss-userspace"> + <glossterm>Userspace</glossterm> + <glossdef> + <para> + A process executing its own code outside the kernel. + </para> + </glossdef> + </glossentry> + + </glossary> +</book> + diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl new file mode 100644 index 00000000..4ee4ba35 --- /dev/null +++ b/Documentation/DocBook/kgdb.tmpl @@ -0,0 +1,919 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="kgdbOnLinux"> + <bookinfo> + <title>Using kgdb, kdb and the kernel debugger internals</title> + + <authorgroup> + <author> + <firstname>Jason</firstname> + <surname>Wessel</surname> + <affiliation> + <address> + <email>jason.wessel@windriver.com</email> + </address> + </affiliation> + </author> + </authorgroup> + <copyright> + <year>2008,2010</year> + <holder>Wind River Systems, Inc.</holder> + </copyright> + <copyright> + <year>2004-2005</year> + <holder>MontaVista Software, Inc.</holder> + </copyright> + <copyright> + <year>2004</year> + <holder>Amit S. Kale</holder> + </copyright> + + <legalnotice> + <para> + This file is licensed under the terms of the GNU General Public License + version 2. This program is licensed "as is" without any warranty of any + kind, whether express or implied. + </para> + + </legalnotice> + </bookinfo> + +<toc></toc> + <chapter id="Introduction"> + <title>Introduction</title> + <para> + The kernel has two different debugger front ends (kdb and kgdb) + which interface to the debug core. It is possible to use either + of the debugger front ends and dynamically transition between them + if you configure the kernel properly at compile and runtime. + </para> + <para> + Kdb is simplistic shell-style interface which you can use on a + system console with a keyboard or serial console. You can use it + to inspect memory, registers, process lists, dmesg, and even set + breakpoints to stop in a certain location. Kdb is not a source + level debugger, although you can set breakpoints and execute some + basic kernel run control. Kdb is mainly aimed at doing some + analysis to aid in development or diagnosing kernel problems. You + can access some symbols by name in kernel built-ins or in kernel + modules if the code was built + with <symbol>CONFIG_KALLSYMS</symbol>. + </para> + <para> + Kgdb is intended to be used as a source level debugger for the + Linux kernel. It is used along with gdb to debug a Linux kernel. + The expectation is that gdb can be used to "break in" to the + kernel to inspect memory, variables and look through call stack + information similar to the way an application developer would use + gdb to debug an application. It is possible to place breakpoints + in kernel code and perform some limited execution stepping. + </para> + <para> + Two machines are required for using kgdb. One of these machines is + a development machine and the other is the target machine. The + kernel to be debugged runs on the target machine. The development + machine runs an instance of gdb against the vmlinux file which + contains the symbols (not boot image such as bzImage, zImage, + uImage...). In gdb the developer specifies the connection + parameters and connects to kgdb. The type of connection a + developer makes with gdb depends on the availability of kgdb I/O + modules compiled as built-ins or loadable kernel modules in the test + machine's kernel. + </para> + </chapter> + <chapter id="CompilingAKernel"> + <title>Compiling a kernel</title> + <para> + <itemizedlist> + <listitem><para>In order to enable compilation of kdb, you must first enable kgdb.</para></listitem> + <listitem><para>The kgdb test compile options are described in the kgdb test suite chapter.</para></listitem> + </itemizedlist> + </para> + <sect1 id="CompileKGDB"> + <title>Kernel config options for kgdb</title> + <para> + To enable <symbol>CONFIG_KGDB</symbol> you should first turn on + "Prompt for development and/or incomplete code/drivers" + (CONFIG_EXPERIMENTAL) in "General setup", then under the + "Kernel debugging" select "KGDB: kernel debugger". + </para> + <para> + While it is not a hard requirement that you have symbols in your + vmlinux file, gdb tends not to be very useful without the symbolic + data, so you will want to turn + on <symbol>CONFIG_DEBUG_INFO</symbol> which is called "Compile the + kernel with debug info" in the config menu. + </para> + <para> + It is advised, but not required that you turn on the + <symbol>CONFIG_FRAME_POINTER</symbol> kernel option which is called "Compile the + kernel with frame pointers" in the config menu. This option + inserts code to into the compiled executable which saves the frame + information in registers or on the stack at different points which + allows a debugger such as gdb to more accurately construct + stack back traces while debugging the kernel. + </para> + <para> + If the architecture that you are using supports the kernel option + CONFIG_DEBUG_RODATA, you should consider turning it off. This + option will prevent the use of software breakpoints because it + marks certain regions of the kernel's memory space as read-only. + If kgdb supports it for the architecture you are using, you can + use hardware breakpoints if you desire to run with the + CONFIG_DEBUG_RODATA option turned on, else you need to turn off + this option. + </para> + <para> + Next you should choose one of more I/O drivers to interconnect + debugging host and debugged target. Early boot debugging requires + a KGDB I/O driver that supports early debugging and the driver + must be built into the kernel directly. Kgdb I/O driver + configuration takes place via kernel or module parameters which + you can learn more about in the in the section that describes the + parameter "kgdboc". + </para> + <para>Here is an example set of .config symbols to enable or + disable for kgdb: + <itemizedlist> + <listitem><para># CONFIG_DEBUG_RODATA is not set</para></listitem> + <listitem><para>CONFIG_FRAME_POINTER=y</para></listitem> + <listitem><para>CONFIG_KGDB=y</para></listitem> + <listitem><para>CONFIG_KGDB_SERIAL_CONSOLE=y</para></listitem> + </itemizedlist> + </para> + </sect1> + <sect1 id="CompileKDB"> + <title>Kernel config options for kdb</title> + <para>Kdb is quite a bit more complex than the simple gdbstub + sitting on top of the kernel's debug core. Kdb must implement a + shell, and also adds some helper functions in other parts of the + kernel, responsible for printing out interesting data such as what + you would see if you ran "lsmod", or "ps". In order to build kdb + into the kernel you follow the same steps as you would for kgdb. + </para> + <para>The main config option for kdb + is <symbol>CONFIG_KGDB_KDB</symbol> which is called "KGDB_KDB: + include kdb frontend for kgdb" in the config menu. In theory you + would have already also selected an I/O driver such as the + CONFIG_KGDB_SERIAL_CONSOLE interface if you plan on using kdb on a + serial port, when you were configuring kgdb. + </para> + <para>If you want to use a PS/2-style keyboard with kdb, you would + select CONFIG_KDB_KEYBOARD which is called "KGDB_KDB: keyboard as + input device" in the config menu. The CONFIG_KDB_KEYBOARD option + is not used for anything in the gdb interface to kgdb. The + CONFIG_KDB_KEYBOARD option only works with kdb. + </para> + <para>Here is an example set of .config symbols to enable/disable kdb: + <itemizedlist> + <listitem><para># CONFIG_DEBUG_RODATA is not set</para></listitem> + <listitem><para>CONFIG_FRAME_POINTER=y</para></listitem> + <listitem><para>CONFIG_KGDB=y</para></listitem> + <listitem><para>CONFIG_KGDB_SERIAL_CONSOLE=y</para></listitem> + <listitem><para>CONFIG_KGDB_KDB=y</para></listitem> + <listitem><para>CONFIG_KDB_KEYBOARD=y</para></listitem> + </itemizedlist> + </para> + </sect1> + </chapter> + <chapter id="kgdbKernelArgs"> + <title>Kernel Debugger Boot Arguments</title> + <para>This section describes the various runtime kernel + parameters that affect the configuration of the kernel debugger. + The following chapter covers using kdb and kgdb as well as + provides some examples of the configuration parameters.</para> + <sect1 id="kgdboc"> + <title>Kernel parameter: kgdboc</title> + <para>The kgdboc driver was originally an abbreviation meant to + stand for "kgdb over console". Today it is the primary mechanism + to configure how to communicate from gdb to kgdb as well as the + devices you want to use to interact with the kdb shell. + </para> + <para>For kgdb/gdb, kgdboc is designed to work with a single serial + port. It is intended to cover the circumstance where you want to + use a serial console as your primary console as well as using it to + perform kernel debugging. It is also possible to use kgdb on a + serial port which is not designated as a system console. Kgdboc + may be configured as a kernel built-in or a kernel loadable module. + You can only make use of <constant>kgdbwait</constant> and early + debugging if you build kgdboc into the kernel as a built-in. + <para>Optionally you can elect to activate kms (Kernel Mode + Setting) integration. When you use kms with kgdboc and you have a + video driver that has atomic mode setting hooks, it is possible to + enter the debugger on the graphics console. When the kernel + execution is resumed, the previous graphics mode will be restored. + This integration can serve as a useful tool to aid in diagnosing + crashes or doing analysis of memory with kdb while allowing the + full graphics console applications to run. + </para> + </para> + <sect2 id="kgdbocArgs"> + <title>kgdboc arguments</title> + <para>Usage: <constant>kgdboc=[kms][[,]kbd][[,]serial_device][,baud]</constant></para> + <para>The order listed above must be observed if you use any of the + optional configurations together. + </para> + <para>Abbreviations: + <itemizedlist> + <listitem><para>kms = Kernel Mode Setting</para></listitem> + <listitem><para>kbd = Keyboard</para></listitem> + </itemizedlist> + </para> + <para>You can configure kgdboc to use the keyboard, and or a serial + device depending on if you are using kdb and or kgdb, in one of the + following scenarios. The order listed above must be observed if + you use any of the optional configurations together. Using kms + + only gdb is generally not a useful combination.</para> + <sect3 id="kgdbocArgs1"> + <title>Using loadable module or built-in</title> + <para> + <orderedlist> + <listitem><para>As a kernel built-in:</para> + <para>Use the kernel boot argument: <constant>kgdboc=<tty-device>,[baud]</constant></para></listitem> + <listitem> + <para>As a kernel loadable module:</para> + <para>Use the command: <constant>modprobe kgdboc kgdboc=<tty-device>,[baud]</constant></para> + <para>Here are two examples of how you might format the kgdboc + string. The first is for an x86 target using the first serial port. + The second example is for the ARM Versatile AB using the second + serial port. + <orderedlist> + <listitem><para><constant>kgdboc=ttyS0,115200</constant></para></listitem> + <listitem><para><constant>kgdboc=ttyAMA1,115200</constant></para></listitem> + </orderedlist> + </para> + </listitem> + </orderedlist></para> + </sect3> + <sect3 id="kgdbocArgs2"> + <title>Configure kgdboc at runtime with sysfs</title> + <para>At run time you can enable or disable kgdboc by echoing a + parameters into the sysfs. Here are two examples:</para> + <orderedlist> + <listitem><para>Enable kgdboc on ttyS0</para> + <para><constant>echo ttyS0 > /sys/module/kgdboc/parameters/kgdboc</constant></para></listitem> + <listitem><para>Disable kgdboc</para> + <para><constant>echo "" > /sys/module/kgdboc/parameters/kgdboc</constant></para></listitem> + </orderedlist> + <para>NOTE: You do not need to specify the baud if you are + configuring the console on tty which is already configured or + open.</para> + </sect3> + <sect3 id="kgdbocArgs3"> + <title>More examples</title> + <para>You can configure kgdboc to use the keyboard, and or a serial + device depending on if you are using kdb and or kgdb, in one of the + following scenarios.</para> + <para>You can configure kgdboc to use the keyboard, and or a serial device + depending on if you are using kdb and or kgdb, in one of the + following scenarios. + <orderedlist> + <listitem><para>kdb and kgdb over only a serial port</para> + <para><constant>kgdboc=<serial_device>[,baud]</constant></para> + <para>Example: <constant>kgdboc=ttyS0,115200</constant></para> + </listitem> + <listitem><para>kdb and kgdb with keyboard and a serial port</para> + <para><constant>kgdboc=kbd,<serial_device>[,baud]</constant></para> + <para>Example: <constant>kgdboc=kbd,ttyS0,115200</constant></para> + </listitem> + <listitem><para>kdb with a keyboard</para> + <para><constant>kgdboc=kbd</constant></para> + </listitem> + <listitem><para>kdb with kernel mode setting</para> + <para><constant>kgdboc=kms,kbd</constant></para> + </listitem> + <listitem><para>kdb with kernel mode setting and kgdb over a serial port</para> + <para><constant>kgdboc=kms,kbd,ttyS0,115200</constant></para> + </listitem> + </orderedlist> + </para> + </sect3> + <para>NOTE: Kgdboc does not support interrupting the target via the + gdb remote protocol. You must manually send a sysrq-g unless you + have a proxy that splits console output to a terminal program. + A console proxy has a separate TCP port for the debugger and a separate + TCP port for the "human" console. The proxy can take care of sending + the sysrq-g for you. + </para> + <para>When using kgdboc with no debugger proxy, you can end up + connecting the debugger at one of two entry points. If an + exception occurs after you have loaded kgdboc, a message should + print on the console stating it is waiting for the debugger. In + this case you disconnect your terminal program and then connect the + debugger in its place. If you want to interrupt the target system + and forcibly enter a debug session you have to issue a Sysrq + sequence and then type the letter <constant>g</constant>. Then + you disconnect the terminal session and connect gdb. Your options + if you don't like this are to hack gdb to send the sysrq-g for you + as well as on the initial connect, or to use a debugger proxy that + allows an unmodified gdb to do the debugging. + </para> + </sect2> + </sect1> + <sect1 id="kgdbwait"> + <title>Kernel parameter: kgdbwait</title> + <para> + The Kernel command line option <constant>kgdbwait</constant> makes + kgdb wait for a debugger connection during booting of a kernel. You + can only use this option you compiled a kgdb I/O driver into the + kernel and you specified the I/O driver configuration as a kernel + command line option. The kgdbwait parameter should always follow the + configuration parameter for the kgdb I/O driver in the kernel + command line else the I/O driver will not be configured prior to + asking the kernel to use it to wait. + </para> + <para> + The kernel will stop and wait as early as the I/O driver and + architecture allows when you use this option. If you build the + kgdb I/O driver as a loadable kernel module kgdbwait will not do + anything. + </para> + </sect1> + <sect1 id="kgdbcon"> + <title>Kernel parameter: kgdbcon</title> + <para> The kgdbcon feature allows you to see printk() messages + inside gdb while gdb is connected to the kernel. Kdb does not make + use of the kgdbcon feature. + </para> + <para>Kgdb supports using the gdb serial protocol to send console + messages to the debugger when the debugger is connected and running. + There are two ways to activate this feature. + <orderedlist> + <listitem><para>Activate with the kernel command line option:</para> + <para><constant>kgdbcon</constant></para> + </listitem> + <listitem><para>Use sysfs before configuring an I/O driver</para> + <para> + <constant>echo 1 > /sys/module/kgdb/parameters/kgdb_use_con</constant> + </para> + <para> + NOTE: If you do this after you configure the kgdb I/O driver, the + setting will not take effect until the next point the I/O is + reconfigured. + </para> + </listitem> + </orderedlist> + <para>IMPORTANT NOTE: You cannot use kgdboc + kgdbcon on a tty that is an + active system console. An example incorrect usage is <constant>console=ttyS0,115200 kgdboc=ttyS0 kgdbcon</constant> + </para> + <para>It is possible to use this option with kgdboc on a tty that is not a system console. + </para> + </para> + </sect1> + <sect1 id="kgdbreboot"> + <title>Run time parameter: kgdbreboot</title> + <para> The kgdbreboot feature allows you to change how the debugger + deals with the reboot notification. You have 3 choices for the + behavior. The default behavior is always set to 0.</para> + <orderedlist> + <listitem><para>echo -1 > /sys/module/debug_core/parameters/kgdbreboot</para> + <para>Ignore the reboot notification entirely.</para> + </listitem> + <listitem><para>echo 0 > /sys/module/debug_core/parameters/kgdbreboot</para> + <para>Send the detach message to any attached debugger client.</para> + </listitem> + <listitem><para>echo 1 > /sys/module/debug_core/parameters/kgdbreboot</para> + <para>Enter the debugger on reboot notify.</para> + </listitem> + </orderedlist> + </sect1> + </chapter> + <chapter id="usingKDB"> + <title>Using kdb</title> + <para> + </para> + <sect1 id="quickKDBserial"> + <title>Quick start for kdb on a serial port</title> + <para>This is a quick example of how to use kdb.</para> + <para><orderedlist> + <listitem><para>Boot kernel with arguments: + <itemizedlist> + <listitem><para><constant>console=ttyS0,115200 kgdboc=ttyS0,115200</constant></para></listitem> + </itemizedlist></para> + <para>OR</para> + <para>Configure kgdboc after the kernel booted; assuming you are using a serial port console: + <itemizedlist> + <listitem><para><constant>echo ttyS0 > /sys/module/kgdboc/parameters/kgdboc</constant></para></listitem> + </itemizedlist> + </para> + </listitem> + <listitem><para>Enter the kernel debugger manually or by waiting for an oops or fault. There are several ways you can enter the kernel debugger manually; all involve using the sysrq-g, which means you must have enabled CONFIG_MAGIC_SYSRQ=y in your kernel config.</para> + <itemizedlist> + <listitem><para>When logged in as root or with a super user session you can run:</para> + <para><constant>echo g > /proc/sysrq-trigger</constant></para></listitem> + <listitem><para>Example using minicom 2.2</para> + <para>Press: <constant>Control-a</constant></para> + <para>Press: <constant>f</constant></para> + <para>Press: <constant>g</constant></para> + </listitem> + <listitem><para>When you have telneted to a terminal server that supports sending a remote break</para> + <para>Press: <constant>Control-]</constant></para> + <para>Type in:<constant>send break</constant></para> + <para>Press: <constant>Enter</constant></para> + <para>Press: <constant>g</constant></para> + </listitem> + </itemizedlist> + </listitem> + <listitem><para>From the kdb prompt you can run the "help" command to see a complete list of the commands that are available.</para> + <para>Some useful commands in kdb include: + <itemizedlist> + <listitem><para>lsmod -- Shows where kernel modules are loaded</para></listitem> + <listitem><para>ps -- Displays only the active processes</para></listitem> + <listitem><para>ps A -- Shows all the processes</para></listitem> + <listitem><para>summary -- Shows kernel version info and memory usage</para></listitem> + <listitem><para>bt -- Get a backtrace of the current process using dump_stack()</para></listitem> + <listitem><para>dmesg -- View the kernel syslog buffer</para></listitem> + <listitem><para>go -- Continue the system</para></listitem> + </itemizedlist> + </para> + </listitem> + <listitem> + <para>When you are done using kdb you need to consider rebooting the + system or using the "go" command to resuming normal kernel + execution. If you have paused the kernel for a lengthy period of + time, applications that rely on timely networking or anything to do + with real wall clock time could be adversely affected, so you + should take this into consideration when using the kernel + debugger.</para> + </listitem> + </orderedlist></para> + </sect1> + <sect1 id="quickKDBkeyboard"> + <title>Quick start for kdb using a keyboard connected console</title> + <para>This is a quick example of how to use kdb with a keyboard.</para> + <para><orderedlist> + <listitem><para>Boot kernel with arguments: + <itemizedlist> + <listitem><para><constant>kgdboc=kbd</constant></para></listitem> + </itemizedlist></para> + <para>OR</para> + <para>Configure kgdboc after the kernel booted: + <itemizedlist> + <listitem><para><constant>echo kbd > /sys/module/kgdboc/parameters/kgdboc</constant></para></listitem> + </itemizedlist> + </para> + </listitem> + <listitem><para>Enter the kernel debugger manually or by waiting for an oops or fault. There are several ways you can enter the kernel debugger manually; all involve using the sysrq-g, which means you must have enabled CONFIG_MAGIC_SYSRQ=y in your kernel config.</para> + <itemizedlist> + <listitem><para>When logged in as root or with a super user session you can run:</para> + <para><constant>echo g > /proc/sysrq-trigger</constant></para></listitem> + <listitem><para>Example using a laptop keyboard</para> + <para>Press and hold down: <constant>Alt</constant></para> + <para>Press and hold down: <constant>Fn</constant></para> + <para>Press and release the key with the label: <constant>SysRq</constant></para> + <para>Release: <constant>Fn</constant></para> + <para>Press and release: <constant>g</constant></para> + <para>Release: <constant>Alt</constant></para> + </listitem> + <listitem><para>Example using a PS/2 101-key keyboard</para> + <para>Press and hold down: <constant>Alt</constant></para> + <para>Press and release the key with the label: <constant>SysRq</constant></para> + <para>Press and release: <constant>g</constant></para> + <para>Release: <constant>Alt</constant></para> + </listitem> + </itemizedlist> + </listitem> + <listitem> + <para>Now type in a kdb command such as "help", "dmesg", "bt" or "go" to continue kernel execution.</para> + </listitem> + </orderedlist></para> + </sect1> + </chapter> + <chapter id="EnableKGDB"> + <title>Using kgdb / gdb</title> + <para>In order to use kgdb you must activate it by passing + configuration information to one of the kgdb I/O drivers. If you + do not pass any configuration information kgdb will not do anything + at all. Kgdb will only actively hook up to the kernel trap hooks + if a kgdb I/O driver is loaded and configured. If you unconfigure + a kgdb I/O driver, kgdb will unregister all the kernel hook points. + </para> + <para> All kgdb I/O drivers can be reconfigured at run time, if + <symbol>CONFIG_SYSFS</symbol> and <symbol>CONFIG_MODULES</symbol> + are enabled, by echo'ing a new config string to + <constant>/sys/module/<driver>/parameter/<option></constant>. + The driver can be unconfigured by passing an empty string. You cannot + change the configuration while the debugger is attached. Make sure + to detach the debugger with the <constant>detach</constant> command + prior to trying to unconfigure a kgdb I/O driver. + </para> + <sect1 id="ConnectingGDB"> + <title>Connecting with gdb to a serial port</title> + <orderedlist> + <listitem><para>Configure kgdboc</para> + <para>Boot kernel with arguments: + <itemizedlist> + <listitem><para><constant>kgdboc=ttyS0,115200</constant></para></listitem> + </itemizedlist></para> + <para>OR</para> + <para>Configure kgdboc after the kernel booted: + <itemizedlist> + <listitem><para><constant>echo ttyS0 > /sys/module/kgdboc/parameters/kgdboc</constant></para></listitem> + </itemizedlist></para> + </listitem> + <listitem> + <para>Stop kernel execution (break into the debugger)</para> + <para>In order to connect to gdb via kgdboc, the kernel must + first be stopped. There are several ways to stop the kernel which + include using kgdbwait as a boot argument, via a sysrq-g, or running + the kernel until it takes an exception where it waits for the + debugger to attach. + <itemizedlist> + <listitem><para>When logged in as root or with a super user session you can run:</para> + <para><constant>echo g > /proc/sysrq-trigger</constant></para></listitem> + <listitem><para>Example using minicom 2.2</para> + <para>Press: <constant>Control-a</constant></para> + <para>Press: <constant>f</constant></para> + <para>Press: <constant>g</constant></para> + </listitem> + <listitem><para>When you have telneted to a terminal server that supports sending a remote break</para> + <para>Press: <constant>Control-]</constant></para> + <para>Type in:<constant>send break</constant></para> + <para>Press: <constant>Enter</constant></para> + <para>Press: <constant>g</constant></para> + </listitem> + </itemizedlist> + </para> + </listitem> + <listitem> + <para>Connect from from gdb</para> + <para> + Example (using a directly connected port): + </para> + <programlisting> + % gdb ./vmlinux + (gdb) set remotebaud 115200 + (gdb) target remote /dev/ttyS0 + </programlisting> + <para> + Example (kgdb to a terminal server on TCP port 2012): + </para> + <programlisting> + % gdb ./vmlinux + (gdb) target remote 192.168.2.2:2012 + </programlisting> + <para> + Once connected, you can debug a kernel the way you would debug an + application program. + </para> + <para> + If you are having problems connecting or something is going + seriously wrong while debugging, it will most often be the case + that you want to enable gdb to be verbose about its target + communications. You do this prior to issuing the <constant>target + remote</constant> command by typing in: <constant>set debug remote 1</constant> + </para> + </listitem> + </orderedlist> + <para>Remember if you continue in gdb, and need to "break in" again, + you need to issue an other sysrq-g. It is easy to create a simple + entry point by putting a breakpoint at <constant>sys_sync</constant> + and then you can run "sync" from a shell or script to break into the + debugger.</para> + </sect1> + </chapter> + <chapter id="switchKdbKgdb"> + <title>kgdb and kdb interoperability</title> + <para>It is possible to transition between kdb and kgdb dynamically. + The debug core will remember which you used the last time and + automatically start in the same mode.</para> + <sect1> + <title>Switching between kdb and kgdb</title> + <sect2> + <title>Switching from kgdb to kdb</title> + <para> + There are two ways to switch from kgdb to kdb: you can use gdb to + issue a maintenance packet, or you can blindly type the command $3#33. + Whenever kernel debugger stops in kgdb mode it will print the + message <constant>KGDB or $3#33 for KDB</constant>. It is important + to note that you have to type the sequence correctly in one pass. + You cannot type a backspace or delete because kgdb will interpret + that as part of the debug stream. + <orderedlist> + <listitem><para>Change from kgdb to kdb by blindly typing:</para> + <para><constant>$3#33</constant></para></listitem> + <listitem><para>Change from kgdb to kdb with gdb</para> + <para><constant>maintenance packet 3</constant></para> + <para>NOTE: Now you must kill gdb. Typically you press control-z and + issue the command: kill -9 %</para></listitem> + </orderedlist> + </para> + </sect2> + <sect2> + <title>Change from kdb to kgdb</title> + <para>There are two ways you can change from kdb to kgdb. You can + manually enter kgdb mode by issuing the kgdb command from the kdb + shell prompt, or you can connect gdb while the kdb shell prompt is + active. The kdb shell looks for the typical first commands that gdb + would issue with the gdb remote protocol and if it sees one of those + commands it automatically changes into kgdb mode.</para> + <orderedlist> + <listitem><para>From kdb issue the command:</para> + <para><constant>kgdb</constant></para> + <para>Now disconnect your terminal program and connect gdb in its place</para></listitem> + <listitem><para>At the kdb prompt, disconnect the terminal program and connect gdb in its place.</para></listitem> + </orderedlist> + </sect2> + </sect1> + <sect1> + <title>Running kdb commands from gdb</title> + <para>It is possible to run a limited set of kdb commands from gdb, + using the gdb monitor command. You don't want to execute any of the + run control or breakpoint operations, because it can disrupt the + state of the kernel debugger. You should be using gdb for + breakpoints and run control operations if you have gdb connected. + The more useful commands to run are things like lsmod, dmesg, ps or + possibly some of the memory information commands. To see all the kdb + commands you can run <constant>monitor help</constant>.</para> + <para>Example: + <informalexample><programlisting> +(gdb) monitor ps +1 idle process (state I) and +27 sleeping system daemon (state M) processes suppressed, +use 'ps A' to see all. +Task Addr Pid Parent [*] cpu State Thread Command + +0xc78291d0 1 0 0 0 S 0xc7829404 init +0xc7954150 942 1 0 0 S 0xc7954384 dropbear +0xc78789c0 944 1 0 0 S 0xc7878bf4 sh +(gdb) + </programlisting></informalexample> + </para> + </sect1> + </chapter> + <chapter id="KGDBTestSuite"> + <title>kgdb Test Suite</title> + <para> + When kgdb is enabled in the kernel config you can also elect to + enable the config parameter KGDB_TESTS. Turning this on will + enable a special kgdb I/O module which is designed to test the + kgdb internal functions. + </para> + <para> + The kgdb tests are mainly intended for developers to test the kgdb + internals as well as a tool for developing a new kgdb architecture + specific implementation. These tests are not really for end users + of the Linux kernel. The primary source of documentation would be + to look in the drivers/misc/kgdbts.c file. + </para> + <para> + The kgdb test suite can also be configured at compile time to run + the core set of tests by setting the kernel config parameter + KGDB_TESTS_ON_BOOT. This particular option is aimed at automated + regression testing and does not require modifying the kernel boot + config arguments. If this is turned on, the kgdb test suite can + be disabled by specifying "kgdbts=" as a kernel boot argument. + </para> + </chapter> + <chapter id="CommonBackEndReq"> + <title>Kernel Debugger Internals</title> + <sect1 id="kgdbArchitecture"> + <title>Architecture Specifics</title> + <para> + The kernel debugger is organized into a number of components: + <orderedlist> + <listitem><para>The debug core</para> + <para> + The debug core is found in kernel/debugger/debug_core.c. It contains: + <itemizedlist> + <listitem><para>A generic OS exception handler which includes + sync'ing the processors into a stopped state on an multi-CPU + system.</para></listitem> + <listitem><para>The API to talk to the kgdb I/O drivers</para></listitem> + <listitem><para>The API to make calls to the arch-specific kgdb implementation</para></listitem> + <listitem><para>The logic to perform safe memory reads and writes to memory while using the debugger</para></listitem> + <listitem><para>A full implementation for software breakpoints unless overridden by the arch</para></listitem> + <listitem><para>The API to invoke either the kdb or kgdb frontend to the debug core.</para></listitem> + <listitem><para>The structures and callback API for atomic kernel mode setting.</para> + <para>NOTE: kgdboc is where the kms callbacks are invoked.</para></listitem> + </itemizedlist> + </para> + </listitem> + <listitem><para>kgdb arch-specific implementation</para> + <para> + This implementation is generally found in arch/*/kernel/kgdb.c. + As an example, arch/x86/kernel/kgdb.c contains the specifics to + implement HW breakpoint as well as the initialization to + dynamically register and unregister for the trap handlers on + this architecture. The arch-specific portion implements: + <itemizedlist> + <listitem><para>contains an arch-specific trap catcher which + invokes kgdb_handle_exception() to start kgdb about doing its + work</para></listitem> + <listitem><para>translation to and from gdb specific packet format to pt_regs</para></listitem> + <listitem><para>Registration and unregistration of architecture specific trap hooks</para></listitem> + <listitem><para>Any special exception handling and cleanup</para></listitem> + <listitem><para>NMI exception handling and cleanup</para></listitem> + <listitem><para>(optional)HW breakpoints</para></listitem> + </itemizedlist> + </para> + </listitem> + <listitem><para>gdbstub frontend (aka kgdb)</para> + <para>The gdbstub is located in kernel/debug/gdbstub.c. It contains:</para> + <itemizedlist> + <listitem><para>All the logic to implement the gdb serial protocol</para></listitem> + </itemizedlist> + </listitem> + <listitem><para>kdb frontend</para> + <para>The kdb debugger shell is broken down into a number of + components. The kdb core is located in kernel/debug/kdb. There + are a number of helper functions in some of the other kernel + components to make it possible for kdb to examine and report + information about the kernel without taking locks that could + cause a kernel deadlock. The kdb core contains implements the following functionality.</para> + <itemizedlist> + <listitem><para>A simple shell</para></listitem> + <listitem><para>The kdb core command set</para></listitem> + <listitem><para>A registration API to register additional kdb shell commands.</para> + <itemizedlist> + <listitem><para>A good example of a self-contained kdb module + is the "ftdump" command for dumping the ftrace buffer. See: + kernel/trace/trace_kdb.c</para></listitem> + <listitem><para>For an example of how to dynamically register + a new kdb command you can build the kdb_hello.ko kernel module + from samples/kdb/kdb_hello.c. To build this example you can + set CONFIG_SAMPLES=y and CONFIG_SAMPLE_KDB=m in your kernel + config. Later run "modprobe kdb_hello" and the next time you + enter the kdb shell, you can run the "hello" + command.</para></listitem> + </itemizedlist></listitem> + <listitem><para>The implementation for kdb_printf() which + emits messages directly to I/O drivers, bypassing the kernel + log.</para></listitem> + <listitem><para>SW / HW breakpoint management for the kdb shell</para></listitem> + </itemizedlist> + </listitem> + <listitem><para>kgdb I/O driver</para> + <para> + Each kgdb I/O driver has to provide an implementation for the following: + <itemizedlist> + <listitem><para>configuration via built-in or module</para></listitem> + <listitem><para>dynamic configuration and kgdb hook registration calls</para></listitem> + <listitem><para>read and write character interface</para></listitem> + <listitem><para>A cleanup handler for unconfiguring from the kgdb core</para></listitem> + <listitem><para>(optional) Early debug methodology</para></listitem> + </itemizedlist> + Any given kgdb I/O driver has to operate very closely with the + hardware and must do it in such a way that does not enable + interrupts or change other parts of the system context without + completely restoring them. The kgdb core will repeatedly "poll" + a kgdb I/O driver for characters when it needs input. The I/O + driver is expected to return immediately if there is no data + available. Doing so allows for the future possibility to touch + watch dog hardware in such a way as to have a target system not + reset when these are enabled. + </para> + </listitem> + </orderedlist> + </para> + <para> + If you are intent on adding kgdb architecture specific support + for a new architecture, the architecture should define + <constant>HAVE_ARCH_KGDB</constant> in the architecture specific + Kconfig file. This will enable kgdb for the architecture, and + at that point you must create an architecture specific kgdb + implementation. + </para> + <para> + There are a few flags which must be set on every architecture in + their <asm/kgdb.h> file. These are: + <itemizedlist> + <listitem> + <para> + NUMREGBYTES: The size in bytes of all of the registers, so + that we can ensure they will all fit into a packet. + </para> + <para> + BUFMAX: The size in bytes of the buffer GDB will read into. + This must be larger than NUMREGBYTES. + </para> + <para> + CACHE_FLUSH_IS_SAFE: Set to 1 if it is always safe to call + flush_cache_range or flush_icache_range. On some architectures, + these functions may not be safe to call on SMP since we keep other + CPUs in a holding pattern. + </para> + </listitem> + </itemizedlist> + </para> + <para> + There are also the following functions for the common backend, + found in kernel/kgdb.c, that must be supplied by the + architecture-specific backend unless marked as (optional), in + which case a default function maybe used if the architecture + does not need to provide a specific implementation. + </para> +!Iinclude/linux/kgdb.h + </sect1> + <sect1 id="kgdbocDesign"> + <title>kgdboc internals</title> + <sect2> + <title>kgdboc and uarts</title> + <para> + The kgdboc driver is actually a very thin driver that relies on the + underlying low level to the hardware driver having "polling hooks" + which the to which the tty driver is attached. In the initial + implementation of kgdboc it the serial_core was changed to expose a + low level UART hook for doing polled mode reading and writing of a + single character while in an atomic context. When kgdb makes an I/O + request to the debugger, kgdboc invokes a callback in the serial + core which in turn uses the callback in the UART driver.</para> + <para> + When using kgdboc with a UART, the UART driver must implement two callbacks in the <constant>struct uart_ops</constant>. Example from drivers/8250.c:<programlisting> +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif + </programlisting> + Any implementation specifics around creating a polling driver use the + <constant>#ifdef CONFIG_CONSOLE_POLL</constant>, as shown above. + Keep in mind that polling hooks have to be implemented in such a way + that they can be called from an atomic context and have to restore + the state of the UART chip on return such that the system can return + to normal when the debugger detaches. You need to be very careful + with any kind of lock you consider, because failing here is most likely + going to mean pressing the reset button. + </para> + </sect2> + <sect2 id="kgdbocKbd"> + <title>kgdboc and keyboards</title> + <para>The kgdboc driver contains logic to configure communications + with an attached keyboard. The keyboard infrastructure is only + compiled into the kernel when CONFIG_KDB_KEYBOARD=y is set in the + kernel configuration.</para> + <para>The core polled keyboard driver driver for PS/2 type keyboards + is in drivers/char/kdb_keyboard.c. This driver is hooked into the + debug core when kgdboc populates the callback in the array + called <constant>kdb_poll_funcs[]</constant>. The + kdb_get_kbd_char() is the top-level function which polls hardware + for single character input. + </para> + </sect2> + <sect2 id="kgdbocKms"> + <title>kgdboc and kms</title> + <para>The kgdboc driver contains logic to request the graphics + display to switch to a text context when you are using + "kgdboc=kms,kbd", provided that you have a video driver which has a + frame buffer console and atomic kernel mode setting support.</para> + <para> + Every time the kernel + debugger is entered it calls kgdboc_pre_exp_handler() which in turn + calls con_debug_enter() in the virtual console layer. On resuming kernel + execution, the kernel debugger calls kgdboc_post_exp_handler() which + in turn calls con_debug_leave().</para> + <para>Any video driver that wants to be compatible with the kernel + debugger and the atomic kms callbacks must implement the + mode_set_base_atomic, fb_debug_enter and fb_debug_leave operations. + For the fb_debug_enter and fb_debug_leave the option exists to use + the generic drm fb helper functions or implement something custom for + the hardware. The following example shows the initialization of the + .mode_set_base_atomic operation in + drivers/gpu/drm/i915/intel_display.c: + <informalexample> + <programlisting> +static const struct drm_crtc_helper_funcs intel_helper_funcs = { +[...] + .mode_set_base_atomic = intel_pipe_set_base_atomic, +[...] +}; + </programlisting> + </informalexample> + </para> + <para>Here is an example of how the i915 driver initializes the fb_debug_enter and fb_debug_leave functions to use the generic drm helpers in + drivers/gpu/drm/i915/intel_fb.c: + <informalexample> + <programlisting> +static struct fb_ops intelfb_ops = { +[...] + .fb_debug_enter = drm_fb_helper_debug_enter, + .fb_debug_leave = drm_fb_helper_debug_leave, +[...] +}; + </programlisting> + </informalexample> + </para> + </sect2> + </sect1> + </chapter> + <chapter id="credits"> + <title>Credits</title> + <para> + The following people have contributed to this document: + <orderedlist> + <listitem><para>Amit Kale<email>amitkale@linsyssoft.com</email></para></listitem> + <listitem><para>Tom Rini<email>trini@kernel.crashing.org</email></para></listitem> + </orderedlist> + In March 2008 this document was completely rewritten by: + <itemizedlist> + <listitem><para>Jason Wessel<email>jason.wessel@windriver.com</email></para></listitem> + </itemizedlist> + In Jan 2010 this document was updated to include kdb. + <itemizedlist> + <listitem><para>Jason Wessel<email>jason.wessel@windriver.com</email></para></listitem> + </itemizedlist> + </para> + </chapter> +</book> + diff --git a/Documentation/DocBook/libata.tmpl b/Documentation/DocBook/libata.tmpl new file mode 100644 index 00000000..31df1aa0 --- /dev/null +++ b/Documentation/DocBook/libata.tmpl @@ -0,0 +1,1625 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="libataDevGuide"> + <bookinfo> + <title>libATA Developer's Guide</title> + + <authorgroup> + <author> + <firstname>Jeff</firstname> + <surname>Garzik</surname> + </author> + </authorgroup> + + <copyright> + <year>2003-2006</year> + <holder>Jeff Garzik</holder> + </copyright> + + <legalnotice> + <para> + The contents of this file are subject to the Open + Software License version 1.1 that can be found at + <ulink url="http://fedoraproject.org/wiki/Licensing:OSL1.1">http://fedoraproject.org/wiki/Licensing:OSL1.1</ulink> + and is included herein by reference. + </para> + + <para> + Alternatively, the contents of this file may be used under the terms + of the GNU General Public License version 2 (the "GPL") as distributed + in the kernel source COPYING file, in which case the provisions of + the GPL are applicable instead of the above. If you wish to allow + the use of your version of this file only under the terms of the + GPL and not to allow others to use your version of this file under + the OSL, indicate your decision by deleting the provisions above and + replace them with the notice and other provisions required by the GPL. + If you do not delete the provisions above, a recipient may use your + version of this file under either the OSL or the GPL. + </para> + + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="libataIntroduction"> + <title>Introduction</title> + <para> + libATA is a library used inside the Linux kernel to support ATA host + controllers and devices. libATA provides an ATA driver API, class + transports for ATA and ATAPI devices, and SCSI<->ATA translation + for ATA devices according to the T10 SAT specification. + </para> + <para> + This Guide documents the libATA driver API, library functions, library + internals, and a couple sample ATA low-level drivers. + </para> + </chapter> + + <chapter id="libataDriverApi"> + <title>libata Driver API</title> + <para> + struct ata_port_operations is defined for every low-level libata + hardware driver, and it controls how the low-level driver + interfaces with the ATA and SCSI layers. + </para> + <para> + FIS-based drivers will hook into the system with ->qc_prep() and + ->qc_issue() high-level hooks. Hardware which behaves in a manner + similar to PCI IDE hardware may utilize several generic helpers, + defining at a bare minimum the bus I/O addresses of the ATA shadow + register blocks. + </para> + <sect1> + <title>struct ata_port_operations</title> + + <sect2><title>Disable ATA port</title> + <programlisting> +void (*port_disable) (struct ata_port *); + </programlisting> + + <para> + Called from ata_bus_probe() error path, as well as when + unregistering from the SCSI module (rmmod, hot unplug). + This function should do whatever needs to be done to take the + port out of use. In most cases, ata_port_disable() can be used + as this hook. + </para> + <para> + Called from ata_bus_probe() on a failed probe. + Called from ata_scsi_release(). + </para> + + </sect2> + + <sect2><title>Post-IDENTIFY device configuration</title> + <programlisting> +void (*dev_config) (struct ata_port *, struct ata_device *); + </programlisting> + + <para> + Called after IDENTIFY [PACKET] DEVICE is issued to each device + found. Typically used to apply device-specific fixups prior to + issue of SET FEATURES - XFER MODE, and prior to operation. + </para> + <para> + This entry may be specified as NULL in ata_port_operations. + </para> + + </sect2> + + <sect2><title>Set PIO/DMA mode</title> + <programlisting> +void (*set_piomode) (struct ata_port *, struct ata_device *); +void (*set_dmamode) (struct ata_port *, struct ata_device *); +void (*post_set_mode) (struct ata_port *); +unsigned int (*mode_filter) (struct ata_port *, struct ata_device *, unsigned int); + </programlisting> + + <para> + Hooks called prior to the issue of SET FEATURES - XFER MODE + command. The optional ->mode_filter() hook is called when libata + has built a mask of the possible modes. This is passed to the + ->mode_filter() function which should return a mask of valid modes + after filtering those unsuitable due to hardware limits. It is not + valid to use this interface to add modes. + </para> + <para> + dev->pio_mode and dev->dma_mode are guaranteed to be valid when + ->set_piomode() and when ->set_dmamode() is called. The timings for + any other drive sharing the cable will also be valid at this point. + That is the library records the decisions for the modes of each + drive on a channel before it attempts to set any of them. + </para> + <para> + ->post_set_mode() is + called unconditionally, after the SET FEATURES - XFER MODE + command completes successfully. + </para> + + <para> + ->set_piomode() is always called (if present), but + ->set_dma_mode() is only called if DMA is possible. + </para> + + </sect2> + + <sect2><title>Taskfile read/write</title> + <programlisting> +void (*sff_tf_load) (struct ata_port *ap, struct ata_taskfile *tf); +void (*sff_tf_read) (struct ata_port *ap, struct ata_taskfile *tf); + </programlisting> + + <para> + ->tf_load() is called to load the given taskfile into hardware + registers / DMA buffers. ->tf_read() is called to read the + hardware registers / DMA buffers, to obtain the current set of + taskfile register values. + Most drivers for taskfile-based hardware (PIO or MMIO) use + ata_sff_tf_load() and ata_sff_tf_read() for these hooks. + </para> + + </sect2> + + <sect2><title>PIO data read/write</title> + <programlisting> +void (*sff_data_xfer) (struct ata_device *, unsigned char *, unsigned int, int); + </programlisting> + + <para> +All bmdma-style drivers must implement this hook. This is the low-level +operation that actually copies the data bytes during a PIO data +transfer. +Typically the driver will choose one of ata_sff_data_xfer_noirq(), +ata_sff_data_xfer(), or ata_sff_data_xfer32(). + </para> + + </sect2> + + <sect2><title>ATA command execute</title> + <programlisting> +void (*sff_exec_command)(struct ata_port *ap, struct ata_taskfile *tf); + </programlisting> + + <para> + causes an ATA command, previously loaded with + ->tf_load(), to be initiated in hardware. + Most drivers for taskfile-based hardware use ata_sff_exec_command() + for this hook. + </para> + + </sect2> + + <sect2><title>Per-cmd ATAPI DMA capabilities filter</title> + <programlisting> +int (*check_atapi_dma) (struct ata_queued_cmd *qc); + </programlisting> + + <para> +Allow low-level driver to filter ATA PACKET commands, returning a status +indicating whether or not it is OK to use DMA for the supplied PACKET +command. + </para> + <para> + This hook may be specified as NULL, in which case libata will + assume that atapi dma can be supported. + </para> + + </sect2> + + <sect2><title>Read specific ATA shadow registers</title> + <programlisting> +u8 (*sff_check_status)(struct ata_port *ap); +u8 (*sff_check_altstatus)(struct ata_port *ap); + </programlisting> + + <para> + Reads the Status/AltStatus ATA shadow register from + hardware. On some hardware, reading the Status register has + the side effect of clearing the interrupt condition. + Most drivers for taskfile-based hardware use + ata_sff_check_status() for this hook. + </para> + + </sect2> + + <sect2><title>Write specific ATA shadow register</title> + <programlisting> +void (*sff_set_devctl)(struct ata_port *ap, u8 ctl); + </programlisting> + + <para> + Write the device control ATA shadow register to the hardware. + Most drivers don't need to define this. + </para> + + </sect2> + + <sect2><title>Select ATA device on bus</title> + <programlisting> +void (*sff_dev_select)(struct ata_port *ap, unsigned int device); + </programlisting> + + <para> + Issues the low-level hardware command(s) that causes one of N + hardware devices to be considered 'selected' (active and + available for use) on the ATA bus. This generally has no + meaning on FIS-based devices. + </para> + <para> + Most drivers for taskfile-based hardware use + ata_sff_dev_select() for this hook. + </para> + + </sect2> + + <sect2><title>Private tuning method</title> + <programlisting> +void (*set_mode) (struct ata_port *ap); + </programlisting> + + <para> + By default libata performs drive and controller tuning in + accordance with the ATA timing rules and also applies blacklists + and cable limits. Some controllers need special handling and have + custom tuning rules, typically raid controllers that use ATA + commands but do not actually do drive timing. + </para> + + <warning> + <para> + This hook should not be used to replace the standard controller + tuning logic when a controller has quirks. Replacing the default + tuning logic in that case would bypass handling for drive and + bridge quirks that may be important to data reliability. If a + controller needs to filter the mode selection it should use the + mode_filter hook instead. + </para> + </warning> + + </sect2> + + <sect2><title>Control PCI IDE BMDMA engine</title> + <programlisting> +void (*bmdma_setup) (struct ata_queued_cmd *qc); +void (*bmdma_start) (struct ata_queued_cmd *qc); +void (*bmdma_stop) (struct ata_port *ap); +u8 (*bmdma_status) (struct ata_port *ap); + </programlisting> + + <para> +When setting up an IDE BMDMA transaction, these hooks arm +(->bmdma_setup), fire (->bmdma_start), and halt (->bmdma_stop) +the hardware's DMA engine. ->bmdma_status is used to read the standard +PCI IDE DMA Status register. + </para> + + <para> +These hooks are typically either no-ops, or simply not implemented, in +FIS-based drivers. + </para> + <para> +Most legacy IDE drivers use ata_bmdma_setup() for the bmdma_setup() +hook. ata_bmdma_setup() will write the pointer to the PRD table to +the IDE PRD Table Address register, enable DMA in the DMA Command +register, and call exec_command() to begin the transfer. + </para> + <para> +Most legacy IDE drivers use ata_bmdma_start() for the bmdma_start() +hook. ata_bmdma_start() will write the ATA_DMA_START flag to the DMA +Command register. + </para> + <para> +Many legacy IDE drivers use ata_bmdma_stop() for the bmdma_stop() +hook. ata_bmdma_stop() clears the ATA_DMA_START flag in the DMA +command register. + </para> + <para> +Many legacy IDE drivers use ata_bmdma_status() as the bmdma_status() hook. + </para> + + </sect2> + + <sect2><title>High-level taskfile hooks</title> + <programlisting> +void (*qc_prep) (struct ata_queued_cmd *qc); +int (*qc_issue) (struct ata_queued_cmd *qc); + </programlisting> + + <para> + Higher-level hooks, these two hooks can potentially supercede + several of the above taskfile/DMA engine hooks. ->qc_prep is + called after the buffers have been DMA-mapped, and is typically + used to populate the hardware's DMA scatter-gather table. + Most drivers use the standard ata_qc_prep() helper function, but + more advanced drivers roll their own. + </para> + <para> + ->qc_issue is used to make a command active, once the hardware + and S/G tables have been prepared. IDE BMDMA drivers use the + helper function ata_qc_issue_prot() for taskfile protocol-based + dispatch. More advanced drivers implement their own ->qc_issue. + </para> + <para> + ata_qc_issue_prot() calls ->tf_load(), ->bmdma_setup(), and + ->bmdma_start() as necessary to initiate a transfer. + </para> + + </sect2> + + <sect2><title>Exception and probe handling (EH)</title> + <programlisting> +void (*eng_timeout) (struct ata_port *ap); +void (*phy_reset) (struct ata_port *ap); + </programlisting> + + <para> +Deprecated. Use ->error_handler() instead. + </para> + + <programlisting> +void (*freeze) (struct ata_port *ap); +void (*thaw) (struct ata_port *ap); + </programlisting> + + <para> +ata_port_freeze() is called when HSM violations or some other +condition disrupts normal operation of the port. A frozen port +is not allowed to perform any operation until the port is +thawed, which usually follows a successful reset. + </para> + + <para> +The optional ->freeze() callback can be used for freezing the port +hardware-wise (e.g. mask interrupt and stop DMA engine). If a +port cannot be frozen hardware-wise, the interrupt handler +must ack and clear interrupts unconditionally while the port +is frozen. + </para> + <para> +The optional ->thaw() callback is called to perform the opposite of ->freeze(): +prepare the port for normal operation once again. Unmask interrupts, +start DMA engine, etc. + </para> + + <programlisting> +void (*error_handler) (struct ata_port *ap); + </programlisting> + + <para> +->error_handler() is a driver's hook into probe, hotplug, and recovery +and other exceptional conditions. The primary responsibility of an +implementation is to call ata_do_eh() or ata_bmdma_drive_eh() with a set +of EH hooks as arguments: + </para> + + <para> +'prereset' hook (may be NULL) is called during an EH reset, before any other actions +are taken. + </para> + + <para> +'postreset' hook (may be NULL) is called after the EH reset is performed. Based on +existing conditions, severity of the problem, and hardware capabilities, + </para> + + <para> +Either 'softreset' (may be NULL) or 'hardreset' (may be NULL) will be +called to perform the low-level EH reset. + </para> + + <programlisting> +void (*post_internal_cmd) (struct ata_queued_cmd *qc); + </programlisting> + + <para> +Perform any hardware-specific actions necessary to finish processing +after executing a probe-time or EH-time command via ata_exec_internal(). + </para> + + </sect2> + + <sect2><title>Hardware interrupt handling</title> + <programlisting> +irqreturn_t (*irq_handler)(int, void *, struct pt_regs *); +void (*irq_clear) (struct ata_port *); + </programlisting> + + <para> + ->irq_handler is the interrupt handling routine registered with + the system, by libata. ->irq_clear is called during probe just + before the interrupt handler is registered, to be sure hardware + is quiet. + </para> + <para> + The second argument, dev_instance, should be cast to a pointer + to struct ata_host_set. + </para> + <para> + Most legacy IDE drivers use ata_sff_interrupt() for the + irq_handler hook, which scans all ports in the host_set, + determines which queued command was active (if any), and calls + ata_sff_host_intr(ap,qc). + </para> + <para> + Most legacy IDE drivers use ata_sff_irq_clear() for the + irq_clear() hook, which simply clears the interrupt and error + flags in the DMA status register. + </para> + + </sect2> + + <sect2><title>SATA phy read/write</title> + <programlisting> +int (*scr_read) (struct ata_port *ap, unsigned int sc_reg, + u32 *val); +int (*scr_write) (struct ata_port *ap, unsigned int sc_reg, + u32 val); + </programlisting> + + <para> + Read and write standard SATA phy registers. Currently only used + if ->phy_reset hook called the sata_phy_reset() helper function. + sc_reg is one of SCR_STATUS, SCR_CONTROL, SCR_ERROR, or SCR_ACTIVE. + </para> + + </sect2> + + <sect2><title>Init and shutdown</title> + <programlisting> +int (*port_start) (struct ata_port *ap); +void (*port_stop) (struct ata_port *ap); +void (*host_stop) (struct ata_host_set *host_set); + </programlisting> + + <para> + ->port_start() is called just after the data structures for each + port are initialized. Typically this is used to alloc per-port + DMA buffers / tables / rings, enable DMA engines, and similar + tasks. Some drivers also use this entry point as a chance to + allocate driver-private memory for ap->private_data. + </para> + <para> + Many drivers use ata_port_start() as this hook or call + it from their own port_start() hooks. ata_port_start() + allocates space for a legacy IDE PRD table and returns. + </para> + <para> + ->port_stop() is called after ->host_stop(). Its sole function + is to release DMA/memory resources, now that they are no longer + actively being used. Many drivers also free driver-private + data from port at this time. + </para> + <para> + ->host_stop() is called after all ->port_stop() calls +have completed. The hook must finalize hardware shutdown, release DMA +and other resources, etc. + This hook may be specified as NULL, in which case it is not called. + </para> + + </sect2> + + </sect1> + </chapter> + + <chapter id="libataEH"> + <title>Error handling</title> + + <para> + This chapter describes how errors are handled under libata. + Readers are advised to read SCSI EH + (Documentation/scsi/scsi_eh.txt) and ATA exceptions doc first. + </para> + + <sect1><title>Origins of commands</title> + <para> + In libata, a command is represented with struct ata_queued_cmd + or qc. qc's are preallocated during port initialization and + repetitively used for command executions. Currently only one + qc is allocated per port but yet-to-be-merged NCQ branch + allocates one for each tag and maps each qc to NCQ tag 1-to-1. + </para> + <para> + libata commands can originate from two sources - libata itself + and SCSI midlayer. libata internal commands are used for + initialization and error handling. All normal blk requests + and commands for SCSI emulation are passed as SCSI commands + through queuecommand callback of SCSI host template. + </para> + </sect1> + + <sect1><title>How commands are issued</title> + + <variablelist> + + <varlistentry><term>Internal commands</term> + <listitem> + <para> + First, qc is allocated and initialized using + ata_qc_new_init(). Although ata_qc_new_init() doesn't + implement any wait or retry mechanism when qc is not + available, internal commands are currently issued only during + initialization and error recovery, so no other command is + active and allocation is guaranteed to succeed. + </para> + <para> + Once allocated qc's taskfile is initialized for the command to + be executed. qc currently has two mechanisms to notify + completion. One is via qc->complete_fn() callback and the + other is completion qc->waiting. qc->complete_fn() callback + is the asynchronous path used by normal SCSI translated + commands and qc->waiting is the synchronous (issuer sleeps in + process context) path used by internal commands. + </para> + <para> + Once initialization is complete, host_set lock is acquired + and the qc is issued. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>SCSI commands</term> + <listitem> + <para> + All libata drivers use ata_scsi_queuecmd() as + hostt->queuecommand callback. scmds can either be simulated + or translated. No qc is involved in processing a simulated + scmd. The result is computed right away and the scmd is + completed. + </para> + <para> + For a translated scmd, ata_qc_new_init() is invoked to + allocate a qc and the scmd is translated into the qc. SCSI + midlayer's completion notification function pointer is stored + into qc->scsidone. + </para> + <para> + qc->complete_fn() callback is used for completion + notification. ATA commands use ata_scsi_qc_complete() while + ATAPI commands use atapi_qc_complete(). Both functions end up + calling qc->scsidone to notify upper layer when the qc is + finished. After translation is completed, the qc is issued + with ata_qc_issue(). + </para> + <para> + Note that SCSI midlayer invokes hostt->queuecommand while + holding host_set lock, so all above occur while holding + host_set lock. + </para> + </listitem> + </varlistentry> + + </variablelist> + </sect1> + + <sect1><title>How commands are processed</title> + <para> + Depending on which protocol and which controller are used, + commands are processed differently. For the purpose of + discussion, a controller which uses taskfile interface and all + standard callbacks is assumed. + </para> + <para> + Currently 6 ATA command protocols are used. They can be + sorted into the following four categories according to how + they are processed. + </para> + + <variablelist> + <varlistentry><term>ATA NO DATA or DMA</term> + <listitem> + <para> + ATA_PROT_NODATA and ATA_PROT_DMA fall into this category. + These types of commands don't require any software + intervention once issued. Device will raise interrupt on + completion. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>ATA PIO</term> + <listitem> + <para> + ATA_PROT_PIO is in this category. libata currently + implements PIO with polling. ATA_NIEN bit is set to turn + off interrupt and pio_task on ata_wq performs polling and + IO. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>ATAPI NODATA or DMA</term> + <listitem> + <para> + ATA_PROT_ATAPI_NODATA and ATA_PROT_ATAPI_DMA are in this + category. packet_task is used to poll BSY bit after + issuing PACKET command. Once BSY is turned off by the + device, packet_task transfers CDB and hands off processing + to interrupt handler. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>ATAPI PIO</term> + <listitem> + <para> + ATA_PROT_ATAPI is in this category. ATA_NIEN bit is set + and, as in ATAPI NODATA or DMA, packet_task submits cdb. + However, after submitting cdb, further processing (data + transfer) is handed off to pio_task. + </para> + </listitem> + </varlistentry> + </variablelist> + </sect1> + + <sect1><title>How commands are completed</title> + <para> + Once issued, all qc's are either completed with + ata_qc_complete() or time out. For commands which are handled + by interrupts, ata_host_intr() invokes ata_qc_complete(), and, + for PIO tasks, pio_task invokes ata_qc_complete(). In error + cases, packet_task may also complete commands. + </para> + <para> + ata_qc_complete() does the following. + </para> + + <orderedlist> + + <listitem> + <para> + DMA memory is unmapped. + </para> + </listitem> + + <listitem> + <para> + ATA_QCFLAG_ACTIVE is clared from qc->flags. + </para> + </listitem> + + <listitem> + <para> + qc->complete_fn() callback is invoked. If the return value of + the callback is not zero. Completion is short circuited and + ata_qc_complete() returns. + </para> + </listitem> + + <listitem> + <para> + __ata_qc_complete() is called, which does + <orderedlist> + + <listitem> + <para> + qc->flags is cleared to zero. + </para> + </listitem> + + <listitem> + <para> + ap->active_tag and qc->tag are poisoned. + </para> + </listitem> + + <listitem> + <para> + qc->waiting is claread & completed (in that order). + </para> + </listitem> + + <listitem> + <para> + qc is deallocated by clearing appropriate bit in ap->qactive. + </para> + </listitem> + + </orderedlist> + </para> + </listitem> + + </orderedlist> + + <para> + So, it basically notifies upper layer and deallocates qc. One + exception is short-circuit path in #3 which is used by + atapi_qc_complete(). + </para> + <para> + For all non-ATAPI commands, whether it fails or not, almost + the same code path is taken and very little error handling + takes place. A qc is completed with success status if it + succeeded, with failed status otherwise. + </para> + <para> + However, failed ATAPI commands require more handling as + REQUEST SENSE is needed to acquire sense data. If an ATAPI + command fails, ata_qc_complete() is invoked with error status, + which in turn invokes atapi_qc_complete() via + qc->complete_fn() callback. + </para> + <para> + This makes atapi_qc_complete() set scmd->result to + SAM_STAT_CHECK_CONDITION, complete the scmd and return 1. As + the sense data is empty but scmd->result is CHECK CONDITION, + SCSI midlayer will invoke EH for the scmd, and returning 1 + makes ata_qc_complete() to return without deallocating the qc. + This leads us to ata_scsi_error() with partially completed qc. + </para> + + </sect1> + + <sect1><title>ata_scsi_error()</title> + <para> + ata_scsi_error() is the current transportt->eh_strategy_handler() + for libata. As discussed above, this will be entered in two + cases - timeout and ATAPI error completion. This function + calls low level libata driver's eng_timeout() callback, the + standard callback for which is ata_eng_timeout(). It checks + if a qc is active and calls ata_qc_timeout() on the qc if so. + Actual error handling occurs in ata_qc_timeout(). + </para> + <para> + If EH is invoked for timeout, ata_qc_timeout() stops BMDMA and + completes the qc. Note that as we're currently in EH, we + cannot call scsi_done. As described in SCSI EH doc, a + recovered scmd should be either retried with + scsi_queue_insert() or finished with scsi_finish_command(). + Here, we override qc->scsidone with scsi_finish_command() and + calls ata_qc_complete(). + </para> + <para> + If EH is invoked due to a failed ATAPI qc, the qc here is + completed but not deallocated. The purpose of this + half-completion is to use the qc as place holder to make EH + code reach this place. This is a bit hackish, but it works. + </para> + <para> + Once control reaches here, the qc is deallocated by invoking + __ata_qc_complete() explicitly. Then, internal qc for REQUEST + SENSE is issued. Once sense data is acquired, scmd is + finished by directly invoking scsi_finish_command() on the + scmd. Note that as we already have completed and deallocated + the qc which was associated with the scmd, we don't need + to/cannot call ata_qc_complete() again. + </para> + + </sect1> + + <sect1><title>Problems with the current EH</title> + + <itemizedlist> + + <listitem> + <para> + Error representation is too crude. Currently any and all + error conditions are represented with ATA STATUS and ERROR + registers. Errors which aren't ATA device errors are treated + as ATA device errors by setting ATA_ERR bit. Better error + descriptor which can properly represent ATA and other + errors/exceptions is needed. + </para> + </listitem> + + <listitem> + <para> + When handling timeouts, no action is taken to make device + forget about the timed out command and ready for new commands. + </para> + </listitem> + + <listitem> + <para> + EH handling via ata_scsi_error() is not properly protected + from usual command processing. On EH entrance, the device is + not in quiescent state. Timed out commands may succeed or + fail any time. pio_task and atapi_task may still be running. + </para> + </listitem> + + <listitem> + <para> + Too weak error recovery. Devices / controllers causing HSM + mismatch errors and other errors quite often require reset to + return to known state. Also, advanced error handling is + necessary to support features like NCQ and hotplug. + </para> + </listitem> + + <listitem> + <para> + ATA errors are directly handled in the interrupt handler and + PIO errors in pio_task. This is problematic for advanced + error handling for the following reasons. + </para> + <para> + First, advanced error handling often requires context and + internal qc execution. + </para> + <para> + Second, even a simple failure (say, CRC error) needs + information gathering and could trigger complex error handling + (say, resetting & reconfiguring). Having multiple code + paths to gather information, enter EH and trigger actions + makes life painful. + </para> + <para> + Third, scattered EH code makes implementing low level drivers + difficult. Low level drivers override libata callbacks. If + EH is scattered over several places, each affected callbacks + should perform its part of error handling. This can be error + prone and painful. + </para> + </listitem> + + </itemizedlist> + </sect1> + </chapter> + + <chapter id="libataExt"> + <title>libata Library</title> +!Edrivers/ata/libata-core.c + </chapter> + + <chapter id="libataInt"> + <title>libata Core Internals</title> +!Idrivers/ata/libata-core.c + </chapter> + + <chapter id="libataScsiInt"> + <title>libata SCSI translation/emulation</title> +!Edrivers/ata/libata-scsi.c +!Idrivers/ata/libata-scsi.c + </chapter> + + <chapter id="ataExceptions"> + <title>ATA errors and exceptions</title> + + <para> + This chapter tries to identify what error/exception conditions exist + for ATA/ATAPI devices and describe how they should be handled in + implementation-neutral way. + </para> + + <para> + The term 'error' is used to describe conditions where either an + explicit error condition is reported from device or a command has + timed out. + </para> + + <para> + The term 'exception' is either used to describe exceptional + conditions which are not errors (say, power or hotplug events), or + to describe both errors and non-error exceptional conditions. Where + explicit distinction between error and exception is necessary, the + term 'non-error exception' is used. + </para> + + <sect1 id="excat"> + <title>Exception categories</title> + <para> + Exceptions are described primarily with respect to legacy + taskfile + bus master IDE interface. If a controller provides + other better mechanism for error reporting, mapping those into + categories described below shouldn't be difficult. + </para> + + <para> + In the following sections, two recovery actions - reset and + reconfiguring transport - are mentioned. These are described + further in <xref linkend="exrec"/>. + </para> + + <sect2 id="excatHSMviolation"> + <title>HSM violation</title> + <para> + This error is indicated when STATUS value doesn't match HSM + requirement during issuing or excution any ATA/ATAPI command. + </para> + + <itemizedlist> + <title>Examples</title> + + <listitem> + <para> + ATA_STATUS doesn't contain !BSY && DRDY && !DRQ while trying + to issue a command. + </para> + </listitem> + + <listitem> + <para> + !BSY && !DRQ during PIO data transfer. + </para> + </listitem> + + <listitem> + <para> + DRQ on command completion. + </para> + </listitem> + + <listitem> + <para> + !BSY && ERR after CDB transfer starts but before the + last byte of CDB is transferred. ATA/ATAPI standard states + that "The device shall not terminate the PACKET command + with an error before the last byte of the command packet has + been written" in the error outputs description of PACKET + command and the state diagram doesn't include such + transitions. + </para> + </listitem> + + </itemizedlist> + + <para> + In these cases, HSM is violated and not much information + regarding the error can be acquired from STATUS or ERROR + register. IOW, this error can be anything - driver bug, + faulty device, controller and/or cable. + </para> + + <para> + As HSM is violated, reset is necessary to restore known state. + Reconfiguring transport for lower speed might be helpful too + as transmission errors sometimes cause this kind of errors. + </para> + </sect2> + + <sect2 id="excatDevErr"> + <title>ATA/ATAPI device error (non-NCQ / non-CHECK CONDITION)</title> + + <para> + These are errors detected and reported by ATA/ATAPI devices + indicating device problems. For this type of errors, STATUS + and ERROR register values are valid and describe error + condition. Note that some of ATA bus errors are detected by + ATA/ATAPI devices and reported using the same mechanism as + device errors. Those cases are described later in this + section. + </para> + + <para> + For ATA commands, this type of errors are indicated by !BSY + && ERR during command execution and on completion. + </para> + + <para>For ATAPI commands,</para> + + <itemizedlist> + + <listitem> + <para> + !BSY && ERR && ABRT right after issuing PACKET + indicates that PACKET command is not supported and falls in + this category. + </para> + </listitem> + + <listitem> + <para> + !BSY && ERR(==CHK) && !ABRT after the last + byte of CDB is transferred indicates CHECK CONDITION and + doesn't fall in this category. + </para> + </listitem> + + <listitem> + <para> + !BSY && ERR(==CHK) && ABRT after the last byte + of CDB is transferred *probably* indicates CHECK CONDITION and + doesn't fall in this category. + </para> + </listitem> + + </itemizedlist> + + <para> + Of errors detected as above, the followings are not ATA/ATAPI + device errors but ATA bus errors and should be handled + according to <xref linkend="excatATAbusErr"/>. + </para> + + <variablelist> + + <varlistentry> + <term>CRC error during data transfer</term> + <listitem> + <para> + This is indicated by ICRC bit in the ERROR register and + means that corruption occurred during data transfer. Up to + ATA/ATAPI-7, the standard specifies that this bit is only + applicable to UDMA transfers but ATA/ATAPI-8 draft revision + 1f says that the bit may be applicable to multiword DMA and + PIO. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>ABRT error during data transfer or on completion</term> + <listitem> + <para> + Up to ATA/ATAPI-7, the standard specifies that ABRT could be + set on ICRC errors and on cases where a device is not able + to complete a command. Combined with the fact that MWDMA + and PIO transfer errors aren't allowed to use ICRC bit up to + ATA/ATAPI-7, it seems to imply that ABRT bit alone could + indicate transfer errors. + </para> + <para> + However, ATA/ATAPI-8 draft revision 1f removes the part + that ICRC errors can turn on ABRT. So, this is kind of + gray area. Some heuristics are needed here. + </para> + </listitem> + </varlistentry> + + </variablelist> + + <para> + ATA/ATAPI device errors can be further categorized as follows. + </para> + + <variablelist> + + <varlistentry> + <term>Media errors</term> + <listitem> + <para> + This is indicated by UNC bit in the ERROR register. ATA + devices reports UNC error only after certain number of + retries cannot recover the data, so there's nothing much + else to do other than notifying upper layer. + </para> + <para> + READ and WRITE commands report CHS or LBA of the first + failed sector but ATA/ATAPI standard specifies that the + amount of transferred data on error completion is + indeterminate, so we cannot assume that sectors preceding + the failed sector have been transferred and thus cannot + complete those sectors successfully as SCSI does. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>Media changed / media change requested error</term> + <listitem> + <para> + <<TODO: fill here>> + </para> + </listitem> + </varlistentry> + + <varlistentry><term>Address error</term> + <listitem> + <para> + This is indicated by IDNF bit in the ERROR register. + Report to upper layer. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>Other errors</term> + <listitem> + <para> + This can be invalid command or parameter indicated by ABRT + ERROR bit or some other error condition. Note that ABRT + bit can indicate a lot of things including ICRC and Address + errors. Heuristics needed. + </para> + </listitem> + </varlistentry> + + </variablelist> + + <para> + Depending on commands, not all STATUS/ERROR bits are + applicable. These non-applicable bits are marked with + "na" in the output descriptions but up to ATA/ATAPI-7 + no definition of "na" can be found. However, + ATA/ATAPI-8 draft revision 1f describes "N/A" as + follows. + </para> + + <blockquote> + <variablelist> + <varlistentry><term>3.2.3.3a N/A</term> + <listitem> + <para> + A keyword the indicates a field has no defined value in + this standard and should not be checked by the host or + device. N/A fields should be cleared to zero. + </para> + </listitem> + </varlistentry> + </variablelist> + </blockquote> + + <para> + So, it seems reasonable to assume that "na" bits are + cleared to zero by devices and thus need no explicit masking. + </para> + + </sect2> + + <sect2 id="excatATAPIcc"> + <title>ATAPI device CHECK CONDITION</title> + + <para> + ATAPI device CHECK CONDITION error is indicated by set CHK bit + (ERR bit) in the STATUS register after the last byte of CDB is + transferred for a PACKET command. For this kind of errors, + sense data should be acquired to gather information regarding + the errors. REQUEST SENSE packet command should be used to + acquire sense data. + </para> + + <para> + Once sense data is acquired, this type of errors can be + handled similary to other SCSI errors. Note that sense data + may indicate ATA bus error (e.g. Sense Key 04h HARDWARE ERROR + && ASC/ASCQ 47h/00h SCSI PARITY ERROR). In such + cases, the error should be considered as an ATA bus error and + handled according to <xref linkend="excatATAbusErr"/>. + </para> + + </sect2> + + <sect2 id="excatNCQerr"> + <title>ATA device error (NCQ)</title> + + <para> + NCQ command error is indicated by cleared BSY and set ERR bit + during NCQ command phase (one or more NCQ commands + outstanding). Although STATUS and ERROR registers will + contain valid values describing the error, READ LOG EXT is + required to clear the error condition, determine which command + has failed and acquire more information. + </para> + + <para> + READ LOG EXT Log Page 10h reports which tag has failed and + taskfile register values describing the error. With this + information the failed command can be handled as a normal ATA + command error as in <xref linkend="excatDevErr"/> and all + other in-flight commands must be retried. Note that this + retry should not be counted - it's likely that commands + retried this way would have completed normally if it were not + for the failed command. + </para> + + <para> + Note that ATA bus errors can be reported as ATA device NCQ + errors. This should be handled as described in <xref + linkend="excatATAbusErr"/>. + </para> + + <para> + If READ LOG EXT Log Page 10h fails or reports NQ, we're + thoroughly screwed. This condition should be treated + according to <xref linkend="excatHSMviolation"/>. + </para> + + </sect2> + + <sect2 id="excatATAbusErr"> + <title>ATA bus error</title> + + <para> + ATA bus error means that data corruption occurred during + transmission over ATA bus (SATA or PATA). This type of errors + can be indicated by + </para> + + <itemizedlist> + + <listitem> + <para> + ICRC or ABRT error as described in <xref linkend="excatDevErr"/>. + </para> + </listitem> + + <listitem> + <para> + Controller-specific error completion with error information + indicating transmission error. + </para> + </listitem> + + <listitem> + <para> + On some controllers, command timeout. In this case, there may + be a mechanism to determine that the timeout is due to + transmission error. + </para> + </listitem> + + <listitem> + <para> + Unknown/random errors, timeouts and all sorts of weirdities. + </para> + </listitem> + + </itemizedlist> + + <para> + As described above, transmission errors can cause wide variety + of symptoms ranging from device ICRC error to random device + lockup, and, for many cases, there is no way to tell if an + error condition is due to transmission error or not; + therefore, it's necessary to employ some kind of heuristic + when dealing with errors and timeouts. For example, + encountering repetitive ABRT errors for known supported + command is likely to indicate ATA bus error. + </para> + + <para> + Once it's determined that ATA bus errors have possibly + occurred, lowering ATA bus transmission speed is one of + actions which may alleviate the problem. See <xref + linkend="exrecReconf"/> for more information. + </para> + + </sect2> + + <sect2 id="excatPCIbusErr"> + <title>PCI bus error</title> + + <para> + Data corruption or other failures during transmission over PCI + (or other system bus). For standard BMDMA, this is indicated + by Error bit in the BMDMA Status register. This type of + errors must be logged as it indicates something is very wrong + with the system. Resetting host controller is recommended. + </para> + + </sect2> + + <sect2 id="excatLateCompletion"> + <title>Late completion</title> + + <para> + This occurs when timeout occurs and the timeout handler finds + out that the timed out command has completed successfully or + with error. This is usually caused by lost interrupts. This + type of errors must be logged. Resetting host controller is + recommended. + </para> + + </sect2> + + <sect2 id="excatUnknown"> + <title>Unknown error (timeout)</title> + + <para> + This is when timeout occurs and the command is still + processing or the host and device are in unknown state. When + this occurs, HSM could be in any valid or invalid state. To + bring the device to known state and make it forget about the + timed out command, resetting is necessary. The timed out + command may be retried. + </para> + + <para> + Timeouts can also be caused by transmission errors. Refer to + <xref linkend="excatATAbusErr"/> for more details. + </para> + + </sect2> + + <sect2 id="excatHoplugPM"> + <title>Hotplug and power management exceptions</title> + + <para> + <<TODO: fill here>> + </para> + + </sect2> + + </sect1> + + <sect1 id="exrec"> + <title>EH recovery actions</title> + + <para> + This section discusses several important recovery actions. + </para> + + <sect2 id="exrecClr"> + <title>Clearing error condition</title> + + <para> + Many controllers require its error registers to be cleared by + error handler. Different controllers may have different + requirements. + </para> + + <para> + For SATA, it's strongly recommended to clear at least SError + register during error handling. + </para> + </sect2> + + <sect2 id="exrecRst"> + <title>Reset</title> + + <para> + During EH, resetting is necessary in the following cases. + </para> + + <itemizedlist> + + <listitem> + <para> + HSM is in unknown or invalid state + </para> + </listitem> + + <listitem> + <para> + HBA is in unknown or invalid state + </para> + </listitem> + + <listitem> + <para> + EH needs to make HBA/device forget about in-flight commands + </para> + </listitem> + + <listitem> + <para> + HBA/device behaves weirdly + </para> + </listitem> + + </itemizedlist> + + <para> + Resetting during EH might be a good idea regardless of error + condition to improve EH robustness. Whether to reset both or + either one of HBA and device depends on situation but the + following scheme is recommended. + </para> + + <itemizedlist> + + <listitem> + <para> + When it's known that HBA is in ready state but ATA/ATAPI + device is in unknown state, reset only device. + </para> + </listitem> + + <listitem> + <para> + If HBA is in unknown state, reset both HBA and device. + </para> + </listitem> + + </itemizedlist> + + <para> + HBA resetting is implementation specific. For a controller + complying to taskfile/BMDMA PCI IDE, stopping active DMA + transaction may be sufficient iff BMDMA state is the only HBA + context. But even mostly taskfile/BMDMA PCI IDE complying + controllers may have implementation specific requirements and + mechanism to reset themselves. This must be addressed by + specific drivers. + </para> + + <para> + OTOH, ATA/ATAPI standard describes in detail ways to reset + ATA/ATAPI devices. + </para> + + <variablelist> + + <varlistentry><term>PATA hardware reset</term> + <listitem> + <para> + This is hardware initiated device reset signalled with + asserted PATA RESET- signal. There is no standard way to + initiate hardware reset from software although some + hardware provides registers that allow driver to directly + tweak the RESET- signal. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>Software reset</term> + <listitem> + <para> + This is achieved by turning CONTROL SRST bit on for at + least 5us. Both PATA and SATA support it but, in case of + SATA, this may require controller-specific support as the + second Register FIS to clear SRST should be transmitted + while BSY bit is still set. Note that on PATA, this resets + both master and slave devices on a channel. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>EXECUTE DEVICE DIAGNOSTIC command</term> + <listitem> + <para> + Although ATA/ATAPI standard doesn't describe exactly, EDD + implies some level of resetting, possibly similar level + with software reset. Host-side EDD protocol can be handled + with normal command processing and most SATA controllers + should be able to handle EDD's just like other commands. + As in software reset, EDD affects both devices on a PATA + bus. + </para> + <para> + Although EDD does reset devices, this doesn't suit error + handling as EDD cannot be issued while BSY is set and it's + unclear how it will act when device is in unknown/weird + state. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>ATAPI DEVICE RESET command</term> + <listitem> + <para> + This is very similar to software reset except that reset + can be restricted to the selected device without affecting + the other device sharing the cable. + </para> + </listitem> + </varlistentry> + + <varlistentry><term>SATA phy reset</term> + <listitem> + <para> + This is the preferred way of resetting a SATA device. In + effect, it's identical to PATA hardware reset. Note that + this can be done with the standard SCR Control register. + As such, it's usually easier to implement than software + reset. + </para> + </listitem> + </varlistentry> + + </variablelist> + + <para> + One more thing to consider when resetting devices is that + resetting clears certain configuration parameters and they + need to be set to their previous or newly adjusted values + after reset. + </para> + + <para> + Parameters affected are. + </para> + + <itemizedlist> + + <listitem> + <para> + CHS set up with INITIALIZE DEVICE PARAMETERS (seldom used) + </para> + </listitem> + + <listitem> + <para> + Parameters set with SET FEATURES including transfer mode setting + </para> + </listitem> + + <listitem> + <para> + Block count set with SET MULTIPLE MODE + </para> + </listitem> + + <listitem> + <para> + Other parameters (SET MAX, MEDIA LOCK...) + </para> + </listitem> + + </itemizedlist> + + <para> + ATA/ATAPI standard specifies that some parameters must be + maintained across hardware or software reset, but doesn't + strictly specify all of them. Always reconfiguring needed + parameters after reset is required for robustness. Note that + this also applies when resuming from deep sleep (power-off). + </para> + + <para> + Also, ATA/ATAPI standard requires that IDENTIFY DEVICE / + IDENTIFY PACKET DEVICE is issued after any configuration + parameter is updated or a hardware reset and the result used + for further operation. OS driver is required to implement + revalidation mechanism to support this. + </para> + + </sect2> + + <sect2 id="exrecReconf"> + <title>Reconfigure transport</title> + + <para> + For both PATA and SATA, a lot of corners are cut for cheap + connectors, cables or controllers and it's quite common to see + high transmission error rate. This can be mitigated by + lowering transmission speed. + </para> + + <para> + The following is a possible scheme Jeff Garzik suggested. + </para> + + <blockquote> + <para> + If more than $N (3?) transmission errors happen in 15 minutes, + </para> + <itemizedlist> + <listitem> + <para> + if SATA, decrease SATA PHY speed. if speed cannot be decreased, + </para> + </listitem> + <listitem> + <para> + decrease UDMA xfer speed. if at UDMA0, switch to PIO4, + </para> + </listitem> + <listitem> + <para> + decrease PIO xfer speed. if at PIO3, complain, but continue + </para> + </listitem> + </itemizedlist> + </blockquote> + + </sect2> + + </sect1> + + </chapter> + + <chapter id="PiixInt"> + <title>ata_piix Internals</title> +!Idrivers/ata/ata_piix.c + </chapter> + + <chapter id="SILInt"> + <title>sata_sil Internals</title> +!Idrivers/ata/sata_sil.c + </chapter> + + <chapter id="libataThanks"> + <title>Thanks</title> + <para> + The bulk of the ATA knowledge comes thanks to long conversations with + Andre Hedrick (www.linux-ide.org), and long hours pondering the ATA + and SCSI specifications. + </para> + <para> + Thanks to Alan Cox for pointing out similarities + between SATA and SCSI, and in general for motivation to hack on + libata. + </para> + <para> + libata's device detection + method, ata_pio_devchk, and in general all the early probing was + based on extensive study of Hale Landis's probe/reset code in his + ATADRVR driver (www.ata-atapi.com). + </para> + </chapter> + +</book> diff --git a/Documentation/DocBook/librs.tmpl b/Documentation/DocBook/librs.tmpl new file mode 100644 index 00000000..94f21361 --- /dev/null +++ b/Documentation/DocBook/librs.tmpl @@ -0,0 +1,289 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="Reed-Solomon-Library-Guide"> + <bookinfo> + <title>Reed-Solomon Library Programming Interface</title> + + <authorgroup> + <author> + <firstname>Thomas</firstname> + <surname>Gleixner</surname> + <affiliation> + <address> + <email>tglx@linutronix.de</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2004</year> + <holder>Thomas Gleixner</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + The generic Reed-Solomon Library provides encoding, decoding + and error correction functions. + </para> + <para> + Reed-Solomon codes are used in communication and storage + applications to ensure data integrity. + </para> + <para> + This documentation is provided for developers who want to utilize + the functions provided by the library. + </para> + </chapter> + + <chapter id="bugs"> + <title>Known Bugs And Assumptions</title> + <para> + None. + </para> + </chapter> + + <chapter id="usage"> + <title>Usage</title> + <para> + This chapter provides examples of how to use the library. + </para> + <sect1> + <title>Initializing</title> + <para> + The init function init_rs returns a pointer to an + rs decoder structure, which holds the necessary + information for encoding, decoding and error correction + with the given polynomial. It either uses an existing + matching decoder or creates a new one. On creation all + the lookup tables for fast en/decoding are created. + The function may take a while, so make sure not to + call it in critical code paths. + </para> + <programlisting> +/* the Reed Solomon control structure */ +static struct rs_control *rs_decoder; + +/* Symbolsize is 10 (bits) + * Primitive polynomial is x^10+x^3+1 + * first consecutive root is 0 + * primitive element to generate roots = 1 + * generator polynomial degree (number of roots) = 6 + */ +rs_decoder = init_rs (10, 0x409, 0, 1, 6); + </programlisting> + </sect1> + <sect1> + <title>Encoding</title> + <para> + The encoder calculates the Reed-Solomon code over + the given data length and stores the result in + the parity buffer. Note that the parity buffer must + be initialized before calling the encoder. + </para> + <para> + The expanded data can be inverted on the fly by + providing a non-zero inversion mask. The expanded data is + XOR'ed with the mask. This is used e.g. for FLASH + ECC, where the all 0xFF is inverted to an all 0x00. + The Reed-Solomon code for all 0x00 is all 0x00. The + code is inverted before storing to FLASH so it is 0xFF + too. This prevents that reading from an erased FLASH + results in ECC errors. + </para> + <para> + The databytes are expanded to the given symbol size + on the fly. There is no support for encoding continuous + bitstreams with a symbol size != 8 at the moment. If + it is necessary it should be not a big deal to implement + such functionality. + </para> + <programlisting> +/* Parity buffer. Size = number of roots */ +uint16_t par[6]; +/* Initialize the parity buffer */ +memset(par, 0, sizeof(par)); +/* Encode 512 byte in data8. Store parity in buffer par */ +encode_rs8 (rs_decoder, data8, 512, par, 0); + </programlisting> + </sect1> + <sect1> + <title>Decoding</title> + <para> + The decoder calculates the syndrome over + the given data length and the received parity symbols + and corrects errors in the data. + </para> + <para> + If a syndrome is available from a hardware decoder + then the syndrome calculation is skipped. + </para> + <para> + The correction of the data buffer can be suppressed + by providing a correction pattern buffer and an error + location buffer to the decoder. The decoder stores the + calculated error location and the correction bitmask + in the given buffers. This is useful for hardware + decoders which use a weird bit ordering scheme. + </para> + <para> + The databytes are expanded to the given symbol size + on the fly. There is no support for decoding continuous + bitstreams with a symbolsize != 8 at the moment. If + it is necessary it should be not a big deal to implement + such functionality. + </para> + + <sect2> + <title> + Decoding with syndrome calculation, direct data correction + </title> + <programlisting> +/* Parity buffer. Size = number of roots */ +uint16_t par[6]; +uint8_t data[512]; +int numerr; +/* Receive data */ +..... +/* Receive parity */ +..... +/* Decode 512 byte in data8.*/ +numerr = decode_rs8 (rs_decoder, data8, par, 512, NULL, 0, NULL, 0, NULL); + </programlisting> + </sect2> + + <sect2> + <title> + Decoding with syndrome given by hardware decoder, direct data correction + </title> + <programlisting> +/* Parity buffer. Size = number of roots */ +uint16_t par[6], syn[6]; +uint8_t data[512]; +int numerr; +/* Receive data */ +..... +/* Receive parity */ +..... +/* Get syndrome from hardware decoder */ +..... +/* Decode 512 byte in data8.*/ +numerr = decode_rs8 (rs_decoder, data8, par, 512, syn, 0, NULL, 0, NULL); + </programlisting> + </sect2> + + <sect2> + <title> + Decoding with syndrome given by hardware decoder, no direct data correction. + </title> + <para> + Note: It's not necessary to give data and received parity to the decoder. + </para> + <programlisting> +/* Parity buffer. Size = number of roots */ +uint16_t par[6], syn[6], corr[8]; +uint8_t data[512]; +int numerr, errpos[8]; +/* Receive data */ +..... +/* Receive parity */ +..... +/* Get syndrome from hardware decoder */ +..... +/* Decode 512 byte in data8.*/ +numerr = decode_rs8 (rs_decoder, NULL, NULL, 512, syn, 0, errpos, 0, corr); +for (i = 0; i < numerr; i++) { + do_error_correction_in_your_buffer(errpos[i], corr[i]); +} + </programlisting> + </sect2> + </sect1> + <sect1> + <title>Cleanup</title> + <para> + The function free_rs frees the allocated resources, + if the caller is the last user of the decoder. + </para> + <programlisting> +/* Release resources */ +free_rs(rs_decoder); + </programlisting> + </sect1> + + </chapter> + + <chapter id="structs"> + <title>Structures</title> + <para> + This chapter contains the autogenerated documentation of the structures which are + used in the Reed-Solomon Library and are relevant for a developer. + </para> +!Iinclude/linux/rslib.h + </chapter> + + <chapter id="pubfunctions"> + <title>Public Functions Provided</title> + <para> + This chapter contains the autogenerated documentation of the Reed-Solomon functions + which are exported. + </para> +!Elib/reed_solomon/reed_solomon.c + </chapter> + + <chapter id="credits"> + <title>Credits</title> + <para> + The library code for encoding and decoding was written by Phil Karn. + </para> + <programlisting> + Copyright 2002, Phil Karn, KA9Q + May be used under the terms of the GNU General Public License (GPL) + </programlisting> + <para> + The wrapper functions and interfaces are written by Thomas Gleixner. + </para> + <para> + Many users have provided bugfixes, improvements and helping hands for testing. + Thanks a lot. + </para> + <para> + The following people have contributed to this document: + </para> + <para> + Thomas Gleixner<email>tglx@linutronix.de</email> + </para> + </chapter> +</book> diff --git a/Documentation/DocBook/lsm.tmpl b/Documentation/DocBook/lsm.tmpl new file mode 100644 index 00000000..fe7664ce --- /dev/null +++ b/Documentation/DocBook/lsm.tmpl @@ -0,0 +1,265 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<article class="whitepaper" id="LinuxSecurityModule" lang="en"> + <articleinfo> + <title>Linux Security Modules: General Security Hooks for Linux</title> + <authorgroup> + <author> + <firstname>Stephen</firstname> + <surname>Smalley</surname> + <affiliation> + <orgname>NAI Labs</orgname> + <address><email>ssmalley@nai.com</email></address> + </affiliation> + </author> + <author> + <firstname>Timothy</firstname> + <surname>Fraser</surname> + <affiliation> + <orgname>NAI Labs</orgname> + <address><email>tfraser@nai.com</email></address> + </affiliation> + </author> + <author> + <firstname>Chris</firstname> + <surname>Vance</surname> + <affiliation> + <orgname>NAI Labs</orgname> + <address><email>cvance@nai.com</email></address> + </affiliation> + </author> + </authorgroup> + </articleinfo> + +<sect1 id="Introduction"><title>Introduction</title> + +<para> +In March 2001, the National Security Agency (NSA) gave a presentation +about Security-Enhanced Linux (SELinux) at the 2.5 Linux Kernel +Summit. SELinux is an implementation of flexible and fine-grained +nondiscretionary access controls in the Linux kernel, originally +implemented as its own particular kernel patch. Several other +security projects (e.g. RSBAC, Medusa) have also developed flexible +access control architectures for the Linux kernel, and various +projects have developed particular access control models for Linux +(e.g. LIDS, DTE, SubDomain). Each project has developed and +maintained its own kernel patch to support its security needs. +</para> + +<para> +In response to the NSA presentation, Linus Torvalds made a set of +remarks that described a security framework he would be willing to +consider for inclusion in the mainstream Linux kernel. He described a +general framework that would provide a set of security hooks to +control operations on kernel objects and a set of opaque security +fields in kernel data structures for maintaining security attributes. +This framework could then be used by loadable kernel modules to +implement any desired model of security. Linus also suggested the +possibility of migrating the Linux capabilities code into such a +module. +</para> + +<para> +The Linux Security Modules (LSM) project was started by WireX to +develop such a framework. LSM is a joint development effort by +several security projects, including Immunix, SELinux, SGI and Janus, +and several individuals, including Greg Kroah-Hartman and James +Morris, to develop a Linux kernel patch that implements this +framework. The patch is currently tracking the 2.4 series and is +targeted for integration into the 2.5 development series. This +technical report provides an overview of the framework and the example +capabilities security module provided by the LSM kernel patch. +</para> + +</sect1> + +<sect1 id="framework"><title>LSM Framework</title> + +<para> +The LSM kernel patch provides a general kernel framework to support +security modules. In particular, the LSM framework is primarily +focused on supporting access control modules, although future +development is likely to address other security needs such as +auditing. By itself, the framework does not provide any additional +security; it merely provides the infrastructure to support security +modules. The LSM kernel patch also moves most of the capabilities +logic into an optional security module, with the system defaulting +to the traditional superuser logic. This capabilities module +is discussed further in <xref linkend="cap"/>. +</para> + +<para> +The LSM kernel patch adds security fields to kernel data structures +and inserts calls to hook functions at critical points in the kernel +code to manage the security fields and to perform access control. It +also adds functions for registering and unregistering security +modules, and adds a general <function>security</function> system call +to support new system calls for security-aware applications. +</para> + +<para> +The LSM security fields are simply <type>void*</type> pointers. For +process and program execution security information, security fields +were added to <structname>struct task_struct</structname> and +<structname>struct linux_binprm</structname>. For filesystem security +information, a security field was added to +<structname>struct super_block</structname>. For pipe, file, and socket +security information, security fields were added to +<structname>struct inode</structname> and +<structname>struct file</structname>. For packet and network device security +information, security fields were added to +<structname>struct sk_buff</structname> and +<structname>struct net_device</structname>. For System V IPC security +information, security fields were added to +<structname>struct kern_ipc_perm</structname> and +<structname>struct msg_msg</structname>; additionally, the definitions +for <structname>struct msg_msg</structname>, <structname>struct +msg_queue</structname>, and <structname>struct +shmid_kernel</structname> were moved to header files +(<filename>include/linux/msg.h</filename> and +<filename>include/linux/shm.h</filename> as appropriate) to allow +the security modules to use these definitions. +</para> + +<para> +Each LSM hook is a function pointer in a global table, +security_ops. This table is a +<structname>security_operations</structname> structure as defined by +<filename>include/linux/security.h</filename>. Detailed documentation +for each hook is included in this header file. At present, this +structure consists of a collection of substructures that group related +hooks based on the kernel object (e.g. task, inode, file, sk_buff, +etc) as well as some top-level hook function pointers for system +operations. This structure is likely to be flattened in the future +for performance. The placement of the hook calls in the kernel code +is described by the "called:" lines in the per-hook documentation in +the header file. The hook calls can also be easily found in the +kernel code by looking for the string "security_ops->". + +</para> + +<para> +Linus mentioned per-process security hooks in his original remarks as a +possible alternative to global security hooks. However, if LSM were +to start from the perspective of per-process hooks, then the base +framework would have to deal with how to handle operations that +involve multiple processes (e.g. kill), since each process might have +its own hook for controlling the operation. This would require a +general mechanism for composing hooks in the base framework. +Additionally, LSM would still need global hooks for operations that +have no process context (e.g. network input operations). +Consequently, LSM provides global security hooks, but a security +module is free to implement per-process hooks (where that makes sense) +by storing a security_ops table in each process' security field and +then invoking these per-process hooks from the global hooks. +The problem of composition is thus deferred to the module. +</para> + +<para> +The global security_ops table is initialized to a set of hook +functions provided by a dummy security module that provides +traditional superuser logic. A <function>register_security</function> +function (in <filename>security/security.c</filename>) is provided to +allow a security module to set security_ops to refer to its own hook +functions, and an <function>unregister_security</function> function is +provided to revert security_ops to the dummy module hooks. This +mechanism is used to set the primary security module, which is +responsible for making the final decision for each hook. +</para> + +<para> +LSM also provides a simple mechanism for stacking additional security +modules with the primary security module. It defines +<function>register_security</function> and +<function>unregister_security</function> hooks in the +<structname>security_operations</structname> structure and provides +<function>mod_reg_security</function> and +<function>mod_unreg_security</function> functions that invoke these +hooks after performing some sanity checking. A security module can +call these functions in order to stack with other modules. However, +the actual details of how this stacking is handled are deferred to the +module, which can implement these hooks in any way it wishes +(including always returning an error if it does not wish to support +stacking). In this manner, LSM again defers the problem of +composition to the module. +</para> + +<para> +Although the LSM hooks are organized into substructures based on +kernel object, all of the hooks can be viewed as falling into two +major categories: hooks that are used to manage the security fields +and hooks that are used to perform access control. Examples of the +first category of hooks include the +<function>alloc_security</function> and +<function>free_security</function> hooks defined for each kernel data +structure that has a security field. These hooks are used to allocate +and free security structures for kernel objects. The first category +of hooks also includes hooks that set information in the security +field after allocation, such as the <function>post_lookup</function> +hook in <structname>struct inode_security_ops</structname>. This hook +is used to set security information for inodes after successful lookup +operations. An example of the second category of hooks is the +<function>permission</function> hook in +<structname>struct inode_security_ops</structname>. This hook checks +permission when accessing an inode. +</para> + +</sect1> + +<sect1 id="cap"><title>LSM Capabilities Module</title> + +<para> +The LSM kernel patch moves most of the existing POSIX.1e capabilities +logic into an optional security module stored in the file +<filename>security/capability.c</filename>. This change allows +users who do not want to use capabilities to omit this code entirely +from their kernel, instead using the dummy module for traditional +superuser logic or any other module that they desire. This change +also allows the developers of the capabilities logic to maintain and +enhance their code more freely, without needing to integrate patches +back into the base kernel. +</para> + +<para> +In addition to moving the capabilities logic, the LSM kernel patch +could move the capability-related fields from the kernel data +structures into the new security fields managed by the security +modules. However, at present, the LSM kernel patch leaves the +capability fields in the kernel data structures. In his original +remarks, Linus suggested that this might be preferable so that other +security modules can be easily stacked with the capabilities module +without needing to chain multiple security structures on the security field. +It also avoids imposing extra overhead on the capabilities module +to manage the security fields. However, the LSM framework could +certainly support such a move if it is determined to be desirable, +with only a few additional changes described below. +</para> + +<para> +At present, the capabilities logic for computing process capabilities +on <function>execve</function> and <function>set*uid</function>, +checking capabilities for a particular process, saving and checking +capabilities for netlink messages, and handling the +<function>capget</function> and <function>capset</function> system +calls have been moved into the capabilities module. There are still a +few locations in the base kernel where capability-related fields are +directly examined or modified, but the current version of the LSM +patch does allow a security module to completely replace the +assignment and testing of capabilities. These few locations would +need to be changed if the capability-related fields were moved into +the security field. The following is a list of known locations that +still perform such direct examination or modification of +capability-related fields: +<itemizedlist> +<listitem><para><filename>fs/open.c</filename>:<function>sys_access</function></para></listitem> +<listitem><para><filename>fs/lockd/host.c</filename>:<function>nlm_bind_host</function></para></listitem> +<listitem><para><filename>fs/nfsd/auth.c</filename>:<function>nfsd_setuser</function></para></listitem> +<listitem><para><filename>fs/proc/array.c</filename>:<function>task_cap</function></para></listitem> +</itemizedlist> +</para> + +</sect1> + +</article> diff --git a/Documentation/DocBook/mcabook.tmpl b/Documentation/DocBook/mcabook.tmpl new file mode 100644 index 00000000..467ccac6 --- /dev/null +++ b/Documentation/DocBook/mcabook.tmpl @@ -0,0 +1,107 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="MCAGuide"> + <bookinfo> + <title>MCA Driver Programming Interface</title> + + <authorgroup> + <author> + <firstname>Alan</firstname> + <surname>Cox</surname> + <affiliation> + <address> + <email>alan@lxorguk.ukuu.org.uk</email> + </address> + </affiliation> + </author> + <author> + <firstname>David</firstname> + <surname>Weinehall</surname> + </author> + <author> + <firstname>Chris</firstname> + <surname>Beauregard</surname> + </author> + </authorgroup> + + <copyright> + <year>2000</year> + <holder>Alan Cox</holder> + <holder>David Weinehall</holder> + <holder>Chris Beauregard</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + The MCA bus functions provide a generalised interface to find MCA + bus cards, to claim them for a driver, and to read and manipulate POS + registers without being aware of the motherboard internals or + certain deep magic specific to onboard devices. + </para> + <para> + The basic interface to the MCA bus devices is the slot. Each slot + is numbered and virtual slot numbers are assigned to the internal + devices. Using a pci_dev as other busses do does not really make + sense in the MCA context as the MCA bus resources require card + specific interpretation. + </para> + <para> + Finally the MCA bus functions provide a parallel set of DMA + functions mimicing the ISA bus DMA functions as closely as possible, + although also supporting the additional DMA functionality on the + MCA bus controllers. + </para> + </chapter> + <chapter id="bugs"> + <title>Known Bugs And Assumptions</title> + <para> + None. + </para> + </chapter> + + <chapter id="pubfunctions"> + <title>Public Functions Provided</title> +!Edrivers/mca/mca-legacy.c + </chapter> + + <chapter id="dmafunctions"> + <title>DMA Functions Provided</title> +!Iarch/x86/include/asm/mca_dma.h + </chapter> + +</book> diff --git a/Documentation/DocBook/media/Makefile b/Documentation/DocBook/media/Makefile new file mode 100644 index 00000000..6628b4b9 --- /dev/null +++ b/Documentation/DocBook/media/Makefile @@ -0,0 +1,386 @@ +### +# Media build rules - Auto-generates media contents/indexes and *.h xml's +# + +SHELL=/bin/bash + +MEDIA_OBJ_DIR=$(objtree)/Documentation/DocBook/ +MEDIA_SRC_DIR=$(srctree)/Documentation/DocBook/media + +MEDIA_TEMP = media-entities.tmpl \ + media-indices.tmpl \ + videodev2.h.xml \ + v4l2.xml \ + audio.h.xml \ + ca.h.xml \ + dmx.h.xml \ + frontend.h.xml \ + net.h.xml \ + video.h.xml \ + +IMGFILES := $(patsubst %.b64,%, $(notdir $(shell ls $(MEDIA_SRC_DIR)/*.b64))) +OBJIMGFILES := $(addprefix $(MEDIA_OBJ_DIR)/, $(IMGFILES)) +GENFILES := $(addprefix $(MEDIA_OBJ_DIR)/, $(MEDIA_TEMP)) + +PHONY += cleanmediadocs + +cleanmediadocs: + -@rm `find $(MEDIA_OBJ_DIR) -type l` $(GENFILES) $(OBJIMGFILES) 2>/dev/null + +$(obj)/media_api.xml: $(GENFILES) FORCE + +#$(MEDIA_OBJ_DIR)/media_api.html: $(MEDIA_OBJ_DIR)/media_api.xml +#$(MEDIA_OBJ_DIR)/media_api.pdf: $(MEDIA_OBJ_DIR)/media_api.xml +#$(MEDIA_OBJ_DIR)/media_api.ps: $(MEDIA_OBJ_DIR)/media_api.xml + +V4L_SGMLS = \ + $(shell ls $(MEDIA_SRC_DIR)/v4l/*.xml|perl -ne 'print "$$1 " if (m,.*/(.*)\n,)') \ + capture.c.xml \ + keytable.c.xml \ + v4l2grab.c.xml + +DVB_SGMLS = \ + $(shell ls $(MEDIA_SRC_DIR)/dvb/*.xml|perl -ne 'print "$$1 " if (m,.*/(.*)\n,)') + +MEDIA_SGMLS = $(addprefix ./,$(V4L_SGMLS)) $(addprefix ./,$(DVB_SGMLS)) $(addprefix ./,$(MEDIA_TEMP)) + +FUNCS = \ + close \ + ioctl \ + mmap \ + munmap \ + open \ + poll \ + read \ + select \ + write \ + +IOCTLS = \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/videodev2.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/dvb/audio.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/dvb/ca.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/dvb/dmx.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/dvb/frontend.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([A-Z][^\s]+)\s+_IO/' $(srctree)/include/linux/dvb/net.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/dvb/video.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/media.h) \ + $(shell perl -ne 'print "$$1 " if /\#define\s+([^\s]+)\s+_IO/' $(srctree)/include/linux/v4l2-subdev.h) \ + VIDIOC_SUBDEV_G_FRAME_INTERVAL \ + VIDIOC_SUBDEV_S_FRAME_INTERVAL \ + VIDIOC_SUBDEV_ENUM_MBUS_CODE \ + VIDIOC_SUBDEV_ENUM_FRAME_SIZE \ + VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL \ + +TYPES = \ + $(shell perl -ne 'print "$$1 " if /^typedef\s+[^\s]+\s+([^\s]+)\;/' $(srctree)/include/linux/videodev2.h) \ + $(shell perl -ne 'print "$$1 " if /^}\s+([a-z0-9_]+_t)/' $(srctree)/include/linux/dvb/frontend.h) + +ENUMS = \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/videodev2.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/dvb/audio.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/dvb/ca.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/dvb/dmx.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/dvb/frontend.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/dvb/net.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/dvb/video.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/media.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/v4l2-mediabus.h) \ + $(shell perl -ne 'print "$$1 " if /^enum\s+([^\s]+)\s+/' $(srctree)/include/linux/v4l2-subdev.h) + +STRUCTS = \ + $(shell perl -ne 'print "$$1 " if /^struct\s+([^\s]+)\s+/' $(srctree)/include/linux/videodev2.h) \ + $(shell perl -ne 'print "$$1 " if (/^struct\s+([^\s\{]+)\s*/)' $(srctree)/include/linux/dvb/audio.h) \ + $(shell perl -ne 'print "$$1 " if (/^struct\s+([^\s]+)\s+/)' $(srctree)/include/linux/dvb/ca.h) \ + $(shell perl -ne 'print "$$1 " if (/^struct\s+([^\s]+)\s+/)' $(srctree)/include/linux/dvb/dmx.h) \ + $(shell perl -ne 'print "$$1 " if (!/dtv\_cmds\_h/ && /^struct\s+([^\s]+)\s+/)' $(srctree)/include/linux/dvb/frontend.h) \ + $(shell perl -ne 'print "$$1 " if (/^struct\s+([A-Z][^\s]+)\s+/)' $(srctree)/include/linux/dvb/net.h) \ + $(shell perl -ne 'print "$$1 " if (/^struct\s+([^\s]+)\s+/)' $(srctree)/include/linux/dvb/video.h) \ + $(shell perl -ne 'print "$$1 " if /^struct\s+([^\s]+)\s+/' $(srctree)/include/linux/media.h) \ + $(shell perl -ne 'print "$$1 " if /^struct\s+([^\s]+)\s+/' $(srctree)/include/linux/v4l2-subdev.h) \ + $(shell perl -ne 'print "$$1 " if /^struct\s+([^\s]+)\s+/' $(srctree)/include/linux/v4l2-mediabus.h) + +ERRORS = \ + E2BIG \ + EACCES \ + EAGAIN \ + EBADF \ + EBADFD \ + EBADR \ + EBADRQC \ + EBUSY \ + ECHILD \ + ECONNRESET \ + EDEADLK \ + EDOM \ + EEXIST \ + EFAULT \ + EFBIG \ + EILSEQ \ + EINIT \ + EINPROGRESS \ + EINTR \ + EINVAL \ + EIO \ + EMFILE \ + ENFILE \ + ENOBUFS \ + ENODATA \ + ENODEV \ + ENOENT \ + ENOIOCTLCMD \ + ENOMEM \ + ENOSPC \ + ENOSR \ + ENOSYS \ + ENOTSUP \ + ENOTSUPP \ + ENOTTY \ + ENXIO \ + EOPNOTSUPP \ + EOVERFLOW \ + EPERM \ + EPIPE \ + EPROTO \ + ERANGE \ + EREMOTE \ + EREMOTEIO \ + ERESTART \ + ERESTARTSYS \ + ESHUTDOWN \ + ESPIPE \ + ETIME \ + ETIMEDOUT \ + EUSERS \ + EWOULDBLOCK \ + EXDEV \ + +ESCAPE = \ + -e "s/&/\\&/g" \ + -e "s/</\\</g" \ + -e "s/>/\\>/g" + +FILENAME = \ + -e s,"^[^\/]*/",, \ + -e s/"\\.xml"// \ + -e s/"\\.tmpl"// \ + -e s/\\\./-/g \ + -e s/"^func-"// \ + -e s/"^pixfmt-"// \ + -e s/"^vidioc-"// + +# Generate references to these structs in videodev2.h.xml. +DOCUMENTED = \ + -e "s/\(enum *\)v4l2_mpeg_cx2341x_video_\([a-z]*_spatial_filter_type\)/\1<link linkend=\"\2\">v4l2_mpeg_cx2341x_video_\2<\/link>/g" \ + -e "s/\(\(enum\|struct\) *\)\(v4l2_[a-zA-Z0-9_]*\)/\1<link linkend=\"\3\">\3<\/link>/g" \ + -e "s/\(V4L2_PIX_FMT_[A-Z0-9_]\+\) /<link linkend=\"\1\">\1<\/link> /g" \ + -e ":a;s/\(linkend=\".*\)_\(.*\">\)/\1-\2/;ta" \ + -e "s/v4l2\-mpeg\-vbi\-ITV0/v4l2-mpeg-vbi-itv0-1/g" + +DVB_DOCUMENTED = \ + -e "s/\(linkend\=\"\)FE_SET_PROPERTY/\1FE_GET_PROPERTY/g" \ + -e "s,\(struct\s\+\)\([a-z0-9_]\+\)\(\s\+{\),\1\<link linkend=\"\2\">\2\<\/link\>\3,g" \ + -e "s,\(}\s\+\)\([a-z0-9_]\+_t\+\),\1\<link linkend=\"\2\">\2\<\/link\>,g" \ + -e "s,\(define\s\+\)\(DTV_[A-Z0-9_]\+\)\(\s\+[0-9]\+\),\1\<link linkend=\"\2\">\2\<\/link\>\3,g" \ + -e "s,<link\s\+linkend=\".*\">\(DTV_IOCTL_MAX_MSGS\|dtv_cmds_h\|__.*_old\)<\/link>,\1,g" \ + -e ":a;s/\(linkend=\".*\)_\(.*\">\)/\1-\2/;ta" \ + -e "s,\(audio-mixer\|audio-karaoke\|audio-status\|ca-slot-info\|ca-descr-info\|ca-caps\|ca-msg\|ca-descr\|ca-pid\|dmx-filter\|dmx-caps\|video-system\|video-highlight\|video-spu\|video-spu-palette\|video-navi-pack\)-t,\1,g" \ + -e "s,DTV-ISDBT-LAYER[A-C],DTV-ISDBT-LAYER,g" \ + -e "s,\(define\s\+\)\([A-Z0-9_]\+\)\(\s\+_IO\),\1\<link linkend=\"\2\">\2\<\/link\>\3,g" \ + -e "s,<link\s\+linkend=\".*\">\(__.*_OLD\)<\/link>,\1,g" \ + +# +# Media targets and dependencies +# + +install_media_images = \ + $(Q)cp $(OBJIMGFILES) $(MEDIA_OBJ_DIR)/media_api + +$(MEDIA_OBJ_DIR)/%: $(MEDIA_SRC_DIR)/%.b64 + $(Q)base64 -d $< >$@ + +$(MEDIA_OBJ_DIR)/v4l2.xml: $(OBJIMGFILES) + @$($(quiet)gen_xml) + @(ln -sf $(MEDIA_SRC_DIR)/v4l/*xml $(MEDIA_OBJ_DIR)/) + @(ln -sf $(MEDIA_SRC_DIR)/dvb/*xml $(MEDIA_OBJ_DIR)/) + +$(MEDIA_OBJ_DIR)/videodev2.h.xml: $(srctree)/include/linux/videodev2.h $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>") > $@ + @( \ + expand --tabs=8 < $< | \ + sed $(ESCAPE) $(DOCUMENTED) | \ + sed 's/i\.e\./&ie;/') >> $@ + @( \ + echo "</programlisting>") >> $@ + +$(MEDIA_OBJ_DIR)/audio.h.xml: $(srctree)/include/linux/dvb/audio.h $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>") > $@ + @( \ + expand --tabs=8 < $< | \ + sed $(ESCAPE) $(DVB_DOCUMENTED) | \ + sed 's/i\.e\./&ie;/') >> $@ + @( \ + echo "</programlisting>") >> $@ + +$(MEDIA_OBJ_DIR)/ca.h.xml: $(srctree)/include/linux/dvb/ca.h $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>") > $@ + @( \ + expand --tabs=8 < $< | \ + sed $(ESCAPE) $(DVB_DOCUMENTED) | \ + sed 's/i\.e\./&ie;/') >> $@ + @( \ + echo "</programlisting>") >> $@ + +$(MEDIA_OBJ_DIR)/dmx.h.xml: $(srctree)/include/linux/dvb/dmx.h $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>") > $@ + @( \ + expand --tabs=8 < $< | \ + sed $(ESCAPE) $(DVB_DOCUMENTED) | \ + sed 's/i\.e\./&ie;/') >> $@ + @( \ + echo "</programlisting>") >> $@ + +$(MEDIA_OBJ_DIR)/frontend.h.xml: $(srctree)/include/linux/dvb/frontend.h $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>") > $@ + @( \ + expand --tabs=8 < $< | \ + sed $(ESCAPE) $(DVB_DOCUMENTED) | \ + sed 's/i\.e\./&ie;/') >> $@ + @( \ + echo "</programlisting>") >> $@ + +$(MEDIA_OBJ_DIR)/net.h.xml: $(srctree)/include/linux/dvb/net.h $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>") > $@ + @( \ + expand --tabs=8 < $< | \ + sed $(ESCAPE) $(DVB_DOCUMENTED) | \ + sed 's/i\.e\./&ie;/') >> $@ + @( \ + echo "</programlisting>") >> $@ + +$(MEDIA_OBJ_DIR)/video.h.xml: $(srctree)/include/linux/dvb/video.h $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<programlisting>") > $@ + @( \ + expand --tabs=8 < $< | \ + sed $(ESCAPE) $(DVB_DOCUMENTED) | \ + sed 's/i\.e\./&ie;/') >> $@ + @( \ + echo "</programlisting>") >> $@ + +$(MEDIA_OBJ_DIR)/media-entities.tmpl: $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<!-- Generated file! Do not edit. -->") >$@ + @( \ + echo -e "\n<!-- Functions -->") >>$@ + @( \ + for ident in $(FUNCS) ; do \ + entity=`echo $$ident | tr _ -` ; \ + echo "<!ENTITY func-$$entity \"<link" \ + "linkend='func-$$entity'><function>$$ident()</function></link>\">" \ + >>$@ ; \ + done) + @( \ + echo -e "\n<!-- Ioctls -->") >>$@ + @( \ + for ident in $(IOCTLS) ; do \ + entity=`echo $$ident | tr _ -` ; \ + id=`grep "<refname>$$ident" $(MEDIA_OBJ_DIR)/vidioc-*.xml | sed -r s,"^.*/(.*).xml.*","\1",` ; \ + echo "<!ENTITY $$entity \"<link" \ + "linkend='$$id'><constant>$$ident</constant></link>\">" \ + >>$@ ; \ + done) + @( \ + echo -e "\n<!-- Types -->") >>$@ + @( \ + for ident in $(TYPES) ; do \ + entity=`echo $$ident | tr _ -` ; \ + echo "<!ENTITY $$entity \"<link" \ + "linkend='$$entity'>$$ident</link>\">" >>$@ ; \ + done) + @( \ + echo -e "\n<!-- Enums -->") >>$@ + @( \ + for ident in $(ENUMS) ; do \ + entity=`echo $$ident | sed -e "s/v4l2_mpeg_cx2341x_video_\([a-z]*_spatial_filter_type\)/\1/" | tr _ -` ; \ + echo "<!ENTITY $$entity \"enum <link" \ + "linkend='$$entity'>$$ident</link>\">" >>$@ ; \ + done) + @( \ + echo -e "\n<!-- Structures -->") >>$@ + @( \ + for ident in $(STRUCTS) ; do \ + entity=`echo $$ident | tr _ - | sed s/v4l2-mpeg-vbi-ITV0/v4l2-mpeg-vbi-itv0-1/g` ; \ + echo "<!ENTITY $$entity \"struct <link" \ + "linkend='$$entity'>$$ident</link>\">" >>$@ ; \ + done) + @( \ + echo -e "\n<!-- Error Codes -->") >>$@ + @( \ + for ident in $(ERRORS) ; do \ + echo "<!ENTITY $$ident \"<errorcode>$$ident</errorcode>" \ + "error code\">" >>$@ ; \ + done) + @( \ + echo -e "\n<!-- Subsections -->") >>$@ + @( \ + for file in $(MEDIA_SGMLS) ; do \ + entity=`echo "$$file" | sed $(FILENAME) -e s/"^([^-]*)"/sub\1/` ; \ + if ! echo "$$file" | \ + grep -q -E -e '^(func|vidioc|pixfmt)-' ; then \ + echo "<!ENTITY sub-$$entity SYSTEM \"$$file\">" >>$@ ; \ + fi ; \ + done) + @( \ + echo -e "\n<!-- Function Reference -->") >>$@ + @( \ + for file in $(MEDIA_SGMLS) ; do \ + if echo "$$file" | \ + grep -q -E -e '(func|vidioc|pixfmt)-' ; then \ + entity=`echo "$$file" |sed $(FILENAME)` ; \ + echo "<!ENTITY $$entity SYSTEM \"$$file\">" >>$@ ; \ + fi ; \ + done) + +# Jade can auto-generate a list-of-tables, which includes all structs, +# but we only want data types, all types, and sorted please. +$(MEDIA_OBJ_DIR)/media-indices.tmpl: $(MEDIA_OBJ_DIR)/v4l2.xml + @$($(quiet)gen_xml) + @( \ + echo "<!-- Generated file! Do not edit. -->") >$@ + @( \ + echo -e "\n<index><title>List of Types</title>") >>$@ + @( \ + for ident in $(TYPES) ; do \ + id=`echo $$ident | tr _ -` ; \ + echo "<indexentry><primaryie><link" \ + "linkend='$$id'>$$ident</link></primaryie></indexentry>" >>$@ ; \ + done) + @( \ + for ident in $(ENUMS) ; do \ + id=`echo $$ident | sed -e "s/v4l2_mpeg_cx2341x_video_\([a-z]*_spatial_filter_type\)/\1/" | tr _ -`; \ + echo "<indexentry><primaryie>enum <link" \ + "linkend='$$id'>$$ident</link></primaryie></indexentry>" >>$@ ; \ + done) + @( \ + for ident in $(STRUCTS) ; do \ + id=`echo $$ident | tr _ - | sed s/v4l2-mpeg-vbi-ITV0/v4l2-mpeg-vbi-itv0-1/g` ; \ + echo "<indexentry><primaryie>struct <link" \ + "linkend='$$id'>$$ident</link></primaryie></indexentry>" >>$@ ; \ + done) + @( \ + echo "</index>") >>$@ + diff --git a/Documentation/DocBook/media/bayer.png.b64 b/Documentation/DocBook/media/bayer.png.b64 new file mode 100644 index 00000000..ccdf2bcd --- /dev/null +++ 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It +can be accessed through <emphasis role="tt">/dev/dvb/adapter0/audio0</emphasis>. Data types and and +ioctl definitions can be accessed by including <emphasis role="tt">linux/dvb/video.h</emphasis> in your +application. +</para> +<para>Please note that some DVB cards don’t have their own MPEG decoder, which results in +the omission of the audio and video device. +</para> + +<section id="audio_data_types"> +<title>Audio Data Types</title> +<para>This section describes the structures, data types and defines used when talking to the +audio device. +</para> + +<section id="audio-stream-source-t"> +<title>audio_stream_source_t</title> +<para>The audio stream source is set through the AUDIO_SELECT_SOURCE call and can take +the following values, depending on whether we are replaying from an internal (demux) or +external (user write) source. +</para> +<programlisting> +typedef enum { + AUDIO_SOURCE_DEMUX, + AUDIO_SOURCE_MEMORY +} audio_stream_source_t; +</programlisting> +<para>AUDIO_SOURCE_DEMUX selects the demultiplexer (fed either by the frontend or the +DVR device) as the source of the video stream. If AUDIO_SOURCE_MEMORY +is selected the stream comes from the application through the <emphasis role="tt">write()</emphasis> system +call. +</para> + +</section> +<section id="audio-play-state-t"> +<title>audio_play_state_t</title> +<para>The following values can be returned by the AUDIO_GET_STATUS call representing the +state of audio playback. +</para> +<programlisting> +typedef enum { + AUDIO_STOPPED, + AUDIO_PLAYING, + AUDIO_PAUSED +} audio_play_state_t; +</programlisting> + +</section> +<section id="audio-channel-select-t"> +<title>audio_channel_select_t</title> +<para>The audio channel selected via AUDIO_CHANNEL_SELECT is determined by the +following values. +</para> +<programlisting> +typedef enum { + AUDIO_STEREO, + AUDIO_MONO_LEFT, + AUDIO_MONO_RIGHT, + AUDIO_MONO, + AUDIO_STEREO_SWAPPED +} audio_channel_select_t; +</programlisting> + +</section> +<section id="audio-status"> +<title>struct audio_status</title> +<para>The AUDIO_GET_STATUS call returns the following structure informing about various +states of the playback operation. +</para> +<programlisting> +typedef struct audio_status { + boolean AV_sync_state; + boolean mute_state; + audio_play_state_t play_state; + audio_stream_source_t stream_source; + audio_channel_select_t channel_select; + boolean bypass_mode; + audio_mixer_t mixer_state; +} audio_status_t; +</programlisting> + +</section> +<section id="audio-mixer"> +<title>struct audio_mixer</title> +<para>The following structure is used by the AUDIO_SET_MIXER call to set the audio +volume. +</para> +<programlisting> +typedef struct audio_mixer { + unsigned int volume_left; + unsigned int volume_right; +} audio_mixer_t; +</programlisting> + +</section> +<section id="audio_encodings"> +<title>audio encodings</title> +<para>A call to AUDIO_GET_CAPABILITIES returns an unsigned integer with the following +bits set according to the hardwares capabilities. +</para> +<programlisting> + #define AUDIO_CAP_DTS 1 + #define AUDIO_CAP_LPCM 2 + #define AUDIO_CAP_MP1 4 + #define AUDIO_CAP_MP2 8 + #define AUDIO_CAP_MP3 16 + #define AUDIO_CAP_AAC 32 + #define AUDIO_CAP_OGG 64 + #define AUDIO_CAP_SDDS 128 + #define AUDIO_CAP_AC3 256 +</programlisting> + +</section> +<section id="audio-karaoke"> +<title>struct audio_karaoke</title> +<para>The ioctl AUDIO_SET_KARAOKE uses the following format: +</para> +<programlisting> +typedef +struct audio_karaoke { + int vocal1; + int vocal2; + int melody; +} audio_karaoke_t; +</programlisting> +<para>If Vocal1 or Vocal2 are non-zero, they get mixed into left and right t at 70% each. If both, +Vocal1 and Vocal2 are non-zero, Vocal1 gets mixed into the left channel and Vocal2 into the +right channel at 100% each. Ff Melody is non-zero, the melody channel gets mixed into left +and right. +</para> + +</section> +<section id="audio-attributes-t"> +<title>audio attributes</title> +<para>The following attributes can be set by a call to AUDIO_SET_ATTRIBUTES: +</para> +<programlisting> + typedef uint16_t audio_attributes_t; + /⋆ bits: descr. ⋆/ + /⋆ 15-13 audio coding mode (0=ac3, 2=mpeg1, 3=mpeg2ext, 4=LPCM, 6=DTS, ⋆/ + /⋆ 12 multichannel extension ⋆/ + /⋆ 11-10 audio type (0=not spec, 1=language included) ⋆/ + /⋆ 9- 8 audio application mode (0=not spec, 1=karaoke, 2=surround) ⋆/ + /⋆ 7- 6 Quantization / DRC (mpeg audio: 1=DRC exists)(lpcm: 0=16bit, ⋆/ + /⋆ 5- 4 Sample frequency fs (0=48kHz, 1=96kHz) ⋆/ + /⋆ 2- 0 number of audio channels (n+1 channels) ⋆/ +</programlisting> + </section></section> +<section id="audio_function_calls"> +<title>Audio Function Calls</title> + + +<section id="audio_fopen"> +<title>open()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call opens a named audio device (e.g. /dev/dvb/adapter0/audio0) + for subsequent use. When an open() call has succeeded, the device will be ready + for use. The significance of blocking or non-blocking mode is described in the + documentation for functions where there is a difference. It does not affect the + semantics of the open() call itself. A device opened in blocking mode can later + be put into non-blocking mode (and vice versa) using the F_SETFL command + of the fcntl system call. This is a standard system call, documented in the Linux + manual page for fcntl. Only one user can open the Audio Device in O_RDWR + mode. All other attempts to open the device in this mode will fail, and an error + code will be returned. If the Audio Device is opened in O_RDONLY mode, the + only ioctl call that can be used is AUDIO_GET_STATUS. All other call will + return with an error code.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int open(const char ⋆deviceName, int flags);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>const char + *deviceName</para> +</entry><entry + align="char"> +<para>Name of specific audio device.</para> +</entry> + </row><row><entry + align="char"> +<para>int flags</para> +</entry><entry + align="char"> +<para>A bit-wise OR of the following flags:</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDONLY read-only access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDWR read/write access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_NONBLOCK open in non-blocking mode</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>(blocking mode is the default)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>ENODEV</para> +</entry><entry + align="char"> +<para>Device driver not loaded/available.</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>Device or resource busy.</para> +</entry> + </row><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid argument.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="audio_fclose"> +<title>close()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call closes a previously opened audio device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int close(int fd);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="audio_fwrite"> +<title>write()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call can only be used if AUDIO_SOURCE_MEMORY is selected + in the ioctl call AUDIO_SELECT_SOURCE. The data provided shall be in + PES format. If O_NONBLOCK is not specified the function will block until + buffer space is available. The amount of data to be transferred is implied by + count.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>size_t write(int fd, const void ⋆buf, size_t count);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>void *buf</para> +</entry><entry + align="char"> +<para>Pointer to the buffer containing the PES data.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t count</para> +</entry><entry + align="char"> +<para>Size of buf.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EPERM</para> +</entry><entry + align="char"> +<para>Mode AUDIO_SOURCE_MEMORY not selected.</para> +</entry> + </row><row><entry + align="char"> +<para>ENOMEM</para> +</entry><entry + align="char"> +<para>Attempted to write more data than the internal buffer can + hold.</para> +</entry> + </row><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="AUDIO_STOP" +role="subsection"><title>AUDIO_STOP</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to stop playing the current stream.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_STOP);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_STOP for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_PLAY" +role="subsection"><title>AUDIO_PLAY</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to start playing an audio stream from the + selected source.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_PLAY);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_PLAY for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_PAUSE" +role="subsection"><title>AUDIO_PAUSE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call suspends the audio stream being played. Decoding and playing + are paused. It is then possible to restart again decoding and playing process of + the audio stream using AUDIO_CONTINUE command.</para> +</entry> + </row><row><entry + align="char"> +<para>If AUDIO_SOURCE_MEMORY is selected in the ioctl call + AUDIO_SELECT_SOURCE, the DVB-subsystem will not decode (consume) + any more data until the ioctl call AUDIO_CONTINUE or AUDIO_PLAY is + performed.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_PAUSE);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_PAUSE for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_CONTINUE" +role="subsection"><title>AUDIO_CONTINUE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl restarts the decoding and playing process previously paused +with AUDIO_PAUSE command.</para> +</entry> + </row><row><entry + align="char"> +<para>It only works if the stream were previously stopped with AUDIO_PAUSE</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_CONTINUE);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_CONTINUE for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_SELECT_SOURCE" +role="subsection"><title>AUDIO_SELECT_SOURCE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call informs the audio device which source shall be used + for the input data. The possible sources are demux or memory. If + AUDIO_SOURCE_MEMORY is selected, the data is fed to the Audio Device + through the write command.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_SELECT_SOURCE, + audio_stream_source_t source);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SELECT_SOURCE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>audio_stream_source_t + source</para> +</entry><entry + align="char"> +<para>Indicates the source that shall be used for the Audio + stream.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_SET_MUTE" +role="subsection"><title>AUDIO_SET_MUTE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the audio device to mute the stream that is currently being + played.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_SET_MUTE, + boolean state);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_MUTE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>boolean state</para> +</entry><entry + align="char"> +<para>Indicates if audio device shall mute or not.</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>TRUE Audio Mute</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>FALSE Audio Un-mute</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_SET_AV_SYNC" +role="subsection"><title>AUDIO_SET_AV_SYNC</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to turn ON or OFF A/V synchronization.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_SET_AV_SYNC, + boolean state);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_AV_SYNC for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>boolean state</para> +</entry><entry + align="char"> +<para>Tells the DVB subsystem if A/V synchronization shall be + ON or OFF.</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>TRUE AV-sync ON</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>FALSE AV-sync OFF</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_SET_BYPASS_MODE" +role="subsection"><title>AUDIO_SET_BYPASS_MODE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to bypass the Audio decoder and forward + the stream without decoding. This mode shall be used if streams that can’t be + handled by the DVB system shall be decoded. Dolby DigitalTM streams are + automatically forwarded by the DVB subsystem if the hardware can handle it.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + AUDIO_SET_BYPASS_MODE, boolean mode);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_BYPASS_MODE for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>boolean mode</para> +</entry><entry + align="char"> +<para>Enables or disables the decoding of the current Audio + stream in the DVB subsystem.</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>TRUE Bypass is disabled</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>FALSE Bypass is enabled</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_CHANNEL_SELECT" +role="subsection"><title>AUDIO_CHANNEL_SELECT</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to select the requested channel if possible.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + AUDIO_CHANNEL_SELECT, audio_channel_select_t);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_CHANNEL_SELECT for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>audio_channel_select_t + ch</para> +</entry><entry + align="char"> +<para>Select the output format of the audio (mono left/right, + stereo).</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_GET_STATUS" +role="subsection"><title>AUDIO_GET_STATUS</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to return the current state of the Audio + Device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_GET_STATUS, + struct audio_status ⋆status);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_GET_STATUS for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct audio_status + *status</para> +</entry><entry + align="char"> +<para>Returns the current state of Audio Device.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_GET_CAPABILITIES" +role="subsection"><title>AUDIO_GET_CAPABILITIES</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to tell us about the decoding capabilities + of the audio hardware.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + AUDIO_GET_CAPABILITIES, unsigned int ⋆cap);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_GET_CAPABILITIES for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>unsigned int *cap</para> +</entry><entry + align="char"> +<para>Returns a bit array of supported sound formats.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_CLEAR_BUFFER" +role="subsection"><title>AUDIO_CLEAR_BUFFER</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Audio Device to clear all software and hardware buffers + of the audio decoder device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_CLEAR_BUFFER);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_CLEAR_BUFFER for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_SET_ID" +role="subsection"><title>AUDIO_SET_ID</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl selects which sub-stream is to be decoded if a program or system + stream is sent to the video device. If no audio stream type is set the id has to be + in [0xC0,0xDF] for MPEG sound, in [0x80,0x87] for AC3 and in [0xA0,0xA7] + for LPCM. More specifications may follow for other stream types. If the stream + type is set the id just specifies the substream id of the audio stream and only + the first 5 bits are recognized.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_SET_ID, int + id);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_ID for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int id</para> +</entry><entry + align="char"> +<para>audio sub-stream id</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_SET_MIXER" +role="subsection"><title>AUDIO_SET_MIXER</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl lets you adjust the mixer settings of the audio decoder.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = AUDIO_SET_MIXER, + audio_mixer_t ⋆mix);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_ID for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>audio_mixer_t *mix</para> +</entry><entry + align="char"> +<para>mixer settings.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="AUDIO_SET_STREAMTYPE" +role="subsection"><title>AUDIO_SET_STREAMTYPE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl tells the driver which kind of audio stream to expect. This is useful + if the stream offers several audio sub-streams like LPCM and AC3.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = AUDIO_SET_STREAMTYPE, + int type);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_STREAMTYPE for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>int type</para> +</entry><entry + align="char"> +<para>stream type</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>type is not a valid or supported stream type.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="AUDIO_SET_EXT_ID" +role="subsection"><title>AUDIO_SET_EXT_ID</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl can be used to set the extension id for MPEG streams in DVD + playback. Only the first 3 bits are recognized.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = AUDIO_SET_EXT_ID, int + id);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_EXT_ID for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int id</para> +</entry><entry + align="char"> +<para>audio sub_stream_id</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>id is not a valid id.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="AUDIO_SET_ATTRIBUTES" +role="subsection"><title>AUDIO_SET_ATTRIBUTES</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl is intended for DVD playback and allows you to set certain + information about the audio stream.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = AUDIO_SET_ATTRIBUTES, + audio_attributes_t attr );</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_ATTRIBUTES for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>audio_attributes_t + attr</para> +</entry><entry + align="char"> +<para>audio attributes according to section ??</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>attr is not a valid or supported attribute setting.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="AUDIO_SET_KARAOKE" +role="subsection"><title>AUDIO_SET_KARAOKE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl allows one to set the mixer settings for a karaoke DVD.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = AUDIO_SET_KARAOKE, + audio_karaoke_t ⋆karaoke);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals AUDIO_SET_KARAOKE for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>audio_karaoke_t + *karaoke</para> +</entry><entry + align="char"> +<para>karaoke settings according to section ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>karaoke is not a valid or supported karaoke setting.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section> +</section> diff --git a/Documentation/DocBook/media/dvb/ca.xml b/Documentation/DocBook/media/dvb/ca.xml new file mode 100644 index 00000000..5c4adb44 --- /dev/null +++ b/Documentation/DocBook/media/dvb/ca.xml @@ -0,0 +1,229 @@ +<title>DVB CA Device</title> +<para>The DVB CA device controls the conditional access hardware. It can be accessed through +<emphasis role="tt">/dev/dvb/adapter0/ca0</emphasis>. Data types and and ioctl definitions can be accessed by +including <emphasis role="tt">linux/dvb/ca.h</emphasis> in your application. +</para> + +<section id="ca_data_types"> +<title>CA Data Types</title> + + +<section id="ca-slot-info"> +<title>ca_slot_info_t</title> + <programlisting> +typedef struct ca_slot_info { + int num; /⋆ slot number ⋆/ + + int type; /⋆ CA interface this slot supports ⋆/ +#define CA_CI 1 /⋆ CI high level interface ⋆/ +#define CA_CI_LINK 2 /⋆ CI link layer level interface ⋆/ +#define CA_CI_PHYS 4 /⋆ CI physical layer level interface ⋆/ +#define CA_DESCR 8 /⋆ built-in descrambler ⋆/ +#define CA_SC 128 /⋆ simple smart card interface ⋆/ + + unsigned int flags; +#define CA_CI_MODULE_PRESENT 1 /⋆ module (or card) inserted ⋆/ +#define CA_CI_MODULE_READY 2 +} ca_slot_info_t; +</programlisting> + +</section> +<section id="ca-descr-info"> +<title>ca_descr_info_t</title> +<programlisting> +typedef struct ca_descr_info { + unsigned int num; /⋆ number of available descramblers (keys) ⋆/ + unsigned int type; /⋆ type of supported scrambling system ⋆/ +#define CA_ECD 1 +#define CA_NDS 2 +#define CA_DSS 4 +} ca_descr_info_t; +</programlisting> + +</section> +<section id="ca-caps"> +<title>ca_caps_t</title> +<programlisting> +typedef struct ca_caps { + unsigned int slot_num; /⋆ total number of CA card and module slots ⋆/ + unsigned int slot_type; /⋆ OR of all supported types ⋆/ + unsigned int descr_num; /⋆ total number of descrambler slots (keys) ⋆/ + unsigned int descr_type;/⋆ OR of all supported types ⋆/ + } ca_cap_t; +</programlisting> + +</section> +<section id="ca-msg"> +<title>ca_msg_t</title> +<programlisting> +/⋆ a message to/from a CI-CAM ⋆/ +typedef struct ca_msg { + unsigned int index; + unsigned int type; + unsigned int length; + unsigned char msg[256]; +} ca_msg_t; +</programlisting> + +</section> +<section id="ca-descr"> +<title>ca_descr_t</title> +<programlisting> +typedef struct ca_descr { + unsigned int index; + unsigned int parity; + unsigned char cw[8]; +} ca_descr_t; +</programlisting> +</section> + +<section id="ca-pid"> +<title>ca-pid</title> +<programlisting> +typedef struct ca_pid { + unsigned int pid; + int index; /⋆ -1 == disable⋆/ +} ca_pid_t; +</programlisting> +</section></section> + +<section id="ca_function_calls"> +<title>CA Function Calls</title> + + +<section id="ca_fopen"> +<title>open()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call opens a named ca device (e.g. /dev/ost/ca) for subsequent use.</para> +<para>When an open() call has succeeded, the device will be ready for use. + The significance of blocking or non-blocking mode is described in the + documentation for functions where there is a difference. It does not affect the + semantics of the open() call itself. A device opened in blocking mode can later + be put into non-blocking mode (and vice versa) using the F_SETFL command + of the fcntl system call. This is a standard system call, documented in the Linux + manual page for fcntl. Only one user can open the CA Device in O_RDWR + mode. All other attempts to open the device in this mode will fail, and an error + code will be returned.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int open(const char ⋆deviceName, int flags);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>const char + *deviceName</para> +</entry><entry + align="char"> +<para>Name of specific video device.</para> +</entry> + </row><row><entry + align="char"> +<para>int flags</para> +</entry><entry + align="char"> +<para>A bit-wise OR of the following flags:</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDONLY read-only access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDWR read/write access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_NONBLOCK open in non-blocking mode</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>(blocking mode is the default)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>ENODEV</para> +</entry><entry + align="char"> +<para>Device driver not loaded/available.</para> +</entry> + </row><row><entry + align="char"> +<para>EINTERNAL</para> +</entry><entry + align="char"> +<para>Internal error.</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>Device or resource busy.</para> +</entry> + </row><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid argument.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="ca_fclose"> +<title>close()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call closes a previously opened audio device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int close(int fd);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section> +</section> diff --git a/Documentation/DocBook/media/dvb/demux.xml b/Documentation/DocBook/media/dvb/demux.xml new file mode 100644 index 00000000..37c17908 --- /dev/null +++ b/Documentation/DocBook/media/dvb/demux.xml @@ -0,0 +1,902 @@ +<title>DVB Demux Device</title> + +<para>The DVB demux device controls the filters of the DVB hardware/software. It can be +accessed through <emphasis role="tt">/dev/adapter0/demux0</emphasis>. Data types and and ioctl definitions can be +accessed by including <emphasis role="tt">linux/dvb/dmx.h</emphasis> in your application. +</para> +<section id="dmx_types"> +<title>Demux Data Types</title> + +<section id="dmx-output-t"> +<title>dmx_output_t</title> +<programlisting> +typedef enum +{ + DMX_OUT_DECODER, /⋆ Streaming directly to decoder. ⋆/ + DMX_OUT_TAP, /⋆ Output going to a memory buffer ⋆/ + /⋆ (to be retrieved via the read command).⋆/ + DMX_OUT_TS_TAP, /⋆ Output multiplexed into a new TS ⋆/ + /⋆ (to be retrieved by reading from the ⋆/ + /⋆ logical DVR device). ⋆/ + DMX_OUT_TSDEMUX_TAP /⋆ Like TS_TAP but retrieved from the DMX device ⋆/ +} dmx_output_t; +</programlisting> +<para><emphasis role="tt">DMX_OUT_TAP</emphasis> delivers the stream output to the demux device on which the ioctl is +called. +</para> +<para><emphasis role="tt">DMX_OUT_TS_TAP</emphasis> routes output to the logical DVR device <emphasis role="tt">/dev/dvb/adapter0/dvr0</emphasis>, +which delivers a TS multiplexed from all filters for which <emphasis role="tt">DMX_OUT_TS_TAP</emphasis> was +specified. +</para> +</section> + +<section id="dmx-input-t"> +<title>dmx_input_t</title> +<programlisting> +typedef enum +{ + DMX_IN_FRONTEND, /⋆ Input from a front-end device. ⋆/ + DMX_IN_DVR /⋆ Input from the logical DVR device. ⋆/ +} dmx_input_t; +</programlisting> +</section> + +<section id="dmx-pes-type-t"> +<title>dmx_pes_type_t</title> +<programlisting> +typedef enum +{ + DMX_PES_AUDIO0, + DMX_PES_VIDEO0, + DMX_PES_TELETEXT0, + DMX_PES_SUBTITLE0, + DMX_PES_PCR0, + + DMX_PES_AUDIO1, + DMX_PES_VIDEO1, + DMX_PES_TELETEXT1, + DMX_PES_SUBTITLE1, + DMX_PES_PCR1, + + DMX_PES_AUDIO2, + DMX_PES_VIDEO2, + DMX_PES_TELETEXT2, + DMX_PES_SUBTITLE2, + DMX_PES_PCR2, + + DMX_PES_AUDIO3, + DMX_PES_VIDEO3, + DMX_PES_TELETEXT3, + DMX_PES_SUBTITLE3, + DMX_PES_PCR3, + + DMX_PES_OTHER +} dmx_pes_type_t; +</programlisting> +</section> + +<section id="dmx-filter"> +<title>struct dmx_filter</title> + <programlisting> + typedef struct dmx_filter +{ + __u8 filter[DMX_FILTER_SIZE]; + __u8 mask[DMX_FILTER_SIZE]; + __u8 mode[DMX_FILTER_SIZE]; +} dmx_filter_t; +</programlisting> +</section> + +<section id="dmx-sct-filter-params"> +<title>struct dmx_sct_filter_params</title> +<programlisting> +struct dmx_sct_filter_params +{ + __u16 pid; + dmx_filter_t filter; + __u32 timeout; + __u32 flags; +#define DMX_CHECK_CRC 1 +#define DMX_ONESHOT 2 +#define DMX_IMMEDIATE_START 4 +#define DMX_KERNEL_CLIENT 0x8000 +}; +</programlisting> +</section> + +<section id="dmx-pes-filter-params"> +<title>struct dmx_pes_filter_params</title> +<programlisting> +struct dmx_pes_filter_params +{ + __u16 pid; + dmx_input_t input; + dmx_output_t output; + dmx_pes_type_t pes_type; + __u32 flags; +}; +</programlisting> +</section> + +<section id="dmx-event"> +<title>struct dmx_event</title> + <programlisting> + struct dmx_event + { + dmx_event_t event; + time_t timeStamp; + union + { + dmx_scrambling_status_t scrambling; + } u; + }; +</programlisting> +</section> + +<section id="dmx-stc"> +<title>struct dmx_stc</title> +<programlisting> +struct dmx_stc { + unsigned int num; /⋆ input : which STC? 0..N ⋆/ + unsigned int base; /⋆ output: divisor for stc to get 90 kHz clock ⋆/ + __u64 stc; /⋆ output: stc in 'base'⋆90 kHz units ⋆/ +}; +</programlisting> +</section> + +<section id="dmx-caps"> +<title>struct dmx_caps</title> +<programlisting> + typedef struct dmx_caps { + __u32 caps; + int num_decoders; +} dmx_caps_t; +</programlisting> +</section> + +<section id="dmx-source-t"> +<title>enum dmx_source_t</title> +<programlisting> +typedef enum { + DMX_SOURCE_FRONT0 = 0, + DMX_SOURCE_FRONT1, + DMX_SOURCE_FRONT2, + DMX_SOURCE_FRONT3, + DMX_SOURCE_DVR0 = 16, + DMX_SOURCE_DVR1, + DMX_SOURCE_DVR2, + DMX_SOURCE_DVR3 +} dmx_source_t; +</programlisting> +</section> + +</section> +<section id="dmx_fcalls"> +<title>Demux Function Calls</title> + +<section id="dmx_fopen"> +<title>open()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call, used with a device name of /dev/dvb/adapter0/demux0, + allocates a new filter and returns a handle which can be used for subsequent + control of that filter. This call has to be made for each filter to be used, i.e. every + returned file descriptor is a reference to a single filter. /dev/dvb/adapter0/dvr0 + is a logical device to be used for retrieving Transport Streams for digital + video recording. When reading from this device a transport stream containing + the packets from all PES filters set in the corresponding demux device + (/dev/dvb/adapter0/demux0) having the output set to DMX_OUT_TS_TAP. A + recorded Transport Stream is replayed by writing to this device. </para> +<para>The significance of blocking or non-blocking mode is described in the + documentation for functions where there is a difference. It does not affect the + semantics of the open() call itself. A device opened in blocking mode can later + be put into non-blocking mode (and vice versa) using the F_SETFL command + of the fcntl system call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int open(const char ⋆deviceName, int flags);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>const char + *deviceName</para> +</entry><entry + align="char"> +<para>Name of demux device.</para> +</entry> + </row><row><entry + align="char"> +<para>int flags</para> +</entry><entry + align="char"> +<para>A bit-wise OR of the following flags:</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDWR read/write access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_NONBLOCK open in non-blocking mode</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>(blocking mode is the default)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>ENODEV</para> +</entry><entry + align="char"> +<para>Device driver not loaded/available.</para> +</entry> + </row><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid argument.</para> +</entry> + </row><row><entry + align="char"> +<para>EMFILE</para> +</entry><entry + align="char"> +<para>“Too many open files”, i.e. no more filters available.</para> +</entry> + </row><row><entry + align="char"> +<para>ENOMEM</para> +</entry><entry + align="char"> +<para>The driver failed to allocate enough memory.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="dmx_fclose"> +<title>close()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call deactivates and deallocates a filter that was previously + allocated via the open() call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int close(int fd);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="dmx_fread"> +<title>read()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call returns filtered data, which might be section or PES data. The + filtered data is transferred from the driver’s internal circular buffer to buf. The + maximum amount of data to be transferred is implied by count.</para> +</entry> + </row><row><entry + align="char"> +<para>When returning section data the driver always tries to return a complete single + section (even though buf would provide buffer space for more data). If the size + of the buffer is smaller than the section as much as possible will be returned, + and the remaining data will be provided in subsequent calls.</para> +</entry> + </row><row><entry + align="char"> +<para>The size of the internal buffer is 2 * 4096 bytes (the size of two maximum + sized sections) by default. The size of this buffer may be changed by using the + DMX_SET_BUFFER_SIZE function. If the buffer is not large enough, or if + the read operations are not performed fast enough, this may result in a buffer + overflow error. In this case EOVERFLOW will be returned, and the circular + buffer will be emptied. This call is blocking if there is no data to return, i.e. the + process will be put to sleep waiting for data, unless the O_NONBLOCK flag + is specified.</para> +</entry> + </row><row><entry + align="char"> +<para>Note that in order to be able to read, the filtering process has to be started + by defining either a section or a PES filter by means of the ioctl functions, + and then starting the filtering process via the DMX_START ioctl function + or by setting the DMX_IMMEDIATE_START flag. If the reading is done + from a logical DVR demux device, the data will constitute a Transport Stream + including the packets from all PES filters in the corresponding demux device + /dev/dvb/adapter0/demux0 having the output set to DMX_OUT_TS_TAP.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>size_t read(int fd, void ⋆buf, size_t count);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>void *buf</para> +</entry><entry + align="char"> +<para>Pointer to the buffer to be used for returned filtered data.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t count</para> +</entry><entry + align="char"> +<para>Size of buf.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EWOULDBLOCK</para> +</entry><entry + align="char"> +<para>No data to return and O_NONBLOCK was specified.</para> +</entry> + </row><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row><row><entry + align="char"> +<para>ECRC</para> +</entry><entry + align="char"> +<para>Last section had a CRC error - no data returned. The + buffer is flushed.</para> +</entry> + </row><row><entry + align="char"> +<para>EOVERFLOW</para> +</entry><entry + align="char"> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>The filtered data was not read from the buffer in due + time, resulting in non-read data being lost. The buffer is + flushed.</para> +</entry> + </row><row><entry + align="char"> +<para>ETIMEDOUT</para> +</entry><entry + align="char"> +<para>The section was not loaded within the stated timeout + period. See ioctl DMX_SET_FILTER for how to set a + timeout.</para> +</entry> + </row><row><entry + align="char"> +<para>EFAULT</para> +</entry><entry + align="char"> +<para>The driver failed to write to the callers buffer due to an + invalid *buf pointer.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="dmx_fwrite"> +<title>write()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call is only provided by the logical device /dev/dvb/adapter0/dvr0, + associated with the physical demux device that provides the actual DVR + functionality. It is used for replay of a digitally recorded Transport Stream. + Matching filters have to be defined in the corresponding physical demux + device, /dev/dvb/adapter0/demux0. The amount of data to be transferred is + implied by count.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>ssize_t write(int fd, const void ⋆buf, size_t + count);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>void *buf</para> +</entry><entry + align="char"> +<para>Pointer to the buffer containing the Transport Stream.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t count</para> +</entry><entry + align="char"> +<para>Size of buf.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EWOULDBLOCK</para> +</entry><entry + align="char"> +<para>No data was written. This + might happen if O_NONBLOCK was specified and there + is no more buffer space available (if O_NONBLOCK is + not specified the function will block until buffer space is + available).</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>This error code indicates that there are conflicting + requests. The corresponding demux device is setup to + receive data from the front- end. Make sure that these + filters are stopped and that the filters with input set to + DMX_IN_DVR are started.</para> +</entry> + </row><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="DMX_START"> +<title>DMX_START</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call is used to start the actual filtering operation defined via the ioctl + calls DMX_SET_FILTER or DMX_SET_PES_FILTER.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = DMX_START);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals DMX_START for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid argument, i.e. no filtering parameters provided via + the DMX_SET_FILTER or DMX_SET_PES_FILTER + functions.</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>This error code indicates that there are conflicting + requests. There are active filters filtering data from + another input source. Make sure that these filters are + stopped before starting this filter.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="DMX_STOP"> +<title>DMX_STOP</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call is used to stop the actual filtering operation defined via the + ioctl calls DMX_SET_FILTER or DMX_SET_PES_FILTER and started via + the DMX_START command.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = DMX_STOP);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals DMX_STOP for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +</section> + +<section id="DMX_SET_FILTER"> +<title>DMX_SET_FILTER</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call sets up a filter according to the filter and mask parameters + provided. A timeout may be defined stating number of seconds to wait for a + section to be loaded. A value of 0 means that no timeout should be applied. + Finally there is a flag field where it is possible to state whether a section should + be CRC-checked, whether the filter should be a ”one-shot” filter, i.e. if the + filtering operation should be stopped after the first section is received, and + whether the filtering operation should be started immediately (without waiting + for a DMX_START ioctl call). If a filter was previously set-up, this filter will + be canceled, and the receive buffer will be flushed.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = DMX_SET_FILTER, + struct dmx_sct_filter_params ⋆params);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals DMX_SET_FILTER for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dmx_sct_filter_params + *params</para> +</entry><entry + align="char"> +<para>Pointer to structure containing filter parameters.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +</section> + +<section id="DMX_SET_PES_FILTER"> +<title>DMX_SET_PES_FILTER</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call sets up a PES filter according to the parameters provided. By a + PES filter is meant a filter that is based just on the packet identifier (PID), i.e. + no PES header or payload filtering capability is supported.</para> +</entry> + </row><row><entry + align="char"> +<para>The transport stream destination for the filtered output may be set. Also the + PES type may be stated in order to be able to e.g. direct a video stream directly + to the video decoder. Finally there is a flag field where it is possible to state + whether the filtering operation should be started immediately (without waiting + for a DMX_START ioctl call). If a filter was previously set-up, this filter will + be cancelled, and the receive buffer will be flushed.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = DMX_SET_PES_FILTER, + struct dmx_pes_filter_params ⋆params);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals DMX_SET_PES_FILTER for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dmx_pes_filter_params + *params</para> +</entry><entry + align="char"> +<para>Pointer to structure containing filter parameters.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>This error code indicates that there are conflicting + requests. There are active filters filtering data from + another input source. Make sure that these filters are + stopped before starting this filter.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="DMX_SET_BUFFER_SIZE"> +<title>DMX_SET_BUFFER_SIZE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call is used to set the size of the circular buffer used for filtered data. + The default size is two maximum sized sections, i.e. if this function is not called + a buffer size of 2 * 4096 bytes will be used.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = + DMX_SET_BUFFER_SIZE, unsigned long size);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals DMX_SET_BUFFER_SIZE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>unsigned long size</para> +</entry><entry + align="char"> +<para>Size of circular buffer.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +</section> + +<section id="DMX_GET_EVENT"> +<title>DMX_GET_EVENT</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns an event if available. If an event is not available, + the behavior depends on whether the device is in blocking or non-blocking + mode. In the latter case, the call fails immediately with errno set to + EWOULDBLOCK. In the former case, the call blocks until an event becomes + available.</para> +</entry> + </row><row><entry + align="char"> +<para>The standard Linux poll() and/or select() system calls can be used with the + device file descriptor to watch for new events. For select(), the file descriptor + should be included in the exceptfds argument, and for poll(), POLLPRI should + be specified as the wake-up condition. Only the latest event for each filter is + saved.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = DMX_GET_EVENT, + struct dmx_event ⋆ev);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals DMX_GET_EVENT for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct dmx_event *ev</para> +</entry><entry + align="char"> +<para>Pointer to the location where the event is to be stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EWOULDBLOCK</para> +</entry><entry + align="char"> +<para>There is no event pending, and the device is in + non-blocking mode.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="DMX_GET_STC"> +<title>DMX_GET_STC</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns the current value of the system time counter (which is driven + by a PES filter of type DMX_PES_PCR). Some hardware supports more than one + STC, so you must specify which one by setting the num field of stc before the ioctl + (range 0...n). The result is returned in form of a ratio with a 64 bit numerator + and a 32 bit denominator, so the real 90kHz STC value is stc->stc / + stc->base + .</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = DMX_GET_STC, struct + dmx_stc ⋆stc);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals DMX_GET_STC for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct dmx_stc *stc</para> +</entry><entry + align="char"> +<para>Pointer to the location where the stc is to be stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid stc number.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> diff --git a/Documentation/DocBook/media/dvb/dvbapi.xml b/Documentation/DocBook/media/dvb/dvbapi.xml new file mode 100644 index 00000000..2ab6ddcf --- /dev/null +++ b/Documentation/DocBook/media/dvb/dvbapi.xml @@ -0,0 +1,141 @@ +<partinfo> +<authorgroup> +<author> +<firstname>Ralph</firstname> +<surname>Metzler</surname> +<othername role="mi">J. K.</othername> +<affiliation><address><email>rjkm@metzlerbros.de</email></address></affiliation> +</author> +<author> +<firstname>Marcus</firstname> +<surname>Metzler</surname> +<othername role="mi">O. C.</othername> +<affiliation><address><email>rjkm@metzlerbros.de</email></address></affiliation> +</author> +</authorgroup> +<authorgroup> +<author> +<firstname>Mauro</firstname> +<othername role="mi">Carvalho</othername> +<surname>Chehab</surname> +<affiliation><address><email>mchehab@redhat.com</email></address></affiliation> +<contrib>Ported document to Docbook XML.</contrib> +</author> +</authorgroup> +<copyright> + <year>2002</year> + <year>2003</year> + <holder>Convergence GmbH</holder> +</copyright> +<copyright> + <year>2009-2011</year> + <holder>Mauro Carvalho Chehab</holder> +</copyright> + +<revhistory> +<!-- Put document revisions here, newest first. --> +<revision> + <revnumber>2.0.4</revnumber> + <date>2011-05-06</date> + <authorinitials>mcc</authorinitials> + <revremark> + Add more information about DVB APIv5, better describing the frontend GET/SET props ioctl's. + </revremark> +</revision> +<revision> + <revnumber>2.0.3</revnumber> + <date>2010-07-03</date> + <authorinitials>mcc</authorinitials> + <revremark> + Add some frontend capabilities flags, present on kernel, but missing at the specs. + </revremark> +</revision> +<revision> + <revnumber>2.0.2</revnumber> + <date>2009-10-25</date> + <authorinitials>mcc</authorinitials> + <revremark> + documents FE_SET_FRONTEND_TUNE_MODE and FE_DISHETWORK_SEND_LEGACY_CMD ioctls. + </revremark> +</revision> +<revision> +<revnumber>2.0.1</revnumber> +<date>2009-09-16</date> +<authorinitials>mcc</authorinitials> +<revremark> +Added ISDB-T test originally written by Patrick Boettcher +</revremark> +</revision> +<revision> +<revnumber>2.0.0</revnumber> +<date>2009-09-06</date> +<authorinitials>mcc</authorinitials> +<revremark>Conversion from LaTex to DocBook XML. The + contents is the same as the original LaTex version.</revremark> +</revision> +<revision> +<revnumber>1.0.0</revnumber> +<date>2003-07-24</date> +<authorinitials>rjkm</authorinitials> +<revremark>Initial revision on LaTEX.</revremark> +</revision> +</revhistory> +</partinfo> + + +<title>LINUX DVB API</title> +<subtitle>Version 5.2</subtitle> +<!-- ADD THE CHAPTERS HERE --> + <chapter id="dvb_introdution"> + &sub-intro; + </chapter> + <chapter id="dvb_frontend"> + &sub-frontend; + </chapter> + <chapter id="dvb_demux"> + &sub-demux; + </chapter> + <chapter id="dvb_video"> + &sub-video; + </chapter> + <chapter id="dvb_audio"> + &sub-audio; + </chapter> + <chapter id="dvb_ca"> + &sub-ca; + </chapter> + <chapter id="dvb_net"> + &sub-net; + </chapter> + <chapter id="dvb_kdapi"> + &sub-kdapi; + </chapter> + <chapter id="dvb_examples"> + &sub-examples; + </chapter> +<!-- END OF CHAPTERS --> + <appendix id="audio_h"> + <title>DVB Audio Header File</title> + &sub-audio-h; + </appendix> + <appendix id="ca_h"> + <title>DVB Conditional Access Header File</title> + &sub-ca-h; + </appendix> + <appendix id="dmx_h"> + <title>DVB Demux Header File</title> + &sub-dmx-h; + </appendix> + <appendix id="frontend_h"> + <title>DVB Frontend Header File</title> + &sub-frontend-h; + </appendix> + <appendix id="net_h"> + <title>DVB Network Header File</title> + &sub-net-h; + </appendix> + <appendix id="video_h"> + <title>DVB Video Header File</title> + &sub-video-h; + </appendix> + diff --git a/Documentation/DocBook/media/dvb/dvbproperty.xml b/Documentation/DocBook/media/dvb/dvbproperty.xml new file mode 100644 index 00000000..c7a4ca51 --- /dev/null +++ b/Documentation/DocBook/media/dvb/dvbproperty.xml @@ -0,0 +1,868 @@ +<section id="FE_GET_SET_PROPERTY"> +<title><constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant></title> +<para>This section describes the DVB version 5 extention of the DVB-API, also +called "S2API", as this API were added to provide support for DVB-S2. It was +designed to be able to replace the old frontend API. Yet, the DISEQC and +the capability ioctls weren't implemented yet via the new way.</para> +<para>The typical usage for the <constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant> +API is to replace the ioctl's were the <link linkend="dvb-frontend-parameters"> +struct <constant>dvb_frontend_parameters</constant></link> were used.</para> +<section id="dtv-property"> +<title>DTV property type</title> +<programlisting> +/* Reserved fields should be set to 0 */ +struct dtv_property { + __u32 cmd; + union { + __u32 data; + struct { + __u8 data[32]; + __u32 len; + __u32 reserved1[3]; + void *reserved2; + } buffer; + } u; + int result; +} __attribute__ ((packed)); + +/* num of properties cannot exceed DTV_IOCTL_MAX_MSGS per ioctl */ +#define DTV_IOCTL_MAX_MSGS 64 +</programlisting> +</section> +<section id="dtv-properties"> +<title>DTV properties type</title> +<programlisting> +struct dtv_properties { + __u32 num; + struct dtv_property *props; +}; +</programlisting> +</section> + +<section id="FE_GET_PROPERTY"> +<title>FE_GET_PROPERTY</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns one or more frontend properties. This call only + requires read-only access to the device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY</link>, + dtv_properties ⋆props);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int num</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct dtv_property *props</para> +</entry><entry + align="char"> +<para>Points to the location where the front-end property commands are stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row> + <entry align="char"><para>EOPNOTSUPP</para></entry> + <entry align="char"><para>Property type not supported.</para></entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="FE_SET_PROPERTY"> +<title>FE_SET_PROPERTY</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call sets one or more frontend properties. This call only + requires read-only access to the device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_SET_PROPERTY">FE_SET_PROPERTY</link>, + dtv_properties ⋆props);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int num</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_SET_PROPERTY">FE_SET_PROPERTY</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct dtv_property *props</para> +</entry><entry + align="char"> +<para>Points to the location where the front-end property commands are stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row> + <entry align="char"><para>EOPNOTSUPP</para></entry> + <entry align="char"><para>Property type not supported.</para></entry> + </row></tbody></tgroup></informaltable> +</section> + +<section> + <title>Property types</title> +<para> +On <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY</link>/<link linkend="FE_SET_PROPERTY">FE_SET_PROPERTY</link>, +the actual action is determined by the dtv_property cmd/data pairs. With one single ioctl, is possible to +get/set up to 64 properties. The actual meaning of each property is described on the next sections. +</para> + +<para>The available frontend property types are shown on the next section.</para> +</section> + +<section id="fe_property_parameters"> + <title>Digital TV property parameters</title> + <section id="DTV-UNDEFINED"> + <title><constant>DTV_UNDEFINED</constant></title> + <para>Used internally. A GET/SET operation for it won't change or return anything.</para> + </section> + <section id="DTV-TUNE"> + <title><constant>DTV_TUNE</constant></title> + <para>Interpret the cache of data, build either a traditional frontend tunerequest so we can pass validation in the <constant>FE_SET_FRONTEND</constant> ioctl.</para> + </section> + <section id="DTV-CLEAR"> + <title><constant>DTV_CLEAR</constant></title> + <para>Reset a cache of data specific to the frontend here. This does not effect hardware.</para> + </section> + <section id="DTV-FREQUENCY"> + <title><constant>DTV_FREQUENCY</constant></title> + + <para>Central frequency of the channel.</para> + + <para>Notes:</para> + <para>1)For satellital delivery systems, it is measured in kHz. + For the other ones, it is measured in Hz.</para> + <para>2)For ISDB-T, the channels are usually transmitted with an offset of 143kHz. + E.g. a valid frequncy could be 474143 kHz. The stepping is bound to the bandwidth of + the channel which is 6MHz.</para> + + <para>3)As in ISDB-Tsb the channel consists of only one or three segments the + frequency step is 429kHz, 3*429 respectively. As for ISDB-T the + central frequency of the channel is expected.</para> + </section> + <section id="DTV-MODULATION"> + <title><constant>DTV_MODULATION</constant></title> +<para>Specifies the frontend modulation type for cable and satellite types. The modulation can be one of the types bellow:</para> +<programlisting> + typedef enum fe_modulation { + QPSK, + QAM_16, + QAM_32, + QAM_64, + QAM_128, + QAM_256, + QAM_AUTO, + VSB_8, + VSB_16, + PSK_8, + APSK_16, + APSK_32, + DQPSK, + } fe_modulation_t; +</programlisting> + </section> + <section id="DTV-BANDWIDTH-HZ"> + <title><constant>DTV_BANDWIDTH_HZ</constant></title> + + <para>Bandwidth for the channel, in HZ.</para> + + <para>Possible values: + <constant>1712000</constant>, + <constant>5000000</constant>, + <constant>6000000</constant>, + <constant>7000000</constant>, + <constant>8000000</constant>, + <constant>10000000</constant>. + </para> + + <para>Notes:</para> + + <para>1) For ISDB-T it should be always 6000000Hz (6MHz)</para> + <para>2) For ISDB-Tsb it can vary depending on the number of connected segments</para> + <para>3) Bandwidth doesn't apply for DVB-C transmissions, as the bandwidth + for DVB-C depends on the symbol rate</para> + <para>4) Bandwidth in ISDB-T is fixed (6MHz) or can be easily derived from + other parameters (DTV_ISDBT_SB_SEGMENT_IDX, + DTV_ISDBT_SB_SEGMENT_COUNT).</para> + <para>5) DVB-T supports 6, 7 and 8MHz.</para> + <para>6) In addition, DVB-T2 supports 1.172, 5 and 10MHz.</para> + </section> + <section id="DTV-INVERSION"> + <title><constant>DTV_INVERSION</constant></title> + <para>The Inversion field can take one of these values: + </para> + <programlisting> + typedef enum fe_spectral_inversion { + INVERSION_OFF, + INVERSION_ON, + INVERSION_AUTO + } fe_spectral_inversion_t; + </programlisting> + <para>It indicates if spectral inversion should be presumed or not. In the automatic setting + (<constant>INVERSION_AUTO</constant>) the hardware will try to figure out the correct setting by + itself. + </para> + </section> + <section id="DTV-DISEQC-MASTER"> + <title><constant>DTV_DISEQC_MASTER</constant></title> + <para>Currently not implemented.</para> + </section> + <section id="DTV-SYMBOL-RATE"> + <title><constant>DTV_SYMBOL_RATE</constant></title> + <para>Digital TV symbol rate, in bauds (symbols/second). Used on cable standards.</para> + </section> + <section id="DTV-INNER-FEC"> + <title><constant>DTV_INNER_FEC</constant></title> + <para>Used cable/satellite transmissions. The acceptable values are: + </para> + <programlisting> +typedef enum fe_code_rate { + FEC_NONE = 0, + FEC_1_2, + FEC_2_3, + FEC_3_4, + FEC_4_5, + FEC_5_6, + FEC_6_7, + FEC_7_8, + FEC_8_9, + FEC_AUTO, + FEC_3_5, + FEC_9_10, +} fe_code_rate_t; + </programlisting> + <para>which correspond to error correction rates of 1/2, 2/3, etc., + no error correction or auto detection.</para> + </section> + <section id="DTV-VOLTAGE"> + <title><constant>DTV_VOLTAGE</constant></title> + <para>The voltage is usually used with non-DiSEqC capable LNBs to switch + the polarzation (horizontal/vertical). When using DiSEqC epuipment this + voltage has to be switched consistently to the DiSEqC commands as + described in the DiSEqC spec.</para> + <programlisting> + typedef enum fe_sec_voltage { + SEC_VOLTAGE_13, + SEC_VOLTAGE_18 + } fe_sec_voltage_t; + </programlisting> + </section> + <section id="DTV-TONE"> + <title><constant>DTV_TONE</constant></title> + <para>Currently not used.</para> + </section> + <section id="DTV-PILOT"> + <title><constant>DTV_PILOT</constant></title> + <para>Sets DVB-S2 pilot</para> + <section id="fe-pilot-t"> + <title>fe_pilot type</title> + <programlisting> +typedef enum fe_pilot { + PILOT_ON, + PILOT_OFF, + PILOT_AUTO, +} fe_pilot_t; + </programlisting> + </section> + </section> + <section id="DTV-ROLLOFF"> + <title><constant>DTV_ROLLOFF</constant></title> + <para>Sets DVB-S2 rolloff</para> + + <section id="fe-rolloff-t"> + <title>fe_rolloff type</title> + <programlisting> +typedef enum fe_rolloff { + ROLLOFF_35, /* Implied value in DVB-S, default for DVB-S2 */ + ROLLOFF_20, + ROLLOFF_25, + ROLLOFF_AUTO, +} fe_rolloff_t; + </programlisting> + </section> + </section> + <section id="DTV-DISEQC-SLAVE-REPLY"> + <title><constant>DTV_DISEQC_SLAVE_REPLY</constant></title> + <para>Currently not implemented.</para> + </section> + <section id="DTV-FE-CAPABILITY-COUNT"> + <title><constant>DTV_FE_CAPABILITY_COUNT</constant></title> + <para>Currently not implemented.</para> + </section> + <section id="DTV-FE-CAPABILITY"> + <title><constant>DTV_FE_CAPABILITY</constant></title> + <para>Currently not implemented.</para> + </section> + <section id="DTV-DELIVERY-SYSTEM"> + <title><constant>DTV_DELIVERY_SYSTEM</constant></title> + <para>Specifies the type of Delivery system</para> + <section id="fe-delivery-system-t"> + <title>fe_delivery_system type</title> + <para>Possible values: </para> +<programlisting> + +typedef enum fe_delivery_system { + SYS_UNDEFINED, + SYS_DVBC_ANNEX_A, + SYS_DVBC_ANNEX_B, + SYS_DVBT, + SYS_DSS, + SYS_DVBS, + SYS_DVBS2, + SYS_DVBH, + SYS_ISDBT, + SYS_ISDBS, + SYS_ISDBC, + SYS_ATSC, + SYS_ATSCMH, + SYS_DMBTH, + SYS_CMMB, + SYS_DAB, + SYS_DVBT2, + SYS_TURBO, + SYS_DVBC_ANNEX_C, +} fe_delivery_system_t; +</programlisting> + </section> + </section> + <section id="DTV-ISDBT-PARTIAL-RECEPTION"> + <title><constant>DTV_ISDBT_PARTIAL_RECEPTION</constant></title> + + <para>If <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '0' this bit-field represents whether + the channel is in partial reception mode or not.</para> + + <para>If '1' <constant>DTV_ISDBT_LAYERA_*</constant> values are assigned to the center segment and + <constant>DTV_ISDBT_LAYERA_SEGMENT_COUNT</constant> has to be '1'.</para> + + <para>If in addition <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1' + <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> represents whether this ISDB-Tsb channel + is consisting of one segment and layer or three segments and two layers.</para> + + <para>Possible values: 0, 1, -1 (AUTO)</para> + </section> + <section id="DTV-ISDBT-SOUND-BROADCASTING"> + <title><constant>DTV_ISDBT_SOUND_BROADCASTING</constant></title> + + <para>This field represents whether the other DTV_ISDBT_*-parameters are + referring to an ISDB-T and an ISDB-Tsb channel. (See also + <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>).</para> + + <para>Possible values: 0, 1, -1 (AUTO)</para> + </section> + <section id="DTV-ISDBT-SB-SUBCHANNEL-ID"> + <title><constant>DTV_ISDBT_SB_SUBCHANNEL_ID</constant></title> + + <para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para> + + <para>(Note of the author: This might not be the correct description of the + <constant>SUBCHANNEL-ID</constant> in all details, but it is my understanding of the technical + background needed to program a device)</para> + + <para>An ISDB-Tsb channel (1 or 3 segments) can be broadcasted alone or in a + set of connected ISDB-Tsb channels. In this set of channels every + channel can be received independently. The number of connected + ISDB-Tsb segment can vary, e.g. depending on the frequency spectrum + bandwidth available.</para> + + <para>Example: Assume 8 ISDB-Tsb connected segments are broadcasted. The + broadcaster has several possibilities to put those channels in the + air: Assuming a normal 13-segment ISDB-T spectrum he can align the 8 + segments from position 1-8 to 5-13 or anything in between.</para> + + <para>The underlying layer of segments are subchannels: each segment is + consisting of several subchannels with a predefined IDs. A sub-channel + is used to help the demodulator to synchronize on the channel.</para> + + <para>An ISDB-T channel is always centered over all sub-channels. As for + the example above, in ISDB-Tsb it is no longer as simple as that.</para> + + <para><constant>The DTV_ISDBT_SB_SUBCHANNEL_ID</constant> parameter is used to give the + sub-channel ID of the segment to be demodulated.</para> + + <para>Possible values: 0 .. 41, -1 (AUTO)</para> + </section> + <section id="DTV-ISDBT-SB-SEGMENT-IDX"> + <title><constant>DTV_ISDBT_SB_SEGMENT_IDX</constant></title> + <para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para> + <para><constant>DTV_ISDBT_SB_SEGMENT_IDX</constant> gives the index of the segment to be + demodulated for an ISDB-Tsb channel where several of them are + transmitted in the connected manner.</para> + <para>Possible values: 0 .. <constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant> - 1</para> + <para>Note: This value cannot be determined by an automatic channel search.</para> + </section> + <section id="DTV-ISDBT-SB-SEGMENT-COUNT"> + <title><constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant></title> + <para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para> + <para><constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant> gives the total count of connected ISDB-Tsb + channels.</para> + <para>Possible values: 1 .. 13</para> + <para>Note: This value cannot be determined by an automatic channel search.</para> + </section> + <section id="isdb-hierq-layers"> + <title><constant>DTV-ISDBT-LAYER*</constant> parameters</title> + <para>ISDB-T channels can be coded hierarchically. As opposed to DVB-T in + ISDB-T hierarchical layers can be decoded simultaneously. For that + reason a ISDB-T demodulator has 3 viterbi and 3 reed-solomon-decoders.</para> + <para>ISDB-T has 3 hierarchical layers which each can use a part of the + available segments. The total number of segments over all layers has + to 13 in ISDB-T.</para> + <para>There are 3 parameter sets, for Layers A, B and C.</para> + <section id="DTV-ISDBT-LAYER-ENABLED"> + <title><constant>DTV_ISDBT_LAYER_ENABLED</constant></title> + <para>Hierarchical reception in ISDB-T is achieved by enabling or disabling + layers in the decoding process. Setting all bits of + <constant>DTV_ISDBT_LAYER_ENABLED</constant> to '1' forces all layers (if applicable) to be + demodulated. This is the default.</para> + <para>If the channel is in the partial reception mode + (<constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> = 1) the central segment can be decoded + independently of the other 12 segments. In that mode layer A has to + have a <constant>SEGMENT_COUNT</constant> of 1.</para> + <para>In ISDB-Tsb only layer A is used, it can be 1 or 3 in ISDB-Tsb + according to <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>. <constant>SEGMENT_COUNT</constant> must be filled + accordingly.</para> + <para>Possible values: 0x1, 0x2, 0x4 (|-able)</para> + <para><constant>DTV_ISDBT_LAYER_ENABLED[0:0]</constant> - layer A</para> + <para><constant>DTV_ISDBT_LAYER_ENABLED[1:1]</constant> - layer B</para> + <para><constant>DTV_ISDBT_LAYER_ENABLED[2:2]</constant> - layer C</para> + <para><constant>DTV_ISDBT_LAYER_ENABLED[31:3]</constant> unused</para> + </section> + <section id="DTV-ISDBT-LAYER-FEC"> + <title><constant>DTV_ISDBT_LAYER*_FEC</constant></title> + <para>Possible values: <constant>FEC_AUTO</constant>, <constant>FEC_1_2</constant>, <constant>FEC_2_3</constant>, <constant>FEC_3_4</constant>, <constant>FEC_5_6</constant>, <constant>FEC_7_8</constant></para> + </section> + <section id="DTV-ISDBT-LAYER-MODULATION"> + <title><constant>DTV_ISDBT_LAYER*_MODULATION</constant></title> + <para>Possible values: <constant>QAM_AUTO</constant>, QP<constant>SK, QAM_16</constant>, <constant>QAM_64</constant>, <constant>DQPSK</constant></para> + <para>Note: If layer C is <constant>DQPSK</constant> layer B has to be <constant>DQPSK</constant>. If layer B is <constant>DQPSK</constant> + and <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>=0 layer has to be <constant>DQPSK</constant>.</para> + </section> + <section id="DTV-ISDBT-LAYER-SEGMENT-COUNT"> + <title><constant>DTV_ISDBT_LAYER*_SEGMENT_COUNT</constant></title> + <para>Possible values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, -1 (AUTO)</para> + <para>Note: Truth table for <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> and + <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> and <constant>LAYER</constant>*_SEGMENT_COUNT</para> + <informaltable id="isdbt-layer_seg-cnt-table"> + <tgroup cols="6"> + <tbody> + <row> + <entry>PR</entry> + <entry>SB</entry> + <entry>Layer A width</entry> + <entry>Layer B width</entry> + <entry>Layer C width</entry> + <entry>total width</entry> + </row> + <row> + <entry>0</entry> + <entry>0</entry> + <entry>1 .. 13</entry> + <entry>1 .. 13</entry> + <entry>1 .. 13</entry> + <entry>13</entry> + </row> + <row> + <entry>1</entry> + <entry>0</entry> + <entry>1</entry> + <entry>1 .. 13</entry> + <entry>1 .. 13</entry> + <entry>13</entry> + </row> + <row> + <entry>0</entry> + <entry>1</entry> + <entry>1</entry> + <entry>0</entry> + <entry>0</entry> + <entry>1</entry> + </row> + <row> + <entry>1</entry> + <entry>1</entry> + <entry>1</entry> + <entry>2</entry> + <entry>0</entry> + <entry>13</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </section> + <section id="DTV-ISDBT-LAYER-TIME-INTERLEAVING"> + <title><constant>DTV_ISDBT_LAYER*_TIME_INTERLEAVING</constant></title> + <para>Possible values: 0, 1, 2, 3, -1 (AUTO)</para> + <para>Note: The real inter-leaver depth-names depend on the mode (fft-size); the values + here are referring to what can be found in the TMCC-structure - + independent of the mode.</para> + </section> + </section> + <section id="DTV-API-VERSION"> + <title><constant>DTV_API_VERSION</constant></title> + <para>Returns the major/minor version of the DVB API</para> + </section> + <section id="DTV-CODE-RATE-HP"> + <title><constant>DTV_CODE_RATE_HP</constant></title> + <para>Used on terrestrial transmissions. The acceptable values are: + </para> + <programlisting> +typedef enum fe_code_rate { + FEC_NONE = 0, + FEC_1_2, + FEC_2_3, + FEC_3_4, + FEC_4_5, + FEC_5_6, + FEC_6_7, + FEC_7_8, + FEC_8_9, + FEC_AUTO, + FEC_3_5, + FEC_9_10, +} fe_code_rate_t; + </programlisting> + </section> + <section id="DTV-CODE-RATE-LP"> + <title><constant>DTV_CODE_RATE_LP</constant></title> + <para>Used on terrestrial transmissions. The acceptable values are: + </para> + <programlisting> +typedef enum fe_code_rate { + FEC_NONE = 0, + FEC_1_2, + FEC_2_3, + FEC_3_4, + FEC_4_5, + FEC_5_6, + FEC_6_7, + FEC_7_8, + FEC_8_9, + FEC_AUTO, + FEC_3_5, + FEC_9_10, +} fe_code_rate_t; + </programlisting> + </section> + <section id="DTV-GUARD-INTERVAL"> + <title><constant>DTV_GUARD_INTERVAL</constant></title> + + <para>Possible values are:</para> +<programlisting> +typedef enum fe_guard_interval { + GUARD_INTERVAL_1_32, + GUARD_INTERVAL_1_16, + GUARD_INTERVAL_1_8, + GUARD_INTERVAL_1_4, + GUARD_INTERVAL_AUTO, + GUARD_INTERVAL_1_128, + GUARD_INTERVAL_19_128, + GUARD_INTERVAL_19_256, +} fe_guard_interval_t; +</programlisting> + + <para>Notes:</para> + <para>1) If <constant>DTV_GUARD_INTERVAL</constant> is set the <constant>GUARD_INTERVAL_AUTO</constant> the hardware will + try to find the correct guard interval (if capable) and will use TMCC to fill + in the missing parameters.</para> + <para>2) Intervals 1/128, 19/128 and 19/256 are used only for DVB-T2 at present</para> + </section> + <section id="DTV-TRANSMISSION-MODE"> + <title><constant>DTV_TRANSMISSION_MODE</constant></title> + + <para>Specifies the number of carriers used by the standard</para> + + <para>Possible values are:</para> +<programlisting> +typedef enum fe_transmit_mode { + TRANSMISSION_MODE_2K, + TRANSMISSION_MODE_8K, + TRANSMISSION_MODE_AUTO, + TRANSMISSION_MODE_4K, + TRANSMISSION_MODE_1K, + TRANSMISSION_MODE_16K, + TRANSMISSION_MODE_32K, +} fe_transmit_mode_t; +</programlisting> + <para>Notes:</para> + <para>1) ISDB-T supports three carrier/symbol-size: 8K, 4K, 2K. It is called + 'mode' in the standard: Mode 1 is 2K, mode 2 is 4K, mode 3 is 8K</para> + + <para>2) If <constant>DTV_TRANSMISSION_MODE</constant> is set the <constant>TRANSMISSION_MODE_AUTO</constant> the + hardware will try to find the correct FFT-size (if capable) and will + use TMCC to fill in the missing parameters.</para> + <para>3) DVB-T specifies 2K and 8K as valid sizes.</para> + <para>4) DVB-T2 specifies 1K, 2K, 4K, 8K, 16K and 32K.</para> + </section> + <section id="DTV-HIERARCHY"> + <title><constant>DTV_HIERARCHY</constant></title> + <para>Frontend hierarchy</para> + <programlisting> +typedef enum fe_hierarchy { + HIERARCHY_NONE, + HIERARCHY_1, + HIERARCHY_2, + HIERARCHY_4, + HIERARCHY_AUTO + } fe_hierarchy_t; + </programlisting> + </section> + <section id="DTV-ISDBS-TS-ID"> + <title><constant>DTV_ISDBS_TS_ID</constant></title> + <para>Currently unused.</para> + </section> + <section id="DTV-DVBT2-PLP-ID"> + <title><constant>DTV_DVBT2_PLP_ID</constant></title> + <para>DVB-T2 supports Physical Layer Pipes (PLP) to allow transmission of + many data types via a single multiplex. The API will soon support this + at which point this section will be expanded.</para> + </section> + <section id="DTV_ENUM_DELSYS"> + <title><constant>DTV_ENUM_DELSYS</constant></title> + <para>A Multi standard frontend needs to advertise the delivery systems provided. + Applications need to enumerate the provided delivery systems, before using + any other operation with the frontend. Prior to it's introduction, + FE_GET_INFO was used to determine a frontend type. A frontend which + provides more than a single delivery system, FE_GET_INFO doesn't help much. + Applications which intends to use a multistandard frontend must enumerate + the delivery systems associated with it, rather than trying to use + FE_GET_INFO. In the case of a legacy frontend, the result is just the same + as with FE_GET_INFO, but in a more structured format </para> + </section> +</section> + <section id="frontend-property-terrestrial-systems"> + <title>Properties used on terrestrial delivery systems</title> + <section id="dvbt-params"> + <title>DVB-T delivery system</title> + <para>The following parameters are valid for DVB-T:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-BANDWIDTH-HZ"><constant>DTV_BANDWIDTH_HZ</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CODE-RATE-HP"><constant>DTV_CODE_RATE_HP</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CODE-RATE-LP"><constant>DTV_CODE_RATE_LP</constant></link></para></listitem> + <listitem><para><link linkend="DTV-GUARD-INTERVAL"><constant>DTV_GUARD_INTERVAL</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TRANSMISSION-MODE"><constant>DTV_TRANSMISSION_MODE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-HIERARCHY"><constant>DTV_HIERARCHY</constant></link></para></listitem> + </itemizedlist> + </section> + <section id="dvbt2-params"> + <title>DVB-T2 delivery system</title> + <para>DVB-T2 support is currently in the early stages + of development, so expect that this section maygrow and become + more detailed with time.</para> + <para>The following parameters are valid for DVB-T2:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-BANDWIDTH-HZ"><constant>DTV_BANDWIDTH_HZ</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CODE-RATE-HP"><constant>DTV_CODE_RATE_HP</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CODE-RATE-LP"><constant>DTV_CODE_RATE_LP</constant></link></para></listitem> + <listitem><para><link linkend="DTV-GUARD-INTERVAL"><constant>DTV_GUARD_INTERVAL</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TRANSMISSION-MODE"><constant>DTV_TRANSMISSION_MODE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-HIERARCHY"><constant>DTV_HIERARCHY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DVBT2-PLP-ID"><constant>DTV_DVBT2_PLP_ID</constant></link></para></listitem> + </itemizedlist> + </section> + <section id="isdbt"> + <title>ISDB-T delivery system</title> + <para>This ISDB-T/ISDB-Tsb API extension should reflect all information + needed to tune any ISDB-T/ISDB-Tsb hardware. Of course it is possible + that some very sophisticated devices won't need certain parameters to + tune.</para> + <para>The information given here should help application writers to know how + to handle ISDB-T and ISDB-Tsb hardware using the Linux DVB-API.</para> + <para>The details given here about ISDB-T and ISDB-Tsb are just enough to + basically show the dependencies between the needed parameter values, + but surely some information is left out. For more detailed information + see the following documents:</para> + <para>ARIB STD-B31 - "Transmission System for Digital Terrestrial + Television Broadcasting" and</para> + <para>ARIB TR-B14 - "Operational Guidelines for Digital Terrestrial + Television Broadcasting".</para> + <para>In order to understand the ISDB specific parameters, + one has to have some knowledge the channel structure in + ISDB-T and ISDB-Tsb. I.e. it has to be known to + the reader that an ISDB-T channel consists of 13 segments, + that it can have up to 3 layer sharing those segments, + and things like that.</para> + <para>The following parameters are valid for ISDB-T:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-BANDWIDTH-HZ"><constant>DTV_BANDWIDTH_HZ</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-GUARD-INTERVAL"><constant>DTV_GUARD_INTERVAL</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TRANSMISSION-MODE"><constant>DTV_TRANSMISSION_MODE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-ENABLED"><constant>DTV_ISDBT_LAYER_ENABLED</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-PARTIAL-RECEPTION"><constant>DTV_ISDBT_PARTIAL_RECEPTION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-SOUND-BROADCASTING"><constant>DTV_ISDBT_SOUND_BROADCASTING</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-SB-SUBCHANNEL-ID"><constant>DTV_ISDBT_SB_SUBCHANNEL_ID</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-SB-SEGMENT-IDX"><constant>DTV_ISDBT_SB_SEGMENT_IDX</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-SB-SEGMENT-COUNT"><constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-FEC"><constant>DTV_ISDBT_LAYERA_FEC</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-MODULATION"><constant>DTV_ISDBT_LAYERA_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-SEGMENT-COUNT"><constant>DTV_ISDBT_LAYERA_SEGMENT_COUNT</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-TIME-INTERLEAVING"><constant>DTV_ISDBT_LAYERA_TIME_INTERLEAVING</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-FEC"><constant>DTV_ISDBT_LAYERB_FEC</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-MODULATION"><constant>DTV_ISDBT_LAYERB_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-SEGMENT-COUNT"><constant>DTV_ISDBT_LAYERB_SEGMENT_COUNT</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-TIME-INTERLEAVING"><constant>DTV_ISDBT_LAYERB_TIME_INTERLEAVING</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-FEC"><constant>DTV_ISDBT_LAYERC_FEC</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-MODULATION"><constant>DTV_ISDBT_LAYERC_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-SEGMENT-COUNT"><constant>DTV_ISDBT_LAYERC_SEGMENT_COUNT</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBT-LAYER-TIME-INTERLEAVING"><constant>DTV_ISDBT_LAYERC_TIME_INTERLEAVING</constant></link></para></listitem> + </itemizedlist> + </section> + <section id="atsc-params"> + <title>ATSC delivery system</title> + <para>The following parameters are valid for ATSC:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-BANDWIDTH-HZ"><constant>DTV_BANDWIDTH_HZ</constant></link></para></listitem> + </itemizedlist> + </section> + </section> + <section id="frontend-property-cable-systems"> + <title>Properties used on cable delivery systems</title> + <section id="dvbc-params"> + <title>DVB-C delivery system</title> + <para>The DVB-C Annex-A is the widely used cable standard. Transmission uses QAM modulation.</para> + <para>The DVB-C Annex-C is optimized for 6MHz, and is used in Japan. It supports a subset of the Annex A modulation types, and a roll-off of 0.13, instead of 0.15</para> + <para>The following parameters are valid for DVB-C Annex A/C:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-SYMBOL-RATE"><constant>DTV_SYMBOL_RATE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INNER-FEC"><constant>DTV_INNER_FEC</constant></link></para></listitem> + </itemizedlist> + </section> + <section id="dvbc-annex-b-params"> + <title>DVB-C Annex B delivery system</title> + <para>The DVB-C Annex-B is only used on a few Countries like the United States.</para> + <para>The following parameters are valid for DVB-C Annex B:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem> + </itemizedlist> + </section> + </section> + <section id="frontend-property-satellital-systems"> + <title>Properties used on satellital delivery systems</title> + <section id="dvbs-params"> + <title>DVB-S delivery system</title> + <para>The following parameters are valid for DVB-S:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-SYMBOL-RATE"><constant>DTV_SYMBOL_RATE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INNER-FEC"><constant>DTV_INNER_FEC</constant></link></para></listitem> + <listitem><para><link linkend="DTV-VOLTAGE"><constant>DTV_VOLTAGE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TONE"><constant>DTV_TONE</constant></link></para></listitem> + </itemizedlist> + <para>Future implementations might add those two missing parameters:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-DISEQC-MASTER"><constant>DTV_DISEQC_MASTER</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DISEQC-SLAVE-REPLY"><constant>DTV_DISEQC_SLAVE_REPLY</constant></link></para></listitem> + </itemizedlist> + </section> + <section id="dvbs2-params"> + <title>DVB-S2 delivery system</title> + <para>In addition to all parameters valid for DVB-S, DVB-S2 supports the following parameters:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-PILOT"><constant>DTV_PILOT</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ROLLOFF"><constant>DTV_ROLLOFF</constant></link></para></listitem> + </itemizedlist> + </section> + <section id="turbo-params"> + <title>Turbo code delivery system</title> + <para>In addition to all parameters valid for DVB-S, turbo code supports the following parameters:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem> + </itemizedlist> + </section> + <section id="isdbs-params"> + <title>ISDB-S delivery system</title> + <para>The following parameters are valid for ISDB-S:</para> + <itemizedlist mark='opencircle'> + <listitem><para><link linkend="DTV-API-VERSION"><constant>DTV_API_VERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-DELIVERY-SYSTEM"><constant>DTV_DELIVERY_SYSTEM</constant></link></para></listitem> + <listitem><para><link linkend="DTV-TUNE"><constant>DTV_TUNE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-CLEAR"><constant>DTV_CLEAR</constant></link></para></listitem> + <listitem><para><link linkend="DTV-FREQUENCY"><constant>DTV_FREQUENCY</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem> + <listitem><para><link linkend="DTV-SYMBOL-RATE"><constant>DTV_SYMBOL_RATE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-INNER-FEC"><constant>DTV_INNER_FEC</constant></link></para></listitem> + <listitem><para><link linkend="DTV-VOLTAGE"><constant>DTV_VOLTAGE</constant></link></para></listitem> + <listitem><para><link linkend="DTV-ISDBS-TS-ID"><constant>DTV_ISDBS_TS_ID</constant></link></para></listitem> + </itemizedlist> + </section> + </section> +</section> diff --git a/Documentation/DocBook/media/dvb/dvbstb.pdf b/Documentation/DocBook/media/dvb/dvbstb.pdf Binary files differnew file mode 100644 index 00000000..0fa75d90 --- /dev/null +++ b/Documentation/DocBook/media/dvb/dvbstb.pdf diff --git a/Documentation/DocBook/media/dvb/examples.xml b/Documentation/DocBook/media/dvb/examples.xml new file mode 100644 index 00000000..f037e568 --- /dev/null +++ b/Documentation/DocBook/media/dvb/examples.xml @@ -0,0 +1,365 @@ +<title>Examples</title> +<para>In this section we would like to present some examples for using the DVB API. +</para> +<para>Maintainer note: This section is out of date. Please refer to the sample programs packaged +with the driver distribution from <ulink url="http://linuxtv.org/hg/dvb-apps" />. +</para> + +<section id="tuning"> +<title>Tuning</title> +<para>We will start with a generic tuning subroutine that uses the frontend and SEC, as well as +the demux devices. The example is given for QPSK tuners, but can easily be adjusted for +QAM. +</para> +<programlisting> + #include <sys/ioctl.h> + #include <stdio.h> + #include <stdint.h> + #include <sys/types.h> + #include <sys/stat.h> + #include <fcntl.h> + #include <time.h> + #include <unistd.h> + + #include <linux/dvb/dmx.h> + #include <linux/dvb/frontend.h> + #include <linux/dvb/sec.h> + #include <sys/poll.h> + + #define DMX "/dev/dvb/adapter0/demux1" + #define FRONT "/dev/dvb/adapter0/frontend1" + #define SEC "/dev/dvb/adapter0/sec1" + + /⋆ routine for checking if we have a signal and other status information⋆/ + int FEReadStatus(int fd, fe_status_t ⋆stat) + { + int ans; + + if ( (ans = ioctl(fd,FE_READ_STATUS,stat) < 0)){ + perror("FE READ STATUS: "); + return -1; + } + + if (⋆stat & FE_HAS_POWER) + printf("FE HAS POWER\n"); + + if (⋆stat & FE_HAS_SIGNAL) + printf("FE HAS SIGNAL\n"); + + if (⋆stat & FE_SPECTRUM_INV) + printf("SPEKTRUM INV\n"); + + return 0; + } + + + /⋆ tune qpsk ⋆/ + /⋆ freq: frequency of transponder ⋆/ + /⋆ vpid, apid, tpid: PIDs of video, audio and teletext TS packets ⋆/ + /⋆ diseqc: DiSEqC address of the used LNB ⋆/ + /⋆ pol: Polarisation ⋆/ + /⋆ srate: Symbol Rate ⋆/ + /⋆ fec. FEC ⋆/ + /⋆ lnb_lof1: local frequency of lower LNB band ⋆/ + /⋆ lnb_lof2: local frequency of upper LNB band ⋆/ + /⋆ lnb_slof: switch frequency of LNB ⋆/ + + int set_qpsk_channel(int freq, int vpid, int apid, int tpid, + int diseqc, int pol, int srate, int fec, int lnb_lof1, + int lnb_lof2, int lnb_slof) + { + struct secCommand scmd; + struct secCmdSequence scmds; + struct dmx_pes_filter_params pesFilterParams; + FrontendParameters frp; + struct pollfd pfd[1]; + FrontendEvent event; + int demux1, demux2, demux3, front; + + frequency = (uint32_t) freq; + symbolrate = (uint32_t) srate; + + if((front = open(FRONT,O_RDWR)) < 0){ + perror("FRONTEND DEVICE: "); + return -1; + } + + if((sec = open(SEC,O_RDWR)) < 0){ + perror("SEC DEVICE: "); + return -1; + } + + if (demux1 < 0){ + if ((demux1=open(DMX, O_RDWR|O_NONBLOCK)) + < 0){ + perror("DEMUX DEVICE: "); + return -1; + } + } + + if (demux2 < 0){ + if ((demux2=open(DMX, O_RDWR|O_NONBLOCK)) + < 0){ + perror("DEMUX DEVICE: "); + return -1; + } + } + + if (demux3 < 0){ + if ((demux3=open(DMX, O_RDWR|O_NONBLOCK)) + < 0){ + perror("DEMUX DEVICE: "); + return -1; + } + } + + if (freq < lnb_slof) { + frp.Frequency = (freq - lnb_lof1); + scmds.continuousTone = SEC_TONE_OFF; + } else { + frp.Frequency = (freq - lnb_lof2); + scmds.continuousTone = SEC_TONE_ON; + } + frp.Inversion = INVERSION_AUTO; + if (pol) scmds.voltage = SEC_VOLTAGE_18; + else scmds.voltage = SEC_VOLTAGE_13; + + scmd.type=0; + scmd.u.diseqc.addr=0x10; + scmd.u.diseqc.cmd=0x38; + scmd.u.diseqc.numParams=1; + scmd.u.diseqc.params[0] = 0xF0 | ((diseqc ⋆ 4) & 0x0F) | + (scmds.continuousTone == SEC_TONE_ON ? 1 : 0) | + (scmds.voltage==SEC_VOLTAGE_18 ? 2 : 0); + + scmds.miniCommand=SEC_MINI_NONE; + scmds.numCommands=1; + scmds.commands=&scmd; + if (ioctl(sec, SEC_SEND_SEQUENCE, &scmds) < 0){ + perror("SEC SEND: "); + return -1; + } + + if (ioctl(sec, SEC_SEND_SEQUENCE, &scmds) < 0){ + perror("SEC SEND: "); + return -1; + } + + frp.u.qpsk.SymbolRate = srate; + frp.u.qpsk.FEC_inner = fec; + + if (ioctl(front, FE_SET_FRONTEND, &frp) < 0){ + perror("QPSK TUNE: "); + return -1; + } + + pfd[0].fd = front; + pfd[0].events = POLLIN; + + if (poll(pfd,1,3000)){ + if (pfd[0].revents & POLLIN){ + printf("Getting QPSK event\n"); + if ( ioctl(front, FE_GET_EVENT, &event) + + == -EOVERFLOW){ + perror("qpsk get event"); + return -1; + } + printf("Received "); + switch(event.type){ + case FE_UNEXPECTED_EV: + printf("unexpected event\n"); + return -1; + case FE_FAILURE_EV: + printf("failure event\n"); + return -1; + + case FE_COMPLETION_EV: + printf("completion event\n"); + } + } + } + + + pesFilterParams.pid = vpid; + pesFilterParams.input = DMX_IN_FRONTEND; + pesFilterParams.output = DMX_OUT_DECODER; + pesFilterParams.pes_type = DMX_PES_VIDEO; + pesFilterParams.flags = DMX_IMMEDIATE_START; + if (ioctl(demux1, DMX_SET_PES_FILTER, &pesFilterParams) < 0){ + perror("set_vpid"); + return -1; + } + + pesFilterParams.pid = apid; + pesFilterParams.input = DMX_IN_FRONTEND; + pesFilterParams.output = DMX_OUT_DECODER; + pesFilterParams.pes_type = DMX_PES_AUDIO; + pesFilterParams.flags = DMX_IMMEDIATE_START; + if (ioctl(demux2, DMX_SET_PES_FILTER, &pesFilterParams) < 0){ + perror("set_apid"); + return -1; + } + + pesFilterParams.pid = tpid; + pesFilterParams.input = DMX_IN_FRONTEND; + pesFilterParams.output = DMX_OUT_DECODER; + pesFilterParams.pes_type = DMX_PES_TELETEXT; + pesFilterParams.flags = DMX_IMMEDIATE_START; + if (ioctl(demux3, DMX_SET_PES_FILTER, &pesFilterParams) < 0){ + perror("set_tpid"); + return -1; + } + + return has_signal(fds); + } + +</programlisting> +<para>The program assumes that you are using a universal LNB and a standard DiSEqC +switch with up to 4 addresses. Of course, you could build in some more checking if +tuning was successful and maybe try to repeat the tuning process. Depending on the +external hardware, i.e. LNB and DiSEqC switch, and weather conditions this may be +necessary. +</para> +</section> + +<section id="the_dvr_device"> +<title>The DVR device</title> +<para>The following program code shows how to use the DVR device for recording. +</para> +<programlisting> + #include <sys/ioctl.h> + #include <stdio.h> + #include <stdint.h> + #include <sys/types.h> + #include <sys/stat.h> + #include <fcntl.h> + #include <time.h> + #include <unistd.h> + + #include <linux/dvb/dmx.h> + #include <linux/dvb/video.h> + #include <sys/poll.h> + #define DVR "/dev/dvb/adapter0/dvr1" + #define AUDIO "/dev/dvb/adapter0/audio1" + #define VIDEO "/dev/dvb/adapter0/video1" + + #define BUFFY (188⋆20) + #define MAX_LENGTH (1024⋆1024⋆5) /⋆ record 5MB ⋆/ + + + /⋆ switch the demuxes to recording, assuming the transponder is tuned ⋆/ + + /⋆ demux1, demux2: file descriptor of video and audio filters ⋆/ + /⋆ vpid, apid: PIDs of video and audio channels ⋆/ + + int switch_to_record(int demux1, int demux2, uint16_t vpid, uint16_t apid) + { + struct dmx_pes_filter_params pesFilterParams; + + if (demux1 < 0){ + if ((demux1=open(DMX, O_RDWR|O_NONBLOCK)) + < 0){ + perror("DEMUX DEVICE: "); + return -1; + } + } + + if (demux2 < 0){ + if ((demux2=open(DMX, O_RDWR|O_NONBLOCK)) + < 0){ + perror("DEMUX DEVICE: "); + return -1; + } + } + + pesFilterParams.pid = vpid; + pesFilterParams.input = DMX_IN_FRONTEND; + pesFilterParams.output = DMX_OUT_TS_TAP; + pesFilterParams.pes_type = DMX_PES_VIDEO; + pesFilterParams.flags = DMX_IMMEDIATE_START; + if (ioctl(demux1, DMX_SET_PES_FILTER, &pesFilterParams) < 0){ + perror("DEMUX DEVICE"); + return -1; + } + pesFilterParams.pid = apid; + pesFilterParams.input = DMX_IN_FRONTEND; + pesFilterParams.output = DMX_OUT_TS_TAP; + pesFilterParams.pes_type = DMX_PES_AUDIO; + pesFilterParams.flags = DMX_IMMEDIATE_START; + if (ioctl(demux2, DMX_SET_PES_FILTER, &pesFilterParams) < 0){ + perror("DEMUX DEVICE"); + return -1; + } + return 0; + } + + /⋆ start recording MAX_LENGTH , assuming the transponder is tuned ⋆/ + + /⋆ demux1, demux2: file descriptor of video and audio filters ⋆/ + /⋆ vpid, apid: PIDs of video and audio channels ⋆/ + int record_dvr(int demux1, int demux2, uint16_t vpid, uint16_t apid) + { + int i; + int len; + int written; + uint8_t buf[BUFFY]; + uint64_t length; + struct pollfd pfd[1]; + int dvr, dvr_out; + + /⋆ open dvr device ⋆/ + if ((dvr = open(DVR, O_RDONLY|O_NONBLOCK)) < 0){ + perror("DVR DEVICE"); + return -1; + } + + /⋆ switch video and audio demuxes to dvr ⋆/ + printf ("Switching dvr on\n"); + i = switch_to_record(demux1, demux2, vpid, apid); + printf("finished: "); + + printf("Recording %2.0f MB of test file in TS format\n", + MAX_LENGTH/(1024.0⋆1024.0)); + length = 0; + + /⋆ open output file ⋆/ + if ((dvr_out = open(DVR_FILE,O_WRONLY|O_CREAT + |O_TRUNC, S_IRUSR|S_IWUSR + |S_IRGRP|S_IWGRP|S_IROTH| + S_IWOTH)) < 0){ + perror("Can't open file for dvr test"); + return -1; + } + + pfd[0].fd = dvr; + pfd[0].events = POLLIN; + + /⋆ poll for dvr data and write to file ⋆/ + while (length < MAX_LENGTH ) { + if (poll(pfd,1,1)){ + if (pfd[0].revents & POLLIN){ + len = read(dvr, buf, BUFFY); + if (len < 0){ + perror("recording"); + return -1; + } + if (len > 0){ + written = 0; + while (written < len) + written += + write (dvr_out, + buf, len); + length += len; + printf("written %2.0f MB\r", + length/1024./1024.); + } + } + } + } + return 0; + } + +</programlisting> + +</section> diff --git a/Documentation/DocBook/media/dvb/frontend.xml b/Documentation/DocBook/media/dvb/frontend.xml new file mode 100644 index 00000000..aeaed59d --- /dev/null +++ b/Documentation/DocBook/media/dvb/frontend.xml @@ -0,0 +1,1519 @@ +<title>DVB Frontend API</title> + +<para>The DVB frontend device controls the tuner and DVB demodulator +hardware. It can be accessed through <emphasis +role="tt">/dev/dvb/adapter0/frontend0</emphasis>. Data types and and +ioctl definitions can be accessed by including <emphasis +role="tt">linux/dvb/frontend.h</emphasis> in your application.</para> + +<para>DVB frontends come in three varieties: DVB-S (satellite), DVB-C +(cable) and DVB-T (terrestrial). Transmission via the internet (DVB-IP) +is not yet handled by this API but a future extension is possible. For +DVB-S the frontend device also supports satellite equipment control +(SEC) via DiSEqC and V-SEC protocols. The DiSEqC (digital SEC) +specification is available from +<ulink url="http://www.eutelsat.com/satellites/4_5_5.html">Eutelsat</ulink>.</para> + +<para>Note that the DVB API may also be used for MPEG decoder-only PCI +cards, in which case there exists no frontend device.</para> + +<section id="frontend_types"> +<title>Frontend Data Types</title> + +<section id="fe-type-t"> +<title>Frontend type</title> + +<para>For historical reasons, frontend types are named by the type of modulation used in +transmission. The fontend types are given by fe_type_t type, defined as:</para> + +<table pgwide="1" frame="none" id="fe-type"> +<title>Frontend types</title> +<tgroup cols="3"> + &cs-def; + <thead> + <row> + <entry>fe_type</entry> + <entry>Description</entry> + <entry><link linkend="DTV-DELIVERY-SYSTEM">DTV_DELIVERY_SYSTEM</link> equivalent type</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry id="FE_QPSK"><constant>FE_QPSK</constant></entry> + <entry>For DVB-S standard</entry> + <entry><constant>SYS_DVBS</constant></entry> + </row> + <row> + <entry id="FE_QAM"><constant>FE_QAM</constant></entry> + <entry>For DVB-C annex A standard</entry> + <entry><constant>SYS_DVBC_ANNEX_A</constant></entry> + </row> + <row> + <entry id="FE_OFDM"><constant>FE_OFDM</constant></entry> + <entry>For DVB-T standard</entry> + <entry><constant>SYS_DVBT</constant></entry> + </row> + <row> + <entry id="FE_ATSC"><constant>FE_ATSC</constant></entry> + <entry>For ATSC standard (terrestrial) or for DVB-C Annex B (cable) used in US.</entry> + <entry><constant>SYS_ATSC</constant> (terrestrial) or <constant>SYS_DVBC_ANNEX_B</constant> (cable)</entry> + </row> +</tbody></tgroup></table> + +<para>Newer formats like DVB-S2, ISDB-T, ISDB-S and DVB-T2 are not described at the above, as they're +supported via the new <link linkend="FE_GET_SET_PROPERTY">FE_GET_PROPERTY/FE_GET_SET_PROPERTY</link> ioctl's, using the <link linkend="DTV-DELIVERY-SYSTEM">DTV_DELIVERY_SYSTEM</link> parameter. +</para> + +<para>The usage of this field is deprecated, as it doesn't report all supported standards, and +will provide an incomplete information for frontends that support multiple delivery systems. +Please use <link linkend="DTV_ENUM_DELSYS">DTV_ENUM_DELSYS</link> instead.</para> +</section> + +<section id="fe-caps-t"> +<title>frontend capabilities</title> + +<para>Capabilities describe what a frontend can do. Some capabilities can only be supported for +a specific frontend type.</para> +<programlisting> + typedef enum fe_caps { + FE_IS_STUPID = 0, + FE_CAN_INVERSION_AUTO = 0x1, + FE_CAN_FEC_1_2 = 0x2, + FE_CAN_FEC_2_3 = 0x4, + FE_CAN_FEC_3_4 = 0x8, + FE_CAN_FEC_4_5 = 0x10, + FE_CAN_FEC_5_6 = 0x20, + FE_CAN_FEC_6_7 = 0x40, + FE_CAN_FEC_7_8 = 0x80, + FE_CAN_FEC_8_9 = 0x100, + FE_CAN_FEC_AUTO = 0x200, + FE_CAN_QPSK = 0x400, + FE_CAN_QAM_16 = 0x800, + FE_CAN_QAM_32 = 0x1000, + FE_CAN_QAM_64 = 0x2000, + FE_CAN_QAM_128 = 0x4000, + FE_CAN_QAM_256 = 0x8000, + FE_CAN_QAM_AUTO = 0x10000, + FE_CAN_TRANSMISSION_MODE_AUTO = 0x20000, + FE_CAN_BANDWIDTH_AUTO = 0x40000, + FE_CAN_GUARD_INTERVAL_AUTO = 0x80000, + FE_CAN_HIERARCHY_AUTO = 0x100000, + FE_CAN_8VSB = 0x200000, + FE_CAN_16VSB = 0x400000, + FE_HAS_EXTENDED_CAPS = 0x800000, + FE_CAN_TURBO_FEC = 0x8000000, + FE_CAN_2G_MODULATION = 0x10000000, + FE_NEEDS_BENDING = 0x20000000, + FE_CAN_RECOVER = 0x40000000, + FE_CAN_MUTE_TS = 0x80000000 + } fe_caps_t; +</programlisting> +</section> + +<section id="dvb-frontend-info"> +<title>frontend information</title> + +<para>Information about the frontend ca be queried with + <link linkend="FE_GET_INFO">FE_GET_INFO</link>.</para> + +<programlisting> + struct dvb_frontend_info { + char name[128]; + fe_type_t type; + uint32_t frequency_min; + uint32_t frequency_max; + uint32_t frequency_stepsize; + uint32_t frequency_tolerance; + uint32_t symbol_rate_min; + uint32_t symbol_rate_max; + uint32_t symbol_rate_tolerance; /⋆ ppm ⋆/ + uint32_t notifier_delay; /⋆ ms ⋆/ + fe_caps_t caps; + }; +</programlisting> +</section> + +<section id="dvb-diseqc-master-cmd"> +<title>diseqc master command</title> + +<para>A message sent from the frontend to DiSEqC capable equipment.</para> +<programlisting> + struct dvb_diseqc_master_cmd { + uint8_t msg [6]; /⋆ { framing, address, command, data[3] } ⋆/ + uint8_t msg_len; /⋆ valid values are 3...6 ⋆/ + }; +</programlisting> +</section> +<section role="subsection" id="dvb-diseqc-slave-reply"> +<title>diseqc slave reply</title> + +<para>A reply to the frontend from DiSEqC 2.0 capable equipment.</para> +<programlisting> + struct dvb_diseqc_slave_reply { + uint8_t msg [4]; /⋆ { framing, data [3] } ⋆/ + uint8_t msg_len; /⋆ valid values are 0...4, 0 means no msg ⋆/ + int timeout; /⋆ return from ioctl after timeout ms with ⋆/ + }; /⋆ errorcode when no message was received ⋆/ +</programlisting> +</section> + +<section id="fe-sec-voltage-t"> +<title>diseqc slave reply</title> +<para>The voltage is usually used with non-DiSEqC capable LNBs to switch the polarzation +(horizontal/vertical). When using DiSEqC epuipment this voltage has to be switched +consistently to the DiSEqC commands as described in the DiSEqC spec.</para> +<programlisting> + typedef enum fe_sec_voltage { + SEC_VOLTAGE_13, + SEC_VOLTAGE_18 + } fe_sec_voltage_t; +</programlisting> +</section> + +<section id="fe-sec-tone-mode-t"> +<title>SEC continuous tone</title> + +<para>The continuous 22KHz tone is usually used with non-DiSEqC capable LNBs to switch the +high/low band of a dual-band LNB. When using DiSEqC epuipment this voltage has to +be switched consistently to the DiSEqC commands as described in the DiSEqC +spec.</para> +<programlisting> + typedef enum fe_sec_tone_mode { + SEC_TONE_ON, + SEC_TONE_OFF + } fe_sec_tone_mode_t; +</programlisting> +</section> + +<section id="fe-sec-mini-cmd-t"> +<title>SEC tone burst</title> + +<para>The 22KHz tone burst is usually used with non-DiSEqC capable switches to select +between two connected LNBs/satellites. When using DiSEqC epuipment this voltage has to +be switched consistently to the DiSEqC commands as described in the DiSEqC +spec.</para> +<programlisting> + typedef enum fe_sec_mini_cmd { + SEC_MINI_A, + SEC_MINI_B + } fe_sec_mini_cmd_t; +</programlisting> + +<para></para> +</section> + +<section id="fe-status-t"> +<title>frontend status</title> +<para>Several functions of the frontend device use the fe_status data type defined +by</para> +<programlisting> + typedef enum fe_status { + FE_HAS_SIGNAL = 0x01, /⋆ found something above the noise level ⋆/ + FE_HAS_CARRIER = 0x02, /⋆ found a DVB signal ⋆/ + FE_HAS_VITERBI = 0x04, /⋆ FEC is stable ⋆/ + FE_HAS_SYNC = 0x08, /⋆ found sync bytes ⋆/ + FE_HAS_LOCK = 0x10, /⋆ everything's working... ⋆/ + FE_TIMEDOUT = 0x20, /⋆ no lock within the last ~2 seconds ⋆/ + FE_REINIT = 0x40 /⋆ frontend was reinitialized, ⋆/ + } fe_status_t; /⋆ application is recommned to reset ⋆/ +</programlisting> +<para>to indicate the current state and/or state changes of the frontend hardware. +</para> + +</section> + +<section id="dvb-frontend-parameters"> +<title>frontend parameters</title> +<para>The kind of parameters passed to the frontend device for tuning depend on +the kind of hardware you are using.</para> +<para>The struct <constant>dvb_frontend_parameters</constant> uses an +union with specific per-system parameters. However, as newer delivery systems +required more data, the structure size weren't enough to fit, and just +extending its size would break the existing applications. So, those parameters +were replaced by the usage of <link linkend="FE_GET_SET_PROPERTY"> +<constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant></link> ioctl's. The +new API is flexible enough to add new parameters to existing delivery systems, +and to add newer delivery systems.</para> +<para>So, newer applications should use <link linkend="FE_GET_SET_PROPERTY"> +<constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant></link> instead, in +order to be able to support the newer System Delivery like DVB-S2, DVB-T2, +DVB-C2, ISDB, etc.</para> +<para>All kinds of parameters are combined as an union in the FrontendParameters structure:</para> +<programlisting> +struct dvb_frontend_parameters { + uint32_t frequency; /⋆ (absolute) frequency in Hz for QAM/OFDM ⋆/ + /⋆ intermediate frequency in kHz for QPSK ⋆/ + fe_spectral_inversion_t inversion; + union { + struct dvb_qpsk_parameters qpsk; + struct dvb_qam_parameters qam; + struct dvb_ofdm_parameters ofdm; + struct dvb_vsb_parameters vsb; + } u; +}; +</programlisting> +<para>In the case of QPSK frontends the <constant>frequency</constant> field specifies the intermediate +frequency, i.e. the offset which is effectively added to the local oscillator frequency (LOF) of +the LNB. The intermediate frequency has to be specified in units of kHz. For QAM and +OFDM frontends the <constant>frequency</constant> specifies the absolute frequency and is given in Hz. +</para> +<section id="dvb-qpsk-parameters"> +<title>QPSK parameters</title> +<para>For satellite QPSK frontends you have to use the <constant>dvb_qpsk_parameters</constant> structure:</para> +<programlisting> + struct dvb_qpsk_parameters { + uint32_t symbol_rate; /⋆ symbol rate in Symbols per second ⋆/ + fe_code_rate_t fec_inner; /⋆ forward error correction (see above) ⋆/ + }; +</programlisting> +</section> +<section id="dvb-qam-parameters"> +<title>QAM parameters</title> +<para>for cable QAM frontend you use the <constant>dvb_qam_parameters</constant> structure:</para> +<programlisting> + struct dvb_qam_parameters { + uint32_t symbol_rate; /⋆ symbol rate in Symbols per second ⋆/ + fe_code_rate_t fec_inner; /⋆ forward error correction (see above) ⋆/ + fe_modulation_t modulation; /⋆ modulation type (see above) ⋆/ + }; +</programlisting> +</section> +<section id="dvb-vsb-parameters"> +<title>VSB parameters</title> +<para>ATSC frontends are supported by the <constant>dvb_vsb_parameters</constant> structure:</para> +<programlisting> +struct dvb_vsb_parameters { + fe_modulation_t modulation; /⋆ modulation type (see above) ⋆/ +}; +</programlisting> +</section> +<section id="dvb-ofdm-parameters"> +<title>OFDM parameters</title> +<para>DVB-T frontends are supported by the <constant>dvb_ofdm_parameters</constant> structure:</para> +<programlisting> + struct dvb_ofdm_parameters { + fe_bandwidth_t bandwidth; + fe_code_rate_t code_rate_HP; /⋆ high priority stream code rate ⋆/ + fe_code_rate_t code_rate_LP; /⋆ low priority stream code rate ⋆/ + fe_modulation_t constellation; /⋆ modulation type (see above) ⋆/ + fe_transmit_mode_t transmission_mode; + fe_guard_interval_t guard_interval; + fe_hierarchy_t hierarchy_information; + }; +</programlisting> +</section> +<section id="fe-spectral-inversion-t"> +<title>frontend spectral inversion</title> +<para>The Inversion field can take one of these values: +</para> +<programlisting> +typedef enum fe_spectral_inversion { + INVERSION_OFF, + INVERSION_ON, + INVERSION_AUTO +} fe_spectral_inversion_t; +</programlisting> +<para>It indicates if spectral inversion should be presumed or not. In the automatic setting +(<constant>INVERSION_AUTO</constant>) the hardware will try to figure out the correct setting by +itself. +</para> +</section> +<section id="fe-code-rate-t"> +<title>frontend code rate</title> +<para>The possible values for the <constant>fec_inner</constant> field used on +<link refend="dvb-qpsk-parameters"><constant>struct dvb_qpsk_parameters</constant></link> and +<link refend="dvb-qam-parameters"><constant>struct dvb_qam_parameters</constant></link> are: +</para> +<programlisting> +typedef enum fe_code_rate { + FEC_NONE = 0, + FEC_1_2, + FEC_2_3, + FEC_3_4, + FEC_4_5, + FEC_5_6, + FEC_6_7, + FEC_7_8, + FEC_8_9, + FEC_AUTO, + FEC_3_5, + FEC_9_10, +} fe_code_rate_t; +</programlisting> +<para>which correspond to error correction rates of 1/2, 2/3, etc., no error correction or auto +detection. +</para> +</section> +<section id="fe-modulation-t"> +<title>frontend modulation type for QAM, OFDM and VSB</title> +<para>For cable and terrestrial frontends, e. g. for +<link refend="dvb-qam-parameters"><constant>struct dvb_qpsk_parameters</constant></link>, +<link refend="dvb-ofdm-parameters"><constant>struct dvb_qam_parameters</constant></link> and +<link refend="dvb-vsb-parameters"><constant>struct dvb_qam_parameters</constant></link>, +it needs to specify the quadrature modulation mode which can be one of the following: +</para> +<programlisting> + typedef enum fe_modulation { + QPSK, + QAM_16, + QAM_32, + QAM_64, + QAM_128, + QAM_256, + QAM_AUTO, + VSB_8, + VSB_16, + PSK_8, + APSK_16, + APSK_32, + DQPSK, + } fe_modulation_t; +</programlisting> +</section> +<para>Finally, there are several more parameters for OFDM: +</para> +<section id="fe-transmit-mode-t"> +<title>Number of carriers per channel</title> +<programlisting> +typedef enum fe_transmit_mode { + TRANSMISSION_MODE_2K, + TRANSMISSION_MODE_8K, + TRANSMISSION_MODE_AUTO, + TRANSMISSION_MODE_4K, + TRANSMISSION_MODE_1K, + TRANSMISSION_MODE_16K, + TRANSMISSION_MODE_32K, + } fe_transmit_mode_t; +</programlisting> +</section> +<section id="fe-bandwidth-t"> +<title>frontend bandwidth</title> +<programlisting> +typedef enum fe_bandwidth { + BANDWIDTH_8_MHZ, + BANDWIDTH_7_MHZ, + BANDWIDTH_6_MHZ, + BANDWIDTH_AUTO, + BANDWIDTH_5_MHZ, + BANDWIDTH_10_MHZ, + BANDWIDTH_1_712_MHZ, +} fe_bandwidth_t; +</programlisting> +</section> +<section id="fe-guard-interval-t"> +<title>frontend guard inverval</title> +<programlisting> +typedef enum fe_guard_interval { + GUARD_INTERVAL_1_32, + GUARD_INTERVAL_1_16, + GUARD_INTERVAL_1_8, + GUARD_INTERVAL_1_4, + GUARD_INTERVAL_AUTO, + GUARD_INTERVAL_1_128, + GUARD_INTERVAL_19_128, + GUARD_INTERVAL_19_256, +} fe_guard_interval_t; +</programlisting> +</section> +<section id="fe-hierarchy-t"> +<title>frontend hierarchy</title> +<programlisting> +typedef enum fe_hierarchy { + HIERARCHY_NONE, + HIERARCHY_1, + HIERARCHY_2, + HIERARCHY_4, + HIERARCHY_AUTO + } fe_hierarchy_t; +</programlisting> +</section> + +</section> + +<section id="dvb-frontend-event"> +<title>frontend events</title> + <programlisting> + struct dvb_frontend_event { + fe_status_t status; + struct dvb_frontend_parameters parameters; + }; +</programlisting> + </section> +</section> + + +<section id="frontend_fcalls"> +<title>Frontend Function Calls</title> + +<section id="frontend_f_open"> +<title>open()</title> +<para>DESCRIPTION</para> +<informaltable><tgroup cols="1"><tbody><row> +<entry align="char"> +<para>This system call opens a named frontend device (/dev/dvb/adapter0/frontend0) + for subsequent use. Usually the first thing to do after a successful open is to + find out the frontend type with <link linkend="FE_GET_INFO">FE_GET_INFO</link>.</para> +<para>The device can be opened in read-only mode, which only allows monitoring of + device status and statistics, or read/write mode, which allows any kind of use + (e.g. performing tuning operations.) +</para> +<para>In a system with multiple front-ends, it is usually the case that multiple devices + cannot be open in read/write mode simultaneously. As long as a front-end + device is opened in read/write mode, other open() calls in read/write mode will + either fail or block, depending on whether non-blocking or blocking mode was + specified. A front-end device opened in blocking mode can later be put into + non-blocking mode (and vice versa) using the F_SETFL command of the fcntl + system call. This is a standard system call, documented in the Linux manual + page for fcntl. When an open() call has succeeded, the device will be ready + for use in the specified mode. This implies that the corresponding hardware is + powered up, and that other front-ends may have been powered down to make + that possible.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int open(const char ⋆deviceName, int flags);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>const char + *deviceName</para> +</entry><entry + align="char"> +<para>Name of specific video device.</para> +</entry> + </row><row><entry + align="char"> +<para>int flags</para> +</entry><entry + align="char"> +<para>A bit-wise OR of the following flags:</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDONLY read-only access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDWR read/write access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_NONBLOCK open in non-blocking mode</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>(blocking mode is the default)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>ENODEV</para> +</entry><entry + align="char"> +<para>Device driver not loaded/available.</para> +</entry> + </row><row><entry + align="char"> +<para>EINTERNAL</para> +</entry><entry + align="char"> +<para>Internal error.</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>Device or resource busy.</para> +</entry> + </row><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid argument.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="frontend_f_close"> +<title>close()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call closes a previously opened front-end device. After closing + a front-end device, its corresponding hardware might be powered down + automatically.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int close(int fd);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="FE_READ_STATUS"> +<title>FE_READ_STATUS</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns status information about the front-end. This call only + requires read-only access to the device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_READ_STATUS">FE_READ_STATUS</link>, + fe_status_t ⋆status);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> + +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_READ_STATUS">FE_READ_STATUS</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct fe_status_t + *status</para> +</entry><entry + align="char"> +<para>Points to the location where the front-end status word is + to be stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row><row><entry + align="char"> +<para>EFAULT</para> +</entry><entry + align="char"> +<para>status points to invalid address.</para> +</entry> + </row></tbody></tgroup></informaltable> +</section> + +<section id="FE_READ_BER"> +<title>FE_READ_BER</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns the bit error rate for the signal currently + received/demodulated by the front-end. For this command, read-only access to + the device is sufficient.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_READ_BER">FE_READ_BER</link>, + uint32_t ⋆ber);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_READ_BER">FE_READ_BER</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>uint32_t *ber</para> +</entry><entry + align="char"> +<para>The bit error rate is stored into *ber.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_READ_SNR"> +<title>FE_READ_SNR</title> + +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns the signal-to-noise ratio for the signal currently received + by the front-end. For this command, read-only access to the device is sufficient.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_READ_SNR">FE_READ_SNR</link>, int16_t + ⋆snr);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_READ_SNR">FE_READ_SNR</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int16_t *snr</para> +</entry><entry + align="char"> +<para>The signal-to-noise ratio is stored into *snr.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_READ_SIGNAL_STRENGTH"> +<title>FE_READ_SIGNAL_STRENGTH</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns the signal strength value for the signal currently received + by the front-end. For this command, read-only access to the device is sufficient.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = + <link linkend="FE_READ_SIGNAL_STRENGTH">FE_READ_SIGNAL_STRENGTH</link>, int16_t ⋆strength);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_READ_SIGNAL_STRENGTH">FE_READ_SIGNAL_STRENGTH</link> for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>int16_t *strength</para> +</entry><entry + align="char"> +<para>The signal strength value is stored into *strength.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_READ_UNCORRECTED_BLOCKS"> +<title>FE_READ_UNCORRECTED_BLOCKS</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns the number of uncorrected blocks detected by the device + driver during its lifetime. For meaningful measurements, the increment in block + count during a specific time interval should be calculated. For this command, + read-only access to the device is sufficient.</para> +</entry> + </row><row><entry + align="char"> +<para>Note that the counter will wrap to zero after its maximum count has been + reached.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl( int fd, int request = + <link linkend="FE_READ_UNCORRECTED_BLOCKS">FE_READ_UNCORRECTED_BLOCKS</link>, uint32_t ⋆ublocks);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_READ_UNCORRECTED_BLOCKS">FE_READ_UNCORRECTED_BLOCKS</link> for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>uint32_t *ublocks</para> +</entry><entry + align="char"> +<para>The total number of uncorrected blocks seen by the driver + so far.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_SET_FRONTEND"> +<title>FE_SET_FRONTEND</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call starts a tuning operation using specified parameters. The result + of this call will be successful if the parameters were valid and the tuning could + be initiated. The result of the tuning operation in itself, however, will arrive + asynchronously as an event (see documentation for <link linkend="FE_GET_EVENT">FE_GET_EVENT</link> and + FrontendEvent.) If a new <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link> operation is initiated before + the previous one was completed, the previous operation will be aborted in favor + of the new one. This command requires read/write access to the device.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link>, + struct dvb_frontend_parameters ⋆p);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dvb_frontend_parameters + *p</para> +</entry><entry + align="char"> +<para>Points to parameters for tuning operation.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Maximum supported symbol rate reached.</para> +</entry> +</row></tbody></tgroup></informaltable> +</section> + +<section id="FE_GET_FRONTEND"> +<title>FE_GET_FRONTEND</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call queries the currently effective frontend parameters. For this + command, read-only access to the device is sufficient.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_GET_FRONTEND">FE_GET_FRONTEND</link>, + struct dvb_frontend_parameters ⋆p);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dvb_frontend_parameters + *p</para> +</entry><entry + align="char"> +<para>Points to parameters for tuning operation.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Maximum supported symbol rate reached.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> + +<section id="FE_GET_EVENT"> +<title>FE_GET_EVENT</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns a frontend event if available. If an event is not + available, the behavior depends on whether the device is in blocking or + non-blocking mode. In the latter case, the call fails immediately with errno + set to EWOULDBLOCK. In the former case, the call blocks until an event + becomes available.</para> +</entry> + </row><row><entry + align="char"> +<para>The standard Linux poll() and/or select() system calls can be used with the + device file descriptor to watch for new events. For select(), the file descriptor + should be included in the exceptfds argument, and for poll(), POLLPRI should + be specified as the wake-up condition. Since the event queue allocated is + rather small (room for 8 events), the queue must be serviced regularly to avoid + overflow. If an overflow happens, the oldest event is discarded from the queue, + and an error (EOVERFLOW) occurs the next time the queue is read. After + reporting the error condition in this fashion, subsequent + <link linkend="FE_GET_EVENT">FE_GET_EVENT</link> + calls will return events from the queue as usual.</para> +</entry> + </row><row><entry + align="char"> +<para>For the sake of implementation simplicity, this command requires read/write + access to the device.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = QPSK_GET_EVENT, + struct dvb_frontend_event ⋆ev);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_GET_EVENT">FE_GET_EVENT</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dvb_frontend_event + *ev</para> +</entry><entry + align="char"> +<para>Points to the location where the event,</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>if any, is to be stored.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EWOULDBLOCK</para> +</entry><entry + align="char"> +<para>There is no event pending, and the device is in + non-blocking mode.</para> +</entry> + </row><row><entry + align="char"> +<para>EOVERFLOW</para> +</entry><entry + align="char"> +<para>Overflow in event queue - one or more events were lost.</para> +</entry> +</row></tbody></tgroup></informaltable> +</section> + +<section id="FE_GET_INFO"> +<title>FE_GET_INFO</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns information about the front-end. This call only requires + read-only access to the device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> + +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(int fd, int request = <link linkend="FE_GET_INFO">FE_GET_INFO</link>, struct + dvb_frontend_info ⋆info);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> + +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_GET_INFO">FE_GET_INFO</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dvb_frontend_info + *info</para> +</entry><entry + align="char"> +<para>Points to the location where the front-end information is + to be stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +</section> + +<section id="FE_DISEQC_RESET_OVERLOAD"> +<title>FE_DISEQC_RESET_OVERLOAD</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>If the bus has been automatically powered off due to power overload, this ioctl + call restores the power to the bus. The call requires read/write access to the + device. This call has no effect if the device is manually powered off. Not all + DVB adapters support this ioctl.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + <link linkend="FE_DISEQC_RESET_OVERLOAD">FE_DISEQC_RESET_OVERLOAD</link>);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_DISEQC_RESET_OVERLOAD">FE_DISEQC_RESET_OVERLOAD</link> for this + command.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_DISEQC_SEND_MASTER_CMD"> +<title>FE_DISEQC_SEND_MASTER_CMD</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call is used to send a a DiSEqC command.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + <link linkend="FE_DISEQC_SEND_MASTER_CMD">FE_DISEQC_SEND_MASTER_CMD</link>, struct + dvb_diseqc_master_cmd ⋆cmd);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_DISEQC_SEND_MASTER_CMD">FE_DISEQC_SEND_MASTER_CMD</link> for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dvb_diseqc_master_cmd + *cmd</para> +</entry><entry + align="char"> +<para>Pointer to the command to be transmitted.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_DISEQC_RECV_SLAVE_REPLY"> +<title>FE_DISEQC_RECV_SLAVE_REPLY</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call is used to receive reply to a DiSEqC 2.0 command.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + <link linkend="FE_DISEQC_RECV_SLAVE_REPLY">FE_DISEQC_RECV_SLAVE_REPLY</link>, struct + dvb_diseqc_slave_reply ⋆reply);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_DISEQC_RECV_SLAVE_REPLY">FE_DISEQC_RECV_SLAVE_REPLY</link> for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + dvb_diseqc_slave_reply + *reply</para> +</entry><entry + align="char"> +<para>Pointer to the command to be received.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +</section> + +<section id="FE_DISEQC_SEND_BURST"> +<title>FE_DISEQC_SEND_BURST</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call is used to send a 22KHz tone burst.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + <link linkend="FE_DISEQC_SEND_BURST">FE_DISEQC_SEND_BURST</link>, fe_sec_mini_cmd_t burst);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_DISEQC_SEND_BURST">FE_DISEQC_SEND_BURST</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>fe_sec_mini_cmd_t + burst</para> +</entry><entry + align="char"> +<para>burst A or B.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_SET_TONE"> +<title>FE_SET_TONE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This call is used to set the generation of the continuous 22kHz tone. This call + requires read/write permissions.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_SET_TONE">FE_SET_TONE</link>, + fe_sec_tone_mode_t tone);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_SET_TONE">FE_SET_TONE</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>fe_sec_tone_mode_t + tone</para> +</entry><entry + align="char"> +<para>The requested tone generation mode (on/off).</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +</section> + +<section id="FE_SET_VOLTAGE"> +<title>FE_SET_VOLTAGE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This call is used to set the bus voltage. This call requires read/write + permissions.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = <link linkend="FE_SET_VOLTAGE">FE_SET_VOLTAGE</link>, + fe_sec_voltage_t voltage);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_SET_VOLTAGE">FE_SET_VOLTAGE</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>fe_sec_voltage_t + voltage</para> +</entry><entry + align="char"> +<para>The requested bus voltage.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_ENABLE_HIGH_LNB_VOLTAGE"> +<title>FE_ENABLE_HIGH_LNB_VOLTAGE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>If high != 0 enables slightly higher voltages instead of 13/18V (to compensate + for long cables). This call requires read/write permissions. Not all DVB + adapters support this ioctl.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = + <link linkend="FE_ENABLE_HIGH_LNB_VOLTAGE">FE_ENABLE_HIGH_LNB_VOLTAGE</link>, int high);</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals <link linkend="FE_SET_VOLTAGE">FE_SET_VOLTAGE</link> for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int high</para> +</entry><entry + align="char"> +<para>The requested bus voltage.</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_SET_FRONTEND_TUNE_MODE"> +<title>FE_SET_FRONTEND_TUNE_MODE</title> +<para>DESCRIPTION</para> +<informaltable><tgroup cols="1"><tbody><row> +<entry align="char"> +<para>Allow setting tuner mode flags to the frontend.</para> +</entry> +</row></tbody></tgroup></informaltable> + +<para>SYNOPSIS</para> +<informaltable><tgroup cols="1"><tbody><row> +<entry align="char"> +<para>int ioctl(int fd, int request = +<link linkend="FE_SET_FRONTEND_TUNE_MODE">FE_SET_FRONTEND_TUNE_MODE</link>, unsigned int flags);</para> +</entry> +</row></tbody></tgroup></informaltable> + +<para>PARAMETERS</para> +<informaltable><tgroup cols="2"><tbody><row> +<entry align="char"> + <para>unsigned int flags</para> +</entry> +<entry align="char"> +<para> +FE_TUNE_MODE_ONESHOT When set, this flag will disable any zigzagging or other "normal" tuning behaviour. Additionally, there will be no automatic monitoring of the lock status, and hence no frontend events will be generated. If a frontend device is closed, this flag will be automatically turned off when the device is reopened read-write. +</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +<section id="FE_DISHNETWORK_SEND_LEGACY_CMD"> + <title>FE_DISHNETWORK_SEND_LEGACY_CMD</title> +<para>DESCRIPTION</para> +<informaltable><tgroup cols="1"><tbody><row> +<entry align="char"> +<para>WARNING: This is a very obscure legacy command, used only at stv0299 driver. Should not be used on newer drivers.</para> +<para>It provides a non-standard method for selecting Diseqc voltage on the frontend, for Dish Network legacy switches.</para> +<para>As support for this ioctl were added in 2004, this means that such dishes were already legacy in 2004.</para> +</entry> +</row></tbody></tgroup></informaltable> + +<para>SYNOPSIS</para> +<informaltable><tgroup cols="1"><tbody><row> +<entry align="char"> +<para>int ioctl(int fd, int request = + <link linkend="FE_DISHNETWORK_SEND_LEGACY_CMD">FE_DISHNETWORK_SEND_LEGACY_CMD</link>, unsigned long cmd);</para> +</entry> +</row></tbody></tgroup></informaltable> + +<para>PARAMETERS</para> +<informaltable><tgroup cols="2"><tbody><row> +<entry align="char"> + <para>unsigned long cmd</para> +</entry> +<entry align="char"> +<para> +sends the specified raw cmd to the dish via DISEqC. +</para> +</entry> + </row></tbody></tgroup></informaltable> + +&return-value-dvb; +</section> + +</section> + +&sub-dvbproperty; diff --git a/Documentation/DocBook/media/dvb/intro.xml b/Documentation/DocBook/media/dvb/intro.xml new file mode 100644 index 00000000..170064a3 --- /dev/null +++ b/Documentation/DocBook/media/dvb/intro.xml @@ -0,0 +1,212 @@ +<title>Introduction</title> + +<section id="requisites"> +<title>What you need to know</title> + +<para>The reader of this document is required to have some knowledge in +the area of digital video broadcasting (DVB) and should be familiar with +part I of the MPEG2 specification ISO/IEC 13818 (aka ITU-T H.222), i.e +you should know what a program/transport stream (PS/TS) is and what is +meant by a packetized elementary stream (PES) or an I-frame.</para> + +<para>Various DVB standards documents are available from +<ulink url="http://www.dvb.org" /> and/or +<ulink url="http://www.etsi.org" />.</para> + +<para>It is also necessary to know how to access unix/linux devices and +how to use ioctl calls. This also includes the knowledge of C or C++. +</para> +</section> + +<section id="history"> +<title>History</title> + +<para>The first API for DVB cards we used at Convergence in late 1999 +was an extension of the Video4Linux API which was primarily developed +for frame grabber cards. As such it was not really well suited to be +used for DVB cards and their new features like recording MPEG streams +and filtering several section and PES data streams at the same time. +</para> + +<para>In early 2000, we were approached by Nokia with a proposal for a +new standard Linux DVB API. As a commitment to the development of +terminals based on open standards, Nokia and Convergence made it +available to all Linux developers and published it on +<ulink url="http://www.linuxtv.org/" /> in September 2000. +Convergence is the maintainer of the Linux DVB API. Together with the +LinuxTV community (i.e. you, the reader of this document), the Linux DVB +API will be constantly reviewed and improved. With the Linux driver for +the Siemens/Hauppauge DVB PCI card Convergence provides a first +implementation of the Linux DVB API.</para> +</section> + +<section id="overview"> +<title>Overview</title> + +<figure id="stb_components"> +<title>Components of a DVB card/STB</title> +<mediaobject> +<imageobject> +<imagedata fileref="dvbstb.pdf" format="PS" /> +</imageobject> +<imageobject> +<imagedata fileref="dvbstb.png" format="PNG" /> +</imageobject> +</mediaobject> +</figure> + +<para>A DVB PCI card or DVB set-top-box (STB) usually consists of the +following main hardware components: </para> + +<itemizedlist> + <listitem> + +<para>Frontend consisting of tuner and DVB demodulator</para> + +<para>Here the raw signal reaches the DVB hardware from a satellite dish +or antenna or directly from cable. The frontend down-converts and +demodulates this signal into an MPEG transport stream (TS). In case of a +satellite frontend, this includes a facility for satellite equipment +control (SEC), which allows control of LNB polarization, multi feed +switches or dish rotors.</para> + +</listitem> + <listitem> + +<para>Conditional Access (CA) hardware like CI adapters and smartcard slots +</para> + +<para>The complete TS is passed through the CA hardware. Programs to +which the user has access (controlled by the smart card) are decoded in +real time and re-inserted into the TS.</para> + +</listitem> + <listitem> + <para>Demultiplexer which filters the incoming DVB stream</para> + +<para>The demultiplexer splits the TS into its components like audio and +video streams. Besides usually several of such audio and video streams +it also contains data streams with information about the programs +offered in this or other streams of the same provider.</para> + +</listitem> +<listitem> + +<para>MPEG2 audio and video decoder</para> + +<para>The main targets of the demultiplexer are the MPEG2 audio and +video decoders. After decoding they pass on the uncompressed audio and +video to the computer screen or (through a PAL/NTSC encoder) to a TV +set.</para> + + +</listitem> +</itemizedlist> + +<para><xref linkend="stb_components" /> shows a crude schematic of the control and data flow +between those components.</para> + +<para>On a DVB PCI card not all of these have to be present since some +functionality can be provided by the main CPU of the PC (e.g. MPEG +picture and sound decoding) or is not needed (e.g. for data-only uses +like “internet over satellite”). Also not every card or STB +provides conditional access hardware.</para> + +</section> + +<section id="dvb_devices"> +<title>Linux DVB Devices</title> + +<para>The Linux DVB API lets you control these hardware components +through currently six Unix-style character devices for video, audio, +frontend, demux, CA and IP-over-DVB networking. The video and audio +devices control the MPEG2 decoder hardware, the frontend device the +tuner and the DVB demodulator. The demux device gives you control over +the PES and section filters of the hardware. If the hardware does not +support filtering these filters can be implemented in software. Finally, +the CA device controls all the conditional access capabilities of the +hardware. It can depend on the individual security requirements of the +platform, if and how many of the CA functions are made available to the +application through this device.</para> + +<para>All devices can be found in the <emphasis role="tt">/dev</emphasis> +tree under <emphasis role="tt">/dev/dvb</emphasis>. The individual devices +are called:</para> + +<itemizedlist> +<listitem> + +<para><emphasis role="tt">/dev/dvb/adapterN/audioM</emphasis>,</para> +</listitem> +<listitem> +<para><emphasis role="tt">/dev/dvb/adapterN/videoM</emphasis>,</para> +</listitem> +<listitem> +<para><emphasis role="tt">/dev/dvb/adapterN/frontendM</emphasis>,</para> +</listitem> + <listitem> + +<para><emphasis role="tt">/dev/dvb/adapterN/netM</emphasis>,</para> +</listitem> + <listitem> + +<para><emphasis role="tt">/dev/dvb/adapterN/demuxM</emphasis>,</para> +</listitem> + <listitem> + +<para><emphasis role="tt">/dev/dvb/adapterN/dvrM</emphasis>,</para> +</listitem> + <listitem> + +<para><emphasis role="tt">/dev/dvb/adapterN/caM</emphasis>,</para></listitem></itemizedlist> + +<para>where N enumerates the DVB PCI cards in a system starting +from 0, and M enumerates the devices of each type within each +adapter, starting from 0, too. We will omit the “<emphasis +role="tt">/dev/dvb/adapterN/</emphasis>” in the further dicussion +of these devices. The naming scheme for the devices is the same wheter +devfs is used or not.</para> + +<para>More details about the data structures and function calls of all +the devices are described in the following chapters.</para> + +</section> + +<section id="include_files"> +<title>API include files</title> + +<para>For each of the DVB devices a corresponding include file exists. +The DVB API include files should be included in application sources with +a partial path like:</para> + +<programlisting> + #include <linux/dvb/audio.h> +</programlisting> +<programlisting> + #include <linux/dvb/ca.h> +</programlisting> +<programlisting> + #include <linux/dvb/dmx.h> +</programlisting> +<programlisting> + #include <linux/dvb/frontend.h> +</programlisting> +<programlisting> + #include <linux/dvb/net.h> +</programlisting> +<programlisting> + #include <linux/dvb/osd.h> +</programlisting> +<programlisting> + #include <linux/dvb/video.h> +</programlisting> + +<para>To enable applications to support different API version, an +additional include file <emphasis +role="tt">linux/dvb/version.h</emphasis> exists, which defines the +constant <emphasis role="tt">DVB_API_VERSION</emphasis>. This document +describes <emphasis role="tt">DVB_API_VERSION 5.4</emphasis>. +</para> + +</section> + diff --git a/Documentation/DocBook/media/dvb/kdapi.xml b/Documentation/DocBook/media/dvb/kdapi.xml new file mode 100644 index 00000000..6c67481e --- /dev/null +++ b/Documentation/DocBook/media/dvb/kdapi.xml @@ -0,0 +1,2309 @@ +<title>Kernel Demux API</title> +<para>The kernel demux API defines a driver-internal interface for registering low-level, +hardware specific driver to a hardware independent demux layer. It is only of interest for +DVB device driver writers. The header file for this API is named <emphasis role="tt">demux.h</emphasis> and located in +<emphasis role="tt">drivers/media/dvb/dvb-core</emphasis>. +</para> +<para>Maintainer note: This section must be reviewed. It is probably out of date. +</para> + +<section id="kernel_demux_data_types"> +<title>Kernel Demux Data Types</title> + + +<section id="dmx_success_t"> +<title>dmx_success_t</title> + <programlisting> + typedef enum { + DMX_OK = 0, /⋆ Received Ok ⋆/ + DMX_LENGTH_ERROR, /⋆ Incorrect length ⋆/ + DMX_OVERRUN_ERROR, /⋆ Receiver ring buffer overrun ⋆/ + DMX_CRC_ERROR, /⋆ Incorrect CRC ⋆/ + DMX_FRAME_ERROR, /⋆ Frame alignment error ⋆/ + DMX_FIFO_ERROR, /⋆ Receiver FIFO overrun ⋆/ + DMX_MISSED_ERROR /⋆ Receiver missed packet ⋆/ + } dmx_success_t; +</programlisting> + +</section> +<section id="ts_filter_types"> +<title>TS filter types</title> + <programlisting> + /⋆--------------------------------------------------------------------------⋆/ + /⋆ TS packet reception ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + /⋆ TS filter type for set_type() ⋆/ + + #define TS_PACKET 1 /⋆ send TS packets (188 bytes) to callback (default) ⋆/ + #define TS_PAYLOAD_ONLY 2 /⋆ in case TS_PACKET is set, only send the TS + payload (<=184 bytes per packet) to callback ⋆/ + #define TS_DECODER 4 /⋆ send stream to built-in decoder (if present) ⋆/ +</programlisting> + +</section> +<section id="dmx_ts_pes_t"> +<title>dmx_ts_pes_t</title> +<para>The structure +</para> +<programlisting> + typedef enum + { + DMX_TS_PES_AUDIO, /⋆ also send packets to audio decoder (if it exists) ⋆/ + DMX_TS_PES_VIDEO, /⋆ ... ⋆/ + DMX_TS_PES_TELETEXT, + DMX_TS_PES_SUBTITLE, + DMX_TS_PES_PCR, + DMX_TS_PES_OTHER, + } dmx_ts_pes_t; +</programlisting> +<para>describes the PES type for filters which write to a built-in decoder. The correspond (and +should be kept identical) to the types in the demux device. +</para> +<programlisting> + struct dmx_ts_feed_s { + int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/ + struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int (⋆set) (struct dmx_ts_feed_s⋆ feed, + __u16 pid, + size_t callback_length, + size_t circular_buffer_size, + int descramble, + struct timespec timeout); + int (⋆start_filtering) (struct dmx_ts_feed_s⋆ feed); + int (⋆stop_filtering) (struct dmx_ts_feed_s⋆ feed); + int (⋆set_type) (struct dmx_ts_feed_s⋆ feed, + int type, + dmx_ts_pes_t pes_type); + }; + + typedef struct dmx_ts_feed_s dmx_ts_feed_t; +</programlisting> + <programlisting> + /⋆--------------------------------------------------------------------------⋆/ + /⋆ PES packet reception (not supported yet) ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + typedef struct dmx_pes_filter_s { + struct dmx_pes_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + } dmx_pes_filter_t; +</programlisting> + <programlisting> + typedef struct dmx_pes_feed_s { + int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/ + struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int (⋆set) (struct dmx_pes_feed_s⋆ feed, + __u16 pid, + size_t circular_buffer_size, + int descramble, + struct timespec timeout); + int (⋆start_filtering) (struct dmx_pes_feed_s⋆ feed); + int (⋆stop_filtering) (struct dmx_pes_feed_s⋆ feed); + int (⋆allocate_filter) (struct dmx_pes_feed_s⋆ feed, + dmx_pes_filter_t⋆⋆ filter); + int (⋆release_filter) (struct dmx_pes_feed_s⋆ feed, + dmx_pes_filter_t⋆ filter); + } dmx_pes_feed_t; +</programlisting> + <programlisting> + typedef struct { + __u8 filter_value [DMX_MAX_FILTER_SIZE]; + __u8 filter_mask [DMX_MAX_FILTER_SIZE]; + struct dmx_section_feed_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + } dmx_section_filter_t; +</programlisting> + <programlisting> + struct dmx_section_feed_s { + int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/ + struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int (⋆set) (struct dmx_section_feed_s⋆ feed, + __u16 pid, + size_t circular_buffer_size, + int descramble, + int check_crc); + int (⋆allocate_filter) (struct dmx_section_feed_s⋆ feed, + dmx_section_filter_t⋆⋆ filter); + int (⋆release_filter) (struct dmx_section_feed_s⋆ feed, + dmx_section_filter_t⋆ filter); + int (⋆start_filtering) (struct dmx_section_feed_s⋆ feed); + int (⋆stop_filtering) (struct dmx_section_feed_s⋆ feed); + }; + typedef struct dmx_section_feed_s dmx_section_feed_t; + + /⋆--------------------------------------------------------------------------⋆/ + /⋆ Callback functions ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + typedef int (⋆dmx_ts_cb) ( __u8 ⋆ buffer1, + size_t buffer1_length, + __u8 ⋆ buffer2, + size_t buffer2_length, + dmx_ts_feed_t⋆ source, + dmx_success_t success); + + typedef int (⋆dmx_section_cb) ( __u8 ⋆ buffer1, + size_t buffer1_len, + __u8 ⋆ buffer2, + size_t buffer2_len, + dmx_section_filter_t ⋆ source, + dmx_success_t success); + + typedef int (⋆dmx_pes_cb) ( __u8 ⋆ buffer1, + size_t buffer1_len, + __u8 ⋆ buffer2, + size_t buffer2_len, + dmx_pes_filter_t⋆ source, + dmx_success_t success); + + /⋆--------------------------------------------------------------------------⋆/ + /⋆ DVB Front-End ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + typedef enum { + DMX_OTHER_FE = 0, + DMX_SATELLITE_FE, + DMX_CABLE_FE, + DMX_TERRESTRIAL_FE, + DMX_LVDS_FE, + DMX_ASI_FE, /⋆ DVB-ASI interface ⋆/ + DMX_MEMORY_FE + } dmx_frontend_source_t; + + typedef struct { + /⋆ The following char⋆ fields point to NULL terminated strings ⋆/ + char⋆ id; /⋆ Unique front-end identifier ⋆/ + char⋆ vendor; /⋆ Name of the front-end vendor ⋆/ + char⋆ model; /⋆ Name of the front-end model ⋆/ + struct list_head connectivity_list; /⋆ List of front-ends that can + be connected to a particular + demux ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + dmx_frontend_source_t source; + } dmx_frontend_t; + + /⋆--------------------------------------------------------------------------⋆/ + /⋆ MPEG-2 TS Demux ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + /⋆ + ⋆ Flags OR'ed in the capabilites field of struct dmx_demux_s. + ⋆/ + + #define DMX_TS_FILTERING 1 + #define DMX_PES_FILTERING 2 + #define DMX_SECTION_FILTERING 4 + #define DMX_MEMORY_BASED_FILTERING 8 /⋆ write() available ⋆/ + #define DMX_CRC_CHECKING 16 + #define DMX_TS_DESCRAMBLING 32 + #define DMX_SECTION_PAYLOAD_DESCRAMBLING 64 + #define DMX_MAC_ADDRESS_DESCRAMBLING 128 +</programlisting> + +</section> +<section id="demux_demux_t"> +<title>demux_demux_t</title> + <programlisting> + /⋆ + ⋆ DMX_FE_ENTRY(): Casts elements in the list of registered + ⋆ front-ends from the generic type struct list_head + ⋆ to the type ⋆ dmx_frontend_t + ⋆. + ⋆/ + + #define DMX_FE_ENTRY(list) list_entry(list, dmx_frontend_t, connectivity_list) + + struct dmx_demux_s { + /⋆ The following char⋆ fields point to NULL terminated strings ⋆/ + char⋆ id; /⋆ Unique demux identifier ⋆/ + char⋆ vendor; /⋆ Name of the demux vendor ⋆/ + char⋆ model; /⋆ Name of the demux model ⋆/ + __u32 capabilities; /⋆ Bitfield of capability flags ⋆/ + dmx_frontend_t⋆ frontend; /⋆ Front-end connected to the demux ⋆/ + struct list_head reg_list; /⋆ List of registered demuxes ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int users; /⋆ Number of users ⋆/ + int (⋆open) (struct dmx_demux_s⋆ demux); + int (⋆close) (struct dmx_demux_s⋆ demux); + int (⋆write) (struct dmx_demux_s⋆ demux, const char⋆ buf, size_t count); + int (⋆allocate_ts_feed) (struct dmx_demux_s⋆ demux, + dmx_ts_feed_t⋆⋆ feed, + dmx_ts_cb callback); + int (⋆release_ts_feed) (struct dmx_demux_s⋆ demux, + dmx_ts_feed_t⋆ feed); + int (⋆allocate_pes_feed) (struct dmx_demux_s⋆ demux, + dmx_pes_feed_t⋆⋆ feed, + dmx_pes_cb callback); + int (⋆release_pes_feed) (struct dmx_demux_s⋆ demux, + dmx_pes_feed_t⋆ feed); + int (⋆allocate_section_feed) (struct dmx_demux_s⋆ demux, + dmx_section_feed_t⋆⋆ feed, + dmx_section_cb callback); + int (⋆release_section_feed) (struct dmx_demux_s⋆ demux, + dmx_section_feed_t⋆ feed); + int (⋆descramble_mac_address) (struct dmx_demux_s⋆ demux, + __u8⋆ buffer1, + size_t buffer1_length, + __u8⋆ buffer2, + size_t buffer2_length, + __u16 pid); + int (⋆descramble_section_payload) (struct dmx_demux_s⋆ demux, + __u8⋆ buffer1, + size_t buffer1_length, + __u8⋆ buffer2, size_t buffer2_length, + __u16 pid); + int (⋆add_frontend) (struct dmx_demux_s⋆ demux, + dmx_frontend_t⋆ frontend); + int (⋆remove_frontend) (struct dmx_demux_s⋆ demux, + dmx_frontend_t⋆ frontend); + struct list_head⋆ (⋆get_frontends) (struct dmx_demux_s⋆ demux); + int (⋆connect_frontend) (struct dmx_demux_s⋆ demux, + dmx_frontend_t⋆ frontend); + int (⋆disconnect_frontend) (struct dmx_demux_s⋆ demux); + + + /⋆ added because js cannot keep track of these himself ⋆/ + int (⋆get_pes_pids) (struct dmx_demux_s⋆ demux, __u16 ⋆pids); + }; + typedef struct dmx_demux_s dmx_demux_t; +</programlisting> + +</section> +<section id="demux_directory"> +<title>Demux directory</title> + <programlisting> + /⋆ + ⋆ DMX_DIR_ENTRY(): Casts elements in the list of registered + ⋆ demuxes from the generic type struct list_head⋆ to the type dmx_demux_t + ⋆. + ⋆/ + + #define DMX_DIR_ENTRY(list) list_entry(list, dmx_demux_t, reg_list) + + int dmx_register_demux (dmx_demux_t⋆ demux); + int dmx_unregister_demux (dmx_demux_t⋆ demux); + struct list_head⋆ dmx_get_demuxes (void); +</programlisting> + </section></section> +<section id="demux_directory_api"> +<title>Demux Directory API</title> +<para>The demux directory is a Linux kernel-wide facility for registering and accessing the +MPEG-2 TS demuxes in the system. Run-time registering and unregistering of demux drivers +is possible using this API. +</para> +<para>All demux drivers in the directory implement the abstract interface dmx_demux_t. +</para> + +<section +role="subsection"><title>dmx_register_demux()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function makes a demux driver interface available to the Linux kernel. It is + usually called by the init_module() function of the kernel module that contains + the demux driver. The caller of this function is responsible for allocating + dynamic or static memory for the demux structure and for initializing its fields + before calling this function. The memory allocated for the demux structure + must not be freed before calling dmx_unregister_demux(),</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_register_demux ( dmx_demux_t ⋆demux )</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux structure.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EEXIST</para> +</entry><entry + align="char"> +<para>A demux with the same value of the id field already stored + in the directory.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSPC</para> +</entry><entry + align="char"> +<para>No space left in the directory.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>dmx_unregister_demux()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function is called to indicate that the given demux interface is no + longer available. The caller of this function is responsible for freeing the + memory of the demux structure, if it was dynamically allocated before calling + dmx_register_demux(). The cleanup_module() function of the kernel module + that contains the demux driver should call this function. Note that this function + fails if the demux is currently in use, i.e., release_demux() has not been called + for the interface.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_unregister_demux ( dmx_demux_t ⋆demux )</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux structure which is to be + unregistered.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>ENODEV</para> +</entry><entry + align="char"> +<para>The specified demux is not registered in the demux + directory.</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>The specified demux is currently in use.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>dmx_get_demuxes()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Provides the caller with the list of registered demux interfaces, using the + standard list structure defined in the include file linux/list.h. The include file + demux.h defines the macro DMX_DIR_ENTRY() for converting an element of + the generic type struct list_head* to the type dmx_demux_t*. The caller must + not free the memory of any of the elements obtained via this function call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>struct list_head ⋆dmx_get_demuxes ()</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>none</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>struct list_head *</para> +</entry><entry + align="char"> +<para>A list of demux interfaces, or NULL in the case of an + empty list.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="demux_api"> +<title>Demux API</title> +<para>The demux API should be implemented for each demux in the system. It is used to select +the TS source of a demux and to manage the demux resources. When the demux +client allocates a resource via the demux API, it receives a pointer to the API of that +resource. +</para> +<para>Each demux receives its TS input from a DVB front-end or from memory, as set via the +demux API. In a system with more than one front-end, the API can be used to select one of +the DVB front-ends as a TS source for a demux, unless this is fixed in the HW platform. The +demux API only controls front-ends regarding their connections with demuxes; the APIs +used to set the other front-end parameters, such as tuning, are not defined in this +document. +</para> +<para>The functions that implement the abstract interface demux should be defined static or +module private and registered to the Demux Directory for external access. It is not necessary +to implement every function in the demux_t struct, however (for example, a demux interface +might support Section filtering, but not TS or PES filtering). The API client is expected to +check the value of any function pointer before calling the function: the value of NULL means +“function not available”. +</para> +<para>Whenever the functions of the demux API modify shared data, the possibilities of lost +update and race condition problems should be addressed, e.g. by protecting parts of code with +mutexes. This is especially important on multi-processor hosts. +</para> +<para>Note that functions called from a bottom half context must not sleep, at least in the 2.2.x +kernels. Even a simple memory allocation can result in a kernel thread being put to sleep if +swapping is needed. For example, the Linux kernel calls the functions of a network device +interface from a bottom half context. Thus, if a demux API function is called from network +device code, the function must not sleep. +</para> + + +<section id="kdapi_fopen"> +<title>open()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function reserves the demux for use by the caller and, if necessary, + initializes the demux. When the demux is no longer needed, the function close() + should be called. It should be possible for multiple clients to access the demux + at the same time. Thus, the function implementation should increment the + demux usage count when open() is called and decrement it when close() is + called.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int open ( demux_t⋆ demux );</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EUSERS</para> +</entry><entry + align="char"> +<para>Maximum usage count reached.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="kdapi_fclose"> +<title>close()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function reserves the demux for use by the caller and, if necessary, + initializes the demux. When the demux is no longer needed, the function close() + should be called. It should be possible for multiple clients to access the demux + at the same time. Thus, the function implementation should increment the + demux usage count when open() is called and decrement it when close() is + called.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int close(demux_t⋆ demux);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENODEV</para> +</entry><entry + align="char"> +<para>The demux was not in use.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="kdapi_fwrite"> +<title>write()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function provides the demux driver with a memory buffer containing TS + packets. Instead of receiving TS packets from the DVB front-end, the demux + driver software will read packets from memory. Any clients of this demux + with active TS, PES or Section filters will receive filtered data via the Demux + callback API (see 0). The function returns when all the data in the buffer has + been consumed by the demux. Demux hardware typically cannot read TS from + memory. If this is the case, memory-based filtering has to be implemented + entirely in software.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int write(demux_t⋆ demux, const char⋆ buf, size_t + count);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>const char* buf</para> +</entry><entry + align="char"> +<para>Pointer to the TS data in kernel-space memory.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t length</para> +</entry><entry + align="char"> +<para>Length of the TS data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>The command is not implemented.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>allocate_ts_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Allocates a new TS feed, which is used to filter the TS packets carrying a + certain PID. The TS feed normally corresponds to a hardware PID filter on the + demux chip.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int allocate_ts_feed(dmx_demux_t⋆ demux, + dmx_ts_feed_t⋆⋆ feed, dmx_ts_cb callback);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_feed_t** + feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_cb callback</para> +</entry><entry + align="char"> +<para>Pointer to the callback function for passing received TS + packet</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>No more TS feeds available.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>The command is not implemented.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>release_ts_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Releases the resources allocated with allocate_ts_feed(). Any filtering in + progress on the TS feed should be stopped before calling this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int release_ts_feed(dmx_demux_t⋆ demux, + dmx_ts_feed_t⋆ feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>allocate_section_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Allocates a new section feed, i.e. a demux resource for filtering and receiving + sections. On platforms with hardware support for section filtering, a section + feed is directly mapped to the demux HW. On other platforms, TS packets are + first PID filtered in hardware and a hardware section filter then emulated in + software. The caller obtains an API pointer of type dmx_section_feed_t as an + out parameter. Using this API the caller can set filtering parameters and start + receiving sections.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int allocate_section_feed(dmx_demux_t⋆ demux, + dmx_section_feed_t ⋆⋆feed, dmx_section_cb callback);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_feed_t + **feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_cb + callback</para> +</entry><entry + align="char"> +<para>Pointer to the callback function for passing received + sections.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>No more section feeds available.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>The command is not implemented.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>release_section_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Releases the resources allocated with allocate_section_feed(), including + allocated filters. Any filtering in progress on the section feed should be stopped + before calling this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int release_section_feed(dmx_demux_t⋆ demux, + dmx_section_feed_t ⋆feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_feed_t + *feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>descramble_mac_address()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function runs a descrambling algorithm on the destination MAC + address field of a DVB Datagram Section, replacing the original address + with its un-encrypted version. Otherwise, the description on the function + descramble_section_payload() applies also to this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int descramble_mac_address(dmx_demux_t⋆ demux, __u8 + ⋆buffer1, size_t buffer1_length, __u8 ⋆buffer2, + size_t buffer2_length, __u16 pid);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t + *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8 *buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the first byte of the section.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer1.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8* buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the section data, or NULL. The + pointer has a non-NULL value if the section wraps past + the end of a circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer2.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>The PID on which the section was received. Useful + for obtaining the descrambling key, e.g. from a DVB + Common Access facility.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>descramble_section_payload()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function runs a descrambling algorithm on the payload of a DVB + Datagram Section, replacing the original payload with its un-encrypted + version. The function will be called from the demux API implementation; + the API client need not call this function directly. Section-level scrambling + algorithms are currently standardized only for DVB-RCC (return channel + over 2-directional cable TV network) systems. For all other DVB networks, + encryption schemes are likely to be proprietary to each data broadcaster. Thus, + it is expected that this function pointer will have the value of NULL (i.e., + function not available) in most demux API implementations. Nevertheless, it + should be possible to use the function pointer as a hook for dynamically adding + a “plug-in” descrambling facility to a demux driver.</para> +</entry> + </row><row><entry + align="char"> +<para>While this function is not needed with hardware-based section descrambling, + the descramble_section_payload function pointer can be used to override the + default hardware-based descrambling algorithm: if the function pointer has a + non-NULL value, the corresponding function should be used instead of any + descrambling hardware.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int descramble_section_payload(dmx_demux_t⋆ demux, + __u8 ⋆buffer1, size_t buffer1_length, __u8 ⋆buffer2, + size_t buffer2_length, __u16 pid);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t + *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8 *buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the first byte of the section.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer1.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8 *buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the section data, or NULL. The + pointer has a non-NULL value if the section wraps past + the end of a circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer2.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>The PID on which the section was received. Useful + for obtaining the descrambling key, e.g. from a DVB + Common Access facility.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>add_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Registers a connectivity between a demux and a front-end, i.e., indicates that + the demux can be connected via a call to connect_frontend() to use the given + front-end as a TS source. The client of this function has to allocate dynamic or + static memory for the frontend structure and initialize its fields before calling + this function. This function is normally called during the driver initialization. + The caller must not free the memory of the frontend struct before successfully + calling remove_frontend().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int add_frontend(dmx_demux_t ⋆demux, dmx_frontend_t + ⋆frontend);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_frontend_t* + frontend</para> +</entry><entry + align="char"> +<para>Pointer to the front-end instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EEXIST</para> +</entry><entry + align="char"> +<para>A front-end with the same value of the id field already + registered.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINUSE</para> +</entry><entry + align="char"> +<para>The demux is in use.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOMEM</para> +</entry><entry + align="char"> +<para>No more front-ends can be added.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>remove_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Indicates that the given front-end, registered by a call to add_frontend(), can + no longer be connected as a TS source by this demux. The function should be + called when a front-end driver or a demux driver is removed from the system. + If the front-end is in use, the function fails with the return value of -EBUSY. + After successfully calling this function, the caller can free the memory of + the frontend struct if it was dynamically allocated before the add_frontend() + operation.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int remove_frontend(dmx_demux_t⋆ demux, + dmx_frontend_t⋆ frontend);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_frontend_t* + frontend</para> +</entry><entry + align="char"> +<para>Pointer to the front-end instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>The front-end is in use, i.e. a call to connect_frontend() + has not been followed by a call to disconnect_frontend().</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>get_frontends()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Provides the APIs of the front-ends that have been registered for this demux. + Any of the front-ends obtained with this call can be used as a parameter for + connect_frontend().</para> +</entry> + </row><row><entry + align="char"> +<para>The include file demux.h contains the macro DMX_FE_ENTRY() for + converting an element of the generic type struct list_head* to the type + dmx_frontend_t*. The caller must not free the memory of any of the elements + obtained via this function call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>struct list_head⋆ get_frontends(dmx_demux_t⋆ demux);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t*</para> +</entry><entry + align="char"> +<para>A list of front-end interfaces, or NULL in the case of an + empty list.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>connect_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Connects the TS output of the front-end to the input of the demux. A demux + can only be connected to a front-end registered to the demux with the function + add_frontend().</para> +</entry> + </row><row><entry + align="char"> +<para>It may or may not be possible to connect multiple demuxes to the same + front-end, depending on the capabilities of the HW platform. When not used, + the front-end should be released by calling disconnect_frontend().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int connect_frontend(dmx_demux_t⋆ demux, + dmx_frontend_t⋆ frontend);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_frontend_t* + frontend</para> +</entry><entry + align="char"> +<para>Pointer to the front-end instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>The front-end is in use.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>disconnect_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Disconnects the demux and a front-end previously connected by a + connect_frontend() call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int disconnect_frontend(dmx_demux_t⋆ demux);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="demux_callback_api"> +<title>Demux Callback API</title> +<para>This kernel-space API comprises the callback functions that deliver filtered data to the +demux client. Unlike the other APIs, these API functions are provided by the client and called +from the demux code. +</para> +<para>The function pointers of this abstract interface are not packed into a structure as in the +other demux APIs, because the callback functions are registered and used independent +of each other. As an example, it is possible for the API client to provide several +callback functions for receiving TS packets and no callbacks for PES packets or +sections. +</para> +<para>The functions that implement the callback API need not be re-entrant: when a demux +driver calls one of these functions, the driver is not allowed to call the function again before +the original call returns. If a callback is triggered by a hardware interrupt, it is recommended +to use the Linux “bottom half” mechanism or start a tasklet instead of making the callback +function call directly from a hardware interrupt. +</para> + +<section +role="subsection"><title>dmx_ts_cb()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function, provided by the client of the demux API, is called from the + demux code. The function is only called when filtering on this TS feed has + been enabled using the start_filtering() function.</para> +</entry> + </row><row><entry + align="char"> +<para>Any TS packets that match the filter settings are copied to a circular buffer. The + filtered TS packets are delivered to the client using this callback function. The + size of the circular buffer is controlled by the circular_buffer_size parameter + of the set() function in the TS Feed API. It is expected that the buffer1 and + buffer2 callback parameters point to addresses within the circular buffer, but + other implementations are also possible. Note that the called party should not + try to free the memory the buffer1 and buffer2 parameters point to.</para> +</entry> + </row><row><entry + align="char"> +<para>When this function is called, the buffer1 parameter typically points to the + start of the first undelivered TS packet within a circular buffer. The buffer2 + buffer parameter is normally NULL, except when the received TS packets have + crossed the last address of the circular buffer and ”wrapped” to the beginning + of the buffer. In the latter case the buffer1 parameter would contain an address + within the circular buffer, while the buffer2 parameter would contain the first + address of the circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>The number of bytes delivered with this function (i.e. buffer1_length + + buffer2_length) is usually equal to the value of callback_length parameter + given in the set() function, with one exception: if a timeout occurs before + receiving callback_length bytes of TS data, any undelivered packets are + immediately delivered to the client by calling this function. The timeout + duration is controlled by the set() function in the TS Feed API.</para> +</entry> + </row><row><entry + align="char"> +<para>If a TS packet is received with errors that could not be fixed by the TS-level + forward error correction (FEC), the Transport_error_indicator flag of the TS + packet header should be set. The TS packet should not be discarded, as + the error can possibly be corrected by a higher layer protocol. If the called + party is slow in processing the callback, it is possible that the circular buffer + eventually fills up. If this happens, the demux driver should discard any TS + packets received while the buffer is full. The error should be indicated to the + client on the next callback by setting the success parameter to the value of + DMX_OVERRUN_ERROR.</para> +</entry> + </row><row><entry + align="char"> +<para>The type of data returned to the callback can be selected by the new + function int (*set_type) (struct dmx_ts_feed_s* feed, int type, dmx_ts_pes_t + pes_type) which is part of the dmx_ts_feed_s struct (also cf. to the + include file ost/demux.h) The type parameter decides if the raw TS packet + (TS_PACKET) or just the payload (TS_PACKET—TS_PAYLOAD_ONLY) + should be returned. If additionally the TS_DECODER bit is set the stream + will also be sent to the hardware MPEG decoder. In this case, the second + flag decides as what kind of data the stream should be interpreted. The + possible choices are one of DMX_TS_PES_AUDIO, DMX_TS_PES_VIDEO, + DMX_TS_PES_TELETEXT, DMX_TS_PES_SUBTITLE, + DMX_TS_PES_PCR, or DMX_TS_PES_OTHER.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_ts_cb(__u8⋆ buffer1, size_t buffer1_length, + __u8⋆ buffer2, size_t buffer2_length, dmx_ts_feed_t⋆ + source, dmx_success_t success);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>__u8* buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the start of the filtered TS packets.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the TS data in buffer1.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8* buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the filtered TS packets, or NULL.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the TS data in buffer2.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_feed_t* + source</para> +</entry><entry + align="char"> +<para>Indicates which TS feed is the source of the callback.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_success_t + success</para> +</entry><entry + align="char"> +<para>Indicates if there was an error in TS reception.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>Continue filtering.</para> +</entry> + </row><row><entry + align="char"> +<para>-1</para> +</entry><entry + align="char"> +<para>Stop filtering - has the same effect as a call to + stop_filtering() on the TS Feed API.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>dmx_section_cb()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function, provided by the client of the demux API, is called from the + demux code. The function is only called when filtering of sections has been + enabled using the function start_filtering() of the section feed API. When the + demux driver has received a complete section that matches at least one section + filter, the client is notified via this callback function. Normally this function is + called for each received section; however, it is also possible to deliver multiple + sections with one callback, for example when the system load is high. If an + error occurs while receiving a section, this function should be called with + the corresponding error type set in the success field, whether or not there is + data to deliver. The Section Feed implementation should maintain a circular + buffer for received sections. However, this is not necessary if the Section Feed + API is implemented as a client of the TS Feed API, because the TS Feed + implementation then buffers the received data. The size of the circular buffer + can be configured using the set() function in the Section Feed API. If there + is no room in the circular buffer when a new section is received, the section + must be discarded. If this happens, the value of the success parameter should + be DMX_OVERRUN_ERROR on the next callback.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_section_cb(__u8⋆ buffer1, size_t + buffer1_length, __u8⋆ buffer2, size_t + buffer2_length, dmx_section_filter_t⋆ source, + dmx_success_t success);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>__u8* buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the start of the filtered section, e.g. within the + circular buffer of the demux driver.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the filtered section data in buffer1, including + headers and CRC.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8* buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the filtered section data, or NULL. + Useful to handle the wrapping of a circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the filtered section data in buffer2, including + headers and CRC.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_filter_t* + filter</para> +</entry><entry + align="char"> +<para>Indicates the filter that triggered the callback.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_success_t + success</para> +</entry><entry + align="char"> +<para>Indicates if there was an error in section reception.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>Continue filtering.</para> +</entry> + </row><row><entry + align="char"> +<para>-1</para> +</entry><entry + align="char"> +<para>Stop filtering - has the same effect as a call to + stop_filtering() on the Section Feed API.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="ts_feed_api"> +<title>TS Feed API</title> +<para>A TS feed is typically mapped to a hardware PID filter on the demux chip. +Using this API, the client can set the filtering properties to start/stop filtering TS +packets on a particular TS feed. The API is defined as an abstract interface of the type +dmx_ts_feed_t. +</para> +<para>The functions that implement the interface should be defined static or module private. The +client can get the handle of a TS feed API by calling the function allocate_ts_feed() in the +demux API. +</para> + +<section +role="subsection"><title>set()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function sets the parameters of a TS feed. Any filtering in progress on the + TS feed must be stopped before calling this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int set ( dmx_ts_feed_t⋆ feed, __u16 pid, size_t + callback_length, size_t circular_buffer_size, int + descramble, struct timespec timeout);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>PID value to filter. Only the TS packets carrying the + specified PID will be passed to the API client.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t + callback_length</para> +</entry><entry + align="char"> +<para>Number of bytes to deliver with each call to the + dmx_ts_cb() callback function. The value of this + parameter should be a multiple of 188.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t + circular_buffer_size</para> +</entry><entry + align="char"> +<para>Size of the circular buffer for the filtered TS packets.</para> +</entry> + </row><row><entry + align="char"> +<para>int descramble</para> +</entry><entry + align="char"> +<para>If non-zero, descramble the filtered TS packets.</para> +</entry> + </row><row><entry + align="char"> +<para>struct timespec + timeout</para> +</entry><entry + align="char"> +<para>Maximum time to wait before delivering received TS + packets to the client.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOMEM</para> +</entry><entry + align="char"> +<para>Not enough memory for the requested buffer size.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available for TS.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>start_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Starts filtering TS packets on this TS feed, according to its settings. The PID + value to filter can be set by the API client. All matching TS packets are + delivered asynchronously to the client, using the callback function registered + with allocate_ts_feed().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int start_filtering(dmx_ts_feed_t⋆ feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>stop_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Stops filtering TS packets on this TS feed.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int stop_filtering(dmx_ts_feed_t⋆ feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="section_feed_api"> +<title>Section Feed API</title> +<para>A section feed is a resource consisting of a PID filter and a set of section filters. Using this +API, the client can set the properties of a section feed and to start/stop filtering. The API is +defined as an abstract interface of the type dmx_section_feed_t. The functions that implement +the interface should be defined static or module private. The client can get the handle of +a section feed API by calling the function allocate_section_feed() in the demux +API. +</para> +<para>On demux platforms that provide section filtering in hardware, the Section Feed API +implementation provides a software wrapper for the demux hardware. Other platforms may +support only PID filtering in hardware, requiring that TS packets are converted to sections in +software. In the latter case the Section Feed API implementation can be a client of the TS +Feed API. +</para> + +</section> +<section id="kdapi_set"> +<title>set()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function sets the parameters of a section feed. Any filtering in progress on + the section feed must be stopped before calling this function. If descrambling + is enabled, the payload_scrambling_control and address_scrambling_control + fields of received DVB datagram sections should be observed. If either one is + non-zero, the section should be descrambled either in hardware or using the + functions descramble_mac_address() and descramble_section_payload() of the + demux API. Note that according to the MPEG-2 Systems specification, only + the payloads of private sections can be scrambled while the rest of the section + data must be sent in the clear.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int set(dmx_section_feed_t⋆ feed, __u16 pid, size_t + circular_buffer_size, int descramble, int + check_crc);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>PID value to filter; only the TS packets carrying the + specified PID will be accepted.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t + circular_buffer_size</para> +</entry><entry + align="char"> +<para>Size of the circular buffer for filtered sections.</para> +</entry> + </row><row><entry + align="char"> +<para>int descramble</para> +</entry><entry + align="char"> +<para>If non-zero, descramble any sections that are scrambled.</para> +</entry> + </row><row><entry + align="char"> +<para>int check_crc</para> +</entry><entry + align="char"> +<para>If non-zero, check the CRC values of filtered sections.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOMEM</para> +</entry><entry + align="char"> +<para>Not enough memory for the requested buffer size.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available for sections.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameters.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>allocate_filter()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function is used to allocate a section filter on the demux. It should only be + called when no filtering is in progress on this section feed. If a filter cannot be + allocated, the function fails with -ENOSPC. See in section ?? for the format of + the section filter.</para> +</entry> + </row><row><entry + align="char"> +<para>The bitfields filter_mask and filter_value should only be modified when no + filtering is in progress on this section feed. filter_mask controls which bits of + filter_value are compared with the section headers/payload. On a binary value + of 1 in filter_mask, the corresponding bits are compared. The filter only accepts + sections that are equal to filter_value in all the tested bit positions. Any changes + to the values of filter_mask and filter_value are guaranteed to take effect only + when the start_filtering() function is called next time. The parent pointer in + the struct is initialized by the API implementation to the value of the feed + parameter. The priv pointer is not used by the API implementation, and can + thus be freely utilized by the caller of this function. Any data pointed to by the + priv pointer is available to the recipient of the dmx_section_cb() function call.</para> +</entry> + </row><row><entry + align="char"> +<para>While the maximum section filter length (DMX_MAX_FILTER_SIZE) is + currently set at 16 bytes, hardware filters of that size are not available on all + platforms. Therefore, section filtering will often take place first in hardware, + followed by filtering in software for the header bytes that were not covered + by a hardware filter. The filter_mask field can be checked to determine how + many bytes of the section filter are actually used, and if the hardware filter will + suffice. Additionally, software-only section filters can optionally be allocated + to clients when all hardware section filters are in use. Note that on most demux + hardware it is not possible to filter on the section_length field of the section + header – thus this field is ignored, even though it is included in filter_value and + filter_mask fields.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int allocate_filter(dmx_section_feed_t⋆ feed, + dmx_section_filter_t⋆⋆ filter);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_filter_t** + filter</para> +</entry><entry + align="char"> +<para>Pointer to the allocated filter.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSPC</para> +</entry><entry + align="char"> +<para>No filters of given type and length available.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameters.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>release_filter()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function releases all the resources of a previously allocated section filter. + The function should not be called while filtering is in progress on this section + feed. After calling this function, the caller should not try to dereference the + filter pointer.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int release_filter ( dmx_section_feed_t⋆ feed, + dmx_section_filter_t⋆ filter);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_filter_t* + filter</para> +</entry><entry + align="char"> +<para>I/O Pointer to the instance data of a section filter.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENODEV</para> +</entry><entry + align="char"> +<para>No such filter allocated.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>start_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Starts filtering sections on this section feed, according to its settings. Sections + are first filtered based on their PID and then matched with the section + filters allocated for this feed. If the section matches the PID filter and + at least one section filter, it is delivered to the API client. The section + is delivered asynchronously using the callback function registered with + allocate_section_feed().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int start_filtering ( dmx_section_feed_t⋆ feed );</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>stop_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Stops filtering sections on this section feed. Note that any changes to the + filtering parameters (filter_value, filter_mask, etc.) should only be made when + filtering is stopped.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int stop_filtering ( dmx_section_feed_t⋆ feed );</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> diff --git a/Documentation/DocBook/media/dvb/net.xml b/Documentation/DocBook/media/dvb/net.xml new file mode 100644 index 00000000..67d37e5c --- /dev/null +++ b/Documentation/DocBook/media/dvb/net.xml @@ -0,0 +1,29 @@ +<title>DVB Network API</title> +<para>The DVB net device enables feeding of MPE (multi protocol encapsulation) packets +received via DVB into the Linux network protocol stack, e.g. for internet via satellite +applications. It can be accessed through <emphasis role="tt">/dev/dvb/adapter0/net0</emphasis>. Data types and +and ioctl definitions can be accessed by including <emphasis role="tt">linux/dvb/net.h</emphasis> in your +application. +</para> +<section id="dvb_net_types"> +<title>DVB Net Data Types</title> + +<section id="dvb-net-if"> +<title>struct dvb_net_if</title> +<programlisting> +struct dvb_net_if { + __u16 pid; + __u16 if_num; + __u8 feedtype; +#define DVB_NET_FEEDTYPE_MPE 0 /⋆ multi protocol encapsulation ⋆/ +#define DVB_NET_FEEDTYPE_ULE 1 /⋆ ultra lightweight encapsulation ⋆/ +}; +</programlisting> +</section> + +</section> +<section id="net_fcalls"> +<title>DVB net Function Calls</title> +<para>To be written… +</para> +</section> diff --git a/Documentation/DocBook/media/dvb/video.xml b/Documentation/DocBook/media/dvb/video.xml new file mode 100644 index 00000000..25fb8232 --- /dev/null +++ b/Documentation/DocBook/media/dvb/video.xml @@ -0,0 +1,1657 @@ +<title>DVB Video Device</title> +<para>The DVB video device controls the MPEG2 video decoder of the DVB hardware. It +can be accessed through <emphasis role="tt">/dev/dvb/adapter0/video0</emphasis>. Data types and and +ioctl definitions can be accessed by including <emphasis role="tt">linux/dvb/video.h</emphasis> in your +application. +</para> +<para>Note that the DVB video device only controls decoding of the MPEG video stream, not +its presentation on the TV or computer screen. On PCs this is typically handled by an +associated video4linux device, e.g. <emphasis role="tt">/dev/video</emphasis>, which allows scaling and defining output +windows. +</para> +<para>Some DVB cards don’t have their own MPEG decoder, which results in the omission of +the audio and video device as well as the video4linux device. +</para> +<para>The ioctls that deal with SPUs (sub picture units) and navigation packets are only +supported on some MPEG decoders made for DVD playback. +</para> +<section id="video_types"> +<title>Video Data Types</title> + +<section id="video-format-t"> +<title>video_format_t</title> +<para>The <emphasis role="tt">video_format_t</emphasis> data type defined by +</para> +<programlisting> +typedef enum { + VIDEO_FORMAT_4_3, /⋆ Select 4:3 format ⋆/ + VIDEO_FORMAT_16_9, /⋆ Select 16:9 format. ⋆/ + VIDEO_FORMAT_221_1 /⋆ 2.21:1 ⋆/ +} video_format_t; +</programlisting> +<para>is used in the VIDEO_SET_FORMAT function (??) to tell the driver which aspect ratio +the output hardware (e.g. TV) has. It is also used in the data structures video_status +(??) returned by VIDEO_GET_STATUS (??) and video_event (??) returned by +VIDEO_GET_EVENT (??) which report about the display format of the current video +stream. +</para> +</section> + +<section id="video-displayformat-t"> +<title>video_displayformat_t</title> +<para>In case the display format of the video stream and of the display hardware differ the +application has to specify how to handle the cropping of the picture. This can be done using +the VIDEO_SET_DISPLAY_FORMAT call (??) which accepts +</para> +<programlisting> +typedef enum { + VIDEO_PAN_SCAN, /⋆ use pan and scan format ⋆/ + VIDEO_LETTER_BOX, /⋆ use letterbox format ⋆/ + VIDEO_CENTER_CUT_OUT /⋆ use center cut out format ⋆/ +} video_displayformat_t; +</programlisting> +<para>as argument. +</para> +</section> + +<section id="video-stream-source-t"> +<title>video stream source</title> +<para>The video stream source is set through the VIDEO_SELECT_SOURCE call and can take +the following values, depending on whether we are replaying from an internal (demuxer) or +external (user write) source. +</para> +<programlisting> +typedef enum { + VIDEO_SOURCE_DEMUX, /⋆ Select the demux as the main source ⋆/ + VIDEO_SOURCE_MEMORY /⋆ If this source is selected, the stream + comes from the user through the write + system call ⋆/ +} video_stream_source_t; +</programlisting> +<para>VIDEO_SOURCE_DEMUX selects the demultiplexer (fed either by the frontend or the +DVR device) as the source of the video stream. If VIDEO_SOURCE_MEMORY +is selected the stream comes from the application through the <emphasis role="tt">write()</emphasis> system +call. +</para> +</section> + +<section id="video-play-state-t"> +<title>video play state</title> +<para>The following values can be returned by the VIDEO_GET_STATUS call representing the +state of video playback. +</para> +<programlisting> +typedef enum { + VIDEO_STOPPED, /⋆ Video is stopped ⋆/ + VIDEO_PLAYING, /⋆ Video is currently playing ⋆/ + VIDEO_FREEZED /⋆ Video is freezed ⋆/ +} video_play_state_t; +</programlisting> +</section> + +<section id="video-command"> +<para>The structure must be zeroed before use by the application +This ensures it can be extended safely in the future.</para> +<title>struct video-command</title> +<programlisting> +struct video_command { + __u32 cmd; + __u32 flags; + union { + struct { + __u64 pts; + } stop; + + struct { + /⋆ 0 or 1000 specifies normal speed, + 1 specifies forward single stepping, + -1 specifies backward single stepping, + >>1: playback at speed/1000 of the normal speed, + <-1: reverse playback at (-speed/1000) of the normal speed. ⋆/ + __s32 speed; + __u32 format; + } play; + + struct { + __u32 data[16]; + } raw; + }; +}; +</programlisting> +</section> + +<section id="video-size-t"> +<title>struct video_size-t</title> +<programlisting> +typedef struct { + int w; + int h; + video_format_t aspect_ratio; +} video_size_t; +</programlisting> +</section> + + +<section id="video-event"> +<title>struct video_event</title> +<para>The following is the structure of a video event as it is returned by the VIDEO_GET_EVENT +call. +</para> +<programlisting> +struct video_event { + __s32 type; +#define VIDEO_EVENT_SIZE_CHANGED 1 +#define VIDEO_EVENT_FRAME_RATE_CHANGED 2 +#define VIDEO_EVENT_DECODER_STOPPED 3 +#define VIDEO_EVENT_VSYNC 4 + __kernel_time_t timestamp; + union { + video_size_t size; + unsigned int frame_rate; /⋆ in frames per 1000sec ⋆/ + unsigned char vsync_field; /⋆ unknown/odd/even/progressive ⋆/ + } u; +}; +</programlisting> +</section> + +<section id="video-status"> +<title>struct video_status</title> +<para>The VIDEO_GET_STATUS call returns the following structure informing about various +states of the playback operation. +</para> +<programlisting> +struct video_status { + int video_blank; /⋆ blank video on freeze? ⋆/ + video_play_state_t play_state; /⋆ current state of playback ⋆/ + video_stream_source_t stream_source; /⋆ current source (demux/memory) ⋆/ + video_format_t video_format; /⋆ current aspect ratio of stream ⋆/ + video_displayformat_t display_format;/⋆ selected cropping mode ⋆/ +}; +</programlisting> +<para>If video_blank is set video will be blanked out if the channel is changed or if playback is +stopped. Otherwise, the last picture will be displayed. play_state indicates if the video is +currently frozen, stopped, or being played back. The stream_source corresponds to the seleted +source for the video stream. It can come either from the demultiplexer or from memory. +The video_format indicates the aspect ratio (one of 4:3 or 16:9) of the currently +played video stream. Finally, display_format corresponds to the selected cropping +mode in case the source video format is not the same as the format of the output +device. +</para> +</section> + +<section id="video-still-picture"> +<title>struct video_still_picture</title> +<para>An I-frame displayed via the VIDEO_STILLPICTURE call is passed on within the +following structure. +</para> +<programlisting> +/⋆ pointer to and size of a single iframe in memory ⋆/ +struct video_still_picture { + char ⋆iFrame; /⋆ pointer to a single iframe in memory ⋆/ + int32_t size; +}; +</programlisting> +</section> + +<section id="video_caps"> +<title>video capabilities</title> +<para>A call to VIDEO_GET_CAPABILITIES returns an unsigned integer with the following +bits set according to the hardwares capabilities. +</para> +<programlisting> + /⋆ bit definitions for capabilities: ⋆/ + /⋆ can the hardware decode MPEG1 and/or MPEG2? ⋆/ + #define VIDEO_CAP_MPEG1 1 + #define VIDEO_CAP_MPEG2 2 + /⋆ can you send a system and/or program stream to video device? + (you still have to open the video and the audio device but only + send the stream to the video device) ⋆/ + #define VIDEO_CAP_SYS 4 + #define VIDEO_CAP_PROG 8 + /⋆ can the driver also handle SPU, NAVI and CSS encoded data? + (CSS API is not present yet) ⋆/ + #define VIDEO_CAP_SPU 16 + #define VIDEO_CAP_NAVI 32 + #define VIDEO_CAP_CSS 64 +</programlisting> +</section> + +<section id="video-system"> +<title>video system</title> +<para>A call to VIDEO_SET_SYSTEM sets the desired video system for TV output. The +following system types can be set: +</para> +<programlisting> +typedef enum { + VIDEO_SYSTEM_PAL, + VIDEO_SYSTEM_NTSC, + VIDEO_SYSTEM_PALN, + VIDEO_SYSTEM_PALNc, + VIDEO_SYSTEM_PALM, + VIDEO_SYSTEM_NTSC60, + VIDEO_SYSTEM_PAL60, + VIDEO_SYSTEM_PALM60 +} video_system_t; +</programlisting> +</section> + +<section id="video-highlight"> +<title>struct video_highlight</title> +<para>Calling the ioctl VIDEO_SET_HIGHLIGHTS posts the SPU highlight information. The +call expects the following format for that information: +</para> +<programlisting> + typedef + struct video_highlight { + boolean active; /⋆ 1=show highlight, 0=hide highlight ⋆/ + uint8_t contrast1; /⋆ 7- 4 Pattern pixel contrast ⋆/ + /⋆ 3- 0 Background pixel contrast ⋆/ + uint8_t contrast2; /⋆ 7- 4 Emphasis pixel-2 contrast ⋆/ + /⋆ 3- 0 Emphasis pixel-1 contrast ⋆/ + uint8_t color1; /⋆ 7- 4 Pattern pixel color ⋆/ + /⋆ 3- 0 Background pixel color ⋆/ + uint8_t color2; /⋆ 7- 4 Emphasis pixel-2 color ⋆/ + /⋆ 3- 0 Emphasis pixel-1 color ⋆/ + uint32_t ypos; /⋆ 23-22 auto action mode ⋆/ + /⋆ 21-12 start y ⋆/ + /⋆ 9- 0 end y ⋆/ + uint32_t xpos; /⋆ 23-22 button color number ⋆/ + /⋆ 21-12 start x ⋆/ + /⋆ 9- 0 end x ⋆/ + } video_highlight_t; +</programlisting> + +</section> +<section id="video-spu"> +<title>video SPU</title> +<para>Calling VIDEO_SET_SPU deactivates or activates SPU decoding, according to the +following format: +</para> +<programlisting> + typedef + struct video_spu { + boolean active; + int stream_id; + } video_spu_t; +</programlisting> + +</section> +<section id="video-spu-palette"> +<title>video SPU palette</title> +<para>The following structure is used to set the SPU palette by calling VIDEO_SPU_PALETTE: +</para> +<programlisting> + typedef + struct video_spu_palette{ + int length; + uint8_t ⋆palette; + } video_spu_palette_t; +</programlisting> + +</section> +<section id="video-navi-pack"> +<title>video NAVI pack</title> +<para>In order to get the navigational data the following structure has to be passed to the ioctl +VIDEO_GET_NAVI: +</para> +<programlisting> + typedef + struct video_navi_pack{ + int length; /⋆ 0 ... 1024 ⋆/ + uint8_t data[1024]; + } video_navi_pack_t; +</programlisting> +</section> + + +<section id="video-attributes-t"> +<title>video attributes</title> +<para>The following attributes can be set by a call to VIDEO_SET_ATTRIBUTES: +</para> +<programlisting> + typedef uint16_t video_attributes_t; + /⋆ bits: descr. ⋆/ + /⋆ 15-14 Video compression mode (0=MPEG-1, 1=MPEG-2) ⋆/ + /⋆ 13-12 TV system (0=525/60, 1=625/50) ⋆/ + /⋆ 11-10 Aspect ratio (0=4:3, 3=16:9) ⋆/ + /⋆ 9- 8 permitted display mode on 4:3 monitor (0=both, 1=only pan-sca ⋆/ + /⋆ 7 line 21-1 data present in GOP (1=yes, 0=no) ⋆/ + /⋆ 6 line 21-2 data present in GOP (1=yes, 0=no) ⋆/ + /⋆ 5- 3 source resolution (0=720x480/576, 1=704x480/576, 2=352x480/57 ⋆/ + /⋆ 2 source letterboxed (1=yes, 0=no) ⋆/ + /⋆ 0 film/camera mode (0=camera, 1=film (625/50 only)) ⋆/ +</programlisting> +</section></section> + + +<section id="video_function_calls"> +<title>Video Function Calls</title> + + +<section id="video_fopen"> +<title>open()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call opens a named video device (e.g. /dev/dvb/adapter0/video0) + for subsequent use.</para> +<para>When an open() call has succeeded, the device will be ready for use. + The significance of blocking or non-blocking mode is described in the + documentation for functions where there is a difference. It does not affect the + semantics of the open() call itself. A device opened in blocking mode can later + be put into non-blocking mode (and vice versa) using the F_SETFL command + of the fcntl system call. This is a standard system call, documented in the Linux + manual page for fcntl. Only one user can open the Video Device in O_RDWR + mode. All other attempts to open the device in this mode will fail, and an + error-code will be returned. If the Video Device is opened in O_RDONLY + mode, the only ioctl call that can be used is VIDEO_GET_STATUS. All other + call will return an error code.</para> +</entry> + </row></tbody></tgroup></informaltable> + +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int open(const char ⋆deviceName, int flags);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>const char + *deviceName</para> +</entry><entry + align="char"> +<para>Name of specific video device.</para> +</entry> + </row><row><entry + align="char"> +<para>int flags</para> +</entry><entry + align="char"> +<para>A bit-wise OR of the following flags:</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDONLY read-only access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_RDWR read/write access</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>O_NONBLOCK open in non-blocking mode</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>(blocking mode is the default)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>ENODEV</para> +</entry><entry + align="char"> +<para>Device driver not loaded/available.</para> +</entry> + </row><row><entry + align="char"> +<para>EINTERNAL</para> +</entry><entry + align="char"> +<para>Internal error.</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>Device or resource busy.</para> +</entry> + </row><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid argument.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="video_fclose"> +<title>close()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call closes a previously opened video device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int close(int fd);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="video_fwrite"> +<title>write()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This system call can only be used if VIDEO_SOURCE_MEMORY is selected + in the ioctl call VIDEO_SELECT_SOURCE. The data provided shall be in + PES format, unless the capability allows other formats. If O_NONBLOCK is + not specified the function will block until buffer space is available. The amount + of data to be transferred is implied by count.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>size_t write(int fd, const void ⋆buf, size_t count);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>void *buf</para> +</entry><entry + align="char"> +<para>Pointer to the buffer containing the PES data.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t count</para> +</entry><entry + align="char"> +<para>Size of buf.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURN VALUE</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EPERM</para> +</entry><entry + align="char"> +<para>Mode VIDEO_SOURCE_MEMORY not selected.</para> +</entry> + </row><row><entry + align="char"> +<para>ENOMEM</para> +</entry><entry + align="char"> +<para>Attempted to write more data than the internal buffer can + hold.</para> +</entry> + </row><row><entry + align="char"> +<para>EBADF</para> +</entry><entry + align="char"> +<para>fd is not a valid open file descriptor.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_STOP" +role="subsection"><title>VIDEO_STOP</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Video Device to stop playing the current stream. + Depending on the input parameter, the screen can be blanked out or displaying + the last decoded frame.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_STOP, boolean + mode);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_STOP for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>Boolean mode</para> +</entry><entry + align="char"> +<para>Indicates how the screen shall be handled.</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>TRUE: Blank screen when stop.</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>FALSE: Show last decoded frame.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_PLAY" +role="subsection"><title>VIDEO_PLAY</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Video Device to start playing a video stream from the + selected source.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_PLAY);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_PLAY for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_FREEZE" +role="subsection"><title>VIDEO_FREEZE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call suspends the live video stream being played. Decoding + and playing are frozen. It is then possible to restart the decoding + and playing process of the video stream using the VIDEO_CONTINUE + command. If VIDEO_SOURCE_MEMORY is selected in the ioctl call + VIDEO_SELECT_SOURCE, the DVB subsystem will not decode any more + data until the ioctl call VIDEO_CONTINUE or VIDEO_PLAY is performed.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_FREEZE);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_FREEZE for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_CONTINUE" +role="subsection"><title>VIDEO_CONTINUE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call restarts decoding and playing processes of the video stream + which was played before a call to VIDEO_FREEZE was made.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_CONTINUE);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_CONTINUE for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_SELECT_SOURCE" +role="subsection"><title>VIDEO_SELECT_SOURCE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call informs the video device which source shall be used for the input + data. The possible sources are demux or memory. If memory is selected, the + data is fed to the video device through the write command.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_SELECT_SOURCE, + video_stream_source_t source);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SELECT_SOURCE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_stream_source_t + source</para> +</entry><entry + align="char"> +<para>Indicates which source shall be used for the Video stream.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_SET_BLANK" +role="subsection"><title>VIDEO_SET_BLANK</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Video Device to blank out the picture.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_SET_BLANK, boolean + mode);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_BLANK for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>boolean mode</para> +</entry><entry + align="char"> +<para>TRUE: Blank screen when stop.</para> +</entry> + </row><row><entry + align="char"> +</entry><entry + align="char"> +<para>FALSE: Show last decoded frame.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_GET_STATUS" +role="subsection"><title>VIDEO_GET_STATUS</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Video Device to return the current status of the device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_GET_STATUS, struct + video_status ⋆status);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_GET_STATUS for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct video_status + *status</para> +</entry><entry + align="char"> +<para>Returns the current status of the Video Device.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_GET_EVENT" +role="subsection"><title>VIDEO_GET_EVENT</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call returns an event of type video_event if available. If an event is + not available, the behavior depends on whether the device is in blocking or + non-blocking mode. In the latter case, the call fails immediately with errno + set to EWOULDBLOCK. In the former case, the call blocks until an event + becomes available. The standard Linux poll() and/or select() system calls can + be used with the device file descriptor to watch for new events. For select(), + the file descriptor should be included in the exceptfds argument, and for + poll(), POLLPRI should be specified as the wake-up condition. Read-only + permissions are sufficient for this ioctl call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_GET_EVENT, struct + video_event ⋆ev);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_GET_EVENT for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct video_event + *ev</para> +</entry><entry + align="char"> +<para>Points to the location where the event, if any, is to be + stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EWOULDBLOCK</para> +</entry><entry + align="char"> +<para>There is no event pending, and the device is in + non-blocking mode.</para> +</entry> + </row><row><entry + align="char"> +<para>EOVERFLOW</para> +</entry><entry + align="char"> +<para>Overflow in event queue - one or more events were lost.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_SET_DISPLAY_FORMAT" +role="subsection"><title>VIDEO_SET_DISPLAY_FORMAT</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Video Device to select the video format to be applied + by the MPEG chip on the video.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = + VIDEO_SET_DISPLAY_FORMAT, video_display_format_t + format);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_DISPLAY_FORMAT for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_display_format_t + format</para> +</entry><entry + align="char"> +<para>Selects the video format to be used.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_STILLPICTURE" +role="subsection"><title>VIDEO_STILLPICTURE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Video Device to display a still picture (I-frame). The + input data shall contain an I-frame. If the pointer is NULL, then the current + displayed still picture is blanked.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_STILLPICTURE, + struct video_still_picture ⋆sp);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_STILLPICTURE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>struct + video_still_picture + *sp</para> +</entry><entry + align="char"> +<para>Pointer to a location where an I-frame and size is stored.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_FAST_FORWARD" +role="subsection"><title>VIDEO_FAST_FORWARD</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the Video Device to skip decoding of N number of I-frames. + This call can only be used if VIDEO_SOURCE_MEMORY is selected.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_FAST_FORWARD, int + nFrames);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_FAST_FORWARD for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int nFrames</para> +</entry><entry + align="char"> +<para>The number of frames to skip.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EPERM</para> +</entry><entry + align="char"> +<para>Mode VIDEO_SOURCE_MEMORY not selected.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_SLOWMOTION" +role="subsection"><title>VIDEO_SLOWMOTION</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the video device to repeat decoding frames N number of + times. This call can only be used if VIDEO_SOURCE_MEMORY is selected.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_SLOWMOTION, int + nFrames);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SLOWMOTION for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int nFrames</para> +</entry><entry + align="char"> +<para>The number of times to repeat each frame.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EPERM</para> +</entry><entry + align="char"> +<para>Mode VIDEO_SOURCE_MEMORY not selected.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_GET_CAPABILITIES" +role="subsection"><title>VIDEO_GET_CAPABILITIES</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call asks the video device about its decoding capabilities. On success + it returns and integer which has bits set according to the defines in section ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_GET_CAPABILITIES, + unsigned int ⋆cap);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_GET_CAPABILITIES for this + command.</para> +</entry> + </row><row><entry + align="char"> +<para>unsigned int *cap</para> +</entry><entry + align="char"> +<para>Pointer to a location where to store the capability + information.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_SET_ID" +role="subsection"><title>VIDEO_SET_ID</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl selects which sub-stream is to be decoded if a program or system + stream is sent to the video device.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(int fd, int request = VIDEO_SET_ID, int + id);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_ID for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int id</para> +</entry><entry + align="char"> +<para>video sub-stream id</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>Invalid sub-stream id.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_CLEAR_BUFFER" +role="subsection"><title>VIDEO_CLEAR_BUFFER</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl call clears all video buffers in the driver and in the decoder hardware.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_CLEAR_BUFFER);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_CLEAR_BUFFER for this command.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_SET_STREAMTYPE" +role="subsection"><title>VIDEO_SET_STREAMTYPE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl tells the driver which kind of stream to expect being written to it. If + this call is not used the default of video PES is used. Some drivers might not + support this call and always expect PES.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int ioctl(fd, int request = VIDEO_SET_STREAMTYPE, + int type);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_STREAMTYPE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>int type</para> +</entry><entry + align="char"> +<para>stream type</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_SET_FORMAT" +role="subsection"><title>VIDEO_SET_FORMAT</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl sets the screen format (aspect ratio) of the connected output device + (TV) so that the output of the decoder can be adjusted accordingly.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_SET_FORMAT, + video_format_t format);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_FORMAT for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_format_t + format</para> +</entry><entry + align="char"> +<para>video format of TV as defined in section ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>format is not a valid video format.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_SET_SYSTEM" +role="subsection"><title>VIDEO_SET_SYSTEM</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl sets the television output format. The format (see section ??) may + vary from the color format of the displayed MPEG stream. If the hardware is + not able to display the requested format the call will return an error.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_SET_SYSTEM , + video_system_t system);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_FORMAT for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_system_t + system</para> +</entry><entry + align="char"> +<para>video system of TV output.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>system is not a valid or supported video system.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_SET_HIGHLIGHT" +role="subsection"><title>VIDEO_SET_HIGHLIGHT</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl sets the SPU highlight information for the menu access of a DVD.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_SET_HIGHLIGHT + ,video_highlight_t ⋆vhilite)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_HIGHLIGHT for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_highlight_t + *vhilite</para> +</entry><entry + align="char"> +<para>SPU Highlight information according to section ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; + +</section><section id="VIDEO_SET_SPU" +role="subsection"><title>VIDEO_SET_SPU</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl activates or deactivates SPU decoding in a DVD input stream. It can + only be used, if the driver is able to handle a DVD stream.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_SET_SPU , + video_spu_t ⋆spu)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_SPU for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_spu_t *spu</para> +</entry><entry + align="char"> +<para>SPU decoding (de)activation and subid setting according + to section ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>input is not a valid spu setting or driver cannot handle + SPU.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_SET_SPU_PALETTE" +role="subsection"><title>VIDEO_SET_SPU_PALETTE</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl sets the SPU color palette.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_SET_SPU_PALETTE + ,video_spu_palette_t ⋆palette )</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_SPU_PALETTE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_spu_palette_t + *palette</para> +</entry><entry + align="char"> +<para>SPU palette according to section ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>input is not a valid palette or driver doesn’t handle SPU.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_GET_NAVI" +role="subsection"><title>VIDEO_GET_NAVI</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl returns navigational information from the DVD stream. This is + especially needed if an encoded stream has to be decoded by the hardware.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_GET_NAVI , + video_navi_pack_t ⋆navipack)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_GET_NAVI for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_navi_pack_t + *navipack</para> +</entry><entry + align="char"> +<para>PCI or DSI pack (private stream 2) according to section + ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EFAULT</para> +</entry><entry + align="char"> +<para>driver is not able to return navigational information</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section id="VIDEO_SET_ATTRIBUTES" +role="subsection"><title>VIDEO_SET_ATTRIBUTES</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This ioctl is intended for DVD playback and allows you to set certain + information about the stream. Some hardware may not need this information, + but the call also tells the hardware to prepare for DVD playback.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para> int ioctl(fd, int request = VIDEO_SET_ATTRIBUTE + ,video_attributes_t vattr)</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>int fd</para> +</entry><entry + align="char"> +<para>File descriptor returned by a previous call to open().</para> +</entry> + </row><row><entry + align="char"> +<para>int request</para> +</entry><entry + align="char"> +<para>Equals VIDEO_SET_ATTRIBUTE for this command.</para> +</entry> + </row><row><entry + align="char"> +<para>video_attributes_t + vattr</para> +</entry><entry + align="char"> +<para>video attributes according to section ??.</para> +</entry> + </row></tbody></tgroup></informaltable> +&return-value-dvb; +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>EINVAL</para> +</entry><entry + align="char"> +<para>input is not a valid attribute setting.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> diff --git a/Documentation/DocBook/media/dvbstb.png.b64 b/Documentation/DocBook/media/dvbstb.png.b64 new file mode 100644 index 00000000..e8b52fde --- /dev/null +++ b/Documentation/DocBook/media/dvbstb.png.b64 @@ -0,0 +1,398 @@ +iVBORw0KGgoAAAANSUhEUgAAAzMAAAGaCAYAAAA7Jx25AAAABmJLR0QAAAAAAAD5Q7t/AAAACXBI +WXMAAA3XAAANiQFmEOuiAAAgAElEQVR42uzdd1RU18I28GdgKFZUBE0saFA0KoqFFkEhKhbAQmxJ +bIkNNEpMEUwsMZarJMZrw4KxRExQczUqil0jRBA1GAjGQqLYC4TemdnfH76cj3HodYDntxaLmTll +zuw57Zmz9z4yIYQAkYZzcnJCSkoKGjZsyMIgIiIiquPS09PRoEEDyBhmqCaQyWRo06YN3nvvPRYG +ERERUR137Ngx/Pnnn5CzKKgmMDAwwKpVqxhmiIiIiAj29vZ4//33ocWiICIiIiKimohhhoiIiIiI 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+(WSS)"</title> + </biblioentry> + + <biblioentry id="ets300231"> + <abbrev>ETS 300 231</abbrev> + <authorgroup> + <corpauthor>European Telecommunication Standards Institute +(<ulink +url="http://www.etsi.org">http://www.etsi.org</ulink>)</corpauthor> + </authorgroup> + <title>ETS 300 231 "Specification of the domestic video +Programme Delivery Control system (PDC)"</title> + </biblioentry> + + <biblioentry id="ets300706"> + <abbrev>ETS 300 706</abbrev> + <authorgroup> + <corpauthor>European Telecommunication Standards Institute +(<ulink url="http://www.etsi.org">http://www.etsi.org</ulink>)</corpauthor> + </authorgroup> + <title>ETS 300 706 "Enhanced Teletext specification"</title> + </biblioentry> + + <biblioentry id="mpeg2part1"> + <abbrev>ISO 13818-1</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>), International +Organisation for Standardisation (<ulink +url="http://www.iso.ch">http://www.iso.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-T Rec. H.222.0 | ISO/IEC 13818-1 "Information +technology — Generic coding of moving pictures and associated +audio information: Systems"</title> + </biblioentry> + + <biblioentry id="mpeg2part2"> + <abbrev>ISO 13818-2</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>), International +Organisation for Standardisation (<ulink +url="http://www.iso.ch">http://www.iso.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-T Rec. H.262 | ISO/IEC 13818-2 "Information +technology — Generic coding of moving pictures and associated +audio information: Video"</title> + </biblioentry> + + <biblioentry id="itu470"> + <abbrev>ITU BT.470</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.470-6 "Conventional Television +Systems"</title> + </biblioentry> + + <biblioentry id="itu601"> + <abbrev>ITU BT.601</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.601-5 "Studio Encoding Parameters +of Digital Television for Standard 4:3 and Wide-Screen 16:9 Aspect +Ratios"</title> + </biblioentry> + + <biblioentry id="itu653"> + <abbrev>ITU BT.653</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.653-3 "Teletext systems"</title> + </biblioentry> + + <biblioentry id="itu709"> + <abbrev>ITU BT.709</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.709-5 "Parameter values for the +HDTV standards for production and international programme +exchange"</title> + </biblioentry> + + <biblioentry id="itu1119"> + <abbrev>ITU BT.1119</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.1119 "625-line +television Wide Screen Signalling (WSS)"</title> + </biblioentry> + + <biblioentry id="jfif"> + <abbrev>JFIF</abbrev> + <authorgroup> + <corpauthor>Independent JPEG Group (<ulink +url="http://www.ijg.org">http://www.ijg.org</ulink>)</corpauthor> + </authorgroup> + <title>JPEG File Interchange Format</title> + <subtitle>Version 1.02</subtitle> + </biblioentry> + + <biblioentry id="itu-t81"> + <abbrev>ITU-T.81</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union +(<ulink url="http://www.itu.int">http://www.itu.int</ulink>)</corpauthor> + </authorgroup> + <title>ITU-T Recommendation T.81 +"Information Technology — Digital Compression and Coding of Continous-Tone +Still Images — Requirements and Guidelines"</title> + </biblioentry> + + <biblioentry id="w3c-jpeg-jfif"> + <abbrev>W3C JPEG JFIF</abbrev> + <authorgroup> + <corpauthor>The World Wide Web Consortium (<ulink +url="http://www.w3.org/Graphics/JPEG">http://www.w3.org</ulink>)</corpauthor> + </authorgroup> + <title>JPEG JFIF</title> + </biblioentry> + + <biblioentry id="smpte12m"> + <abbrev>SMPTE 12M</abbrev> + <authorgroup> + <corpauthor>Society of Motion Picture and Television Engineers +(<ulink url="http://www.smpte.org">http://www.smpte.org</ulink>)</corpauthor> + </authorgroup> + <title>SMPTE 12M-1999 "Television, Audio and Film - Time and +Control Code"</title> + </biblioentry> + + <biblioentry id="smpte170m"> + <abbrev>SMPTE 170M</abbrev> + <authorgroup> + <corpauthor>Society of Motion Picture and Television Engineers +(<ulink url="http://www.smpte.org">http://www.smpte.org</ulink>)</corpauthor> + </authorgroup> + <title>SMPTE 170M-1999 "Television - Composite Analog Video +Signal - NTSC for Studio Applications"</title> + </biblioentry> + + <biblioentry id="smpte240m"> + <abbrev>SMPTE 240M</abbrev> + <authorgroup> + <corpauthor>Society of Motion Picture and Television Engineers +(<ulink url="http://www.smpte.org">http://www.smpte.org</ulink>)</corpauthor> + </authorgroup> + <title>SMPTE 240M-1999 "Television - Signal Parameters - +1125-Line High-Definition Production"</title> + </biblioentry> + + <biblioentry id="en50067"> + <abbrev>EN 50067</abbrev> + <authorgroup> + <corpauthor>European Committee for Electrotechnical Standardization +(<ulink url="http://www.cenelec.eu">http://www.cenelec.eu</ulink>)</corpauthor> + </authorgroup> + <title>Specification of the radio data system (RDS) for VHF/FM sound broadcasting +in the frequency range from 87,5 to 108,0 MHz</title> + </biblioentry> + + <biblioentry id="nrsc4"> + <abbrev>NRSC-4</abbrev> + <authorgroup> + <corpauthor>National Radio Systems Committee +(<ulink url="http://www.nrscstandards.org">http://www.nrscstandards.org</ulink>)</corpauthor> + </authorgroup> + <title>NTSC-4: United States RBDS Standard</title> + </biblioentry> + + </bibliography> diff --git a/Documentation/DocBook/media/v4l/capture.c.xml b/Documentation/DocBook/media/v4l/capture.c.xml new file mode 100644 index 00000000..1c5c49a2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/capture.c.xml @@ -0,0 +1,659 @@ +<programlisting> +/* + * V4L2 video capture example + * + * This program can be used and distributed without restrictions. + * + * This program is provided with the V4L2 API + * see http://linuxtv.org/docs.php for more information + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> + +#include <getopt.h> /* getopt_long() */ + +#include <fcntl.h> /* low-level i/o */ +#include <unistd.h> +#include <errno.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/mman.h> +#include <sys/ioctl.h> + +#include <linux/videodev2.h> + +#define CLEAR(x) memset(&(x), 0, sizeof(x)) + +enum io_method { + IO_METHOD_READ, + IO_METHOD_MMAP, + IO_METHOD_USERPTR, +}; + +struct buffer { + void *start; + size_t length; +}; + +static char *dev_name; +static enum io_method io = IO_METHOD_MMAP; +static int fd = -1; +struct buffer *buffers; +static unsigned int n_buffers; +static int out_buf; +static int force_format; +static int frame_count = 70; + +static void errno_exit(const char *s) +{ + fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno)); + exit(EXIT_FAILURE); +} + +static int xioctl(int fh, int request, void *arg) +{ + int r; + + do { + r = ioctl(fh, request, arg); + } while (-1 == r && EINTR == errno); + + return r; +} + +static void process_image(const void *p, int size) +{ + if (out_buf) + fwrite(p, size, 1, stdout); + + fflush(stderr); + fprintf(stderr, "."); + fflush(stdout); +} + +static int read_frame(void) +{ + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + unsigned int i; + + switch (io) { + case IO_METHOD_READ: + if (-1 == read(fd, buffers[0].start, buffers[0].length)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("read"); + } + } + + process_image(buffers[0].start, buffers[0].length); + break; + + case IO_METHOD_MMAP: + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + + if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("VIDIOC_DQBUF"); + } + } + + assert(buf.index < n_buffers); + + process_image(buffers[buf.index].start, buf.bytesused); + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + break; + + case IO_METHOD_USERPTR: + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_USERPTR; + + if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("VIDIOC_DQBUF"); + } + } + + for (i = 0; i < n_buffers; ++i) + if (buf.m.userptr == (unsigned long)buffers[i].start + && buf.length == buffers[i].length) + break; + + assert(i < n_buffers); + + process_image((void *)buf.m.userptr, buf.bytesused); + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + break; + } + + return 1; +} + +static void mainloop(void) +{ + unsigned int count; + + count = frame_count; + + while (count-- > 0) { + for (;;) { + fd_set fds; + struct timeval tv; + int r; + + FD_ZERO(&fds); + FD_SET(fd, &fds); + + /* Timeout. */ + tv.tv_sec = 2; + tv.tv_usec = 0; + + r = select(fd + 1, &fds, NULL, NULL, &tv); + + if (-1 == r) { + if (EINTR == errno) + continue; + errno_exit("select"); + } + + if (0 == r) { + fprintf(stderr, "select timeout\n"); + exit(EXIT_FAILURE); + } + + if (read_frame()) + break; + /* EAGAIN - continue select loop. */ + } + } +} + +static void stop_capturing(void) +{ + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + + switch (io) { + case IO_METHOD_READ: + /* Nothing to do. */ + break; + + case IO_METHOD_MMAP: + case IO_METHOD_USERPTR: + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type)) + errno_exit("VIDIOC_STREAMOFF"); + break; + } +} + +static void start_capturing(void) +{ + unsigned int i; + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + + switch (io) { + case IO_METHOD_READ: + /* Nothing to do. */ + break; + + case IO_METHOD_MMAP: + for (i = 0; i < n_buffers; ++i) { + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = i; + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) + errno_exit("VIDIOC_STREAMON"); + break; + + case IO_METHOD_USERPTR: + for (i = 0; i < n_buffers; ++i) { + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_USERPTR; + buf.index = i; + buf.m.userptr = (unsigned long)buffers[i].start; + buf.length = buffers[i].length; + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) + errno_exit("VIDIOC_STREAMON"); + break; + } +} + +static void uninit_device(void) +{ + unsigned int i; + + switch (io) { + case IO_METHOD_READ: + free(buffers[0].start); + break; + + case IO_METHOD_MMAP: + for (i = 0; i < n_buffers; ++i) + if (-1 == munmap(buffers[i].start, buffers[i].length)) + errno_exit("munmap"); + break; + + case IO_METHOD_USERPTR: + for (i = 0; i < n_buffers; ++i) + free(buffers[i].start); + break; + } + + free(buffers); +} + +static void init_read(unsigned int buffer_size) +{ + buffers = calloc(1, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + buffers[0].length = buffer_size; + buffers[0].start = malloc(buffer_size); + + if (!buffers[0].start) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } +} + +static void init_mmap(void) +{ + struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req; + + CLEAR(req); + + req.count = 4; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_MMAP; + + if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { + if (EINVAL == errno) { + fprintf(stderr, "%s does not support " + "memory mapping\n", dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_REQBUFS"); + } + } + + if (req.count < 2) { + fprintf(stderr, "Insufficient buffer memory on %s\n", + dev_name); + exit(EXIT_FAILURE); + } + + buffers = calloc(req.count, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = n_buffers; + + if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf)) + errno_exit("VIDIOC_QUERYBUF"); + + buffers[n_buffers].length = buf.length; + buffers[n_buffers].start = + mmap(NULL /* start anywhere */, + buf.length, + PROT_READ | PROT_WRITE /* required */, + MAP_SHARED /* recommended */, + fd, buf.m.offset); + + if (MAP_FAILED == buffers[n_buffers].start) + errno_exit("mmap"); + } +} + +static void init_userp(unsigned int buffer_size) +{ + struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req; + + CLEAR(req); + + req.count = 4; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_USERPTR; + + if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { + if (EINVAL == errno) { + fprintf(stderr, "%s does not support " + "user pointer i/o\n", dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_REQBUFS"); + } + } + + buffers = calloc(4, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + for (n_buffers = 0; n_buffers < 4; ++n_buffers) { + buffers[n_buffers].length = buffer_size; + buffers[n_buffers].start = malloc(buffer_size); + + if (!buffers[n_buffers].start) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + } +} + +static void init_device(void) +{ + struct <link linkend="v4l2-capability">v4l2_capability</link> cap; + struct <link linkend="v4l2-cropcap">v4l2_cropcap</link> cropcap; + struct <link linkend="v4l2-crop">v4l2_crop</link> crop; + struct <link linkend="v4l2-format">v4l2_format</link> fmt; + unsigned int min; + + if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) { + if (EINVAL == errno) { + fprintf(stderr, "%s is no V4L2 device\n", + dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_QUERYCAP"); + } + } + + if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) { + fprintf(stderr, "%s is no video capture device\n", + dev_name); + exit(EXIT_FAILURE); + } + + switch (io) { + case IO_METHOD_READ: + if (!(cap.capabilities & V4L2_CAP_READWRITE)) { + fprintf(stderr, "%s does not support read i/o\n", + dev_name); + exit(EXIT_FAILURE); + } + break; + + case IO_METHOD_MMAP: + case IO_METHOD_USERPTR: + if (!(cap.capabilities & V4L2_CAP_STREAMING)) { + fprintf(stderr, "%s does not support streaming i/o\n", + dev_name); + exit(EXIT_FAILURE); + } + break; + } + + + /* Select video input, video standard and tune here. */ + + + CLEAR(cropcap); + + cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + + if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) { + crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + crop.c = cropcap.defrect; /* reset to default */ + + if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) { + switch (errno) { + case EINVAL: + /* Cropping not supported. */ + break; + default: + /* Errors ignored. */ + break; + } + } + } else { + /* Errors ignored. */ + } + + + CLEAR(fmt); + + fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (force_format) { + fmt.fmt.pix.width = 640; + fmt.fmt.pix.height = 480; + fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; + fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; + + if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt)) + errno_exit("VIDIOC_S_FMT"); + + /* Note VIDIOC_S_FMT may change width and height. */ + } else { + /* Preserve original settings as set by v4l2-ctl for example */ + if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt)) + errno_exit("VIDIOC_G_FMT"); + } + + /* Buggy driver paranoia. */ + min = fmt.fmt.pix.width * 2; + if (fmt.fmt.pix.bytesperline < min) + fmt.fmt.pix.bytesperline = min; + min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height; + if (fmt.fmt.pix.sizeimage < min) + fmt.fmt.pix.sizeimage = min; + + switch (io) { + case IO_METHOD_READ: + init_read(fmt.fmt.pix.sizeimage); + break; + + case IO_METHOD_MMAP: + init_mmap(); + break; + + case IO_METHOD_USERPTR: + init_userp(fmt.fmt.pix.sizeimage); + break; + } +} + +static void close_device(void) +{ + if (-1 == close(fd)) + errno_exit("close"); + + fd = -1; +} + +static void open_device(void) +{ + struct stat st; + + if (-1 == stat(dev_name, &st)) { + fprintf(stderr, "Cannot identify '%s': %d, %s\n", + dev_name, errno, strerror(errno)); + exit(EXIT_FAILURE); + } + + if (!S_ISCHR(st.st_mode)) { + fprintf(stderr, "%s is no device\n", dev_name); + exit(EXIT_FAILURE); + } + + fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0); + + if (-1 == fd) { + fprintf(stderr, "Cannot open '%s': %d, %s\n", + dev_name, errno, strerror(errno)); + exit(EXIT_FAILURE); + } +} + +static void usage(FILE *fp, int argc, char **argv) +{ + fprintf(fp, + "Usage: %s [options]\n\n" + "Version 1.3\n" + "Options:\n" + "-d | --device name Video device name [%s]\n" + "-h | --help Print this message\n" + "-m | --mmap Use memory mapped buffers [default]\n" + "-r | --read Use read() calls\n" + "-u | --userp Use application allocated buffers\n" + "-o | --output Outputs stream to stdout\n" + "-f | --format Force format to 640x480 YUYV\n" + "-c | --count Number of frames to grab [%i]\n" + "", + argv[0], dev_name, frame_count); +} + +static const char short_options[] = "d:hmruofc:"; + +static const struct option +long_options[] = { + { "device", required_argument, NULL, 'd' }, + { "help", no_argument, NULL, 'h' }, + { "mmap", no_argument, NULL, 'm' }, + { "read", no_argument, NULL, 'r' }, + { "userp", no_argument, NULL, 'u' }, + { "output", no_argument, NULL, 'o' }, + { "format", no_argument, NULL, 'f' }, + { "count", required_argument, NULL, 'c' }, + { 0, 0, 0, 0 } +}; + +int main(int argc, char **argv) +{ + dev_name = "/dev/video0"; + + for (;;) { + int idx; + int c; + + c = getopt_long(argc, argv, + short_options, long_options, &idx); + + if (-1 == c) + break; + + switch (c) { + case 0: /* getopt_long() flag */ + break; + + case 'd': + dev_name = optarg; + break; + + case 'h': + usage(stdout, argc, argv); + exit(EXIT_SUCCESS); + + case 'm': + io = IO_METHOD_MMAP; + break; + + case 'r': + io = IO_METHOD_READ; + break; + + case 'u': + io = IO_METHOD_USERPTR; + break; + + case 'o': + out_buf++; + break; + + case 'f': + force_format++; + break; + + case 'c': + errno = 0; + frame_count = strtol(optarg, NULL, 0); + if (errno) + errno_exit(optarg); + break; + + default: + usage(stderr, argc, argv); + exit(EXIT_FAILURE); + } + } + + open_device(); + init_device(); + start_capturing(); + mainloop(); + stop_capturing(); + uninit_device(); + close_device(); + fprintf(stderr, "\n"); + return 0; +} +</programlisting> diff --git a/Documentation/DocBook/media/v4l/common.xml b/Documentation/DocBook/media/v4l/common.xml new file mode 100644 index 00000000..c79278ac --- /dev/null +++ b/Documentation/DocBook/media/v4l/common.xml @@ -0,0 +1,1199 @@ + <title>Common API Elements</title> + + <para>Programming a V4L2 device consists of these +steps:</para> + + <itemizedlist> + <listitem> + <para>Opening the device</para> + </listitem> + <listitem> + <para>Changing device properties, selecting a video and audio +input, video standard, picture brightness a. o.</para> + </listitem> + <listitem> + <para>Negotiating a data format</para> + </listitem> + <listitem> + <para>Negotiating an input/output method</para> + </listitem> + <listitem> + <para>The actual input/output loop</para> + </listitem> + <listitem> + <para>Closing the device</para> + </listitem> + </itemizedlist> + + <para>In practice most steps are optional and can be executed out of +order. It depends on the V4L2 device type, you can read about the +details in <xref linkend="devices" />. In this chapter we will discuss +the basic concepts applicable to all devices.</para> + + <section id="open"> + <title>Opening and Closing Devices</title> + + <section> + <title>Device Naming</title> + + <para>V4L2 drivers are implemented as kernel modules, loaded +manually by the system administrator or automatically when a device is +first opened. The driver modules plug into the "videodev" kernel +module. It provides helper functions and a common application +interface specified in this document.</para> + + <para>Each driver thus loaded registers one or more device nodes +with major number 81 and a minor number between 0 and 255. Assigning +minor numbers to V4L2 devices is entirely up to the system administrator, +this is primarily intended to solve conflicts between devices.<footnote> + <para>Access permissions are associated with character +device special files, hence we must ensure device numbers cannot +change with the module load order. To this end minor numbers are no +longer automatically assigned by the "videodev" module as in V4L but +requested by the driver. The defaults will suffice for most people +unless two drivers compete for the same minor numbers.</para> + </footnote> The module options to select minor numbers are named +after the device special file with a "_nr" suffix. For example "video_nr" +for <filename>/dev/video</filename> video capture devices. The number is +an offset to the base minor number associated with the device type. +<footnote> + <para>In earlier versions of the V4L2 API the module options +where named after the device special file with a "unit_" prefix, expressing +the minor number itself, not an offset. Rationale for this change is unknown. +Lastly the naming and semantics are just a convention among driver writers, +the point to note is that minor numbers are not supposed to be hardcoded +into drivers.</para> + </footnote> When the driver supports multiple devices of the same +type more than one minor number can be assigned, separated by commas: +<informalexample> + <screen> +> insmod mydriver.o video_nr=0,1 radio_nr=0,1</screen> + </informalexample></para> + + <para>In <filename>/etc/modules.conf</filename> this may be +written as: <informalexample> + <screen> +alias char-major-81-0 mydriver +alias char-major-81-1 mydriver +alias char-major-81-64 mydriver <co id="alias" /> +options mydriver video_nr=0,1 radio_nr=0,1 <co id="options" /> + </screen> + <calloutlist> + <callout arearefs="alias"> + <para>When an application attempts to open a device +special file with major number 81 and minor number 0, 1, or 64, load +"mydriver" (and the "videodev" module it depends upon).</para> + </callout> + <callout arearefs="options"> + <para>Register the first two video capture devices with +minor number 0 and 1 (base number is 0), the first two radio device +with minor number 64 and 65 (base 64).</para> + </callout> + </calloutlist> + </informalexample> When no minor number is given as module +option the driver supplies a default. <xref linkend="devices" /> +recommends the base minor numbers to be used for the various device +types. Obviously minor numbers must be unique. When the number is +already in use the <emphasis>offending device</emphasis> will not be +registered. <!-- Blessed by Linus Torvalds on +linux-kernel@vger.kernel.org, 2002-11-20. --></para> + + <para>By convention system administrators create various +character device special files with these major and minor numbers in +the <filename>/dev</filename> directory. The names recommended for the +different V4L2 device types are listed in <xref linkend="devices" />. +</para> + + <para>The creation of character special files (with +<application>mknod</application>) is a privileged operation and +devices cannot be opened by major and minor number. That means +applications cannot <emphasis>reliable</emphasis> scan for loaded or +installed drivers. The user must enter a device name, or the +application can try the conventional device names.</para> + + <para>Under the device filesystem (devfs) the minor number +options are ignored. V4L2 drivers (or by proxy the "videodev" module) +automatically create the required device files in the +<filename>/dev/v4l</filename> directory using the conventional device +names above.</para> + </section> + + <section id="related"> + <title>Related Devices</title> + + <para>Devices can support several related functions. For example +video capturing, video overlay and VBI capturing are related because +these functions share, amongst other, the same video input and tuner +frequency. V4L and earlier versions of V4L2 used the same device name +and minor number for video capturing and overlay, but different ones +for VBI. Experience showed this approach has several problems<footnote> + <para>Given a device file name one cannot reliable find +related devices. For once names are arbitrary and in a system with +multiple devices, where only some support VBI capturing, a +<filename>/dev/video2</filename> is not necessarily related to +<filename>/dev/vbi2</filename>. The V4L +<constant>VIDIOCGUNIT</constant> ioctl would require a search for a +device file with a particular major and minor number.</para> + </footnote>, and to make things worse the V4L videodev module +used to prohibit multiple opens of a device.</para> + + <para>As a remedy the present version of the V4L2 API relaxed the +concept of device types with specific names and minor numbers. For +compatibility with old applications drivers must still register different +minor numbers to assign a default function to the device. But if related +functions are supported by the driver they must be available under all +registered minor numbers. The desired function can be selected after +opening the device as described in <xref linkend="devices" />.</para> + + <para>Imagine a driver supporting video capturing, video +overlay, raw VBI capturing, and FM radio reception. It registers three +devices with minor number 0, 64 and 224 (this numbering scheme is +inherited from the V4L API). Regardless if +<filename>/dev/video</filename> (81, 0) or +<filename>/dev/vbi</filename> (81, 224) is opened the application can +select any one of the video capturing, overlay or VBI capturing +functions. Without programming (e. g. reading from the device +with <application>dd</application> or <application>cat</application>) +<filename>/dev/video</filename> captures video images, while +<filename>/dev/vbi</filename> captures raw VBI data. +<filename>/dev/radio</filename> (81, 64) is invariable a radio device, +unrelated to the video functions. Being unrelated does not imply the +devices can be used at the same time, however. The &func-open; +function may very well return an &EBUSY;.</para> + + <para>Besides video input or output the hardware may also +support audio sampling or playback. If so, these functions are +implemented as OSS or ALSA PCM devices and eventually OSS or ALSA +audio mixer. The V4L2 API makes no provisions yet to find these +related devices. If you have an idea please write to the linux-media +mailing list: &v4l-ml;.</para> + </section> + + <section> + <title>Multiple Opens</title> + + <para>In general, V4L2 devices can be opened more than once. +When this is supported by the driver, users can for example start a +"panel" application to change controls like brightness or audio +volume, while another application captures video and audio. In other words, panel +applications are comparable to an OSS or ALSA audio mixer application. +When a device supports multiple functions like capturing and overlay +<emphasis>simultaneously</emphasis>, multiple opens allow concurrent +use of the device by forked processes or specialized applications.</para> + + <para>Multiple opens are optional, although drivers should +permit at least concurrent accesses without data exchange, &ie; panel +applications. This implies &func-open; can return an &EBUSY; when the +device is already in use, as well as &func-ioctl; functions initiating +data exchange (namely the &VIDIOC-S-FMT; ioctl), and the &func-read; +and &func-write; functions.</para> + + <para>Mere opening a V4L2 device does not grant exclusive +access.<footnote> + <para>Drivers could recognize the +<constant>O_EXCL</constant> open flag. Presently this is not required, +so applications cannot know if it really works.</para> + </footnote> Initiating data exchange however assigns the right +to read or write the requested type of data, and to change related +properties, to this file descriptor. Applications can request +additional access privileges using the priority mechanism described in +<xref linkend="app-pri" />.</para> + </section> + + <section> + <title>Shared Data Streams</title> + + <para>V4L2 drivers should not support multiple applications +reading or writing the same data stream on a device by copying +buffers, time multiplexing or similar means. This is better handled by +a proxy application in user space. When the driver supports stream +sharing anyway it must be implemented transparently. The V4L2 API does +not specify how conflicts are solved. <!-- For example O_EXCL when the +application does not want to be preempted, PROT_READ mmapped buffers +which can be mapped twice, what happens when image formats do not +match etc.--></para> + </section> + + <section> + <title>Functions</title> + + <para>To open and close V4L2 devices applications use the +&func-open; and &func-close; function, respectively. Devices are +programmed using the &func-ioctl; function as explained in the +following sections.</para> + </section> + </section> + + <section id="querycap"> + <title>Querying Capabilities</title> + + <para>Because V4L2 covers a wide variety of devices not all +aspects of the API are equally applicable to all types of devices. +Furthermore devices of the same type have different capabilities and +this specification permits the omission of a few complicated and less +important parts of the API.</para> + + <para>The &VIDIOC-QUERYCAP; ioctl is available to check if the kernel +device is compatible with this specification, and to query the <link +linkend="devices">functions</link> and <link linkend="io">I/O +methods</link> supported by the device.</para> + + <para>Starting with kernel version 3.1, VIDIOC-QUERYCAP will return the +V4L2 API version used by the driver, with generally matches the Kernel version. +There's no need of using &VIDIOC-QUERYCAP; to check if an specific ioctl is +supported, the V4L2 core now returns ENOIOCTLCMD if a driver doesn't provide +support for an ioctl.</para> + + <para>Other features can be queried +by calling the respective ioctl, for example &VIDIOC-ENUMINPUT; +to learn about the number, types and names of video connectors on the +device. Although abstraction is a major objective of this API, the +ioctl also allows driver specific applications to reliable identify +the driver.</para> + + <para>All V4L2 drivers must support +<constant>VIDIOC_QUERYCAP</constant>. Applications should always call +this ioctl after opening the device.</para> + </section> + + <section id="app-pri"> + <title>Application Priority</title> + + <para>When multiple applications share a device it may be +desirable to assign them different priorities. Contrary to the +traditional "rm -rf /" school of thought a video recording application +could for example block other applications from changing video +controls or switching the current TV channel. Another objective is to +permit low priority applications working in background, which can be +preempted by user controlled applications and automatically regain +control of the device at a later time.</para> + + <para>Since these features cannot be implemented entirely in user +space V4L2 defines the &VIDIOC-G-PRIORITY; and &VIDIOC-S-PRIORITY; +ioctls to request and query the access priority associate with a file +descriptor. Opening a device assigns a medium priority, compatible +with earlier versions of V4L2 and drivers not supporting these ioctls. +Applications requiring a different priority will usually call +<constant>VIDIOC_S_PRIORITY</constant> after verifying the device with +the &VIDIOC-QUERYCAP; ioctl.</para> + + <para>Ioctls changing driver properties, such as &VIDIOC-S-INPUT;, +return an &EBUSY; after another application obtained higher priority. +An event mechanism to notify applications about asynchronous property +changes has been proposed but not added yet.</para> + </section> + + <section id="video"> + <title>Video Inputs and Outputs</title> + + <para>Video inputs and outputs are physical connectors of a +device. These can be for example RF connectors (antenna/cable), CVBS +a.k.a. Composite Video, S-Video or RGB connectors. Only video and VBI +capture devices have inputs, output devices have outputs, at least one +each. Radio devices have no video inputs or outputs.</para> + + <para>To learn about the number and attributes of the +available inputs and outputs applications can enumerate them with the +&VIDIOC-ENUMINPUT; and &VIDIOC-ENUMOUTPUT; ioctl, respectively. The +&v4l2-input; returned by the <constant>VIDIOC_ENUMINPUT</constant> +ioctl also contains signal status information applicable when the +current video input is queried.</para> + + <para>The &VIDIOC-G-INPUT; and &VIDIOC-G-OUTPUT; ioctl return the +index of the current video input or output. To select a different +input or output applications call the &VIDIOC-S-INPUT; and +&VIDIOC-S-OUTPUT; ioctl. Drivers must implement all the input ioctls +when the device has one or more inputs, all the output ioctls when the +device has one or more outputs.</para> + + <!-- + <figure id=io-tree> + <title>Input and output enumeration is the root of most device properties.</title> + <mediaobject> + <imageobject> + <imagedata fileref="links.pdf" format="ps" /> + </imageobject> + <imageobject> + <imagedata fileref="links.gif" format="gif" /> + </imageobject> + <textobject> + <phrase>Links between various device property structures.</phrase> + </textobject> + </mediaobject> + </figure> + --> + + <example> + <title>Information about the current video input</title> + + <programlisting> +&v4l2-input; input; +int index; + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +memset (&input, 0, sizeof (input)); +input.index = index; + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUMINPUT"); + exit (EXIT_FAILURE); +} + +printf ("Current input: %s\n", input.name); + </programlisting> + </example> + + <example> + <title>Switching to the first video input</title> + + <programlisting> +int index; + +index = 0; + +if (-1 == ioctl (fd, &VIDIOC-S-INPUT;, &index)) { + perror ("VIDIOC_S_INPUT"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + </section> + + <section id="audio"> + <title>Audio Inputs and Outputs</title> + + <para>Audio inputs and outputs are physical connectors of a +device. Video capture devices have inputs, output devices have +outputs, zero or more each. Radio devices have no audio inputs or +outputs. They have exactly one tuner which in fact +<emphasis>is</emphasis> an audio source, but this API associates +tuners with video inputs or outputs only, and radio devices have +none of these.<footnote> + <para>Actually &v4l2-audio; ought to have a +<structfield>tuner</structfield> field like &v4l2-input;, not only +making the API more consistent but also permitting radio devices with +multiple tuners.</para> + </footnote> A connector on a TV card to loop back the received +audio signal to a sound card is not considered an audio output.</para> + + <para>Audio and video inputs and outputs are associated. Selecting +a video source also selects an audio source. This is most evident when +the video and audio source is a tuner. Further audio connectors can +combine with more than one video input or output. Assumed two +composite video inputs and two audio inputs exist, there may be up to +four valid combinations. The relation of video and audio connectors +is defined in the <structfield>audioset</structfield> field of the +respective &v4l2-input; or &v4l2-output;, where each bit represents +the index number, starting at zero, of one audio input or output.</para> + + <para>To learn about the number and attributes of the +available inputs and outputs applications can enumerate them with the +&VIDIOC-ENUMAUDIO; and &VIDIOC-ENUMAUDOUT; ioctl, respectively. The +&v4l2-audio; returned by the <constant>VIDIOC_ENUMAUDIO</constant> ioctl +also contains signal status information applicable when the current +audio input is queried.</para> + + <para>The &VIDIOC-G-AUDIO; and &VIDIOC-G-AUDOUT; ioctl report +the current audio input and output, respectively. Note that, unlike +&VIDIOC-G-INPUT; and &VIDIOC-G-OUTPUT; these ioctls return a structure +as <constant>VIDIOC_ENUMAUDIO</constant> and +<constant>VIDIOC_ENUMAUDOUT</constant> do, not just an index.</para> + + <para>To select an audio input and change its properties +applications call the &VIDIOC-S-AUDIO; ioctl. To select an audio +output (which presently has no changeable properties) applications +call the &VIDIOC-S-AUDOUT; ioctl.</para> + + <para>Drivers must implement all input ioctls when the device +has one or more inputs, all output ioctls when the device has one +or more outputs. When the device has any audio inputs or outputs the +driver must set the <constant>V4L2_CAP_AUDIO</constant> flag in the +&v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl.</para> + + <example> + <title>Information about the current audio input</title> + + <programlisting> +&v4l2-audio; audio; + +memset (&audio, 0, sizeof (audio)); + +if (-1 == ioctl (fd, &VIDIOC-G-AUDIO;, &audio)) { + perror ("VIDIOC_G_AUDIO"); + exit (EXIT_FAILURE); +} + +printf ("Current input: %s\n", audio.name); + </programlisting> + </example> + + <example> + <title>Switching to the first audio input</title> + + <programlisting> +&v4l2-audio; audio; + +memset (&audio, 0, sizeof (audio)); /* clear audio.mode, audio.reserved */ + +audio.index = 0; + +if (-1 == ioctl (fd, &VIDIOC-S-AUDIO;, &audio)) { + perror ("VIDIOC_S_AUDIO"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + </section> + + <section id="tuner"> + <title>Tuners and Modulators</title> + + <section> + <title>Tuners</title> + + <para>Video input devices can have one or more tuners +demodulating a RF signal. Each tuner is associated with one or more +video inputs, depending on the number of RF connectors on the tuner. +The <structfield>type</structfield> field of the respective +&v4l2-input; returned by the &VIDIOC-ENUMINPUT; ioctl is set to +<constant>V4L2_INPUT_TYPE_TUNER</constant> and its +<structfield>tuner</structfield> field contains the index number of +the tuner.</para> + + <para>Radio devices have exactly one tuner with index zero, no +video inputs.</para> + + <para>To query and change tuner properties applications use the +&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; ioctl, respectively. The +&v4l2-tuner; returned by <constant>VIDIOC_G_TUNER</constant> also +contains signal status information applicable when the tuner of the +current video input, or a radio tuner is queried. Note that +<constant>VIDIOC_S_TUNER</constant> does not switch the current tuner, +when there is more than one at all. The tuner is solely determined by +the current video input. Drivers must support both ioctls and set the +<constant>V4L2_CAP_TUNER</constant> flag in the &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl when the device has one or +more tuners.</para> + </section> + + <section> + <title>Modulators</title> + + <para>Video output devices can have one or more modulators, uh, +modulating a video signal for radiation or connection to the antenna +input of a TV set or video recorder. Each modulator is associated with +one or more video outputs, depending on the number of RF connectors on +the modulator. The <structfield>type</structfield> field of the +respective &v4l2-output; returned by the &VIDIOC-ENUMOUTPUT; ioctl is +set to <constant>V4L2_OUTPUT_TYPE_MODULATOR</constant> and its +<structfield>modulator</structfield> field contains the index number +of the modulator. This specification does not define radio output +devices.</para> + + <para>To query and change modulator properties applications use +the &VIDIOC-G-MODULATOR; and &VIDIOC-S-MODULATOR; ioctl. Note that +<constant>VIDIOC_S_MODULATOR</constant> does not switch the current +modulator, when there is more than one at all. The modulator is solely +determined by the current video output. Drivers must support both +ioctls and set the <constant>V4L2_CAP_MODULATOR</constant> flag in +the &v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl when the +device has one or more modulators.</para> + </section> + + <section> + <title>Radio Frequency</title> + + <para>To get and set the tuner or modulator radio frequency +applications use the &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY; +ioctl which both take a pointer to a &v4l2-frequency;. These ioctls +are used for TV and radio devices alike. Drivers must support both +ioctls when the tuner or modulator ioctls are supported, or +when the device is a radio device.</para> + </section> + </section> + + <section id="standard"> + <title>Video Standards</title> + + <para>Video devices typically support one or more different video +standards or variations of standards. Each video input and output may +support another set of standards. This set is reported by the +<structfield>std</structfield> field of &v4l2-input; and +&v4l2-output; returned by the &VIDIOC-ENUMINPUT; and +&VIDIOC-ENUMOUTPUT; ioctl, respectively.</para> + + <para>V4L2 defines one bit for each analog video standard +currently in use worldwide, and sets aside bits for driver defined +standards, ⪚ hybrid standards to watch NTSC video tapes on PAL TVs +and vice versa. Applications can use the predefined bits to select a +particular standard, although presenting the user a menu of supported +standards is preferred. To enumerate and query the attributes of the +supported standards applications use the &VIDIOC-ENUMSTD; ioctl.</para> + + <para>Many of the defined standards are actually just variations +of a few major standards. The hardware may in fact not distinguish +between them, or do so internal and switch automatically. Therefore +enumerated standards also contain sets of one or more standard +bits.</para> + + <para>Assume a hypothetic tuner capable of demodulating B/PAL, +G/PAL and I/PAL signals. The first enumerated standard is a set of B +and G/PAL, switched automatically depending on the selected radio +frequency in UHF or VHF band. Enumeration gives a "PAL-B/G" or "PAL-I" +choice. Similar a Composite input may collapse standards, enumerating +"PAL-B/G/H/I", "NTSC-M" and "SECAM-D/K".<footnote> + <para>Some users are already confused by technical terms PAL, +NTSC and SECAM. There is no point asking them to distinguish between +B, G, D, or K when the software or hardware can do that +automatically.</para> + </footnote></para> + + <para>To query and select the standard used by the current video +input or output applications call the &VIDIOC-G-STD; and +&VIDIOC-S-STD; ioctl, respectively. The <emphasis>received</emphasis> +standard can be sensed with the &VIDIOC-QUERYSTD; ioctl. Note parameter of all these ioctls is a pointer to a &v4l2-std-id; type (a standard set), <emphasis>not</emphasis> an index into the standard enumeration.<footnote> + <para>An alternative to the current scheme is to use pointers +to indices as arguments of <constant>VIDIOC_G_STD</constant> and +<constant>VIDIOC_S_STD</constant>, the &v4l2-input; and +&v4l2-output; <structfield>std</structfield> field would be a set of +indices like <structfield>audioset</structfield>.</para> + <para>Indices are consistent with the rest of the API +and identify the standard unambiguously. In the present scheme of +things an enumerated standard is looked up by &v4l2-std-id;. Now the +standards supported by the inputs of a device can overlap. Just +assume the tuner and composite input in the example above both +exist on a device. An enumeration of "PAL-B/G", "PAL-H/I" suggests +a choice which does not exist. We cannot merge or omit sets, because +applications would be unable to find the standards reported by +<constant>VIDIOC_G_STD</constant>. That leaves separate enumerations +for each input. Also selecting a standard by &v4l2-std-id; can be +ambiguous. Advantage of this method is that applications need not +identify the standard indirectly, after enumerating.</para><para>So in +summary, the lookup itself is unavoidable. The difference is only +whether the lookup is necessary to find an enumerated standard or to +switch to a standard by &v4l2-std-id;.</para> + </footnote> Drivers must implement all video standard ioctls +when the device has one or more video inputs or outputs.</para> + + <para>Special rules apply to USB cameras where the notion of video +standards makes little sense. More generally any capture device, +output devices accordingly, which is <itemizedlist> + <listitem> + <para>incapable of capturing fields or frames at the nominal +rate of the video standard, or</para> + </listitem> + <listitem> + <para>where <link linkend="buffer">timestamps</link> refer +to the instant the field or frame was received by the driver, not the +capture time, or</para> + </listitem> + <listitem> + <para>where <link linkend="buffer">sequence numbers</link> +refer to the frames received by the driver, not the captured +frames.</para> + </listitem> + </itemizedlist> Here the driver shall set the +<structfield>std</structfield> field of &v4l2-input; and &v4l2-output; +to zero, the <constant>VIDIOC_G_STD</constant>, +<constant>VIDIOC_S_STD</constant>, +<constant>VIDIOC_QUERYSTD</constant> and +<constant>VIDIOC_ENUMSTD</constant> ioctls shall return the +&EINVAL;.<footnote> + <para>See <xref linkend="buffer" /> for a rationale. Probably +even USB cameras follow some well known video standard. It might have +been better to explicitly indicate elsewhere if a device cannot live +up to normal expectations, instead of this exception.</para> + </footnote></para> + + <example> + <title>Information about the current video standard</title> + + <programlisting> +&v4l2-std-id; std_id; +&v4l2-standard; standard; + +if (-1 == ioctl (fd, &VIDIOC-G-STD;, &std_id)) { + /* Note when VIDIOC_ENUMSTD always returns EINVAL this + is no video device or it falls under the USB exception, + and VIDIOC_G_STD returning EINVAL is no error. */ + + perror ("VIDIOC_G_STD"); + exit (EXIT_FAILURE); +} + +memset (&standard, 0, sizeof (standard)); +standard.index = 0; + +while (0 == ioctl (fd, &VIDIOC-ENUMSTD;, &standard)) { + if (standard.id & std_id) { + printf ("Current video standard: %s\n", standard.name); + exit (EXIT_SUCCESS); + } + + standard.index++; +} + +/* EINVAL indicates the end of the enumeration, which cannot be + empty unless this device falls under the USB exception. */ + +if (errno == EINVAL || standard.index == 0) { + perror ("VIDIOC_ENUMSTD"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <example> + <title>Listing the video standards supported by the current +input</title> + + <programlisting> +&v4l2-input; input; +&v4l2-standard; standard; + +memset (&input, 0, sizeof (input)); + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &input.index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUM_INPUT"); + exit (EXIT_FAILURE); +} + +printf ("Current input %s supports:\n", input.name); + +memset (&standard, 0, sizeof (standard)); +standard.index = 0; + +while (0 == ioctl (fd, &VIDIOC-ENUMSTD;, &standard)) { + if (standard.id & input.std) + printf ("%s\n", standard.name); + + standard.index++; +} + +/* EINVAL indicates the end of the enumeration, which cannot be + empty unless this device falls under the USB exception. */ + +if (errno != EINVAL || standard.index == 0) { + perror ("VIDIOC_ENUMSTD"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <example> + <title>Selecting a new video standard</title> + + <programlisting> +&v4l2-input; input; +&v4l2-std-id; std_id; + +memset (&input, 0, sizeof (input)); + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &input.index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUM_INPUT"); + exit (EXIT_FAILURE); +} + +if (0 == (input.std & V4L2_STD_PAL_BG)) { + fprintf (stderr, "Oops. B/G PAL is not supported.\n"); + exit (EXIT_FAILURE); +} + +/* Note this is also supposed to work when only B + <emphasis>or</emphasis> G/PAL is supported. */ + +std_id = V4L2_STD_PAL_BG; + +if (-1 == ioctl (fd, &VIDIOC-S-STD;, &std_id)) { + perror ("VIDIOC_S_STD"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + <section id="dv-timings"> + <title>Digital Video (DV) Timings</title> + <para> + The video standards discussed so far has been dealing with Analog TV and the +corresponding video timings. Today there are many more different hardware interfaces +such as High Definition TV interfaces (HDMI), VGA, DVI connectors etc., that carry +video signals and there is a need to extend the API to select the video timings +for these interfaces. Since it is not possible to extend the &v4l2-std-id; due to +the limited bits available, a new set of IOCTLs is added to set/get video timings at +the input and output: </para><itemizedlist> + <listitem> + <para>DV Presets: Digital Video (DV) presets. These are IDs representing a +video timing at the input/output. Presets are pre-defined timings implemented +by the hardware according to video standards. A __u32 data type is used to represent +a preset unlike the bit mask that is used in &v4l2-std-id; allowing future extensions +to support as many different presets as needed.</para> + </listitem> + <listitem> + <para>Custom DV Timings: This will allow applications to define more detailed +custom video timings for the interface. This includes parameters such as width, height, +polarities, frontporch, backporch etc. + </para> + </listitem> + </itemizedlist> + <para>To enumerate and query the attributes of DV presets supported by a device, +applications use the &VIDIOC-ENUM-DV-PRESETS; ioctl. To get the current DV preset, +applications use the &VIDIOC-G-DV-PRESET; ioctl and to set a preset they use the +&VIDIOC-S-DV-PRESET; ioctl.</para> + <para>To set custom DV timings for the device, applications use the +&VIDIOC-S-DV-TIMINGS; ioctl and to get current custom DV timings they use the +&VIDIOC-G-DV-TIMINGS; ioctl.</para> + <para>Applications can make use of the <xref linkend="input-capabilities" /> and +<xref linkend="output-capabilities"/> flags to decide what ioctls are available to set the +video timings for the device.</para> + </section> + </section> + + &sub-controls; + + <section id="format"> + <title>Data Formats</title> + + <section> + <title>Data Format Negotiation</title> + + <para>Different devices exchange different kinds of data with +applications, for example video images, raw or sliced VBI data, RDS +datagrams. Even within one kind many different formats are possible, +in particular an abundance of image formats. Although drivers must +provide a default and the selection persists across closing and +reopening a device, applications should always negotiate a data format +before engaging in data exchange. Negotiation means the application +asks for a particular format and the driver selects and reports the +best the hardware can do to satisfy the request. Of course +applications can also just query the current selection.</para> + + <para>A single mechanism exists to negotiate all data formats +using the aggregate &v4l2-format; and the &VIDIOC-G-FMT; and +&VIDIOC-S-FMT; ioctls. Additionally the &VIDIOC-TRY-FMT; ioctl can be +used to examine what the hardware <emphasis>could</emphasis> do, +without actually selecting a new data format. The data formats +supported by the V4L2 API are covered in the respective device section +in <xref linkend="devices" />. For a closer look at image formats see +<xref linkend="pixfmt" />.</para> + + <para>The <constant>VIDIOC_S_FMT</constant> ioctl is a major +turning-point in the initialization sequence. Prior to this point +multiple panel applications can access the same device concurrently to +select the current input, change controls or modify other properties. +The first <constant>VIDIOC_S_FMT</constant> assigns a logical stream +(video data, VBI data etc.) exclusively to one file descriptor.</para> + + <para>Exclusive means no other application, more precisely no +other file descriptor, can grab this stream or change device +properties inconsistent with the negotiated parameters. A video +standard change for example, when the new standard uses a different +number of scan lines, can invalidate the selected image format. +Therefore only the file descriptor owning the stream can make +invalidating changes. Accordingly multiple file descriptors which +grabbed different logical streams prevent each other from interfering +with their settings. When for example video overlay is about to start +or already in progress, simultaneous video capturing may be restricted +to the same cropping and image size.</para> + + <para>When applications omit the +<constant>VIDIOC_S_FMT</constant> ioctl its locking side effects are +implied by the next step, the selection of an I/O method with the +&VIDIOC-REQBUFS; ioctl or implicit with the first &func-read; or +&func-write; call.</para> + + <para>Generally only one logical stream can be assigned to a +file descriptor, the exception being drivers permitting simultaneous +video capturing and overlay using the same file descriptor for +compatibility with V4L and earlier versions of V4L2. Switching the +logical stream or returning into "panel mode" is possible by closing +and reopening the device. Drivers <emphasis>may</emphasis> support a +switch using <constant>VIDIOC_S_FMT</constant>.</para> + + <para>All drivers exchanging data with +applications must support the <constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl. Implementation of the +<constant>VIDIOC_TRY_FMT</constant> is highly recommended but +optional.</para> + </section> + + <section> + <title>Image Format Enumeration</title> + + <para>Apart of the generic format negotiation functions +a special ioctl to enumerate all image formats supported by video +capture, overlay or output devices is available.<footnote> + <para>Enumerating formats an application has no a-priori +knowledge of (otherwise it could explicitly ask for them and need not +enumerate) seems useless, but there are applications serving as proxy +between drivers and the actual video applications for which this is +useful.</para> + </footnote></para> + + <para>The &VIDIOC-ENUM-FMT; ioctl must be supported +by all drivers exchanging image data with applications.</para> + + <important> + <para>Drivers are not supposed to convert image formats in +kernel space. They must enumerate only formats directly supported by +the hardware. If necessary driver writers should publish an example +conversion routine or library for integration into applications.</para> + </important> + </section> + </section> + + &sub-planar-apis; + + <section id="crop"> + <title>Image Cropping, Insertion and Scaling</title> + + <para>Some video capture devices can sample a subsection of the +picture and shrink or enlarge it to an image of arbitrary size. We +call these abilities cropping and scaling. Some video output devices +can scale an image up or down and insert it at an arbitrary scan line +and horizontal offset into a video signal.</para> + + <para>Applications can use the following API to select an area in +the video signal, query the default area and the hardware limits. +<emphasis>Despite their name, the &VIDIOC-CROPCAP;, &VIDIOC-G-CROP; +and &VIDIOC-S-CROP; ioctls apply to input as well as output +devices.</emphasis></para> + + <para>Scaling requires a source and a target. On a video capture +or overlay device the source is the video signal, and the cropping +ioctls determine the area actually sampled. The target are images +read by the application or overlaid onto the graphics screen. Their +size (and position for an overlay) is negotiated with the +&VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls.</para> + + <para>On a video output device the source are the images passed in +by the application, and their size is again negotiated with the +<constant>VIDIOC_G/S_FMT</constant> ioctls, or may be encoded in a +compressed video stream. The target is the video signal, and the +cropping ioctls determine the area where the images are +inserted.</para> + + <para>Source and target rectangles are defined even if the device +does not support scaling or the <constant>VIDIOC_G/S_CROP</constant> +ioctls. Their size (and position where applicable) will be fixed in +this case. <emphasis>All capture and output device must support the +<constant>VIDIOC_CROPCAP</constant> ioctl such that applications can +determine if scaling takes place.</emphasis></para> + + <section> + <title>Cropping Structures</title> + + <figure id="crop-scale"> + <title>Image Cropping, Insertion and Scaling</title> + <mediaobject> + <imageobject> + <imagedata fileref="crop.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="crop.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>The cropping, insertion and scaling process</phrase> + </textobject> + </mediaobject> + </figure> + + <para>For capture devices the coordinates of the top left +corner, width and height of the area which can be sampled is given by +the <structfield>bounds</structfield> substructure of the +&v4l2-cropcap; returned by the <constant>VIDIOC_CROPCAP</constant> +ioctl. To support a wide range of hardware this specification does not +define an origin or units. However by convention drivers should +horizontally count unscaled samples relative to 0H (the leading edge +of the horizontal sync pulse, see <xref linkend="vbi-hsync" />). +Vertically ITU-R line +numbers of the first field (<xref linkend="vbi-525" />, <xref +linkend="vbi-625" />), multiplied by two if the driver can capture both +fields.</para> + + <para>The top left corner, width and height of the source +rectangle, that is the area actually sampled, is given by &v4l2-crop; +using the same coordinate system as &v4l2-cropcap;. Applications can +use the <constant>VIDIOC_G_CROP</constant> and +<constant>VIDIOC_S_CROP</constant> ioctls to get and set this +rectangle. It must lie completely within the capture boundaries and +the driver may further adjust the requested size and/or position +according to hardware limitations.</para> + + <para>Each capture device has a default source rectangle, given +by the <structfield>defrect</structfield> substructure of +&v4l2-cropcap;. The center of this rectangle shall align with the +center of the active picture area of the video signal, and cover what +the driver writer considers the complete picture. Drivers shall reset +the source rectangle to the default when the driver is first loaded, +but not later.</para> + + <para>For output devices these structures and ioctls are used +accordingly, defining the <emphasis>target</emphasis> rectangle where +the images will be inserted into the video signal.</para> + + </section> + + <section> + <title>Scaling Adjustments</title> + + <para>Video hardware can have various cropping, insertion and +scaling limitations. It may only scale up or down, support only +discrete scaling factors, or have different scaling abilities in +horizontal and vertical direction. Also it may not support scaling at +all. At the same time the &v4l2-crop; rectangle may have to be +aligned, and both the source and target rectangles may have arbitrary +upper and lower size limits. In particular the maximum +<structfield>width</structfield> and <structfield>height</structfield> +in &v4l2-crop; may be smaller than the +&v4l2-cropcap;.<structfield>bounds</structfield> area. Therefore, as +usual, drivers are expected to adjust the requested parameters and +return the actual values selected.</para> + + <para>Applications can change the source or the target rectangle +first, as they may prefer a particular image size or a certain area in +the video signal. If the driver has to adjust both to satisfy hardware +limitations, the last requested rectangle shall take priority, and the +driver should preferably adjust the opposite one. The &VIDIOC-TRY-FMT; +ioctl however shall not change the driver state and therefore only +adjust the requested rectangle.</para> + + <para>Suppose scaling on a video capture device is restricted to +a factor 1:1 or 2:1 in either direction and the target image size must +be a multiple of 16 × 16 pixels. The source cropping +rectangle is set to defaults, which are also the upper limit in this +example, of 640 × 400 pixels at offset 0, 0. An +application requests an image size of 300 × 225 +pixels, assuming video will be scaled down from the "full picture" +accordingly. The driver sets the image size to the closest possible +values 304 × 224, then chooses the cropping rectangle +closest to the requested size, that is 608 × 224 +(224 × 2:1 would exceed the limit 400). The offset +0, 0 is still valid, thus unmodified. Given the default cropping +rectangle reported by <constant>VIDIOC_CROPCAP</constant> the +application can easily propose another offset to center the cropping +rectangle.</para> + + <para>Now the application may insist on covering an area using a +picture aspect ratio closer to the original request, so it asks for a +cropping rectangle of 608 × 456 pixels. The present +scaling factors limit cropping to 640 × 384, so the +driver returns the cropping size 608 × 384 and adjusts +the image size to closest possible 304 × 192.</para> + + </section> + + <section> + <title>Examples</title> + + <para>Source and target rectangles shall remain unchanged across +closing and reopening a device, such that piping data into or out of a +device will work without special preparations. More advanced +applications should ensure the parameters are suitable before starting +I/O.</para> + + <example> + <title>Resetting the cropping parameters</title> + + <para>(A video capture device is assumed; change +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> for other +devices.)</para> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); +crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +crop.c = cropcap.defrect; + +/* Ignore if cropping is not supported (EINVAL). */ + +if (-1 == ioctl (fd, &VIDIOC-S-CROP;, &crop) + && errno != EINVAL) { + perror ("VIDIOC_S_CROP"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <example> + <title>Simple downscaling</title> + + <para>(A video capture device is assumed.)</para> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-format; format; + +reset_cropping_parameters (); + +/* Scale down to 1/4 size of full picture. */ + +memset (&format, 0, sizeof (format)); /* defaults */ + +format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +format.fmt.pix.width = cropcap.defrect.width >> 1; +format.fmt.pix.height = cropcap.defrect.height >> 1; +format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; + +if (-1 == ioctl (fd, &VIDIOC-S-FMT;, &format)) { + perror ("VIDIOC_S_FORMAT"); + exit (EXIT_FAILURE); +} + +/* We could check the actual image size now, the actual scaling factor + or if the driver can scale at all. */ + </programlisting> + </example> + + <example> + <title>Selecting an output area</title> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; + +if (-1 == ioctl (fd, VIDIOC_CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); + +crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; +crop.c = cropcap.defrect; + +/* Scale the width and height to 50 % of their original size + and center the output. */ + +crop.c.width /= 2; +crop.c.height /= 2; +crop.c.left += crop.c.width / 2; +crop.c.top += crop.c.height / 2; + +/* Ignore if cropping is not supported (EINVAL). */ + +if (-1 == ioctl (fd, VIDIOC_S_CROP, &crop) + && errno != EINVAL) { + perror ("VIDIOC_S_CROP"); + exit (EXIT_FAILURE); +} +</programlisting> + </example> + + <example> + <title>Current scaling factor and pixel aspect</title> + + <para>(A video capture device is assumed.)</para> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; +&v4l2-format; format; +double hscale, vscale; +double aspect; +int dwidth, dheight; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); +crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-G-CROP;, &crop)) { + if (errno != EINVAL) { + perror ("VIDIOC_G_CROP"); + exit (EXIT_FAILURE); + } + + /* Cropping not supported. */ + crop.c = cropcap.defrect; +} + +memset (&format, 0, sizeof (format)); +format.fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-G-FMT;, &format)) { + perror ("VIDIOC_G_FMT"); + exit (EXIT_FAILURE); +} + +/* The scaling applied by the driver. */ + +hscale = format.fmt.pix.width / (double) crop.c.width; +vscale = format.fmt.pix.height / (double) crop.c.height; + +aspect = cropcap.pixelaspect.numerator / + (double) cropcap.pixelaspect.denominator; +aspect = aspect * hscale / vscale; + +/* Devices following ITU-R BT.601 do not capture + square pixels. For playback on a computer monitor + we should scale the images to this size. */ + +dwidth = format.fmt.pix.width / aspect; +dheight = format.fmt.pix.height; + </programlisting> + </example> + </section> + </section> + + &sub-selection-api; + + <section id="streaming-par"> + <title>Streaming Parameters</title> + + <para>Streaming parameters are intended to optimize the video +capture process as well as I/O. Presently applications can request a +high quality capture mode with the &VIDIOC-S-PARM; ioctl.</para> + + <para>The current video standard determines a nominal number of +frames per second. If less than this number of frames is to be +captured or output, applications can request frame skipping or +duplicating on the driver side. This is especially useful when using +the &func-read; or &func-write;, which are not augmented by timestamps +or sequence counters, and to avoid unnecessary data copying.</para> + + <para>Finally these ioctls can be used to determine the number of +buffers used internally by a driver in read/write mode. For +implications see the section discussing the &func-read; +function.</para> + + <para>To get and set the streaming parameters applications call +the &VIDIOC-G-PARM; and &VIDIOC-S-PARM; ioctl, respectively. They take +a pointer to a &v4l2-streamparm;, which contains a union holding +separate parameters for input and output devices.</para> + + <para>These ioctls are optional, drivers need not implement +them. If so, they return the &EINVAL;.</para> + </section> diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml new file mode 100644 index 00000000..bce97c50 --- /dev/null +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -0,0 +1,2543 @@ + <title>Changes</title> + + <para>The following chapters document the evolution of the V4L2 API, +errata or extensions. They are also intended to help application and +driver writers to port or update their code.</para> + + <section id="diff-v4l"> + <title>Differences between V4L and V4L2</title> + + <para>The Video For Linux API was first introduced in Linux 2.1 to +unify and replace various TV and radio device related interfaces, +developed independently by driver writers in prior years. Starting +with Linux 2.5 the much improved V4L2 API replaces the V4L API. +The support for the old V4L calls were removed from Kernel, but the +library <xref linkend="libv4l" /> supports the conversion of a V4L +API system call into a V4L2 one.</para> + + <section> + <title>Opening and Closing Devices</title> + + <para>For compatibility reasons the character device file names +recommended for V4L2 video capture, overlay, radio and raw +vbi capture devices did not change from those used by V4L. They are +listed in <xref linkend="devices" /> and below in <xref + linkend="v4l-dev" />.</para> + + <para>The teletext devices (minor range 192-223) have been removed in +V4L2 and no longer exist. There is no hardware available anymore for handling +pure teletext. Instead raw or sliced VBI is used.</para> + + <para>The V4L <filename>videodev</filename> module automatically +assigns minor numbers to drivers in load order, depending on the +registered device type. We recommend that V4L2 drivers by default +register devices with the same numbers, but the system administrator +can assign arbitrary minor numbers using driver module options. The +major device number remains 81.</para> + + <table id="v4l-dev"> + <title>V4L Device Types, Names and Numbers</title> + <tgroup cols="3"> + <thead> + <row> + <entry>Device Type</entry> + <entry>File Name</entry> + <entry>Minor Numbers</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry>Video capture and overlay</entry> + <entry><para><filename>/dev/video</filename> and +<filename>/dev/bttv0</filename><footnote> <para>According to +Documentation/devices.txt these should be symbolic links to +<filename>/dev/video0</filename>. Note the original bttv interface is +not compatible with V4L or V4L2.</para> </footnote>, +<filename>/dev/video0</filename> to +<filename>/dev/video63</filename></para></entry> + <entry>0-63</entry> + </row> + <row> + <entry>Radio receiver</entry> + <entry><para><filename>/dev/radio</filename><footnote> + <para>According to +<filename>Documentation/devices.txt</filename> a symbolic link to +<filename>/dev/radio0</filename>.</para> + </footnote>, <filename>/dev/radio0</filename> to +<filename>/dev/radio63</filename></para></entry> + <entry>64-127</entry> + </row> + <row> + <entry>Raw VBI capture</entry> + <entry><para><filename>/dev/vbi</filename>, +<filename>/dev/vbi0</filename> to +<filename>/dev/vbi31</filename></para></entry> + <entry>224-255</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>V4L prohibits (or used to prohibit) multiple opens of a +device file. V4L2 drivers <emphasis>may</emphasis> support multiple +opens, see <xref linkend="open" /> for details and consequences.</para> + + <para>V4L drivers respond to V4L2 ioctls with an &EINVAL;.</para> + </section> + + <section> + <title>Querying Capabilities</title> + + <para>The V4L <constant>VIDIOCGCAP</constant> ioctl is +equivalent to V4L2's &VIDIOC-QUERYCAP;.</para> + + <para>The <structfield>name</structfield> field in struct +<structname>video_capability</structname> became +<structfield>card</structfield> in &v4l2-capability;, +<structfield>type</structfield> was replaced by +<structfield>capabilities</structfield>. Note V4L2 does not +distinguish between device types like this, better think of basic +video input, video output and radio devices supporting a set of +related functions like video capturing, video overlay and VBI +capturing. See <xref linkend="open" /> for an +introduction.<informaltable> + <tgroup cols="3"> + <thead> + <row> + <entry>struct +<structname>video_capability</structname> +<structfield>type</structfield></entry> + <entry>&v4l2-capability; +<structfield>capabilities</structfield> flags</entry> + <entry>Purpose</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>VID_TYPE_CAPTURE</constant></entry> + <entry><constant>V4L2_CAP_VIDEO_CAPTURE</constant></entry> + <entry>The <link linkend="capture">video +capture</link> interface is supported.</entry> + </row> + <row> + <entry><constant>VID_TYPE_TUNER</constant></entry> + <entry><constant>V4L2_CAP_TUNER</constant></entry> + <entry>The device has a <link linkend="tuner">tuner or +modulator</link>.</entry> + </row> + <row> + <entry><constant>VID_TYPE_TELETEXT</constant></entry> + <entry><constant>V4L2_CAP_VBI_CAPTURE</constant></entry> + <entry>The <link linkend="raw-vbi">raw VBI +capture</link> interface is supported.</entry> + </row> + <row> + <entry><constant>VID_TYPE_OVERLAY</constant></entry> + <entry><constant>V4L2_CAP_VIDEO_OVERLAY</constant></entry> + <entry>The <link linkend="overlay">video +overlay</link> interface is supported.</entry> + </row> + <row> + <entry><constant>VID_TYPE_CHROMAKEY</constant></entry> + <entry><constant>V4L2_FBUF_CAP_CHROMAKEY</constant> in +field <structfield>capability</structfield> of +&v4l2-framebuffer;</entry> + <entry>Whether chromakey overlay is supported. For +more information on overlay see +<xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_CLIPPING</constant></entry> + <entry><constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> +and <constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant> in field +<structfield>capability</structfield> of &v4l2-framebuffer;</entry> + <entry>Whether clipping the overlaid image is +supported, see <xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_FRAMERAM</constant></entry> + <entry><constant>V4L2_FBUF_CAP_EXTERNOVERLAY</constant> +<emphasis>not set</emphasis> in field +<structfield>capability</structfield> of &v4l2-framebuffer;</entry> + <entry>Whether overlay overwrites frame buffer memory, +see <xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_SCALES</constant></entry> + <entry><constant>-</constant></entry> + <entry>This flag indicates if the hardware can scale +images. The V4L2 API implies the scale factor by setting the cropping +dimensions and image size with the &VIDIOC-S-CROP; and &VIDIOC-S-FMT; +ioctl, respectively. The driver returns the closest sizes possible. +For more information on cropping and scaling see <xref + linkend="crop" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MONOCHROME</constant></entry> + <entry><constant>-</constant></entry> + <entry>Applications can enumerate the supported image +formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device +supports grey scale capturing only. For more information on image +formats see <xref linkend="pixfmt" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_SUBCAPTURE</constant></entry> + <entry><constant>-</constant></entry> + <entry>Applications can call the &VIDIOC-G-CROP; ioctl +to determine if the device supports capturing a subsection of the full +picture ("cropping" in V4L2). If not, the ioctl returns the &EINVAL;. +For more information on cropping and scaling see <xref + linkend="crop" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MPEG_DECODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>Applications can enumerate the supported image +formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device +supports MPEG streams.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MPEG_ENCODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>See above.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MJPEG_DECODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>See above.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MJPEG_ENCODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>See above.</entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>The <structfield>audios</structfield> field was replaced +by <structfield>capabilities</structfield> flag +<constant>V4L2_CAP_AUDIO</constant>, indicating +<emphasis>if</emphasis> the device has any audio inputs or outputs. To +determine their number applications can enumerate audio inputs with +the &VIDIOC-G-AUDIO; ioctl. The audio ioctls are described in <xref + linkend="audio" />.</para> + + <para>The <structfield>maxwidth</structfield>, +<structfield>maxheight</structfield>, +<structfield>minwidth</structfield> and +<structfield>minheight</structfield> fields were removed. Calling the +&VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; ioctl with the desired dimensions +returns the closest size possible, taking into account the current +video standard, cropping and scaling limitations.</para> + </section> + + <section> + <title>Video Sources</title> + + <para>V4L provides the <constant>VIDIOCGCHAN</constant> and +<constant>VIDIOCSCHAN</constant> ioctl using struct +<structname>video_channel</structname> to enumerate +the video inputs of a V4L device. The equivalent V4L2 ioctls +are &VIDIOC-ENUMINPUT;, &VIDIOC-G-INPUT; and &VIDIOC-S-INPUT; +using &v4l2-input; as discussed in <xref linkend="video" />.</para> + + <para>The <structfield>channel</structfield> field counting +inputs was renamed to <structfield>index</structfield>, the video +input types were renamed as follows: <informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct <structname>video_channel</structname> +<structfield>type</structfield></entry> + <entry>&v4l2-input; +<structfield>type</structfield></entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>VIDEO_TYPE_TV</constant></entry> + <entry><constant>V4L2_INPUT_TYPE_TUNER</constant></entry> + </row> + <row> + <entry><constant>VIDEO_TYPE_CAMERA</constant></entry> + <entry><constant>V4L2_INPUT_TYPE_CAMERA</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>Unlike the <structfield>tuners</structfield> field +expressing the number of tuners of this input, V4L2 assumes each video +input is connected to at most one tuner. However a tuner can have more +than one input, &ie; RF connectors, and a device can have multiple +tuners. The index number of the tuner associated with the input, if +any, is stored in field <structfield>tuner</structfield> of +&v4l2-input;. Enumeration of tuners is discussed in <xref + linkend="tuner" />.</para> + + <para>The redundant <constant>VIDEO_VC_TUNER</constant> flag was +dropped. Video inputs associated with a tuner are of type +<constant>V4L2_INPUT_TYPE_TUNER</constant>. The +<constant>VIDEO_VC_AUDIO</constant> flag was replaced by the +<structfield>audioset</structfield> field. V4L2 considers devices with +up to 32 audio inputs. Each set bit in the +<structfield>audioset</structfield> field represents one audio input +this video input combines with. For information about audio inputs and +how to switch between them see <xref linkend="audio" />.</para> + + <para>The <structfield>norm</structfield> field describing the +supported video standards was replaced by +<structfield>std</structfield>. The V4L specification mentions a flag +<constant>VIDEO_VC_NORM</constant> indicating whether the standard can +be changed. This flag was a later addition together with the +<structfield>norm</structfield> field and has been removed in the +meantime. V4L2 has a similar, albeit more comprehensive approach +to video standards, see <xref linkend="standard" /> for more +information.</para> + </section> + + <section> + <title>Tuning</title> + + <para>The V4L <constant>VIDIOCGTUNER</constant> and +<constant>VIDIOCSTUNER</constant> ioctl and struct +<structname>video_tuner</structname> can be used to enumerate the +tuners of a V4L TV or radio device. The equivalent V4L2 ioctls are +&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; using &v4l2-tuner;. Tuners are +covered in <xref linkend="tuner" />.</para> + + <para>The <structfield>tuner</structfield> field counting tuners +was renamed to <structfield>index</structfield>. The fields +<structfield>name</structfield>, <structfield>rangelow</structfield> +and <structfield>rangehigh</structfield> remained unchanged.</para> + + <para>The <constant>VIDEO_TUNER_PAL</constant>, +<constant>VIDEO_TUNER_NTSC</constant> and +<constant>VIDEO_TUNER_SECAM</constant> flags indicating the supported +video standards were dropped. This information is now contained in the +associated &v4l2-input;. No replacement exists for the +<constant>VIDEO_TUNER_NORM</constant> flag indicating whether the +video standard can be switched. The <structfield>mode</structfield> +field to select a different video standard was replaced by a whole new +set of ioctls and structures described in <xref linkend="standard" />. +Due to its ubiquity it should be mentioned the BTTV driver supports +several standards in addition to the regular +<constant>VIDEO_MODE_PAL</constant> (0), +<constant>VIDEO_MODE_NTSC</constant>, +<constant>VIDEO_MODE_SECAM</constant> and +<constant>VIDEO_MODE_AUTO</constant> (3). Namely N/PAL Argentina, +M/PAL, N/PAL, and NTSC Japan with numbers 3-6 (sic).</para> + + <para>The <constant>VIDEO_TUNER_STEREO_ON</constant> flag +indicating stereo reception became +<constant>V4L2_TUNER_SUB_STEREO</constant> in field +<structfield>rxsubchans</structfield>. This field also permits the +detection of monaural and bilingual audio, see the definition of +&v4l2-tuner; for details. Presently no replacement exists for the +<constant>VIDEO_TUNER_RDS_ON</constant> and +<constant>VIDEO_TUNER_MBS_ON</constant> flags.</para> + + <para> The <constant>VIDEO_TUNER_LOW</constant> flag was renamed +to <constant>V4L2_TUNER_CAP_LOW</constant> in the &v4l2-tuner; +<structfield>capability</structfield> field.</para> + + <para>The <constant>VIDIOCGFREQ</constant> and +<constant>VIDIOCSFREQ</constant> ioctl to change the tuner frequency +where renamed to &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY;. They +take a pointer to a &v4l2-frequency; instead of an unsigned long +integer.</para> + </section> + + <section id="v4l-image-properties"> + <title>Image Properties</title> + + <para>V4L2 has no equivalent of the +<constant>VIDIOCGPICT</constant> and <constant>VIDIOCSPICT</constant> +ioctl and struct <structname>video_picture</structname>. The following +fields where replaced by V4L2 controls accessible with the +&VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct <structname>video_picture</structname></entry> + <entry>V4L2 Control ID</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><structfield>brightness</structfield></entry> + <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry> + </row> + <row> + <entry><structfield>hue</structfield></entry> + <entry><constant>V4L2_CID_HUE</constant></entry> + </row> + <row> + <entry><structfield>colour</structfield></entry> + <entry><constant>V4L2_CID_SATURATION</constant></entry> + </row> + <row> + <entry><structfield>contrast</structfield></entry> + <entry><constant>V4L2_CID_CONTRAST</constant></entry> + </row> + <row> + <entry><structfield>whiteness</structfield></entry> + <entry><constant>V4L2_CID_WHITENESS</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>The V4L picture controls are assumed to range from 0 to +65535 with no particular reset value. The V4L2 API permits arbitrary +limits and defaults which can be queried with the &VIDIOC-QUERYCTRL; +ioctl. For general information about controls see <xref +linkend="control" />.</para> + + <para>The <structfield>depth</structfield> (average number of +bits per pixel) of a video image is implied by the selected image +format. V4L2 does not explicitely provide such information assuming +applications recognizing the format are aware of the image depth and +others need not know. The <structfield>palette</structfield> field +moved into the &v4l2-pix-format;:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct <structname>video_picture</structname> +<structfield>palette</structfield></entry> + <entry>&v4l2-pix-format; +<structfield>pixfmt</structfield></entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>VIDEO_PALETTE_GREY</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-GREY"><constant>V4L2_PIX_FMT_GREY</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_HI240</constant></entry> + <entry><para><link +linkend="pixfmt-reserved"><constant>V4L2_PIX_FMT_HI240</constant></link><footnote> + <para>This is a custom format used by the BTTV +driver, not one of the V4L2 standard formats.</para> + </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB565</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB565</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB555</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB555</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB24</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR24</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB32</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR32</constant></link><footnote> + <para>Presumably all V4L RGB formats are +little-endian, although some drivers might interpret them according to machine endianness. V4L2 defines little-endian, big-endian and red/blue +swapped variants. For details see <xref linkend="pixfmt-rgb" />.</para> + </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV422</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> + </row> + <row> + <entry><para><constant>VIDEO_PALETTE_YUYV</constant><footnote> + <para><constant>VIDEO_PALETTE_YUV422</constant> +and <constant>VIDEO_PALETTE_YUYV</constant> are the same formats. Some +V4L drivers respond to one, some to the other.</para> + </footnote></para></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_UYVY</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-UYVY"><constant>V4L2_PIX_FMT_UYVY</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV420</constant></entry> + <entry>None</entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV411</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-Y41P"><constant>V4L2_PIX_FMT_Y41P</constant></link><footnote> + <para>Not to be confused with +<constant>V4L2_PIX_FMT_YUV411P</constant>, which is a planar +format.</para> </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RAW</constant></entry> + <entry><para>None<footnote> <para>V4L explains this +as: "RAW capture (BT848)"</para> </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV422P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUV422P"><constant>V4L2_PIX_FMT_YUV422P</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV411P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUV411P"><constant>V4L2_PIX_FMT_YUV411P</constant></link><footnote> + <para>Not to be confused with +<constant>V4L2_PIX_FMT_Y41P</constant>, which is a packed +format.</para> </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV420P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV410P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YVU410"><constant>V4L2_PIX_FMT_YVU410</constant></link></para></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>V4L2 image formats are defined in <xref +linkend="pixfmt" />. The image format can be selected with the +&VIDIOC-S-FMT; ioctl.</para> + </section> + + <section> + <title>Audio</title> + + <para>The <constant>VIDIOCGAUDIO</constant> and +<constant>VIDIOCSAUDIO</constant> ioctl and struct +<structname>video_audio</structname> are used to enumerate the +audio inputs of a V4L device. The equivalent V4L2 ioctls are +&VIDIOC-G-AUDIO; and &VIDIOC-S-AUDIO; using &v4l2-audio; as +discussed in <xref linkend="audio" />.</para> + + <para>The <structfield>audio</structfield> "channel number" +field counting audio inputs was renamed to +<structfield>index</structfield>.</para> + + <para>On <constant>VIDIOCSAUDIO</constant> the +<structfield>mode</structfield> field selects <emphasis>one</emphasis> +of the <constant>VIDEO_SOUND_MONO</constant>, +<constant>VIDEO_SOUND_STEREO</constant>, +<constant>VIDEO_SOUND_LANG1</constant> or +<constant>VIDEO_SOUND_LANG2</constant> audio demodulation modes. When +the current audio standard is BTSC +<constant>VIDEO_SOUND_LANG2</constant> refers to SAP and +<constant>VIDEO_SOUND_LANG1</constant> is meaningless. Also +undocumented in the V4L specification, there is no way to query the +selected mode. On <constant>VIDIOCGAUDIO</constant> the driver returns +the <emphasis>actually received</emphasis> audio programmes in this +field. In the V4L2 API this information is stored in the &v4l2-tuner; +<structfield>rxsubchans</structfield> and +<structfield>audmode</structfield> fields, respectively. See <xref +linkend="tuner" /> for more information on tuners. Related to audio +modes &v4l2-audio; also reports if this is a mono or stereo +input, regardless if the source is a tuner.</para> + + <para>The following fields where replaced by V4L2 controls +accessible with the &VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and +&VIDIOC-S-CTRL; ioctls:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct +<structname>video_audio</structname></entry> + <entry>V4L2 Control ID</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><structfield>volume</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry> + </row> + <row> + <entry><structfield>bass</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry> + </row> + <row> + <entry><structfield>treble</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry> + </row> + <row> + <entry><structfield>balance</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>To determine which of these controls are supported by a +driver V4L provides the <structfield>flags</structfield> +<constant>VIDEO_AUDIO_VOLUME</constant>, +<constant>VIDEO_AUDIO_BASS</constant>, +<constant>VIDEO_AUDIO_TREBLE</constant> and +<constant>VIDEO_AUDIO_BALANCE</constant>. In the V4L2 API the +&VIDIOC-QUERYCTRL; ioctl reports if the respective control is +supported. Accordingly the <constant>VIDEO_AUDIO_MUTABLE</constant> +and <constant>VIDEO_AUDIO_MUTE</constant> flags where replaced by the +boolean <constant>V4L2_CID_AUDIO_MUTE</constant> control.</para> + + <para>All V4L2 controls have a <structfield>step</structfield> +attribute replacing the struct <structname>video_audio</structname> +<structfield>step</structfield> field. The V4L audio controls are +assumed to range from 0 to 65535 with no particular reset value. The +V4L2 API permits arbitrary limits and defaults which can be queried +with the &VIDIOC-QUERYCTRL; ioctl. For general information about +controls see <xref linkend="control" />.</para> + </section> + + <section> + <title>Frame Buffer Overlay</title> + + <para>The V4L2 ioctls equivalent to +<constant>VIDIOCGFBUF</constant> and <constant>VIDIOCSFBUF</constant> +are &VIDIOC-G-FBUF; and &VIDIOC-S-FBUF;. The +<structfield>base</structfield> field of struct +<structname>video_buffer</structname> remained unchanged, except V4L2 +defines a flag to indicate non-destructive overlays instead of a +<constant>NULL</constant> pointer. All other fields moved into the +&v4l2-pix-format; <structfield>fmt</structfield> substructure of +&v4l2-framebuffer;. The <structfield>depth</structfield> field was +replaced by <structfield>pixelformat</structfield>. See <xref + linkend="pixfmt-rgb" /> for a list of RGB formats and their +respective color depths.</para> + + <para>Instead of the special ioctls +<constant>VIDIOCGWIN</constant> and <constant>VIDIOCSWIN</constant> +V4L2 uses the general-purpose data format negotiation ioctls +&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a +&v4l2-format; as argument. Here the <structfield>win</structfield> +member of the <structfield>fmt</structfield> union is used, a +&v4l2-window;.</para> + + <para>The <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> fields of struct +<structname>video_window</structname> moved into &v4l2-rect; +substructure <structfield>w</structfield> of struct +<structname>v4l2_window</structname>. The +<structfield>chromakey</structfield>, +<structfield>clips</structfield>, and +<structfield>clipcount</structfield> fields remained unchanged. Struct +<structname>video_clip</structname> was renamed to &v4l2-clip;, also +containing a struct <structname>v4l2_rect</structname>, but the +semantics are still the same.</para> + + <para>The <constant>VIDEO_WINDOW_INTERLACE</constant> flag was +dropped. Instead applications must set the +<structfield>field</structfield> field to +<constant>V4L2_FIELD_ANY</constant> or +<constant>V4L2_FIELD_INTERLACED</constant>. The +<constant>VIDEO_WINDOW_CHROMAKEY</constant> flag moved into +&v4l2-framebuffer;, under the new name +<constant>V4L2_FBUF_FLAG_CHROMAKEY</constant>.</para> + + <para>In V4L, storing a bitmap pointer in +<structfield>clips</structfield> and setting +<structfield>clipcount</structfield> to +<constant>VIDEO_CLIP_BITMAP</constant> (-1) requests bitmap +clipping, using a fixed size bitmap of 1024 × 625 bits. Struct +<structname>v4l2_window</structname> has a separate +<structfield>bitmap</structfield> pointer field for this purpose and +the bitmap size is determined by <structfield>w.width</structfield> and +<structfield>w.height</structfield>.</para> + + <para>The <constant>VIDIOCCAPTURE</constant> ioctl to enable or +disable overlay was renamed to &VIDIOC-OVERLAY;.</para> + </section> + + <section> + <title>Cropping</title> + + <para>To capture only a subsection of the full picture V4L +defines the <constant>VIDIOCGCAPTURE</constant> and +<constant>VIDIOCSCAPTURE</constant> ioctls using struct +<structname>video_capture</structname>. The equivalent V4L2 ioctls are +&VIDIOC-G-CROP; and &VIDIOC-S-CROP; using &v4l2-crop;, and the related +&VIDIOC-CROPCAP; ioctl. This is a rather complex matter, see +<xref linkend="crop" /> for details.</para> + + <para>The <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> fields moved into &v4l2-rect; +substructure <structfield>c</structfield> of struct +<structname>v4l2_crop</structname>. The +<structfield>decimation</structfield> field was dropped. In the V4L2 +API the scaling factor is implied by the size of the cropping +rectangle and the size of the captured or overlaid image.</para> + + <para>The <constant>VIDEO_CAPTURE_ODD</constant> +and <constant>VIDEO_CAPTURE_EVEN</constant> flags to capture only the +odd or even field, respectively, were replaced by +<constant>V4L2_FIELD_TOP</constant> and +<constant>V4L2_FIELD_BOTTOM</constant> in the field named +<structfield>field</structfield> of &v4l2-pix-format; and +&v4l2-window;. These structures are used to select a capture or +overlay format with the &VIDIOC-S-FMT; ioctl.</para> + </section> + + <section> + <title>Reading Images, Memory Mapping</title> + + <section> + <title>Capturing using the read method</title> + + <para>There is no essential difference between reading images +from a V4L or V4L2 device using the &func-read; function, however V4L2 +drivers are not required to support this I/O method. Applications can +determine if the function is available with the &VIDIOC-QUERYCAP; +ioctl. All V4L2 devices exchanging data with applications must support +the &func-select; and &func-poll; functions.</para> + + <para>To select an image format and size, V4L provides the +<constant>VIDIOCSPICT</constant> and <constant>VIDIOCSWIN</constant> +ioctls. V4L2 uses the general-purpose data format negotiation ioctls +&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a +&v4l2-format; as argument, here the &v4l2-pix-format; named +<structfield>pix</structfield> of its <structfield>fmt</structfield> +union is used.</para> + + <para>For more information about the V4L2 read interface see +<xref linkend="rw" />.</para> + </section> + <section> + <title>Capturing using memory mapping</title> + + <para>Applications can read from V4L devices by mapping +buffers in device memory, or more often just buffers allocated in +DMA-able system memory, into their address space. This avoids the data +copying overhead of the read method. V4L2 supports memory mapping as +well, with a few differences.</para> + + <informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>V4L</entry> + <entry>V4L2</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry></entry> + <entry>The image format must be selected before +buffers are allocated, with the &VIDIOC-S-FMT; ioctl. When no format +is selected the driver may use the last, possibly by another +application requested format.</entry> + </row> + <row> + <entry><para>Applications cannot change the number of +buffers. The it is built into the driver, unless it has a module +option to change the number when the driver module is +loaded.</para></entry> + <entry><para>The &VIDIOC-REQBUFS; ioctl allocates the +desired number of buffers, this is a required step in the initialization +sequence.</para></entry> + </row> + <row> + <entry><para>Drivers map all buffers as one contiguous +range of memory. The <constant>VIDIOCGMBUF</constant> ioctl is +available to query the number of buffers, the offset of each buffer +from the start of the virtual file, and the overall amount of memory +used, which can be used as arguments for the &func-mmap; +function.</para></entry> + <entry><para>Buffers are individually mapped. The +offset and size of each buffer can be determined with the +&VIDIOC-QUERYBUF; ioctl.</para></entry> + </row> + <row> + <entry><para>The <constant>VIDIOCMCAPTURE</constant> +ioctl prepares a buffer for capturing. It also determines the image +format for this buffer. The ioctl returns immediately, eventually with +an &EAGAIN; if no video signal had been detected. When the driver +supports more than one buffer applications can call the ioctl multiple +times and thus have multiple outstanding capture +requests.</para><para>The <constant>VIDIOCSYNC</constant> ioctl +suspends execution until a particular buffer has been +filled.</para></entry> + <entry><para>Drivers maintain an incoming and outgoing +queue. &VIDIOC-QBUF; enqueues any empty buffer into the incoming +queue. Filled buffers are dequeued from the outgoing queue with the +&VIDIOC-DQBUF; ioctl. To wait until filled buffers become available this +function, &func-select; or &func-poll; can be used. The +&VIDIOC-STREAMON; ioctl must be called once after enqueuing one or +more buffers to start capturing. Its counterpart +&VIDIOC-STREAMOFF; stops capturing and dequeues all buffers from both +queues. Applications can query the signal status, if known, with the +&VIDIOC-ENUMINPUT; ioctl.</para></entry> + </row> + </tbody> + </tgroup> + </informaltable> + + <para>For a more in-depth discussion of memory mapping and +examples, see <xref linkend="mmap" />.</para> + </section> + </section> + + <section> + <title>Reading Raw VBI Data</title> + + <para>Originally the V4L API did not specify a raw VBI capture +interface, only the device file <filename>/dev/vbi</filename> was +reserved for this purpose. The only driver supporting this interface +was the BTTV driver, de-facto defining the V4L VBI interface. Reading +from the device yields a raw VBI image with the following +parameters:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>&v4l2-vbi-format;</entry> + <entry>V4L, BTTV driver</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry>sampling_rate</entry> + <entry>28636363 Hz NTSC (or any other 525-line +standard); 35468950 Hz PAL and SECAM (625-line standards)</entry> + </row> + <row> + <entry>offset</entry> + <entry>?</entry> + </row> + <row> + <entry>samples_per_line</entry> + <entry>2048</entry> + </row> + <row> + <entry>sample_format</entry> + <entry>V4L2_PIX_FMT_GREY. The last four bytes (a +machine endianness integer) contain a frame counter.</entry> + </row> + <row> + <entry>start[]</entry> + <entry>10, 273 NTSC; 22, 335 PAL and SECAM</entry> + </row> + <row> + <entry>count[]</entry> + <entry><para>16, 16<footnote><para>Old driver +versions used different values, eventually the custom +<constant>BTTV_VBISIZE</constant> ioctl was added to query the +correct values.</para></footnote></para></entry> + </row> + <row> + <entry>flags</entry> + <entry>0</entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>Undocumented in the V4L specification, in Linux 2.3 the +<constant>VIDIOCGVBIFMT</constant> and +<constant>VIDIOCSVBIFMT</constant> ioctls using struct +<structname>vbi_format</structname> were added to determine the VBI +image parameters. These ioctls are only partially compatible with the +V4L2 VBI interface specified in <xref linkend="raw-vbi" />.</para> + + <para>An <structfield>offset</structfield> field does not +exist, <structfield>sample_format</structfield> is supposed to be +<constant>VIDEO_PALETTE_RAW</constant>, equivalent to +<constant>V4L2_PIX_FMT_GREY</constant>. The remaining fields are +probably equivalent to &v4l2-vbi-format;.</para> + + <para>Apparently only the Zoran (ZR 36120) driver implements +these ioctls. The semantics differ from those specified for V4L2 in two +ways. The parameters are reset on &func-open; and +<constant>VIDIOCSVBIFMT</constant> always returns an &EINVAL; if the +parameters are invalid.</para> + </section> + + <section> + <title>Miscellaneous</title> + + <para>V4L2 has no equivalent of the +<constant>VIDIOCGUNIT</constant> ioctl. Applications can find the VBI +device associated with a video capture device (or vice versa) by +reopening the device and requesting VBI data. For details see +<xref linkend="open" />.</para> + + <para>No replacement exists for <constant>VIDIOCKEY</constant>, +and the V4L functions for microcode programming. A new interface for +MPEG compression and playback devices is documented in <xref + linkend="extended-controls" />.</para> + </section> + + </section> + + <section id="hist-v4l2"> + <title>Changes of the V4L2 API</title> + + <para>Soon after the V4L API was added to the kernel it was +criticised as too inflexible. In August 1998 Bill Dirks proposed a +number of improvements and began to work on documentation, example +drivers and applications. With the help of other volunteers this +eventually became the V4L2 API, not just an extension but a +replacement for the V4L API. However it took another four years and +two stable kernel releases until the new API was finally accepted for +inclusion into the kernel in its present form.</para> + + <section> + <title>Early Versions</title> + <para>1998-08-20: First version.</para> + + <para>1998-08-27: The &func-select; function was introduced.</para> + + <para>1998-09-10: New video standard interface.</para> + + <para>1998-09-18: The <constant>VIDIOC_NONCAP</constant> ioctl +was replaced by the otherwise meaningless <constant>O_TRUNC</constant> +&func-open; flag, and the aliases <constant>O_NONCAP</constant> and +<constant>O_NOIO</constant> were defined. Applications can set this +flag if they intend to access controls only, as opposed to capture +applications which need exclusive access. The +<constant>VIDEO_STD_XXX</constant> identifiers are now ordinals +instead of flags, and the <function>video_std_construct()</function> +helper function takes id and transmission arguments.</para> + + <para>1998-09-28: Revamped video standard. Made video controls +individually enumerable.</para> + + <para>1998-10-02: The <structfield>id</structfield> field was +removed from struct <structname>video_standard</structname> and the +color subcarrier fields were renamed. The &VIDIOC-QUERYSTD; ioctl was +renamed to &VIDIOC-ENUMSTD;, &VIDIOC-G-INPUT; to &VIDIOC-ENUMINPUT;. A +first draft of the Codec API was released.</para> + + <para>1998-11-08: Many minor changes. Most symbols have been +renamed. Some material changes to &v4l2-capability;.</para> + + <para>1998-11-12: The read/write directon of some ioctls was misdefined.</para> + + <para>1998-11-14: <constant>V4L2_PIX_FMT_RGB24</constant> +changed to <constant>V4L2_PIX_FMT_BGR24</constant>, and +<constant>V4L2_PIX_FMT_RGB32</constant> changed to +<constant>V4L2_PIX_FMT_BGR32</constant>. Audio controls are now +accessible with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls under +names starting with <constant>V4L2_CID_AUDIO</constant>. The +<constant>V4L2_MAJOR</constant> define was removed from +<filename>videodev.h</filename> since it was only used once in the +<filename>videodev</filename> kernel module. The +<constant>YUV422</constant> and <constant>YUV411</constant> planar +image formats were added.</para> + + <para>1998-11-28: A few ioctl symbols changed. Interfaces for codecs and +video output devices were added.</para> + + <para>1999-01-14: A raw VBI capture interface was added.</para> + + <para>1999-01-19: The <constant>VIDIOC_NEXTBUF</constant> ioctl + was removed.</para> + </section> + + <section> + <title>V4L2 Version 0.16 1999-01-31</title> + <para>1999-01-27: There is now one QBUF ioctl, VIDIOC_QWBUF and VIDIOC_QRBUF +are gone. VIDIOC_QBUF takes a v4l2_buffer as a parameter. Added +digital zoom (cropping) controls.</para> + </section> + + <!-- Where's 0.17? mhs couldn't find that videodev.h, perhaps Bill + forgot to bump the version number or never released it. --> + + <section> + <title>V4L2 Version 0.18 1999-03-16</title> + <para>Added a v4l to V4L2 ioctl compatibility layer to +videodev.c. Driver writers, this changes how you implement your ioctl +handler. See the Driver Writer's Guide. Added some more control id +codes.</para> + </section> + + <section> + <title>V4L2 Version 0.19 1999-06-05</title> + <para>1999-03-18: Fill in the category and catname fields of +v4l2_queryctrl objects before passing them to the driver. Required a +minor change to the VIDIOC_QUERYCTRL handlers in the sample +drivers.</para> + <para>1999-03-31: Better compatibility for v4l memory capture +ioctls. Requires changes to drivers to fully support new compatibility +features, see Driver Writer's Guide and v4l2cap.c. Added new control +IDs: V4L2_CID_HFLIP, _VFLIP. Changed V4L2_PIX_FMT_YUV422P to _YUV422P, +and _YUV411P to _YUV411P.</para> + <para>1999-04-04: Added a few more control IDs.</para> + <para>1999-04-07: Added the button control type.</para> + <para>1999-05-02: Fixed a typo in videodev.h, and added the +V4L2_CTRL_FLAG_GRAYED (later V4L2_CTRL_FLAG_GRABBED) flag.</para> + <para>1999-05-20: Definition of VIDIOC_G_CTRL was wrong causing +a malfunction of this ioctl.</para> + <para>1999-06-05: Changed the value of +V4L2_CID_WHITENESS.</para> + </section> + + <section> + <title>V4L2 Version 0.20 (1999-09-10)</title> + + <para>Version 0.20 introduced a number of changes which were +<emphasis>not backward compatible</emphasis> with 0.19 and earlier +versions. Purpose of these changes was to simplify the API, while +making it more extensible and following common Linux driver API +conventions.</para> + + <orderedlist> + <listitem> + <para>Some typos in <constant>V4L2_FMT_FLAG</constant> +symbols were fixed. &v4l2-clip; was changed for compatibility with +v4l. (1999-08-30)</para> + </listitem> + + <listitem> + <para><constant>V4L2_TUNER_SUB_LANG1</constant> was added. +(1999-09-05)</para> + </listitem> + + <listitem> + <para>All ioctl() commands that used an integer argument now +take a pointer to an integer. Where it makes sense, ioctls will return +the actual new value in the integer pointed to by the argument, a +common convention in the V4L2 API. The affected ioctls are: +VIDIOC_PREVIEW, VIDIOC_STREAMON, VIDIOC_STREAMOFF, VIDIOC_S_FREQ, +VIDIOC_S_INPUT, VIDIOC_S_OUTPUT, VIDIOC_S_EFFECT. For example +<programlisting> +err = ioctl (fd, VIDIOC_XXX, V4L2_XXX); +</programlisting> becomes <programlisting> +int a = V4L2_XXX; err = ioctl(fd, VIDIOC_XXX, &a); +</programlisting> + </para> + </listitem> + + <listitem> + <para>All the different get- and set-format commands were +swept into one &VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctl taking a union +and a type field selecting the union member as parameter. Purpose is to +simplify the API by eliminating several ioctls and to allow new and +driver private data streams without adding new ioctls.</para> + + <para>This change obsoletes the following ioctls: +<constant>VIDIOC_S_INFMT</constant>, +<constant>VIDIOC_G_INFMT</constant>, +<constant>VIDIOC_S_OUTFMT</constant>, +<constant>VIDIOC_G_OUTFMT</constant>, +<constant>VIDIOC_S_VBIFMT</constant> and +<constant>VIDIOC_G_VBIFMT</constant>. The image format structure +<structname>v4l2_format</structname> was renamed to &v4l2-pix-format;, +while &v4l2-format; is now the envelopping structure for all format +negotiations.</para> + </listitem> + + <listitem> + <para>Similar to the changes above, the +<constant>VIDIOC_G_PARM</constant> and +<constant>VIDIOC_S_PARM</constant> ioctls were merged with +<constant>VIDIOC_G_OUTPARM</constant> and +<constant>VIDIOC_S_OUTPARM</constant>. A +<structfield>type</structfield> field in the new &v4l2-streamparm; +selects the respective union member.</para> + + <para>This change obsoletes the +<constant>VIDIOC_G_OUTPARM</constant> and +<constant>VIDIOC_S_OUTPARM</constant> ioctls.</para> + </listitem> + + <listitem> + <para>Control enumeration was simplified, and two new +control flags were introduced and one dropped. The +<structfield>catname</structfield> field was replaced by a +<structfield>group</structfield> field.</para> + + <para>Drivers can now flag unsupported and temporarily +unavailable controls with <constant>V4L2_CTRL_FLAG_DISABLED</constant> +and <constant>V4L2_CTRL_FLAG_GRABBED</constant> respectively. The +<structfield>group</structfield> name indicates a possibly narrower +classification than the <structfield>category</structfield>. In other +words, there may be multiple groups within a category. Controls within +a group would typically be drawn within a group box. Controls in +different categories might have a greater separation, or may even +appear in separate windows.</para> + </listitem> + + <listitem> + <para>The &v4l2-buffer; <structfield>timestamp</structfield> +was changed to a 64 bit integer, containing the sampling or output +time of the frame in nanoseconds. Additionally timestamps will be in +absolute system time, not starting from zero at the beginning of a +stream. The data type name for timestamps is stamp_t, defined as a +signed 64-bit integer. Output devices should not send a buffer out +until the time in the timestamp field has arrived. I would like to +follow SGI's lead, and adopt a multimedia timestamping system like +their UST (Unadjusted System Time). See +http://web.archive.org/web/*/http://reality.sgi.com +/cpirazzi_engr/lg/time/intro.html. +UST uses timestamps that are 64-bit signed integers +(not struct timeval's) and given in nanosecond units. The UST clock +starts at zero when the system is booted and runs continuously and +uniformly. It takes a little over 292 years for UST to overflow. There +is no way to set the UST clock. The regular Linux time-of-day clock +can be changed periodically, which would cause errors if it were being +used for timestamping a multimedia stream. A real UST style clock will +require some support in the kernel that is not there yet. But in +anticipation, I will change the timestamp field to a 64-bit integer, +and I will change the v4l2_masterclock_gettime() function (used only +by drivers) to return a 64-bit integer.</para> + </listitem> + + <listitem> + <para>A <structfield>sequence</structfield> field was added +to &v4l2-buffer;. The <structfield>sequence</structfield> field counts +captured frames, it is ignored by output devices. When a capture +driver drops a frame, the sequence number of that frame is +skipped.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 Version 0.20 incremental changes</title> + <!-- Version number didn't change anymore, reason unknown. --> + + <para>1999-12-23: In &v4l2-vbi-format; the +<structfield>reserved1</structfield> field became +<structfield>offset</structfield>. Previously drivers were required to +clear the <structfield>reserved1</structfield> field.</para> + + <para>2000-01-13: The + <constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant> flag was added.</para> + + <para>2000-07-31: The <filename>linux/poll.h</filename> header +is now included by <filename>videodev.h</filename> for compatibility +with the original <filename>videodev.h</filename> file.</para> + + <para>2000-11-20: <constant>V4L2_TYPE_VBI_OUTPUT</constant> and +<constant>V4L2_PIX_FMT_Y41P</constant> were added.</para> + + <para>2000-11-25: <constant>V4L2_TYPE_VBI_INPUT</constant> was +added.</para> + + <para>2000-12-04: A couple typos in symbol names were fixed.</para> + + <para>2001-01-18: To avoid namespace conflicts the +<constant>fourcc</constant> macro defined in the +<filename>videodev.h</filename> header file was renamed to +<constant>v4l2_fourcc</constant>.</para> + + <para>2001-01-25: A possible driver-level compatibility problem +between the <filename>videodev.h</filename> file in Linux 2.4.0 and +the <filename>videodev.h</filename> file included in the +<filename>videodevX</filename> patch was fixed. Users of an earlier +version of <filename>videodevX</filename> on Linux 2.4.0 should +recompile their V4L and V4L2 drivers.</para> + + <para>2001-01-26: A possible kernel-level incompatibility +between the <filename>videodev.h</filename> file in the +<filename>videodevX</filename> patch and the +<filename>videodev.h</filename> file in Linux 2.2.x with devfs patches +applied was fixed.</para> + + <para>2001-03-02: Certain V4L ioctls which pass data in both +direction although they are defined with read-only parameter, did not +work correctly through the backward compatibility layer. +[Solution?]</para> + + <para>2001-04-13: Big endian 16-bit RGB formats were added.</para> + + <para>2001-09-17: New YUV formats and the &VIDIOC-G-FREQUENCY; and +&VIDIOC-S-FREQUENCY; ioctls were added. (The old +<constant>VIDIOC_G_FREQ</constant> and +<constant>VIDIOC_S_FREQ</constant> ioctls did not take multiple tuners +into account.)</para> + + <para>2000-09-18: <constant>V4L2_BUF_TYPE_VBI</constant> was +added. This may <emphasis>break compatibility</emphasis> as the +&VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls may fail now if the struct +<structname>v4l2_fmt</structname> <structfield>type</structfield> +field does not contain <constant>V4L2_BUF_TYPE_VBI</constant>. In the +documentation of the &v4l2-vbi-format; +<structfield>offset</structfield> field the ambiguous phrase "rising +edge" was changed to "leading edge".</para> + </section> + + <section> + <title>V4L2 Version 0.20 2000-11-23</title> + + <para>A number of changes were made to the raw VBI +interface.</para> + + <orderedlist> + <listitem> + <para>Figures clarifying the line numbering scheme were +added to the V4L2 API specification. The +<structfield>start</structfield>[0] and +<structfield>start</structfield>[1] fields no longer count line +numbers beginning at zero. Rationale: a) The previous definition was +unclear. b) The <structfield>start</structfield>[] values are ordinal +numbers. c) There is no point in inventing a new line numbering +scheme. We now use line number as defined by ITU-R, period. +Compatibility: Add one to the start values. Applications depending on +the previous semantics may not function correctly.</para> + </listitem> + + <listitem> + <para>The restriction "count[0] > 0 and count[1] > 0" +has been relaxed to "(count[0] + count[1]) > 0". Rationale: +Drivers may allocate resources at scan line granularity and some data +services are transmitted only on the first field. The comment that +both <structfield>count</structfield> values will usually be equal is +misleading and pointless and has been removed. This change +<emphasis>breaks compatibility</emphasis> with earlier versions: +Drivers may return EINVAL, applications may not function +correctly.</para> + </listitem> + + <listitem> + <para>Drivers are again permitted to return negative +(unknown) start values as proposed earlier. Why this feature was +dropped is unclear. This change may <emphasis>break +compatibility</emphasis> with applications depending on the start +values being positive. The use of <constant>EBUSY</constant> and +<constant>EINVAL</constant> error codes with the &VIDIOC-S-FMT; ioctl +was clarified. The &EBUSY; was finally documented, and the +<structfield>reserved2</structfield> field which was previously +mentioned only in the <filename>videodev.h</filename> header +file.</para> + </listitem> + + <listitem> + <para>New buffer types +<constant>V4L2_TYPE_VBI_INPUT</constant> and +<constant>V4L2_TYPE_VBI_OUTPUT</constant> were added. The former is an +alias for the old <constant>V4L2_TYPE_VBI</constant>, the latter was +missing in the <filename>videodev.h</filename> file.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 Version 0.20 2002-07-25</title> + <para>Added sliced VBI interface proposal.</para> + </section> + + <section> + <title>V4L2 in Linux 2.5.46, 2002-10</title> + + <para>Around October-November 2002, prior to an announced +feature freeze of Linux 2.5, the API was revised, drawing from +experience with V4L2 0.20. This unnamed version was finally merged +into Linux 2.5.46.</para> + + <orderedlist> + <listitem> + <para>As specified in <xref linkend="related" />, drivers +must make related device functions available under all minor device +numbers.</para> + </listitem> + + <listitem> + <para>The &func-open; function requires access mode +<constant>O_RDWR</constant> regardless of the device type. All V4L2 +drivers exchanging data with applications must support the +<constant>O_NONBLOCK</constant> flag. The <constant>O_NOIO</constant> +flag, a V4L2 symbol which aliased the meaningless +<constant>O_TRUNC</constant> to indicate accesses without data +exchange (panel applications) was dropped. Drivers must stay in "panel +mode" until the application attempts to initiate a data exchange, see +<xref linkend="open" />.</para> + </listitem> + + <listitem> + <para>The &v4l2-capability; changed dramatically. Note that +also the size of the structure changed, which is encoded in the ioctl +request code, thus older V4L2 devices will respond with an &EINVAL; to +the new &VIDIOC-QUERYCAP; ioctl.</para> + + <para>There are new fields to identify the driver, a new RDS +device function <constant>V4L2_CAP_RDS_CAPTURE</constant>, the +<constant>V4L2_CAP_AUDIO</constant> flag indicates if the device has +any audio connectors, another I/O capability +<constant>V4L2_CAP_ASYNCIO</constant> can be flagged. In response to +these changes the <structfield>type</structfield> field became a bit +set and was merged into the <structfield>flags</structfield> field. +<constant>V4L2_FLAG_TUNER</constant> was renamed to +<constant>V4L2_CAP_TUNER</constant>, +<constant>V4L2_CAP_VIDEO_OVERLAY</constant> replaced +<constant>V4L2_FLAG_PREVIEW</constant> and +<constant>V4L2_CAP_VBI_CAPTURE</constant> and +<constant>V4L2_CAP_VBI_OUTPUT</constant> replaced +<constant>V4L2_FLAG_DATA_SERVICE</constant>. +<constant>V4L2_FLAG_READ</constant> and +<constant>V4L2_FLAG_WRITE</constant> were merged into +<constant>V4L2_CAP_READWRITE</constant>.</para> + + <para>The redundant fields +<structfield>inputs</structfield>, <structfield>outputs</structfield> +and <structfield>audios</structfield> were removed. These properties +can be determined as described in <xref linkend="video" /> and <xref +linkend="audio" />.</para> + + <para>The somewhat volatile and therefore barely useful +fields <structfield>maxwidth</structfield>, +<structfield>maxheight</structfield>, +<structfield>minwidth</structfield>, +<structfield>minheight</structfield>, +<structfield>maxframerate</structfield> were removed. This information +is available as described in <xref linkend="format" /> and +<xref linkend="standard" />.</para> + + <para><constant>V4L2_FLAG_SELECT</constant> was removed. We +believe the select() function is important enough to require support +of it in all V4L2 drivers exchanging data with applications. The +redundant <constant>V4L2_FLAG_MONOCHROME</constant> flag was removed, +this information is available as described in <xref + linkend="format" />.</para> + </listitem> + + <listitem> + <para>In &v4l2-input; the +<structfield>assoc_audio</structfield> field and the +<structfield>capability</structfield> field and its only flag +<constant>V4L2_INPUT_CAP_AUDIO</constant> was replaced by the new +<structfield>audioset</structfield> field. Instead of linking one +video input to one audio input this field reports all audio inputs +this video input combines with.</para> + + <para>New fields are <structfield>tuner</structfield> +(reversing the former link from tuners to video inputs), +<structfield>std</structfield> and +<structfield>status</structfield>.</para> + + <para>Accordingly &v4l2-output; lost its +<structfield>capability</structfield> and +<structfield>assoc_audio</structfield> fields. +<structfield>audioset</structfield>, +<structfield>modulator</structfield> and +<structfield>std</structfield> where added instead.</para> + </listitem> + + <listitem> + <para>The &v4l2-audio; field +<structfield>audio</structfield> was renamed to +<structfield>index</structfield>, for consistency with other +structures. A new capability flag +<constant>V4L2_AUDCAP_STEREO</constant> was added to indicated if the +audio input in question supports stereo sound. +<constant>V4L2_AUDCAP_EFFECTS</constant> and the corresponding +<constant>V4L2_AUDMODE</constant> flags where removed. This can be +easily implemented using controls. (However the same applies to AVL +which is still there.)</para> + + <para>Again for consistency the &v4l2-audioout; field +<structfield>audio</structfield> was renamed to +<structfield>index</structfield>.</para> + </listitem> + + <listitem> + <para>The &v4l2-tuner; +<structfield>input</structfield> field was replaced by an +<structfield>index</structfield> field, permitting devices with +multiple tuners. The link between video inputs and tuners is now +reversed, inputs point to their tuner. The +<structfield>std</structfield> substructure became a +simple set (more about this below) and moved into &v4l2-input;. A +<structfield>type</structfield> field was added.</para> + + <para>Accordingly in &v4l2-modulator; the +<structfield>output</structfield> was replaced by an +<structfield>index</structfield> field.</para> + + <para>In &v4l2-frequency; the +<structfield>port</structfield> field was replaced by a +<structfield>tuner</structfield> field containing the respective tuner +or modulator index number. A tuner <structfield>type</structfield> +field was added and the <structfield>reserved</structfield> field +became larger for future extensions (satellite tuners in +particular).</para> + </listitem> + + <listitem> + <para>The idea of completely transparent video standards was +dropped. Experience showed that applications must be able to work with +video standards beyond presenting the user a menu. Instead of +enumerating supported standards with an ioctl applications can now +refer to standards by &v4l2-std-id; and symbols defined in the +<filename>videodev2.h</filename> header file. For details see <xref + linkend="standard" />. The &VIDIOC-G-STD; and +&VIDIOC-S-STD; now take a pointer to this type as argument. +&VIDIOC-QUERYSTD; was added to autodetect the received standard, if +the hardware has this capability. In &v4l2-standard; an +<structfield>index</structfield> field was added for &VIDIOC-ENUMSTD;. +A &v4l2-std-id; field named <structfield>id</structfield> was added as +machine readable identifier, also replacing the +<structfield>transmission</structfield> field. The misleading +<structfield>framerate</structfield> field was renamed +to <structfield>frameperiod</structfield>. The now obsolete +<structfield>colorstandard</structfield> information, originally +needed to distguish between variations of standards, were +removed.</para> + + <para>Struct <structname>v4l2_enumstd</structname> ceased to +be. &VIDIOC-ENUMSTD; now takes a pointer to a &v4l2-standard; +directly. The information which standards are supported by a +particular video input or output moved into &v4l2-input; and +&v4l2-output; fields named <structfield>std</structfield>, +respectively.</para> + </listitem> + + <listitem> + <para>The &v4l2-queryctrl; fields +<structfield>category</structfield> and +<structfield>group</structfield> did not catch on and/or were not +implemented as expected and therefore removed.</para> + </listitem> + + <listitem> + <para>The &VIDIOC-TRY-FMT; ioctl was added to negotiate data +formats as with &VIDIOC-S-FMT;, but without the overhead of +programming the hardware and regardless of I/O in progress.</para> + + <para>In &v4l2-format; the <structfield>fmt</structfield> +union was extended to contain &v4l2-window;. All image format +negotiations are now possible with <constant>VIDIOC_G_FMT</constant>, +<constant>VIDIOC_S_FMT</constant> and +<constant>VIDIOC_TRY_FMT</constant>; ioctl. The +<constant>VIDIOC_G_WIN</constant> and +<constant>VIDIOC_S_WIN</constant> ioctls to prepare for a video +overlay were removed. The <structfield>type</structfield> field +changed to type &v4l2-buf-type; and the buffer type names changed as +follows.<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>Old defines</entry> + <entry>&v4l2-buf-type;</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_BUF_TYPE_CAPTURE</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant></entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_CODECIN</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_CODECOUT</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_EFFECTSIN</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_EFFECTSIN2</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_EFFECTSOUT</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEOOUT</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant></entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_PRIVATE_BASE</constant></entry> + <entry><constant>V4L2_BUF_TYPE_PRIVATE</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + </listitem> + + <listitem> + <para>In &v4l2-fmtdesc; a &v4l2-buf-type; field named +<structfield>type</structfield> was added as in &v4l2-format;. The +<constant>VIDIOC_ENUM_FBUFFMT</constant> ioctl is no longer needed and +was removed. These calls can be replaced by &VIDIOC-ENUM-FMT; with +type <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para> + </listitem> + + <listitem> + <para>In &v4l2-pix-format; the +<structfield>depth</structfield> field was removed, assuming +applications which recognize the format by its four-character-code +already know the color depth, and others do not care about it. The +same rationale lead to the removal of the +<constant>V4L2_FMT_FLAG_COMPRESSED</constant> flag. The +<constant>V4L2_FMT_FLAG_SWCONVECOMPRESSED</constant> flag was removed +because drivers are not supposed to convert images in kernel space. A +user library of conversion functions should be provided instead. The +<constant>V4L2_FMT_FLAG_BYTESPERLINE</constant> flag was redundant. +Applications can set the <structfield>bytesperline</structfield> field +to zero to get a reasonable default. Since the remaining flags were +replaced as well, the <structfield>flags</structfield> field itself +was removed.</para> + <para>The interlace flags were replaced by a &v4l2-field; +value in a newly added <structfield>field</structfield> +field.<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>Old flag</entry> + <entry>&v4l2-field;</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant></entry> + <entry>?</entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_INTERLACED</constant> += <constant>V4L2_FMT_FLAG_COMBINED</constant></entry> + <entry><constant>V4L2_FIELD_INTERLACED</constant></entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_TOPFIELD</constant> += <constant>V4L2_FMT_FLAG_ODDFIELD</constant></entry> + <entry><constant>V4L2_FIELD_TOP</constant></entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_BOTFIELD</constant> += <constant>V4L2_FMT_FLAG_EVENFIELD</constant></entry> + <entry><constant>V4L2_FIELD_BOTTOM</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_FIELD_SEQ_TB</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_FIELD_SEQ_BT</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_FIELD_ALTERNATE</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>The color space flags were replaced by a +&v4l2-colorspace; value in a newly added +<structfield>colorspace</structfield> field, where one of +<constant>V4L2_COLORSPACE_SMPTE170M</constant>, +<constant>V4L2_COLORSPACE_BT878</constant>, +<constant>V4L2_COLORSPACE_470_SYSTEM_M</constant> or +<constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant> replaces +<constant>V4L2_FMT_CS_601YUV</constant>.</para> + </listitem> + + <listitem> + <para>In &v4l2-requestbuffers; the +<structfield>type</structfield> field was properly defined as +&v4l2-buf-type;. Buffer types changed as mentioned above. A new +<structfield>memory</structfield> field of type &v4l2-memory; was +added to distinguish between I/O methods using buffers allocated +by the driver or the application. See <xref linkend="io" /> for +details.</para> + </listitem> + + <listitem> + <para>In &v4l2-buffer; the <structfield>type</structfield> +field was properly defined as &v4l2-buf-type;. Buffer types changed as +mentioned above. A <structfield>field</structfield> field of type +&v4l2-field; was added to indicate if a buffer contains a top or +bottom field. The old field flags were removed. Since no unadjusted +system time clock was added to the kernel as planned, the +<structfield>timestamp</structfield> field changed back from type +stamp_t, an unsigned 64 bit integer expressing the sample time in +nanoseconds, to struct <structname>timeval</structname>. With the +addition of a second memory mapping method the +<structfield>offset</structfield> field moved into union +<structfield>m</structfield>, and a new +<structfield>memory</structfield> field of type &v4l2-memory; was +added to distinguish between I/O methods. See <xref linkend="io" /> +for details.</para> + + <para>The <constant>V4L2_BUF_REQ_CONTIG</constant> +flag was used by the V4L compatibility layer, after changes to this +code it was no longer needed. The +<constant>V4L2_BUF_ATTR_DEVICEMEM</constant> flag would indicate if +the buffer was indeed allocated in device memory rather than DMA-able +system memory. It was barely useful and so was removed.</para> + </listitem> + + <listitem> + <para>In &v4l2-framebuffer; the +<structfield>base[3]</structfield> array anticipating double- and +triple-buffering in off-screen video memory, however without defining +a synchronization mechanism, was replaced by a single pointer. The +<constant>V4L2_FBUF_CAP_SCALEUP</constant> and +<constant>V4L2_FBUF_CAP_SCALEDOWN</constant> flags were removed. +Applications can determine this capability more accurately using the +new cropping and scaling interface. The +<constant>V4L2_FBUF_CAP_CLIPPING</constant> flag was replaced by +<constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> and +<constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant>.</para> + </listitem> + + <listitem> + <para>In &v4l2-clip; the <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> field moved into a +<structfield>c</structfield> substructure of type &v4l2-rect;. The +<structfield>x</structfield> and <structfield>y</structfield> fields +were renamed to <structfield>left</structfield> and +<structfield>top</structfield>, &ie; offsets to a context dependent +origin.</para> + </listitem> + + <listitem> + <para>In &v4l2-window; the <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> field moved into a +<structfield>w</structfield> substructure as above. A +<structfield>field</structfield> field of type %v4l2-field; was added +to distinguish between field and frame (interlaced) overlay.</para> + </listitem> + + <listitem> + <para>The digital zoom interface, including struct +<structname>v4l2_zoomcap</structname>, struct +<structname>v4l2_zoom</structname>, +<constant>V4L2_ZOOM_NONCAP</constant> and +<constant>V4L2_ZOOM_WHILESTREAMING</constant> was replaced by a new +cropping and scaling interface. The previously unused struct +<structname>v4l2_cropcap</structname> and +<structname>v4l2_crop</structname> where redefined for this purpose. +See <xref linkend="crop" /> for details.</para> + </listitem> + + <listitem> + <para>In &v4l2-vbi-format; the +<structfield>SAMPLE_FORMAT</structfield> field now contains a +four-character-code as used to identify video image formats and +<constant>V4L2_PIX_FMT_GREY</constant> replaces the +<constant>V4L2_VBI_SF_UBYTE</constant> define. The +<structfield>reserved</structfield> field was extended.</para> + </listitem> + + <listitem> + <para>In &v4l2-captureparm; the type of the +<structfield>timeperframe</structfield> field changed from unsigned +long to &v4l2-fract;. This allows the accurate expression of multiples +of the NTSC-M frame rate 30000 / 1001. A new field +<structfield>readbuffers</structfield> was added to control the driver +behaviour in read I/O mode.</para> + + <para>Similar changes were made to &v4l2-outputparm;.</para> + </listitem> + + <listitem> + <para>The struct <structname>v4l2_performance</structname> +and <constant>VIDIOC_G_PERF</constant> ioctl were dropped. Except when +using the <link linkend="rw">read/write I/O method</link>, which is +limited anyway, this information is already available to +applications.</para> + </listitem> + + <listitem> + <para>The example transformation from RGB to YCbCr color +space in the old V4L2 documentation was inaccurate, this has been +corrected in <xref linkend="pixfmt" />.<!-- 0.5670G should be +0.587, and 127/112 != 255/224 --></para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 2003-06-19</title> + + <orderedlist> + <listitem> + <para>A new capability flag +<constant>V4L2_CAP_RADIO</constant> was added for radio devices. Prior +to this change radio devices would identify solely by having exactly one +tuner whose type field reads <constant>V4L2_TUNER_RADIO</constant>.</para> + </listitem> + + <listitem> + <para>An optional driver access priority mechanism was +added, see <xref linkend="app-pri" /> for details.</para> + </listitem> + + <listitem> + <para>The audio input and output interface was found to be +incomplete.</para> + <para>Previously the &VIDIOC-G-AUDIO; +ioctl would enumerate the available audio inputs. An ioctl to +determine the current audio input, if more than one combines with the +current video input, did not exist. So +<constant>VIDIOC_G_AUDIO</constant> was renamed to +<constant>VIDIOC_G_AUDIO_OLD</constant>, this ioctl was removed on +Kernel 2.6.39. The &VIDIOC-ENUMAUDIO; ioctl was added to enumerate +audio inputs, while &VIDIOC-G-AUDIO; now reports the current audio +input.</para> + <para>The same changes were made to &VIDIOC-G-AUDOUT; and +&VIDIOC-ENUMAUDOUT;.</para> + <para>Until further the "videodev" module will automatically +translate between the old and new ioctls, but drivers and applications +must be updated to successfully compile again.</para> + </listitem> + + <listitem> + <para>The &VIDIOC-OVERLAY; ioctl was incorrectly defined with +write-read parameter. It was changed to write-only, while the write-read +version was renamed to <constant>VIDIOC_OVERLAY_OLD</constant>. The old +ioctl was removed on Kernel 2.6.39. Until further the "videodev" +kernel module will automatically translate to the new version, so drivers +must be recompiled, but not applications.</para> + </listitem> + + <listitem> + <para><xref linkend="overlay" /> incorrectly stated that +clipping rectangles define regions where the video can be seen. +Correct is that clipping rectangles define regions where +<emphasis>no</emphasis> video shall be displayed and so the graphics +surface can be seen.</para> + </listitem> + + <listitem> + <para>The &VIDIOC-S-PARM; and &VIDIOC-S-CTRL; ioctls were +defined with write-only parameter, inconsistent with other ioctls +modifying their argument. They were changed to write-read, while a +<constant>_OLD</constant> suffix was added to the write-only versions. +The old ioctls were removed on Kernel 2.6.39. Drivers and +applications assuming a constant parameter need an update.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 2003-11-05</title> + <orderedlist> + <listitem> + <para>In <xref linkend="pixfmt-rgb" /> the following pixel +formats were incorrectly transferred from Bill Dirks' V4L2 +specification. Descriptions below refer to bytes in memory, in +ascending address order.<informaltable> + <tgroup cols="3"> + <thead> + <row> + <entry>Symbol</entry> + <entry>In this document prior to revision +0.5</entry> + <entry>Corrected</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> + <entry>B, G, R</entry> + <entry>R, G, B</entry> + </row> + <row> + <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> + <entry>R, G, B</entry> + <entry>B, G, R</entry> + </row> + <row> + <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> + <entry>B, G, R, X</entry> + <entry>R, G, B, X</entry> + </row> + <row> + <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> + <entry>R, G, B, X</entry> + <entry>B, G, R, X</entry> + </row> + </tbody> + </tgroup> + </informaltable> The +<constant>V4L2_PIX_FMT_BGR24</constant> example was always +correct.</para> + <para>In <xref linkend="v4l-image-properties" /> the mapping +of the V4L <constant>VIDEO_PALETTE_RGB24</constant> and +<constant>VIDEO_PALETTE_RGB32</constant> formats to V4L2 pixel formats +was accordingly corrected.</para> + </listitem> + + <listitem> + <para>Unrelated to the fixes above, drivers may still +interpret some V4L2 RGB pixel formats differently. These issues have +yet to be addressed, for details see <xref + linkend="pixfmt-rgb" />.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.6, 2004-05-09</title> + <orderedlist> + <listitem> + <para>The &VIDIOC-CROPCAP; ioctl was incorrectly defined +with read-only parameter. It is now defined as write-read ioctl, while +the read-only version was renamed to +<constant>VIDIOC_CROPCAP_OLD</constant>. The old ioctl was removed +on Kernel 2.6.39.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.8</title> + <orderedlist> + <listitem> + <para>A new field <structfield>input</structfield> (former +<structfield>reserved[0]</structfield>) was added to the &v4l2-buffer; +structure. Purpose of this field is to alternate between video inputs +(⪚ cameras) in step with the video capturing process. This function +must be enabled with the new <constant>V4L2_BUF_FLAG_INPUT</constant> +flag. The <structfield>flags</structfield> field is no longer +read-only.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2004-08-01</title> + + <orderedlist> + <listitem> + <para>The return value of the +<xref linkend="func-open" /> function was incorrectly documented.</para> + </listitem> + + <listitem> + <para>Audio output ioctls end in -AUDOUT, not -AUDIOOUT.</para> + </listitem> + + <listitem> + <para>In the Current Audio Input example the +<constant>VIDIOC_G_AUDIO</constant> ioctl took the wrong +argument.</para> + </listitem> + + <listitem> + <para>The documentation of the &VIDIOC-QBUF; and +&VIDIOC-DQBUF; ioctls did not mention the &v4l2-buffer; +<structfield>memory</structfield> field. It was also missing from +examples. Also on the <constant>VIDIOC_DQBUF</constant> page the &EIO; +was not documented.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.14</title> + <orderedlist> + <listitem> + <para>A new sliced VBI interface was added. It is documented +in <xref linkend="sliced" /> and replaces the interface first +proposed in V4L2 specification 0.8.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.15</title> + <orderedlist> + <listitem> + <para>The &VIDIOC-LOG-STATUS; ioctl was added.</para> + </listitem> + + <listitem> + <para>New video standards +<constant>V4L2_STD_NTSC_443</constant>, +<constant>V4L2_STD_SECAM_LC</constant>, +<constant>V4L2_STD_SECAM_DK</constant> (a set of SECAM D, K and K1), +and <constant>V4L2_STD_ATSC</constant> (a set of +<constant>V4L2_STD_ATSC_8_VSB</constant> and +<constant>V4L2_STD_ATSC_16_VSB</constant>) were defined. Note the +<constant>V4L2_STD_525_60</constant> set now includes +<constant>V4L2_STD_NTSC_443</constant>. See also <xref + linkend="v4l2-std-id" />.</para> + </listitem> + + <listitem> + <para>The <constant>VIDIOC_G_COMP</constant> and +<constant>VIDIOC_S_COMP</constant> ioctl were renamed to +<constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> respectively. Their argument +was replaced by a struct +<structname>v4l2_mpeg_compression</structname> pointer. (The +<constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> ioctls where removed in Linux +2.6.25.)</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2005-11-27</title> + <para>The capture example in <xref linkend="capture-example" /> +called the &VIDIOC-S-CROP; ioctl without checking if cropping is +supported. In the video standard selection example in +<xref linkend="standard" /> the &VIDIOC-S-STD; call used the wrong +argument type.</para> + </section> + + <section> + <title>V4L2 spec erratum 2006-01-10</title> + <orderedlist> + <listitem> + <para>The <constant>V4L2_IN_ST_COLOR_KILL</constant> flag in +&v4l2-input; not only indicates if the color killer is enabled, but +also if it is active. (The color killer disables color decoding when +it detects no color in the video signal to improve the image +quality.)</para> + </listitem> + + <listitem> + <para>&VIDIOC-S-PARM; is a write-read ioctl, not write-only as +stated on its reference page. The ioctl changed in 2003 as noted above.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-02-03</title> + <orderedlist> + <listitem> + <para>In &v4l2-captureparm; and &v4l2-outputparm; the +<structfield>timeperframe</structfield> field gives the time in +seconds, not microseconds.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-02-04</title> + <orderedlist> + <listitem> + <para>The <structfield>clips</structfield> field in +&v4l2-window; must point to an array of &v4l2-clip;, not a linked +list, because drivers ignore the struct +<structname>v4l2_clip</structname>.<structfield>next</structfield> +pointer.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.17</title> + <orderedlist> + <listitem> + <para>New video standard macros were added: +<constant>V4L2_STD_NTSC_M_KR</constant> (NTSC M South Korea), and the +sets <constant>V4L2_STD_MN</constant>, +<constant>V4L2_STD_B</constant>, <constant>V4L2_STD_GH</constant> and +<constant>V4L2_STD_DK</constant>. The +<constant>V4L2_STD_NTSC</constant> and +<constant>V4L2_STD_SECAM</constant> sets now include +<constant>V4L2_STD_NTSC_M_KR</constant> and +<constant>V4L2_STD_SECAM_LC</constant> respectively.</para> + </listitem> + + <listitem> + <para>A new <constant>V4L2_TUNER_MODE_LANG1_LANG2</constant> +was defined to record both languages of a bilingual program. The +use of <constant>V4L2_TUNER_MODE_STEREO</constant> for this purpose +is deprecated now. See the &VIDIOC-G-TUNER; section for +details.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-09-23 (Draft 0.15)</title> + <orderedlist> + <listitem> + <para>In various places +<constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> and +<constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant> of the sliced VBI +interface were not mentioned along with other buffer types.</para> + </listitem> + + <listitem> + <para>In <xref linkend="vidioc-g-audio" /> it was clarified +that the &v4l2-audio; <structfield>mode</structfield> field is a flags +field.</para> + </listitem> + + <listitem> + <para><xref linkend="vidioc-querycap" /> did not mention the +sliced VBI and radio capability flags.</para> + </listitem> + + <listitem> + <para>In <xref linkend="vidioc-g-frequency" /> it was +clarified that applications must initialize the tuner +<structfield>type</structfield> field of &v4l2-frequency; before +calling &VIDIOC-S-FREQUENCY;.</para> + </listitem> + + <listitem> + <para>The <structfield>reserved</structfield> array +in &v4l2-requestbuffers; has 2 elements, not 32.</para> + </listitem> + + <listitem> + <para>In <xref linkend="output" /> and <xref + linkend="raw-vbi" /> the device file names +<filename>/dev/vout</filename> which never caught on were replaced +by <filename>/dev/video</filename>.</para> + </listitem> + + <listitem> + <para>With Linux 2.6.15 the possible range for VBI device minor +numbers was extended from 224-239 to 224-255. Accordingly device file names +<filename>/dev/vbi0</filename> to <filename>/dev/vbi31</filename> are +possible now.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.18</title> + <orderedlist> + <listitem> + <para>New ioctls &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; +and &VIDIOC-TRY-EXT-CTRLS; were added, a flag to skip unsupported +controls with &VIDIOC-QUERYCTRL;, new control types +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> and +<constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant> (<xref + linkend="v4l2-ctrl-type" />), and new control flags +<constant>V4L2_CTRL_FLAG_READ_ONLY</constant>, +<constant>V4L2_CTRL_FLAG_UPDATE</constant>, +<constant>V4L2_CTRL_FLAG_INACTIVE</constant> and +<constant>V4L2_CTRL_FLAG_SLIDER</constant> (<xref + linkend="control-flags" />). See <xref + linkend="extended-controls" /> for details.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.19</title> + <orderedlist> + <listitem> + <para>In &v4l2-sliced-vbi-cap; a buffer type field was added +replacing a reserved field. Note on architectures where the size of +enum types differs from int types the size of the structure changed. +The &VIDIOC-G-SLICED-VBI-CAP; ioctl was redefined from being read-only +to write-read. Applications must initialize the type field and clear +the reserved fields now. These changes may <emphasis>break the +compatibility</emphasis> with older drivers and applications.</para> + </listitem> + + <listitem> + <para>The ioctls &VIDIOC-ENUM-FRAMESIZES; and +&VIDIOC-ENUM-FRAMEINTERVALS; were added.</para> + </listitem> + + <listitem> + <para>A new pixel format <constant>V4L2_PIX_FMT_RGB444</constant> (<xref +linkend="rgb-formats" />) was added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-10-12 (Draft 0.17)</title> + <orderedlist> + <listitem> + <para><constant>V4L2_PIX_FMT_HM12</constant> (<xref +linkend="reserved-formats" />) is a YUV 4:2:0, not 4:2:2 format.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.21</title> + <orderedlist> + <listitem> + <para>The <filename>videodev2.h</filename> header file is +now dual licensed under GNU General Public License version two or +later, and under a 3-clause BSD-style license.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.22</title> + <orderedlist> + <listitem> + <para>Two new field orders + <constant>V4L2_FIELD_INTERLACED_TB</constant> and + <constant>V4L2_FIELD_INTERLACED_BT</constant> were + added. See <xref linkend="v4l2-field" /> for details.</para> + </listitem> + + <listitem> + <para>Three new clipping/blending methods with a global or +straight or inverted local alpha value were added to the video overlay +interface. See the description of the &VIDIOC-G-FBUF; and +&VIDIOC-S-FBUF; ioctls for details.</para> + <para>A new <structfield>global_alpha</structfield> field +was added to <link +linkend="v4l2-window"><structname>v4l2_window</structname></link>, +extending the structure. This may <emphasis>break +compatibility</emphasis> with applications using a struct +<structname>v4l2_window</structname> directly. However the <link +linkend="vidioc-g-fmt">VIDIOC_G/S/TRY_FMT</link> ioctls, which take a +pointer to a <link linkend="v4l2-format">v4l2_format</link> parent +structure with padding bytes at the end, are not affected.</para> + </listitem> + + <listitem> + <para>The format of the <structfield>chromakey</structfield> +field in &v4l2-window; changed from "host order RGB32" to a pixel +value in the same format as the framebuffer. This may <emphasis>break +compatibility</emphasis> with existing applications. Drivers +supporting the "host order RGB32" format are not known.</para> + </listitem> + + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.24</title> + <orderedlist> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_PAL8</constant>, +<constant>V4L2_PIX_FMT_YUV444</constant>, +<constant>V4L2_PIX_FMT_YUV555</constant>, +<constant>V4L2_PIX_FMT_YUV565</constant> and +<constant>V4L2_PIX_FMT_YUV32</constant> were added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.25</title> + <orderedlist> + <listitem> + <para>The pixel formats <link linkend="V4L2-PIX-FMT-Y16"> +<constant>V4L2_PIX_FMT_Y16</constant></link> and <link +linkend="V4L2-PIX-FMT-SBGGR16"> +<constant>V4L2_PIX_FMT_SBGGR16</constant></link> were added.</para> + </listitem> + <listitem> + <para>New <link linkend="control">controls</link> +<constant>V4L2_CID_POWER_LINE_FREQUENCY</constant>, +<constant>V4L2_CID_HUE_AUTO</constant>, +<constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant>, +<constant>V4L2_CID_SHARPNESS</constant> and +<constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant> were added. The +controls <constant>V4L2_CID_BLACK_LEVEL</constant>, +<constant>V4L2_CID_WHITENESS</constant>, +<constant>V4L2_CID_HCENTER</constant> and +<constant>V4L2_CID_VCENTER</constant> were deprecated. +</para> + </listitem> + <listitem> + <para>A <link linkend="camera-controls">Camera controls +class</link> was added, with the new controls +<constant>V4L2_CID_EXPOSURE_AUTO</constant>, +<constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant>, +<constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant>, +<constant>V4L2_CID_PAN_RELATIVE</constant>, +<constant>V4L2_CID_TILT_RELATIVE</constant>, +<constant>V4L2_CID_PAN_RESET</constant>, +<constant>V4L2_CID_TILT_RESET</constant>, +<constant>V4L2_CID_PAN_ABSOLUTE</constant>, +<constant>V4L2_CID_TILT_ABSOLUTE</constant>, +<constant>V4L2_CID_FOCUS_ABSOLUTE</constant>, +<constant>V4L2_CID_FOCUS_RELATIVE</constant> and +<constant>V4L2_CID_FOCUS_AUTO</constant>.</para> + </listitem> + <listitem> + <para>The <constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> ioctls, which were superseded +by the <link linkend="extended-controls">extended controls</link> +interface in Linux 2.6.18, where finally removed from the +<filename>videodev2.h</filename> header file.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.26</title> + <orderedlist> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_Y16</constant> and +<constant>V4L2_PIX_FMT_SBGGR16</constant> were added.</para> + </listitem> + <listitem> + <para>Added user controls +<constant>V4L2_CID_CHROMA_AGC</constant> and +<constant>V4L2_CID_COLOR_KILLER</constant>.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.27</title> + <orderedlist> + <listitem> + <para>The &VIDIOC-S-HW-FREQ-SEEK; ioctl and the +<constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability were added.</para> + </listitem> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_YVYU</constant>, +<constant>V4L2_PIX_FMT_PCA501</constant>, +<constant>V4L2_PIX_FMT_PCA505</constant>, +<constant>V4L2_PIX_FMT_PCA508</constant>, +<constant>V4L2_PIX_FMT_PCA561</constant>, +<constant>V4L2_PIX_FMT_SGBRG8</constant>, +<constant>V4L2_PIX_FMT_PAC207</constant> and +<constant>V4L2_PIX_FMT_PJPG</constant> were added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.28</title> + <orderedlist> + <listitem> + <para>Added <constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant> and +<constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant> MPEG audio encodings.</para> + </listitem> + <listitem> + <para>Added <constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant> MPEG +video encoding.</para> + </listitem> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_SGRBG10</constant> and +<constant>V4L2_PIX_FMT_SGRBG10DPCM8</constant> were added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.29</title> + <orderedlist> + <listitem> + <para>The <constant>VIDIOC_G_CHIP_IDENT</constant> ioctl was renamed +to <constant>VIDIOC_G_CHIP_IDENT_OLD</constant> and &VIDIOC-DBG-G-CHIP-IDENT; +was introduced in its place. The old struct <structname>v4l2_chip_ident</structname> +was renamed to <structname id="v4l2-chip-ident-old">v4l2_chip_ident_old</structname>.</para> + </listitem> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_VYUY</constant>, +<constant>V4L2_PIX_FMT_NV16</constant> and +<constant>V4L2_PIX_FMT_NV61</constant> were added.</para> + </listitem> + <listitem> + <para>Added camera controls +<constant>V4L2_CID_ZOOM_ABSOLUTE</constant>, +<constant>V4L2_CID_ZOOM_RELATIVE</constant>, +<constant>V4L2_CID_ZOOM_CONTINUOUS</constant> and +<constant>V4L2_CID_PRIVACY</constant>.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.30</title> + <orderedlist> + <listitem> + <para>New control flag <constant>V4L2_CTRL_FLAG_WRITE_ONLY</constant> was added.</para> + </listitem> + <listitem> + <para>New control <constant>V4L2_CID_COLORFX</constant> was added.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.32</title> + <orderedlist> + <listitem> + <para>In order to be easier to compare a V4L2 API and a kernel +version, now V4L2 API is numbered using the Linux Kernel version numeration.</para> + </listitem> + <listitem> + <para>Finalized the RDS capture API. See <xref linkend="rds" /> for +more information.</para> + </listitem> + <listitem> + <para>Added new capabilities for modulators and RDS encoders.</para> + </listitem> + <listitem> + <para>Add description for libv4l API.</para> + </listitem> + <listitem> + <para>Added support for string controls via new type <constant>V4L2_CTRL_TYPE_STRING</constant>.</para> + </listitem> + <listitem> + <para>Added <constant>V4L2_CID_BAND_STOP_FILTER</constant> documentation.</para> + </listitem> + <listitem> + <para>Added FM Modulator (FM TX) Extended Control Class: <constant>V4L2_CTRL_CLASS_FM_TX</constant> and their Control IDs.</para> + </listitem> + <listitem> + <para>Added Remote Controller chapter, describing the default Remote Controller mapping for media devices.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.33</title> + <orderedlist> + <listitem> + <para>Added support for Digital Video timings in order to support HDTV receivers and transmitters.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.34</title> + <orderedlist> + <listitem> + <para>Added +<constant>V4L2_CID_IRIS_ABSOLUTE</constant> and +<constant>V4L2_CID_IRIS_RELATIVE</constant> controls to the + <link linkend="camera-controls">Camera controls class</link>. + </para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.37</title> + <orderedlist> + <listitem> + <para>Remove the vtx (videotext/teletext) API. This API was no longer +used and no hardware exists to verify the API. Nor were any userspace applications found +that used it. It was originally scheduled for removal in 2.6.35. + </para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.39</title> + <orderedlist> + <listitem> + <para>The old VIDIOC_*_OLD symbols and V4L1 support were removed.</para> + </listitem> + <listitem> + <para>Multi-planar API added. Does not affect the compatibility of + current drivers and applications. See + <link linkend="planar-apis">multi-planar API</link> + for details.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 3.1</title> + <orderedlist> + <listitem> + <para>VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one.</para> + <para>Standardize an error code for invalid ioctl.</para> + <para>Added V4L2_CTRL_TYPE_BITMASK.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 3.2</title> + <orderedlist> + <listitem> + <para>V4L2_CTRL_FLAG_VOLATILE was added to signal volatile controls to userspace.</para> + </listitem> + <listitem> + <para>Add selection API for extended control over cropping and +composing. Does not affect the compatibility of current drivers and +applications. See <link linkend="selection-api"> selection API </link> for +details.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 3.3</title> + <orderedlist> + <listitem> + <para>Added <constant>V4L2_CID_ALPHA_COMPONENT</constant> control + to the <link linkend="control">User controls class</link>. + </para> + </listitem> + <listitem> + <para>Added the device_caps field to struct v4l2_capabilities and added the new + V4L2_CAP_DEVICE_CAPS capability.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 3.4</title> + <orderedlist> + <listitem> + <para>Added <link linkend="jpeg-controls">JPEG compression control + class</link>.</para> + </listitem> + </orderedlist> + </section> + + <section id="other"> + <title>Relation of V4L2 to other Linux multimedia APIs</title> + + <section id="xvideo"> + <title>X Video Extension</title> + + <para>The X Video Extension (abbreviated XVideo or just Xv) is +an extension of the X Window system, implemented for example by the +XFree86 project. Its scope is similar to V4L2, an API to video capture +and output devices for X clients. Xv allows applications to display +live video in a window, send window contents to a TV output, and +capture or output still images in XPixmaps<footnote> + <para>This is not implemented in XFree86.</para> + </footnote>. With their implementation XFree86 makes the +extension available across many operating systems and +architectures.</para> + + <para>Because the driver is embedded into the X server Xv has a +number of advantages over the V4L2 <link linkend="overlay">video +overlay interface</link>. The driver can easily determine the overlay +target, &ie; visible graphics memory or off-screen buffers for a +destructive overlay. It can program the RAMDAC for a non-destructive +overlay, scaling or color-keying, or the clipping functions of the +video capture hardware, always in sync with drawing operations or +windows moving or changing their stacking order.</para> + + <para>To combine the advantages of Xv and V4L a special Xv +driver exists in XFree86 and XOrg, just programming any overlay capable +Video4Linux device it finds. To enable it +<filename>/etc/X11/XF86Config</filename> must contain these lines:</para> + <para><screen> +Section "Module" + Load "v4l" +EndSection</screen></para> + + <para>As of XFree86 4.2 this driver still supports only V4L +ioctls, however it should work just fine with all V4L2 devices through +the V4L2 backward-compatibility layer. Since V4L2 permits multiple +opens it is possible (if supported by the V4L2 driver) to capture +video while an X client requested video overlay. Restrictions of +simultaneous capturing and overlay are discussed in <xref + linkend="overlay" /> apply.</para> + + <para>Only marginally related to V4L2, XFree86 extended Xv to +support hardware YUV to RGB conversion and scaling for faster video +playback, and added an interface to MPEG-2 decoding hardware. This API +is useful to display images captured with V4L2 devices.</para> + </section> + + <section> + <title>Digital Video</title> + + <para>V4L2 does not support digital terrestrial, cable or +satellite broadcast. A separate project aiming at digital receivers +exists. You can find its homepage at <ulink +url="http://linuxtv.org">http://linuxtv.org</ulink>. The Linux DVB API +has no connection to the V4L2 API except that drivers for hybrid +hardware may support both.</para> + </section> + + <section> + <title>Audio Interfaces</title> + + <para>[to do - OSS/ALSA]</para> + </section> + </section> + + <section id="experimental"> + <title>Experimental API Elements</title> + + <para>The following V4L2 API elements are currently experimental +and may change in the future.</para> + + <itemizedlist> + <listitem> + <para>Video Output Overlay (OSD) Interface, <xref + linkend="osd" />.</para> + </listitem> + <listitem> + <para><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant>, + &v4l2-buf-type;, <xref linkend="v4l2-buf-type" />.</para> + </listitem> + <listitem> + <para><constant>V4L2_CAP_VIDEO_OUTPUT_OVERLAY</constant>, +&VIDIOC-QUERYCAP; ioctl, <xref linkend="device-capabilities" />.</para> + </listitem> + <listitem> + <para>&VIDIOC-ENUM-FRAMESIZES; and +&VIDIOC-ENUM-FRAMEINTERVALS; ioctls.</para> + </listitem> + <listitem> + <para>&VIDIOC-G-ENC-INDEX; ioctl.</para> + </listitem> + <listitem> + <para>&VIDIOC-ENCODER-CMD; and &VIDIOC-TRY-ENCODER-CMD; +ioctls.</para> + </listitem> + <listitem> + <para>&VIDIOC-DBG-G-REGISTER; and &VIDIOC-DBG-S-REGISTER; +ioctls.</para> + </listitem> + <listitem> + <para>&VIDIOC-DBG-G-CHIP-IDENT; ioctl.</para> + </listitem> + <listitem> + <para>Flash API. <xref linkend="flash-controls" /></para> + </listitem> + <listitem> + <para>&VIDIOC-CREATE-BUFS; and &VIDIOC-PREPARE-BUF; ioctls.</para> + </listitem> + <listitem> + <para>Selection API. <xref linkend="selection-api" /></para> + </listitem> + </itemizedlist> + </section> + + <section id="obsolete"> + <title>Obsolete API Elements</title> + + <para>The following V4L2 API elements were superseded by new +interfaces and should not be implemented in new drivers.</para> + + <itemizedlist> + <listitem> + <para><constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> ioctls. Use Extended Controls, +<xref linkend="extended-controls" />.</para> + </listitem> + </itemizedlist> + </section> + </section> diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml new file mode 100644 index 00000000..b84f25e9 --- /dev/null +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -0,0 +1,3602 @@ + <section id="control"> + <title>User Controls</title> + + <para>Devices typically have a number of user-settable controls +such as brightness, saturation and so on, which would be presented to +the user on a graphical user interface. But, different devices +will have different controls available, and furthermore, the range of +possible values, and the default value will vary from device to +device. The control ioctls provide the information and a mechanism to +create a nice user interface for these controls that will work +correctly with any device.</para> + + <para>All controls are accessed using an ID value. V4L2 defines +several IDs for specific purposes. Drivers can also implement their +own custom controls using <constant>V4L2_CID_PRIVATE_BASE</constant> +and higher values. The pre-defined control IDs have the prefix +<constant>V4L2_CID_</constant>, and are listed in <xref +linkend="control-id" />. The ID is used when querying the attributes of +a control, and when getting or setting the current value.</para> + + <para>Generally applications should present controls to the user +without assumptions about their purpose. Each control comes with a +name string the user is supposed to understand. When the purpose is +non-intuitive the driver writer should provide a user manual, a user +interface plug-in or a driver specific panel application. Predefined +IDs were introduced to change a few controls programmatically, for +example to mute a device during a channel switch.</para> + + <para>Drivers may enumerate different controls after switching +the current video input or output, tuner or modulator, or audio input +or output. Different in the sense of other bounds, another default and +current value, step size or other menu items. A control with a certain +<emphasis>custom</emphasis> ID can also change name and +type.<footnote> + <para>It will be more convenient for applications if drivers +make use of the <constant>V4L2_CTRL_FLAG_DISABLED</constant> flag, but +that was never required.</para> + </footnote> Control values are stored globally, they do not +change when switching except to stay within the reported bounds. They +also do not change ⪚ when the device is opened or closed, when the +tuner radio frequency is changed or generally never without +application request. Since V4L2 specifies no event mechanism, panel +applications intended to cooperate with other panel applications (be +they built into a larger application, as a TV viewer) may need to +regularly poll control values to update their user +interface.<footnote> + <para>Applications could call an ioctl to request events. +After another process called &VIDIOC-S-CTRL; or another ioctl changing +shared properties the &func-select; function would indicate +readability until any ioctl (querying the properties) is +called.</para> + </footnote></para> + + <para> + All controls use machine endianness. + </para> + + <table pgwide="1" frame="none" id="control-id"> + <title>Control IDs</title> + <tgroup cols="3"> + &cs-def; + <thead> + <row> + <entry>ID</entry> + <entry>Type</entry> + <entry>Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_CID_BASE</constant></entry> + <entry></entry> + <entry>First predefined ID, equal to +<constant>V4L2_CID_BRIGHTNESS</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_CID_USER_BASE</constant></entry> + <entry></entry> + <entry>Synonym of <constant>V4L2_CID_BASE</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry> + <entry>integer</entry> + <entry>Picture brightness, or more precisely, the black +level.</entry> + </row> + <row> + <entry><constant>V4L2_CID_CONTRAST</constant></entry> + <entry>integer</entry> + <entry>Picture contrast or luma gain.</entry> + </row> + <row> + <entry><constant>V4L2_CID_SATURATION</constant></entry> + <entry>integer</entry> + <entry>Picture color saturation or chroma gain.</entry> + </row> + <row> + <entry><constant>V4L2_CID_HUE</constant></entry> + <entry>integer</entry> + <entry>Hue or color balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry> + <entry>integer</entry> + <entry>Overall audio volume. Note some drivers also +provide an OSS or ALSA mixer interface.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry> + <entry>integer</entry> + <entry>Audio stereo balance. Minimum corresponds to all +the way left, maximum to right.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry> + <entry>integer</entry> + <entry>Audio bass adjustment.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry> + <entry>integer</entry> + <entry>Audio treble adjustment.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_MUTE</constant></entry> + <entry>boolean</entry> + <entry>Mute audio, &ie; set the volume to zero, however +without affecting <constant>V4L2_CID_AUDIO_VOLUME</constant>. Like +ALSA drivers, V4L2 drivers must mute at load time to avoid excessive +noise. Actually the entire device should be reset to a low power +consumption state.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_LOUDNESS</constant></entry> + <entry>boolean</entry> + <entry>Loudness mode (bass boost).</entry> + </row> + <row> + <entry><constant>V4L2_CID_BLACK_LEVEL</constant></entry> + <entry>integer</entry> + <entry>Another name for brightness (not a synonym of +<constant>V4L2_CID_BRIGHTNESS</constant>). This control is deprecated +and should not be used in new drivers and applications.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUTO_WHITE_BALANCE</constant></entry> + <entry>boolean</entry> + <entry>Automatic white balance (cameras).</entry> + </row> + <row> + <entry><constant>V4L2_CID_DO_WHITE_BALANCE</constant></entry> + <entry>button</entry> + <entry>This is an action control. When set (the value is +ignored), the device will do a white balance and then hold the current +setting. Contrast this with the boolean +<constant>V4L2_CID_AUTO_WHITE_BALANCE</constant>, which, when +activated, keeps adjusting the white balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_RED_BALANCE</constant></entry> + <entry>integer</entry> + <entry>Red chroma balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_BLUE_BALANCE</constant></entry> + <entry>integer</entry> + <entry>Blue chroma balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_GAMMA</constant></entry> + <entry>integer</entry> + <entry>Gamma adjust.</entry> + </row> + <row> + <entry><constant>V4L2_CID_WHITENESS</constant></entry> + <entry>integer</entry> + <entry>Whiteness for grey-scale devices. This is a synonym +for <constant>V4L2_CID_GAMMA</constant>. This control is deprecated +and should not be used in new drivers and applications.</entry> + </row> + <row> + <entry><constant>V4L2_CID_EXPOSURE</constant></entry> + <entry>integer</entry> + <entry>Exposure (cameras). [Unit?]</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUTOGAIN</constant></entry> + <entry>boolean</entry> + <entry>Automatic gain/exposure control.</entry> + </row> + <row> + <entry><constant>V4L2_CID_GAIN</constant></entry> + <entry>integer</entry> + <entry>Gain control.</entry> + </row> + <row> + <entry><constant>V4L2_CID_HFLIP</constant></entry> + <entry>boolean</entry> + <entry>Mirror the picture horizontally.</entry> + </row> + <row> + <entry><constant>V4L2_CID_VFLIP</constant></entry> + <entry>boolean</entry> + <entry>Mirror the picture vertically.</entry> + </row> + <row> + <entry><constant>V4L2_CID_HCENTER_DEPRECATED</constant> (formerly <constant>V4L2_CID_HCENTER</constant>)</entry> + <entry>integer</entry> + <entry>Horizontal image centering. This control is +deprecated. New drivers and applications should use the <link +linkend="camera-controls">Camera class controls</link> +<constant>V4L2_CID_PAN_ABSOLUTE</constant>, +<constant>V4L2_CID_PAN_RELATIVE</constant> and +<constant>V4L2_CID_PAN_RESET</constant> instead.</entry> + </row> + <row> + <entry><constant>V4L2_CID_VCENTER_DEPRECATED</constant> + (formerly <constant>V4L2_CID_VCENTER</constant>)</entry> + <entry>integer</entry> + <entry>Vertical image centering. Centering is intended to +<emphasis>physically</emphasis> adjust cameras. For image cropping see +<xref linkend="crop" />, for clipping <xref linkend="overlay" />. This +control is deprecated. New drivers and applications should use the +<link linkend="camera-controls">Camera class controls</link> +<constant>V4L2_CID_TILT_ABSOLUTE</constant>, +<constant>V4L2_CID_TILT_RELATIVE</constant> and +<constant>V4L2_CID_TILT_RESET</constant> instead.</entry> + </row> + <row id="v4l2-power-line-frequency"> + <entry><constant>V4L2_CID_POWER_LINE_FREQUENCY</constant></entry> + <entry>enum</entry> + <entry>Enables a power line frequency filter to avoid +flicker. Possible values for <constant>enum v4l2_power_line_frequency</constant> are: +<constant>V4L2_CID_POWER_LINE_FREQUENCY_DISABLED</constant> (0), +<constant>V4L2_CID_POWER_LINE_FREQUENCY_50HZ</constant> (1), +<constant>V4L2_CID_POWER_LINE_FREQUENCY_60HZ</constant> (2) and +<constant>V4L2_CID_POWER_LINE_FREQUENCY_AUTO</constant> (3).</entry> + </row> + <row> + <entry><constant>V4L2_CID_HUE_AUTO</constant></entry> + <entry>boolean</entry> + <entry>Enables automatic hue control by the device. The +effect of setting <constant>V4L2_CID_HUE</constant> while automatic +hue control is enabled is undefined, drivers should ignore such +request.</entry> + </row> + <row> + <entry><constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant></entry> + <entry>integer</entry> + <entry>This control specifies the white balance settings +as a color temperature in Kelvin. A driver should have a minimum of +2800 (incandescent) to 6500 (daylight). For more information about +color temperature see <ulink +url="http://en.wikipedia.org/wiki/Color_temperature">Wikipedia</ulink>.</entry> + </row> + <row> + <entry><constant>V4L2_CID_SHARPNESS</constant></entry> + <entry>integer</entry> + <entry>Adjusts the sharpness filters in a camera. The +minimum value disables the filters, higher values give a sharper +picture.</entry> + </row> + <row> + <entry><constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant></entry> + <entry>integer</entry> + <entry>Adjusts the backlight compensation in a camera. The +minimum value disables backlight compensation.</entry> + </row> + <row> + <entry><constant>V4L2_CID_CHROMA_AGC</constant></entry> + <entry>boolean</entry> + <entry>Chroma automatic gain control.</entry> + </row> + <row> + <entry><constant>V4L2_CID_CHROMA_GAIN</constant></entry> + <entry>integer</entry> + <entry>Adjusts the Chroma gain control (for use when chroma AGC + is disabled).</entry> + </row> + <row> + <entry><constant>V4L2_CID_COLOR_KILLER</constant></entry> + <entry>boolean</entry> + <entry>Enable the color killer (&ie; force a black & white image in case of a weak video signal).</entry> + </row> + <row id="v4l2-colorfx"> + <entry><constant>V4L2_CID_COLORFX</constant></entry> + <entry>enum</entry> + <entry>Selects a color effect. Possible values for +<constant>enum v4l2_colorfx</constant> are: +<constant>V4L2_COLORFX_NONE</constant> (0), +<constant>V4L2_COLORFX_BW</constant> (1), +<constant>V4L2_COLORFX_SEPIA</constant> (2), +<constant>V4L2_COLORFX_NEGATIVE</constant> (3), +<constant>V4L2_COLORFX_EMBOSS</constant> (4), +<constant>V4L2_COLORFX_SKETCH</constant> (5), +<constant>V4L2_COLORFX_SKY_BLUE</constant> (6), +<constant>V4L2_COLORFX_GRASS_GREEN</constant> (7), +<constant>V4L2_COLORFX_SKIN_WHITEN</constant> (8) and +<constant>V4L2_COLORFX_VIVID</constant> (9).</entry> + </row> + <row> + <entry><constant>V4L2_CID_ROTATE</constant></entry> + <entry>integer</entry> + <entry>Rotates the image by specified angle. Common angles are 90, + 270 and 180. Rotating the image to 90 and 270 will reverse the height + and width of the display window. It is necessary to set the new height and + width of the picture using the &VIDIOC-S-FMT; ioctl according to + the rotation angle selected.</entry> + </row> + <row> + <entry><constant>V4L2_CID_BG_COLOR</constant></entry> + <entry>integer</entry> + <entry>Sets the background color on the current output device. + Background color needs to be specified in the RGB24 format. The + supplied 32 bit value is interpreted as bits 0-7 Red color information, + bits 8-15 Green color information, bits 16-23 Blue color + information and bits 24-31 must be zero.</entry> + </row> + <row> + <entry><constant>V4L2_CID_ILLUMINATORS_1</constant> + <constant>V4L2_CID_ILLUMINATORS_2</constant></entry> + <entry>boolean</entry> + <entry>Switch on or off the illuminator 1 or 2 of the device + (usually a microscope).</entry> + </row> + <row> + <entry><constant>V4L2_CID_MIN_BUFFERS_FOR_CAPTURE</constant></entry> + <entry>integer</entry> + <entry>This is a read-only control that can be read by the application +and used as a hint to determine the number of CAPTURE buffers to pass to REQBUFS. +The value is the minimum number of CAPTURE buffers that is necessary for hardware +to work.</entry> + </row> + <row> + <entry><constant>V4L2_CID_MIN_BUFFERS_FOR_OUTPUT</constant></entry> + <entry>integer</entry> + <entry>This is a read-only control that can be read by the application +and used as a hint to determine the number of OUTPUT buffers to pass to REQBUFS. +The value is the minimum number of OUTPUT buffers that is necessary for hardware +to work.</entry> + </row> + <row id="v4l2-alpha-component"> + <entry><constant>V4L2_CID_ALPHA_COMPONENT</constant></entry> + <entry>integer</entry> + <entry> Sets the alpha color component on the capture device or on + the capture buffer queue of a mem-to-mem device. When a mem-to-mem + device produces frame format that includes an alpha component + (e.g. <link linkend="rgb-formats">packed RGB image formats</link>) + and the alpha value is not defined by the mem-to-mem input data + this control lets you select the alpha component value of all + pixels. It is applicable to any pixel format that contains an alpha + component. + </entry> + </row> + <row> + <entry><constant>V4L2_CID_LASTP1</constant></entry> + <entry></entry> + <entry>End of the predefined control IDs (currently + <constant>V4L2_CID_ALPHA_COMPONENT</constant> + 1).</entry> + </row> + <row> + <entry><constant>V4L2_CID_PRIVATE_BASE</constant></entry> + <entry></entry> + <entry>ID of the first custom (driver specific) control. +Applications depending on particular custom controls should check the +driver name and version, see <xref linkend="querycap" />.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Applications can enumerate the available controls with the +&VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls, get and set a +control value with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls. +Drivers must implement <constant>VIDIOC_QUERYCTRL</constant>, +<constant>VIDIOC_G_CTRL</constant> and +<constant>VIDIOC_S_CTRL</constant> when the device has one or more +controls, <constant>VIDIOC_QUERYMENU</constant> when it has one or +more menu type controls.</para> + + <example> + <title>Enumerating all controls</title> + + <programlisting> +&v4l2-queryctrl; queryctrl; +&v4l2-querymenu; querymenu; + +static void +enumerate_menu (void) +{ + printf (" Menu items:\n"); + + memset (&querymenu, 0, sizeof (querymenu)); + querymenu.id = queryctrl.id; + + for (querymenu.index = queryctrl.minimum; + querymenu.index <= queryctrl.maximum; + querymenu.index++) { + if (0 == ioctl (fd, &VIDIOC-QUERYMENU;, &querymenu)) { + printf (" %s\n", querymenu.name); + } + } +} + +memset (&queryctrl, 0, sizeof (queryctrl)); + +for (queryctrl.id = V4L2_CID_BASE; + queryctrl.id < V4L2_CID_LASTP1; + queryctrl.id++) { + if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) + continue; + + printf ("Control %s\n", queryctrl.name); + + if (queryctrl.type == V4L2_CTRL_TYPE_MENU) + enumerate_menu (); + } else { + if (errno == EINVAL) + continue; + + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } +} + +for (queryctrl.id = V4L2_CID_PRIVATE_BASE;; + queryctrl.id++) { + if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) + continue; + + printf ("Control %s\n", queryctrl.name); + + if (queryctrl.type == V4L2_CTRL_TYPE_MENU) + enumerate_menu (); + } else { + if (errno == EINVAL) + break; + + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } +} +</programlisting> + </example> + + <example> + <title>Changing controls</title> + + <programlisting> +&v4l2-queryctrl; queryctrl; +&v4l2-control; control; + +memset (&queryctrl, 0, sizeof (queryctrl)); +queryctrl.id = V4L2_CID_BRIGHTNESS; + +if (-1 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (errno != EINVAL) { + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } else { + printf ("V4L2_CID_BRIGHTNESS is not supported\n"); + } +} else if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) { + printf ("V4L2_CID_BRIGHTNESS is not supported\n"); +} else { + memset (&control, 0, sizeof (control)); + control.id = V4L2_CID_BRIGHTNESS; + control.value = queryctrl.default_value; + + if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &control)) { + perror ("VIDIOC_S_CTRL"); + exit (EXIT_FAILURE); + } +} + +memset (&control, 0, sizeof (control)); +control.id = V4L2_CID_CONTRAST; + +if (0 == ioctl (fd, &VIDIOC-G-CTRL;, &control)) { + control.value += 1; + + /* The driver may clamp the value or return ERANGE, ignored here */ + + if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &control) + && errno != ERANGE) { + perror ("VIDIOC_S_CTRL"); + exit (EXIT_FAILURE); + } +/* Ignore if V4L2_CID_CONTRAST is unsupported */ +} else if (errno != EINVAL) { + perror ("VIDIOC_G_CTRL"); + exit (EXIT_FAILURE); +} + +control.id = V4L2_CID_AUDIO_MUTE; +control.value = TRUE; /* silence */ + +/* Errors ignored */ +ioctl (fd, VIDIOC_S_CTRL, &control); +</programlisting> + </example> + </section> + + <section id="extended-controls"> + <title>Extended Controls</title> + + <section> + <title>Introduction</title> + + <para>The control mechanism as originally designed was meant +to be used for user settings (brightness, saturation, etc). However, +it turned out to be a very useful model for implementing more +complicated driver APIs where each driver implements only a subset of +a larger API.</para> + + <para>The MPEG encoding API was the driving force behind +designing and implementing this extended control mechanism: the MPEG +standard is quite large and the currently supported hardware MPEG +encoders each only implement a subset of this standard. Further more, +many parameters relating to how the video is encoded into an MPEG +stream are specific to the MPEG encoding chip since the MPEG standard +only defines the format of the resulting MPEG stream, not how the +video is actually encoded into that format.</para> + + <para>Unfortunately, the original control API lacked some +features needed for these new uses and so it was extended into the +(not terribly originally named) extended control API.</para> + + <para>Even though the MPEG encoding API was the first effort +to use the Extended Control API, nowadays there are also other classes +of Extended Controls, such as Camera Controls and FM Transmitter Controls. +The Extended Controls API as well as all Extended Controls classes are +described in the following text.</para> + </section> + + <section> + <title>The Extended Control API</title> + + <para>Three new ioctls are available: &VIDIOC-G-EXT-CTRLS;, +&VIDIOC-S-EXT-CTRLS; and &VIDIOC-TRY-EXT-CTRLS;. These ioctls act on +arrays of controls (as opposed to the &VIDIOC-G-CTRL; and +&VIDIOC-S-CTRL; ioctls that act on a single control). This is needed +since it is often required to atomically change several controls at +once.</para> + + <para>Each of the new ioctls expects a pointer to a +&v4l2-ext-controls;. This structure contains a pointer to the control +array, a count of the number of controls in that array and a control +class. Control classes are used to group similar controls into a +single class. For example, control class +<constant>V4L2_CTRL_CLASS_USER</constant> contains all user controls +(&ie; all controls that can also be set using the old +<constant>VIDIOC_S_CTRL</constant> ioctl). Control class +<constant>V4L2_CTRL_CLASS_MPEG</constant> contains all controls +relating to MPEG encoding, etc.</para> + + <para>All controls in the control array must belong to the +specified control class. An error is returned if this is not the +case.</para> + + <para>It is also possible to use an empty control array (count +== 0) to check whether the specified control class is +supported.</para> + + <para>The control array is a &v4l2-ext-control; array. The +<structname>v4l2_ext_control</structname> structure is very similar to +&v4l2-control;, except for the fact that it also allows for 64-bit +values and pointers to be passed.</para> + + <para>It is important to realize that due to the flexibility of +controls it is necessary to check whether the control you want to set +actually is supported in the driver and what the valid range of values +is. So use the &VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls to +check this. Also note that it is possible that some of the menu +indices in a control of type <constant>V4L2_CTRL_TYPE_MENU</constant> +may not be supported (<constant>VIDIOC_QUERYMENU</constant> will +return an error). A good example is the list of supported MPEG audio +bitrates. Some drivers only support one or two bitrates, others +support a wider range.</para> + + <para> + All controls use machine endianness. + </para> + </section> + + <section> + <title>Enumerating Extended Controls</title> + + <para>The recommended way to enumerate over the extended +controls is by using &VIDIOC-QUERYCTRL; in combination with the +<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag:</para> + + <informalexample> + <programlisting> +&v4l2-queryctrl; qctrl; + +qctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL; +while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &qctrl)) { + /* ... */ + qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL; +} +</programlisting> + </informalexample> + + <para>The initial control ID is set to 0 ORed with the +<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag. The +<constant>VIDIOC_QUERYCTRL</constant> ioctl will return the first +control with a higher ID than the specified one. When no such controls +are found an error is returned.</para> + + <para>If you want to get all controls within a specific control +class, then you can set the initial +<structfield>qctrl.id</structfield> value to the control class and add +an extra check to break out of the loop when a control of another +control class is found:</para> + + <informalexample> + <programlisting> +qctrl.id = V4L2_CTRL_CLASS_MPEG | V4L2_CTRL_FLAG_NEXT_CTRL; +while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &qctrl)) { + if (V4L2_CTRL_ID2CLASS (qctrl.id) != V4L2_CTRL_CLASS_MPEG) + break; + /* ... */ + qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL; + } +</programlisting> + </informalexample> + + <para>The 32-bit <structfield>qctrl.id</structfield> value is +subdivided into three bit ranges: the top 4 bits are reserved for +flags (⪚ <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>) and are not +actually part of the ID. The remaining 28 bits form the control ID, of +which the most significant 12 bits define the control class and the +least significant 16 bits identify the control within the control +class. It is guaranteed that these last 16 bits are always non-zero +for controls. The range of 0x1000 and up are reserved for +driver-specific controls. The macro +<constant>V4L2_CTRL_ID2CLASS(id)</constant> returns the control class +ID based on a control ID.</para> + + <para>If the driver does not support extended controls, then +<constant>VIDIOC_QUERYCTRL</constant> will fail when used in +combination with <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>. In +that case the old method of enumerating control should be used (see +1.8). But if it is supported, then it is guaranteed to enumerate over +all controls, including driver-private controls.</para> + </section> + + <section> + <title>Creating Control Panels</title> + + <para>It is possible to create control panels for a graphical +user interface where the user can select the various controls. +Basically you will have to iterate over all controls using the method +described above. Each control class starts with a control of type +<constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant>. +<constant>VIDIOC_QUERYCTRL</constant> will return the name of this +control class which can be used as the title of a tab page within a +control panel.</para> + + <para>The flags field of &v4l2-queryctrl; also contains hints on +the behavior of the control. See the &VIDIOC-QUERYCTRL; documentation +for more details.</para> + </section> + + <section id="mpeg-controls"> + <title>MPEG Control Reference</title> + + <para>Below all controls within the MPEG control class are +described. First the generic controls, then controls specific for +certain hardware.</para> + + <section> + <title>Generic MPEG Controls</title> + + <table pgwide="1" frame="none" id="mpeg-control-id"> + <title>MPEG Control IDs</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CLASS</constant> </entry> + <entry>class</entry> + </row><row><entry spanname="descr">The MPEG class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class. This description can be used as the +caption of a Tab page in a GUI, for example.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-stream-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_stream_type</entry> + </row><row><entry spanname="descr">The MPEG-1, -2 or -4 +output stream type. One cannot assume anything here. Each hardware +MPEG encoder tends to support different subsets of the available MPEG +stream types. This control is specific to multiplexed MPEG streams. +The currently defined stream types are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_PS</constant> </entry> + <entry>MPEG-2 program stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_TS</constant> </entry> + <entry>MPEG-2 transport stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_SS</constant> </entry> + <entry>MPEG-1 system stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_DVD</constant> </entry> + <entry>MPEG-2 DVD-compatible stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_VCD</constant> </entry> + <entry>MPEG-1 VCD-compatible stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD</constant> </entry> + <entry>MPEG-2 SVCD-compatible stream</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PMT</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Program Map Table +Packet ID for the MPEG transport stream (default 16)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_AUDIO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Audio Packet ID for +the MPEG transport stream (default 256)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_VIDEO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Video Packet ID for +the MPEG transport stream (default 260)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PCR</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Packet ID for the +MPEG transport stream carrying PCR fields (default 259)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_AUDIO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Audio ID for MPEG +PES</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_VIDEO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Video ID for MPEG +PES</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-stream-vbi-fmt"> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_VBI_FMT</constant> </entry> + <entry>enum v4l2_mpeg_stream_vbi_fmt</entry> + </row><row><entry spanname="descr">Some cards can embed +VBI data (⪚ Closed Caption, Teletext) into the MPEG stream. This +control selects whether VBI data should be embedded, and if so, what +embedding method should be used. The list of possible VBI formats +depends on the driver. The currently defined VBI format types +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_NONE</constant> </entry> + <entry>No VBI in the MPEG stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant> </entry> + <entry>VBI in private packets, IVTV format (documented +in the kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.vbi</filename>)</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-sampling-freq"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ</constant> </entry> + <entry>enum v4l2_mpeg_audio_sampling_freq</entry> + </row><row><entry spanname="descr">MPEG Audio sampling +frequency. Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_44100</constant> </entry> + <entry>44.1 kHz</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000</constant> </entry> + <entry>48 kHz</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_32000</constant> </entry> + <entry>32 kHz</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-encoding"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_ENCODING</constant> </entry> + <entry>enum v4l2_mpeg_audio_encoding</entry> + </row><row><entry spanname="descr">MPEG Audio encoding. +This control is specific to multiplexed MPEG streams. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_1</constant> </entry> + <entry>MPEG-1/2 Layer I encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_2</constant> </entry> + <entry>MPEG-1/2 Layer II encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_3</constant> </entry> + <entry>MPEG-1/2 Layer III encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant> </entry> + <entry>MPEG-2/4 AAC (Advanced Audio Coding)</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant> </entry> + <entry>AC-3 aka ATSC A/52 encoding</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-l1-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L1_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_l1_bitrate</entry> + </row><row><entry spanname="descr">MPEG-1/2 Layer I bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry></row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_288K</constant> </entry> + <entry>288 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_352K</constant> </entry> + <entry>352 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_384K</constant> </entry> + <entry>384 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_416K</constant> </entry> + <entry>416 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_448K</constant> </entry> + <entry>448 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-l2-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L2_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_l2_bitrate</entry> + </row><row><entry spanname="descr">MPEG-1/2 Layer II bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_48K</constant> </entry> + <entry>48 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_56K</constant> </entry> + <entry>56 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_80K</constant> </entry> + <entry>80 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_112K</constant> </entry> + <entry>112 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_384K</constant> </entry> + <entry>384 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-l3-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L3_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_l3_bitrate</entry> + </row><row><entry spanname="descr">MPEG-1/2 Layer III bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_40K</constant> </entry> + <entry>40 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_48K</constant> </entry> + <entry>48 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_56K</constant> </entry> + <entry>56 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_80K</constant> </entry> + <entry>80 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_112K</constant> </entry> + <entry>112 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AAC_BITRATE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">AAC bitrate in bits per second.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-ac3-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AC3_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_ac3_bitrate</entry> + </row><row><entry spanname="descr">AC-3 bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_40K</constant> </entry> + <entry>40 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_48K</constant> </entry> + <entry>48 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_56K</constant> </entry> + <entry>56 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_80K</constant> </entry> + <entry>80 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_112K</constant> </entry> + <entry>112 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_384K</constant> </entry> + <entry>384 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_448K</constant> </entry> + <entry>448 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_512K</constant> </entry> + <entry>512 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_576K</constant> </entry> + <entry>576 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_640K</constant> </entry> + <entry>640 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE</constant> </entry> + <entry>enum v4l2_mpeg_audio_mode</entry> + </row><row><entry spanname="descr">MPEG Audio mode. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_STEREO</constant> </entry> + <entry>Stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_JOINT_STEREO</constant> </entry> + <entry>Joint Stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_DUAL</constant> </entry> + <entry>Bilingual</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_MONO</constant> </entry> + <entry>Mono</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-mode-extension"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE_EXTENSION</constant> </entry> + <entry>enum v4l2_mpeg_audio_mode_extension</entry> + </row><row><entry spanname="descr">Joint Stereo +audio mode extension. In Layer I and II they indicate which subbands +are in intensity stereo. All other subbands are coded in stereo. Layer +III is not (yet) supported. Possible values +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_4</constant> </entry> + <entry>Subbands 4-31 in intensity stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_8</constant> </entry> + <entry>Subbands 8-31 in intensity stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_12</constant> </entry> + <entry>Subbands 12-31 in intensity stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_16</constant> </entry> + <entry>Subbands 16-31 in intensity stereo</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-emphasis"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_EMPHASIS</constant> </entry> + <entry>enum v4l2_mpeg_audio_emphasis</entry> + </row><row><entry spanname="descr">Audio Emphasis. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_NONE</constant> </entry> + <entry>None</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_50_DIV_15_uS</constant> </entry> + <entry>50/15 microsecond emphasis</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_CCITT_J17</constant> </entry> + <entry>CCITT J.17</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-crc"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_CRC</constant> </entry> + <entry>enum v4l2_mpeg_audio_crc</entry> + </row><row><entry spanname="descr">CRC method. Possible +values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_CRC_NONE</constant> </entry> + <entry>None</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_CRC_CRC16</constant> </entry> + <entry>16 bit parity check</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MUTE</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Mutes the audio when +capturing. This is not done by muting audio hardware, which can still +produce a slight hiss, but in the encoder itself, guaranteeing a fixed +and reproducible audio bitstream. 0 = unmuted, 1 = muted.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-dec-playback"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_DEC_PLAYBACK</constant> </entry> + <entry>enum v4l2_mpeg_audio_dec_playback</entry> + </row><row><entry spanname="descr">Determines how monolingual audio should be played back. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_AUTO</constant> </entry> + <entry>Automatically determines the best playback mode.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_STEREO</constant> </entry> + <entry>Stereo playback.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_LEFT</constant> </entry> + <entry>Left channel playback.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_RIGHT</constant> </entry> + <entry>Right channel playback.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_MONO</constant> </entry> + <entry>Mono playback.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_DEC_PLAYBACK_SWAPPED_STEREO</constant> </entry> + <entry>Stereo playback with swapped left and right channels.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-dec-multilingual-playback"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_DEC_MULTILINGUAL_PLAYBACK</constant> </entry> + <entry>enum v4l2_mpeg_audio_dec_playback</entry> + </row><row><entry spanname="descr">Determines how multilingual audio should be played back.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-encoding"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ENCODING</constant> </entry> + <entry>enum v4l2_mpeg_video_encoding</entry> + </row><row><entry spanname="descr">MPEG Video encoding +method. This control is specific to multiplexed MPEG streams. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_1</constant> </entry> + <entry>MPEG-1 Video encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_2</constant> </entry> + <entry>MPEG-2 Video encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant> </entry> + <entry>MPEG-4 AVC (H.264) Video encoding</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-aspect"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ASPECT</constant> </entry> + <entry>enum v4l2_mpeg_video_aspect</entry> + </row><row><entry spanname="descr">Video aspect. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_1x1</constant> </entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_4x3</constant> </entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_16x9</constant> </entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_221x100</constant> </entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_B_FRAMES</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Number of B-Frames +(default 2)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_SIZE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">GOP size (default +12)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_CLOSURE</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">GOP closure (default +1)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_PULLDOWN</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Enable 3:2 pulldown +(default 0)</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-bitrate-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_MODE</constant> </entry> + <entry>enum v4l2_mpeg_video_bitrate_mode</entry> + </row><row><entry spanname="descr">Video bitrate mode. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_VBR</constant> </entry> + <entry>Variable bitrate</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_CBR</constant> </entry> + <entry>Constant bitrate</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Video bitrate in bits +per second.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_PEAK</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Peak video bitrate in +bits per second. Must be larger or equal to the average video bitrate. +It is ignored if the video bitrate mode is set to constant +bitrate.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">For every captured +frame, skip this many subsequent frames (default 0).</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">"Mutes" the video to a +fixed color when capturing. This is useful for testing, to produce a +fixed video bitstream. 0 = unmuted, 1 = muted.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE_YUV</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Sets the "mute" color +of the video. The supplied 32-bit integer is interpreted as follows (bit +0 = least significant bit):</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry>Bit 0:7</entry> + <entry>V chrominance information</entry> + </row> + <row> + <entry>Bit 8:15</entry> + <entry>U chrominance information</entry> + </row> + <row> + <entry>Bit 16:23</entry> + <entry>Y luminance information</entry> + </row> + <row> + <entry>Bit 24:31</entry> + <entry>Must be zero.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-dec-pts"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DEC_PTS</constant> </entry> + <entry>integer64</entry> + </row><row><entry spanname="descr">This read-only control returns the +33-bit video Presentation Time Stamp as defined in ITU T-REC-H.222.0 and ISO/IEC 13818-1 of +the currently displayed frame. This is the same PTS as is used in &VIDIOC-DECODER-CMD;.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-dec-frame"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DEC_FRAME</constant> </entry> + <entry>integer64</entry> + </row><row><entry spanname="descr">This read-only control returns the +frame counter of the frame that is currently displayed (decoded). This value is reset to 0 whenever +the decoder is started.</entry> + </row> + + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">If enabled the decoder expects to receive a single slice per buffer, otherwise +the decoder expects a single frame in per buffer. Applicable to the decoder, all codecs. +</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_ENABLE</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enable writing sample aspect ratio in the Video Usability Information. +Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-h264-vui-sar-idc"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC</constant> </entry> + <entry>enum v4l2_mpeg_video_h264_vui_sar_idc</entry> + </row> + <row><entry spanname="descr">VUI sample aspect ratio indicator for H.264 encoding. The value +is defined in the table E-1 in the standard. Applicable to the H264 encoder.</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_UNSPECIFIED</constant> </entry> + <entry>Unspecified</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_1x1</constant> </entry> + <entry>1x1</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_12x11</constant> </entry> + <entry>12x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_10x11</constant> </entry> + <entry>10x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_16x11</constant> </entry> + <entry>16x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_40x33</constant> </entry> + <entry>40x33</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_24x11</constant> </entry> + <entry>24x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_20x11</constant> </entry> + <entry>20x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_32x11</constant> </entry> + <entry>32x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_80x33</constant> </entry> + <entry>80x33</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_18x11</constant> </entry> + <entry>18x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_15x11</constant> </entry> + <entry>15x11</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_64x33</constant> </entry> + <entry>64x33</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_160x99</constant> </entry> + <entry>160x99</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_4x3</constant> </entry> + <entry>4x3</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_3x2</constant> </entry> + <entry>3x2</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_2x1</constant> </entry> + <entry>2x1</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_VUI_SAR_IDC_EXTENDED</constant> </entry> + <entry>Extended SAR</entry> + </row> + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_EXT_SAR_WIDTH</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Extended sample aspect ratio width for H.264 VUI encoding. +Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_EXT_SAR_HEIGHT</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Extended sample aspect ratio height for H.264 VUI encoding. +Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-h264-level"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LEVEL</constant> </entry> + <entry>enum v4l2_mpeg_video_h264_level</entry> + </row> + <row><entry spanname="descr">The level information for the H264 video elementary stream. +Applicable to the H264 encoder. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_0</constant> </entry> + <entry>Level 1.0</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1B</constant> </entry> + <entry>Level 1B</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_1</constant> </entry> + <entry>Level 1.1</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_2</constant> </entry> + <entry>Level 1.2</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_1_3</constant> </entry> + <entry>Level 1.3</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_2_0</constant> </entry> + <entry>Level 2.0</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_2_1</constant> </entry> + <entry>Level 2.1</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_2_2</constant> </entry> + <entry>Level 2.2</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_3_0</constant> </entry> + <entry>Level 3.0</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_3_1</constant> </entry> + <entry>Level 3.1</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_3_2</constant> </entry> + <entry>Level 3.2</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_4_0</constant> </entry> + <entry>Level 4.0</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_4_1</constant> </entry> + <entry>Level 4.1</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_4_2</constant> </entry> + <entry>Level 4.2</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_5_0</constant> </entry> + <entry>Level 5.0</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LEVEL_5_1</constant> </entry> + <entry>Level 5.1</entry> + </row> + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-mpeg4-level"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL</constant> </entry> + <entry>enum v4l2_mpeg_video_mpeg4_level</entry> + </row> + <row><entry spanname="descr">The level information for the MPEG4 elementary stream. +Applicable to the MPEG4 encoder. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_0</constant> </entry> + <entry>Level 0</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_0B</constant> </entry> + <entry>Level 0b</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_1</constant> </entry> + <entry>Level 1</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_2</constant> </entry> + <entry>Level 2</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_3</constant> </entry> + <entry>Level 3</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_3B</constant> </entry> + <entry>Level 3b</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_4</constant> </entry> + <entry>Level 4</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_LEVEL_5</constant> </entry> + <entry>Level 5</entry> + </row> + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-h264-profile"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_PROFILE</constant> </entry> + <entry>enum v4l2_mpeg_video_h264_profile</entry> + </row> + <row><entry spanname="descr">The profile information for H264. +Applicable to the H264 encoder. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_BASELINE</constant> </entry> + <entry>Baseline profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_CONSTRAINED_BASELINE</constant> </entry> + <entry>Constrained Baseline profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_MAIN</constant> </entry> + <entry>Main profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_EXTENDED</constant> </entry> + <entry>Extended profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH</constant> </entry> + <entry>High profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_10</constant> </entry> + <entry>High 10 profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_422</constant> </entry> + <entry>High 422 profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_444_PREDICTIVE</constant> </entry> + <entry>High 444 Predictive profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_10_INTRA</constant> </entry> + <entry>High 10 Intra profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_422_INTRA</constant> </entry> + <entry>High 422 Intra profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_HIGH_444_INTRA</constant> </entry> + <entry>High 444 Intra profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_CAVLC_444_INTRA</constant> </entry> + <entry>CAVLC 444 Intra profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_BASELINE</constant> </entry> + <entry>Scalable Baseline profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_HIGH</constant> </entry> + <entry>Scalable High profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_SCALABLE_HIGH_INTRA</constant> </entry> + <entry>Scalable High Intra profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_STEREO_HIGH</constant> </entry> + <entry>Stereo High profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_PROFILE_MULTIVIEW_HIGH</constant> </entry> + <entry>Multiview High profile</entry> + </row> + + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-mpeg4-profile"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_PROFILE</constant> </entry> + <entry>enum v4l2_mpeg_video_mpeg4_profile</entry> + </row> + <row><entry spanname="descr">The profile information for MPEG4. +Applicable to the MPEG4 encoder. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_PROFILE_SIMPLE</constant> </entry> + <entry>Simple profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_PROFILE_ADVANCED_SIMPLE</constant> </entry> + <entry>Advanced Simple profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_PROFILE_CORE</constant> </entry> + <entry>Core profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_PROFILE_SIMPLE_SCALABLE</constant> </entry> + <entry>Simple Scalable profile</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_PROFILE_ADVANCED_CODING_EFFICIENCY</constant> </entry> + <entry></entry> + </row> + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MAX_REF_PIC</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">The maximum number of reference pictures used for encoding. +Applicable to the encoder. +</entry> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-multi-slice-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant> </entry> + <entry>enum v4l2_mpeg_video_multi_slice_mode</entry> + </row> + <row><entry spanname="descr">Determines how the encoder should handle division of frame into slices. +Applicable to the encoder. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_SINGLE</constant> </entry> + <entry>Single slice per frame.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB</constant> </entry> + <entry>Multiple slices with set maximum number of macroblocks per slice.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_BYTES</constant> </entry> + <entry>Multiple slice with set maximum size in bytes per slice.</entry> + </row> + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_MB</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">The maximum number of macroblocks in a slice. Used when +<constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant> is set to <constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB</constant>. +Applicable to the encoder.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_BYTES</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">The maximum size of a slice in bytes. Used when +<constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant> is set to <constant>V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_BYTES</constant>. +Applicable to the encoder.</entry> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-h264-loop-filter-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_MODE</constant> </entry> + <entry>enum v4l2_mpeg_video_h264_loop_filter_mode</entry> + </row> + <row><entry spanname="descr">Loop filter mode for H264 encoder. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_ENABLED</constant> </entry> + <entry>Loop filter is enabled.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_DISABLED</constant> </entry> + <entry>Loop filter is disabled.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_LOOP_FILTER_MODE_DISABLED_AT_SLICE_BOUNDARY</constant> </entry> + <entry>Loop filter is disabled at the slice boundary.</entry> + </row> + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_ALPHA</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Loop filter alpha coefficient, defined in the H264 standard. +Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_BETA</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Loop filter beta coefficient, defined in the H264 standard. +Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-h264-entropy-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_ENTROPY_MODE</constant> </entry> + <entry>enum v4l2_mpeg_video_h264_entropy_mode</entry> + </row> + <row><entry spanname="descr">Entropy coding mode for H264 - CABAC/CAVALC. +Applicable to the H264 encoder. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_ENTROPY_MODE_CAVLC</constant> </entry> + <entry>Use CAVLC entropy coding.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_H264_ENTROPY_MODE_CABAC</constant> </entry> + <entry>Use CABAC entropy coding.</entry> + </row> + </tbody> + </entrytbl> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_8X8_TRANSFORM</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enable 8X8 transform for H264. Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_CYCLIC_INTRA_REFRESH_MB</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Cyclic intra macroblock refresh. This is the number of continuous macroblocks +refreshed every frame. Each frame a succesive set of macroblocks is refreshed until the cycle completes and starts from the +top of the frame. Applicable to H264, H263 and MPEG4 encoder.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Frame level rate control enable. +If this control is disabled then the quantization parameter for each frame type is constant and set with appropriate controls +(e.g. <constant>V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP</constant>). +If frame rate control is enabled then quantization parameter is adjusted to meet the chosen bitrate. Minimum and maximum value +for the quantization parameter can be set with appropriate controls (e.g. <constant>V4L2_CID_MPEG_VIDEO_H263_MIN_QP</constant>). +Applicable to encoders.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Macroblock level rate control enable. +Applicable to the MPEG4 and H264 encoders.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_QPEL</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Quarter pixel motion estimation for MPEG4. Applicable to the MPEG4 encoder.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an I frame for H263. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_MIN_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Minimum quantization parameter for H263. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_MAX_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Maximum quantization parameter for H263. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_P_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an P frame for H263. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_B_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an B frame for H263. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_I_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an I frame for H264. Valid range: from 0 to 51.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_MIN_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Minimum quantization parameter for H264. Valid range: from 0 to 51.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_MAX_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Maximum quantization parameter for H264. Valid range: from 0 to 51.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_P_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an P frame for H264. Valid range: from 0 to 51.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_B_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an B frame for H264. Valid range: from 0 to 51.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an I frame for MPEG4. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_MIN_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Minimum quantization parameter for MPEG4. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_MAX_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Maximum quantization parameter for MPEG4. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_P_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an P frame for MPEG4. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_B_FRAME_QP</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Quantization parameter for an B frame for MPEG4. Valid range: from 1 to 31.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_VBV_SIZE</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">The Video Buffer Verifier size in kilobytes, it is used as a limitation of frame skip. +The VBV is defined in the standard as a mean to verify that the produced stream will be succesfully decoded. +The standard describes it as "Part of a hypothetical decoder that is conceptually connected to the +output of the encoder. Its purpose is to provide a constraint on the variability of the data rate that an +encoder or editing process may produce.". +Applicable to the MPEG1, MPEG2, MPEG4 encoders.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_CPB_SIZE</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">The Coded Picture Buffer size in kilobytes, it is used as a limitation of frame skip. +The CPB is defined in the H264 standard as a mean to verify that the produced stream will be succesfully decoded. +Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_I_PERIOD</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Period between I-frames in the open GOP for H264. In case of an open GOP +this is the period between two I-frames. The period between IDR (Instantaneous Decoding Refresh) frames is taken from the GOP_SIZE control. +An IDR frame, which stands for Instantaneous Decoding Refresh is an I-frame after which no prior frames are +referenced. This means that a stream can be restarted from an IDR frame without the need to store or decode any +previous frames. Applicable to the H264 encoder.</entry> + </row> + + <row><entry></entry></row> + <row id="v4l2-mpeg-video-header-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_HEADER_MODE</constant> </entry> + <entry>enum v4l2_mpeg_video_header_mode</entry> + </row> + <row><entry spanname="descr">Determines whether the header is returned as the first buffer or is +it returned together with the first frame. Applicable to encoders. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE</constant> </entry> + <entry>The stream header is returned separately in the first buffer.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME</constant> </entry> + <entry>The stream header is returned together with the first encoded frame.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DECODER_MPEG4_DEBLOCK_FILTER</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Enabled the deblocking post processing filter for MPEG4 decoder. +Applicable to the MPEG4 decoder.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_RES</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">vop_time_increment_resolution value for MPEG4. Applicable to the MPEG4 encoder.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_INC</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">vop_time_increment value for MPEG4. Applicable to the MPEG4 encoder.</entry> + </row> + + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>MFC 5.1 MPEG Controls</title> + + <para>The following MPEG class controls deal with MPEG +decoding and encoding settings that are specific to the Multi Format Codec 5.1 device present +in the S5P family of SoCs by Samsung. +</para> + + <table pgwide="1" frame="none" id="mfc51-control-id"> + <title>MFC 5.1 Control IDs</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY_ENABLE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">If the display delay is enabled then the decoder has to return a +CAPTURE buffer after processing a certain number of OUTPUT buffers. If this number is low, then it may result in +buffers not being dequeued in display order. In addition hardware may still use those buffers as reference, thus +application should not write to those buffers. This feature can be used for example for generating thumbnails of videos. +Applicable to the H264 decoder. + </entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Display delay value for H264 decoder. +The decoder is forced to return a decoded frame after the set 'display delay' number of frames. If this number is +low it may result in frames returned out of dispaly order, in addition the hardware may still be using the returned buffer +as a reference picture for subsequent frames. +</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">The number of reference pictures used for encoding a P picture. +Applicable to the H264 encoder.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_PADDING</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Padding enable in the encoder - use a color instead of repeating border pixels. +Applicable to encoders.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_PADDING_YUV</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Padding color in the encoder. Applicable to encoders. The supplied 32-bit integer is interpreted as follows (bit +0 = least significant bit):</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry>Bit 0:7</entry> + <entry>V chrominance information</entry> + </row> + <row> + <entry>Bit 8:15</entry> + <entry>U chrominance information</entry> + </row> + <row> + <entry>Bit 16:23</entry> + <entry>Y luminance information</entry> + </row> + <row> + <entry>Bit 24:31</entry> + <entry>Must be zero.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_RC_REACTION_COEFF</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Reaction coefficient for MFC rate control. Applicable to encoders. +<para>Note 1: Valid only when the frame level RC is enabled.</para> +<para>Note 2: For tight CBR, this field must be small (ex. 2 ~ 10). +For VBR, this field must be large (ex. 100 ~ 1000).</para> +<para>Note 3: It is not recommended to use the greater number than FRAME_RATE * (10^9 / BIT_RATE).</para> +</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_DARK</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Adaptive rate control for dark region. +Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>). +Applicable to the H264 encoder.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_SMOOTH</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Adaptive rate control for smooth region. +Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>). +Applicable to the H264 encoder.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Adaptive rate control for static region. +Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>). +Applicable to the H264 encoder.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_ACTIVITY</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Adaptive rate control for activity region. +Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE</constant>). +Applicable to the H264 encoder.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-mfc51-video-frame-skip-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FRAME_SKIP_MODE</constant> </entry> + <entry>enum v4l2_mpeg_mfc51_video_frame_skip_mode</entry> + </row> + <row><entry spanname="descr"> +Indicates in what conditions the encoder should skip frames. If encoding a frame would cause the encoded stream to be larger then +a chosen data limit then the frame will be skipped. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_DISABLED</constant> </entry> + <entry>Frame skip mode is disabled.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_LEVEL_LIMIT</constant> </entry> + <entry>Frame skip mode enabled and buffer limit is set by the chosen level and is defined by the standard.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_BUF_LIMIT</constant> </entry> + <entry>Frame skip mode enabled and buffer limit is set by the VBV (MPEG1/2/4) or CPB (H264) buffer size control.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_RC_FIXED_TARGET_BIT</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Enable rate-control with fixed target bit. +If this setting is enabled, then the rate control logic of the encoder will calculate the average bitrate +for a GOP and keep it below or equal the set bitrate target. Otherwise the rate control logic calculates the +overall average bitrate for the stream and keeps it below or equal to the set bitrate. In the first case +the average bitrate for the whole stream will be smaller then the set bitrate. This is caused because the +average is calculated for smaller number of frames, on the other hand enabling this setting will ensure that +the stream will meet tight bandwidth contraints. Applicable to encoders. +</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-mfc51-video-force-frame-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_mfc51_video_force_frame_type</entry> + </row> + <row><entry spanname="descr">Force a frame type for the next queued buffer. Applicable to encoders. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_DISABLED</constant> </entry> + <entry>Forcing a specific frame type disabled.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_I_FRAME</constant> </entry> + <entry>Force an I-frame.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_MFC51_FORCE_FRAME_TYPE_NOT_CODED</constant> </entry> + <entry>Force a non-coded frame.</entry> + </row> + </tbody> + </entrytbl> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>CX2341x MPEG Controls</title> + + <para>The following MPEG class controls deal with MPEG +encoding settings that are specific to the Conexant CX23415 and +CX23416 MPEG encoding chips.</para> + + <table pgwide="1" frame="none" id="cx2341x-control-id"> + <title>CX2341x Control IDs</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row id="v4l2-mpeg-cx2341x-video-spatial-filter-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_spatial_filter_mode</entry> + </row><row><entry spanname="descr">Sets the Spatial +Filter mode (default <constant>MANUAL</constant>). Possible values +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_MANUAL</constant> </entry> + <entry>Choose the filter manually</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_AUTO</constant> </entry> + <entry>Choose the filter automatically</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER</constant> </entry> + <entry>integer (0-15)</entry> + </row><row><entry spanname="descr">The setting for the +Spatial Filter. 0 = off, 15 = maximum. (Default is 0.)</entry> + </row> + <row><entry></entry></row> + <row id="luma-spatial-filter-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_luma_spatial_filter_type</entry> + </row><row><entry spanname="descr">Select the algorithm +to use for the Luma Spatial Filter (default +<constant>1D_HOR</constant>). Possible values:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_OFF</constant> </entry> + <entry>No filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR</constant> </entry> + <entry>One-dimensional horizontal</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_VERT</constant> </entry> + <entry>One-dimensional vertical</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_HV_SEPARABLE</constant> </entry> + <entry>Two-dimensional separable</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_SYM_NON_SEPARABLE</constant> </entry> + <entry>Two-dimensional symmetrical +non-separable</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="chroma-spatial-filter-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_chroma_spatial_filter_type</entry> + </row><row><entry spanname="descr">Select the algorithm +for the Chroma Spatial Filter (default <constant>1D_HOR</constant>). +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_OFF</constant> </entry> + <entry>No filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR</constant> </entry> + <entry>One-dimensional horizontal</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-cx2341x-video-temporal-filter-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_temporal_filter_mode</entry> + </row><row><entry spanname="descr">Sets the Temporal +Filter mode (default <constant>MANUAL</constant>). Possible values +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL</constant> </entry> + <entry>Choose the filter manually</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_AUTO</constant> </entry> + <entry>Choose the filter automatically</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER</constant> </entry> + <entry>integer (0-31)</entry> + </row><row><entry spanname="descr">The setting for the +Temporal Filter. 0 = off, 31 = maximum. (Default is 8 for full-scale +capturing and 0 for scaled capturing.)</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-cx2341x-video-median-filter-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_median_filter_type</entry> + </row><row><entry spanname="descr">Median Filter Type +(default <constant>OFF</constant>). Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF</constant> </entry> + <entry>No filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR</constant> </entry> + <entry>Horizontal filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_VERT</constant> </entry> + <entry>Vertical filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR_VERT</constant> </entry> + <entry>Horizontal and vertical filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_DIAG</constant> </entry> + <entry>Diagonal filter</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_BOTTOM</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold above which +the luminance median filter is enabled (default 0)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_TOP</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold below which +the luminance median filter is enabled (default 255)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_BOTTOM</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold above which +the chroma median filter is enabled (default 0)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_TOP</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold below which +the chroma median filter is enabled (default 255)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">The CX2341X MPEG encoder +can insert one empty MPEG-2 PES packet into the stream between every +four video frames. The packet size is 2048 bytes, including the +packet_start_code_prefix and stream_id fields. The stream_id is 0xBF +(private stream 2). The payload consists of 0x00 bytes, to be filled +in by the application. 0 = do not insert, 1 = insert packets.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + </section> + + <section id="camera-controls"> + <title>Camera Control Reference</title> + + <para>The Camera class includes controls for mechanical (or +equivalent digital) features of a device such as controllable lenses +or sensors.</para> + + <table pgwide="1" frame="none" id="camera-control-id"> + <title>Camera Control IDs</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_CAMERA_CLASS</constant> </entry> + <entry>class</entry> + </row><row><entry spanname="descr">The Camera class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class.</entry> + </row> + <row><entry></entry></row> + + <row id="v4l2-exposure-auto-type"> + <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO</constant> </entry> + <entry>enum v4l2_exposure_auto_type</entry> + </row><row><entry spanname="descr">Enables automatic +adjustments of the exposure time and/or iris aperture. The effect of +manual changes of the exposure time or iris aperture while these +features are enabled is undefined, drivers should ignore such +requests. Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_EXPOSURE_AUTO</constant> </entry> + <entry>Automatic exposure time, automatic iris +aperture.</entry> + </row> + <row> + <entry><constant>V4L2_EXPOSURE_MANUAL</constant> </entry> + <entry>Manual exposure time, manual iris.</entry> + </row> + <row> + <entry><constant>V4L2_EXPOSURE_SHUTTER_PRIORITY</constant> </entry> + <entry>Manual exposure time, auto iris.</entry> + </row> + <row> + <entry><constant>V4L2_EXPOSURE_APERTURE_PRIORITY</constant> </entry> + <entry>Auto exposure time, manual iris.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Determines the exposure +time of the camera sensor. The exposure time is limited by the frame +interval. Drivers should interpret the values as 100 µs units, +where the value 1 stands for 1/10000th of a second, 10000 for 1 second +and 100000 for 10 seconds.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">When +<constant>V4L2_CID_EXPOSURE_AUTO</constant> is set to +<constant>AUTO</constant> or <constant>APERTURE_PRIORITY</constant>, +this control determines if the device may dynamically vary the frame +rate. By default this feature is disabled (0) and the frame rate must +remain constant.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PAN_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control turns the +camera horizontally by the specified amount. The unit is undefined. A +positive value moves the camera to the right (clockwise when viewed +from above), a negative value to the left. A value of zero does not +cause motion. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_TILT_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control turns the +camera vertically by the specified amount. The unit is undefined. A +positive value moves the camera up, a negative value down. A value of +zero does not cause motion. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PAN_RESET</constant> </entry> + <entry>button</entry> + </row><row><entry spanname="descr">When this control is set, +the camera moves horizontally to the default position.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_TILT_RESET</constant> </entry> + <entry>button</entry> + </row><row><entry spanname="descr">When this control is set, +the camera moves vertically to the default position.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PAN_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control +turns the camera horizontally to the specified position. Positive +values move the camera to the right (clockwise when viewed from above), +negative values to the left. Drivers should interpret the values as arc +seconds, with valid values between -180 * 3600 and +180 * 3600 +inclusive.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_TILT_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control +turns the camera vertically to the specified position. Positive values +move the camera up, negative values down. Drivers should interpret the +values as arc seconds, with valid values between -180 * 3600 and +180 +* 3600 inclusive.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_FOCUS_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control sets the +focal point of the camera to the specified position. The unit is +undefined. Positive values set the focus closer to the camera, +negative values towards infinity.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_FOCUS_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control moves the +focal point of the camera by the specified amount. The unit is +undefined. Positive values move the focus closer to the camera, +negative values towards infinity. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_FOCUS_AUTO</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Enables automatic focus +adjustments. The effect of manual focus adjustments while this feature +is enabled is undefined, drivers should ignore such requests.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_ZOOM_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Specify the objective lens +focal length as an absolute value. The zoom unit is driver-specific and its +value should be a positive integer.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_ZOOM_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Specify the objective lens +focal length relatively to the current value. Positive values move the zoom +lens group towards the telephoto direction, negative values towards the +wide-angle direction. The zoom unit is driver-specific. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_ZOOM_CONTINUOUS</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Move the objective lens group +at the specified speed until it reaches physical device limits or until an +explicit request to stop the movement. A positive value moves the zoom lens +group towards the telephoto direction. A value of zero stops the zoom lens +group movement. A negative value moves the zoom lens group towards the +wide-angle direction. The zoom speed unit is driver-specific.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_IRIS_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control sets the +camera's aperture to the specified value. The unit is undefined. +Larger values open the iris wider, smaller values close it.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_IRIS_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control modifies the +camera's aperture by the specified amount. The unit is undefined. +Positive values open the iris one step further, negative values close +it one step further. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PRIVACY</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Prevent video from being acquired +by the camera. When this control is set to <constant>TRUE</constant> (1), no +image can be captured by the camera. Common means to enforce privacy are +mechanical obturation of the sensor and firmware image processing, but the +device is not restricted to these methods. Devices that implement the privacy +control must support read access and may support write access.</entry> + </row> + + <row> + <entry spanname="id"><constant>V4L2_CID_BAND_STOP_FILTER</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Switch the band-stop filter of a +camera sensor on or off, or specify its strength. Such band-stop filters can +be used, for example, to filter out the fluorescent light component.</entry> + </row> + <row><entry></entry></row> + </tbody> + </tgroup> + </table> + </section> + + <section id="fm-tx-controls"> + <title>FM Transmitter Control Reference</title> + + <para>The FM Transmitter (FM_TX) class includes controls for common features of +FM transmissions capable devices. Currently this class includes parameters for audio +compression, pilot tone generation, audio deviation limiter, RDS transmission and +tuning power features.</para> + + <table pgwide="1" frame="none" id="fm-tx-control-id"> + <title>FM_TX Control IDs</title> + + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_FM_TX_CLASS</constant> </entry> + <entry>class</entry> + </row><row><entry spanname="descr">The FM_TX class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_DEVIATION</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures RDS signal frequency deviation level in Hz. +The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_PI</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the RDS Programme Identification field +for transmission.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_PTY</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the RDS Programme Type field for transmission. +This encodes up to 31 pre-defined programme types.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_PS_NAME</constant> </entry> + <entry>string</entry> + </row> + <row><entry spanname="descr">Sets the Programme Service name (PS_NAME) for transmission. +It is intended for static display on a receiver. It is the primary aid to listeners in programme service +identification and selection. In Annex E of <xref linkend="en50067" />, the RDS specification, +there is a full description of the correct character encoding for Programme Service name strings. +Also from RDS specification, PS is usually a single eight character text. However, it is also possible +to find receivers which can scroll strings sized as 8 x N characters. So, this control must be configured +with steps of 8 characters. The result is it must always contain a string with size multiple of 8.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_RADIO_TEXT</constant> </entry> + <entry>string</entry> + </row> + <row><entry spanname="descr">Sets the Radio Text info for transmission. It is a textual description of +what is being broadcasted. RDS Radio Text can be applied when broadcaster wishes to transmit longer PS names, +programme-related information or any other text. In these cases, RadioText should be used in addition to +<constant>V4L2_CID_RDS_TX_PS_NAME</constant>. The encoding for Radio Text strings is also fully described +in Annex E of <xref linkend="en50067" />. The length of Radio Text strings depends on which RDS Block is being +used to transmit it, either 32 (2A block) or 64 (2B block). However, it is also possible +to find receivers which can scroll strings sized as 32 x N or 64 x N characters. So, this control must be configured +with steps of 32 or 64 characters. The result is it must always contain a string with size multiple of 32 or 64. </entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_ENABLED</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enables or disables the audio deviation limiter feature. +The limiter is useful when trying to maximize the audio volume, minimize receiver-generated +distortion and prevent overmodulation. +</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_RELEASE_TIME</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the audio deviation limiter feature release time. +Unit is in useconds. Step and range are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_DEVIATION</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures audio frequency deviation level in Hz. +The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ENABLED</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enables or disables the audio compression feature. +This feature amplifies signals below the threshold by a fixed gain and compresses audio +signals above the threshold by the ratio of Threshold/(Gain + Threshold).</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_GAIN</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the gain for audio compression feature. It is +a dB value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_THRESHOLD</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the threshold level for audio compression freature. +It is a dB value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the attack time for audio compression feature. +It is a useconds value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the release time for audio compression feature. +It is a useconds value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_ENABLED</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enables or disables the pilot tone generation feature.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_DEVIATION</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures pilot tone frequency deviation level. Unit is +in Hz. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_FREQUENCY</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures pilot tone frequency value. Unit is +in Hz. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_TUNE_PREEMPHASIS</constant> </entry> + <entry>integer</entry> + </row> + <row id="v4l2-preemphasis"><entry spanname="descr">Configures the pre-emphasis value for broadcasting. +A pre-emphasis filter is applied to the broadcast to accentuate the high audio frequencies. +Depending on the region, a time constant of either 50 or 75 useconds is used. The enum v4l2_preemphasis +defines possible values for pre-emphasis. Here they are:</entry> + </row><row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_PREEMPHASIS_DISABLED</constant> </entry> + <entry>No pre-emphasis is applied.</entry> + </row> + <row> + <entry><constant>V4L2_PREEMPHASIS_50_uS</constant> </entry> + <entry>A pre-emphasis of 50 uS is used.</entry> + </row> + <row> + <entry><constant>V4L2_PREEMPHASIS_75_uS</constant> </entry> + <entry>A pre-emphasis of 75 uS is used.</entry> + </row> + </tbody> + </entrytbl> + + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_TUNE_POWER_LEVEL</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the output power level for signal transmission. +Unit is in dBuV. Range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_TUNE_ANTENNA_CAPACITOR</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">This selects the value of antenna tuning capacitor +manually or automatically if set to zero. Unit, range and step are driver-specific.</entry> + </row> + <row><entry></entry></row> + </tbody> + </tgroup> + </table> + +<para>For more details about RDS specification, refer to +<xref linkend="en50067" /> document, from CENELEC.</para> + </section> + + <section id="flash-controls"> + <title>Flash Control Reference</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para> + The V4L2 flash controls are intended to provide generic access + to flash controller devices. Flash controller devices are + typically used in digital cameras. + </para> + + <para> + The interface can support both LED and xenon flash devices. As + of writing this, there is no xenon flash driver using this + interface. + </para> + + <section id="flash-controls-use-cases"> + <title>Supported use cases</title> + + <section> + <title>Unsynchronised LED flash (software strobe)</title> + + <para> + Unsynchronised LED flash is controlled directly by the + host as the sensor. The flash must be enabled by the host + before the exposure of the image starts and disabled once + it ends. The host is fully responsible for the timing of + the flash. + </para> + + <para>Example of such device: Nokia N900.</para> + </section> + + <section> + <title>Synchronised LED flash (hardware strobe)</title> + + <para> + The synchronised LED flash is pre-programmed by the host + (power and timeout) but controlled by the sensor through a + strobe signal from the sensor to the flash. + </para> + + <para> + The sensor controls the flash duration and timing. This + information typically must be made available to the + sensor. + </para> + + </section> + + <section> + <title>LED flash as torch</title> + + <para> + LED flash may be used as torch in conjunction with another + use case involving camera or individually. + </para> + + </section> + + </section> + + <table pgwide="1" frame="none" id="flash-control-id"> + <title>Flash Control IDs</title> + + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_CLASS</constant></entry> + <entry>class</entry> + </row> + <row> + <entry spanname="descr">The FLASH class descriptor.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_LED_MODE</constant></entry> + <entry>menu</entry> + </row> + <row id="v4l2-flash-led-mode"> + <entry spanname="descr">Defines the mode of the flash LED, + the high-power white LED attached to the flash controller. + Setting this control may not be possible in presence of + some faults. See V4L2_CID_FLASH_FAULT.</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_FLASH_LED_MODE_NONE</constant></entry> + <entry>Off.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_LED_MODE_FLASH</constant></entry> + <entry>Flash mode.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_LED_MODE_TORCH</constant></entry> + <entry>Torch mode. See V4L2_CID_FLASH_TORCH_INTENSITY.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE_SOURCE</constant></entry> + <entry>menu</entry> + </row> + <row id="v4l2-flash-strobe-source"><entry + spanname="descr">Defines the source of the flash LED + strobe.</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_FLASH_STROBE_SOURCE_SOFTWARE</constant></entry> + <entry>The flash strobe is triggered by using + the V4L2_CID_FLASH_STROBE control.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_STROBE_SOURCE_EXTERNAL</constant></entry> + <entry>The flash strobe is triggered by an + external source. Typically this is a sensor, + which makes it possible to synchronises the + flash strobe start to exposure start.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE</constant></entry> + <entry>button</entry> + </row> + <row> + <entry spanname="descr">Strobe flash. Valid when + V4L2_CID_FLASH_LED_MODE is set to + V4L2_FLASH_LED_MODE_FLASH and V4L2_CID_FLASH_STROBE_SOURCE + is set to V4L2_FLASH_STROBE_SOURCE_SOFTWARE. Setting this + control may not be possible in presence of some faults. + See V4L2_CID_FLASH_FAULT.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE_STOP</constant></entry> + <entry>button</entry> + </row> + <row><entry spanname="descr">Stop flash strobe immediately.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_STROBE_STATUS</constant></entry> + <entry>boolean</entry> + </row> + <row> + <entry spanname="descr">Strobe status: whether the flash + is strobing at the moment or not. This is a read-only + control.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_TIMEOUT</constant></entry> + <entry>integer</entry> + </row> + <row> + <entry spanname="descr">Hardware timeout for flash. The + flash strobe is stopped after this period of time has + passed from the start of the strobe.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_INTENSITY</constant></entry> + <entry>integer</entry> + </row> + <row> + <entry spanname="descr">Intensity of the flash strobe when + the flash LED is in flash mode + (V4L2_FLASH_LED_MODE_FLASH). The unit should be milliamps + (mA) if possible.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_TORCH_INTENSITY</constant></entry> + <entry>integer</entry> + </row> + <row> + <entry spanname="descr">Intensity of the flash LED in + torch mode (V4L2_FLASH_LED_MODE_TORCH). The unit should be + milliamps (mA) if possible. Setting this control may not + be possible in presence of some faults. See + V4L2_CID_FLASH_FAULT.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_INDICATOR_INTENSITY</constant></entry> + <entry>integer</entry> + </row> + <row> + <entry spanname="descr">Intensity of the indicator LED. + The indicator LED may be fully independent of the flash + LED. The unit should be microamps (uA) if possible.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_FAULT</constant></entry> + <entry>bitmask</entry> + </row> + <row> + <entry spanname="descr">Faults related to the flash. The + faults tell about specific problems in the flash chip + itself or the LEDs attached to it. Faults may prevent + further use of some of the flash controls. In particular, + V4L2_CID_FLASH_LED_MODE is set to V4L2_FLASH_LED_MODE_NONE + if the fault affects the flash LED. Exactly which faults + have such an effect is chip dependent. Reading the faults + resets the control and returns the chip to a usable state + if possible.</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_FLASH_FAULT_OVER_VOLTAGE</constant></entry> + <entry>Flash controller voltage to the flash LED + has exceeded the limit specific to the flash + controller.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_FAULT_TIMEOUT</constant></entry> + <entry>The flash strobe was still on when + the timeout set by the user --- + V4L2_CID_FLASH_TIMEOUT control --- has expired. + Not all flash controllers may set this in all + such conditions.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_FAULT_OVER_TEMPERATURE</constant></entry> + <entry>The flash controller has overheated.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_FAULT_SHORT_CIRCUIT</constant></entry> + <entry>The short circuit protection of the flash + controller has been triggered.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_FAULT_OVER_CURRENT</constant></entry> + <entry>Current in the LED power supply has exceeded the limit + specific to the flash controller.</entry> + </row> + <row> + <entry><constant>V4L2_FLASH_FAULT_INDICATOR</constant></entry> + <entry>The flash controller has detected a short or open + circuit condition on the indicator LED.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_CHARGE</constant></entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enable or disable charging of the xenon + flash capacitor.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_FLASH_READY</constant></entry> + <entry>boolean</entry> + </row> + <row> + <entry spanname="descr">Is the flash ready to strobe? + Xenon flashes require their capacitors charged before + strobing. LED flashes often require a cooldown period + after strobe during which another strobe will not be + possible. This is a read-only control.</entry> + </row> + <row><entry></entry></row> + </tbody> + </tgroup> + </table> + </section> + + <section id="jpeg-controls"> + <title>JPEG Control Reference</title> + <para>The JPEG class includes controls for common features of JPEG + encoders and decoders. Currently it includes features for codecs + implementing progressive baseline DCT compression process with + Huffman entrophy coding.</para> + <table pgwide="1" frame="none" id="jpeg-control-id"> + <title>JPEG Control IDs</title> + + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_JPEG_CLASS</constant> </entry> + <entry>class</entry> + </row><row><entry spanname="descr">The JPEG class descriptor. Calling + &VIDIOC-QUERYCTRL; for this control will return a description of this + control class. + + </entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_JPEG_CHROMA_SUBSAMPLING</constant></entry> + <entry>menu</entry> + </row> + <row id="jpeg-chroma-subsampling-control"> + <entry spanname="descr">The chroma subsampling factors describe how + each component of an input image is sampled, in respect to maximum + sample rate in each spatial dimension. See <xref linkend="itu-t81"/>, + clause A.1.1. for more details. The <constant> + V4L2_CID_JPEG_CHROMA_SUBSAMPLING</constant> control determines how + Cb and Cr components are downsampled after coverting an input image + from RGB to Y'CbCr color space. + </entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_444</constant> + </entry><entry>No chroma subsampling, each pixel has + Y, Cr and Cb values.</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_422</constant> + </entry><entry>Horizontally subsample Cr, Cb components + by a factor of 2.</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_420</constant> + </entry><entry>Subsample Cr, Cb components horizontally + and vertically by 2.</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_411</constant> + </entry><entry>Horizontally subsample Cr, Cb components + by a factor of 4.</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_410</constant> + </entry><entry>Subsample Cr, Cb components horizontally + by 4 and vertically by 2.</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_CHROMA_SUBSAMPLING_GRAY</constant> + </entry><entry>Use only luminance component.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_JPEG_RESTART_INTERVAL</constant> + </entry><entry>integer</entry> + </row> + <row><entry spanname="descr"> + The restart interval determines an interval of inserting RSTm + markers (m = 0..7). The purpose of these markers is to additionally + reinitialize the encoder process, in order to process blocks of + an image independently. + For the lossy compression processes the restart interval unit is + MCU (Minimum Coded Unit) and its value is contained in DRI + (Define Restart Interval) marker. If <constant> + V4L2_CID_JPEG_RESTART_INTERVAL</constant> control is set to 0, + DRI and RSTm markers will not be inserted. + </entry> + </row> + <row id="jpeg-quality-control"> + <entry spanname="id"><constant>V4L2_CID_JPEG_COMPRESION_QUALITY</constant></entry> + <entry>integer</entry> + </row> + <row> + <entry spanname="descr"> + <constant>V4L2_CID_JPEG_COMPRESION_QUALITY</constant> control + determines trade-off between image quality and size. + It provides simpler method for applications to control image quality, + without a need for direct reconfiguration of luminance and chrominance + quantization tables. + + In cases where a driver uses quantization tables configured directly + by an application, using interfaces defined elsewhere, <constant> + V4L2_CID_JPEG_COMPRESION_QUALITY</constant> control should be set + by driver to 0. + + <para>The value range of this control is driver-specific. Only + positive, non-zero values are meaningful. The recommended range + is 1 - 100, where larger values correspond to better image quality. + </para> + </entry> + </row> + <row id="jpeg-active-marker-control"> + <entry spanname="id"><constant>V4L2_CID_JPEG_ACTIVE_MARKER</constant></entry> + <entry>bitmask</entry> + </row> + <row> + <entry spanname="descr">Specify which JPEG markers are included + in compressed stream. This control is valid only for encoders. + </entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_JPEG_ACTIVE_MARKER_APP0</constant></entry> + <entry>Application data segment APP<subscript>0</subscript>.</entry> + </row><row> + <entry><constant>V4L2_JPEG_ACTIVE_MARKER_APP1</constant></entry> + <entry>Application data segment APP<subscript>1</subscript>.</entry> + </row><row> + <entry><constant>V4L2_JPEG_ACTIVE_MARKER_COM</constant></entry> + <entry>Comment segment.</entry> + </row><row> + <entry><constant>V4L2_JPEG_ACTIVE_MARKER_DQT</constant></entry> + <entry>Quantization tables segment.</entry> + </row><row> + <entry><constant>V4L2_JPEG_ACTIVE_MARKER_DHT</constant></entry> + <entry>Huffman tables segment.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + </tbody> + </tgroup> + </table> + <para>For more details about JPEG specification, refer + to <xref linkend="itu-t81"/>, <xref linkend="jfif"/>, + <xref linkend="w3c-jpeg-jfif"/>.</para> + </section> +</section> diff --git a/Documentation/DocBook/media/v4l/crop.pdf b/Documentation/DocBook/media/v4l/crop.pdf Binary files differnew file mode 100644 index 00000000..c9fb81cd --- /dev/null +++ b/Documentation/DocBook/media/v4l/crop.pdf diff --git a/Documentation/DocBook/media/v4l/dev-capture.xml b/Documentation/DocBook/media/v4l/dev-capture.xml new file mode 100644 index 00000000..e1c5f940 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-capture.xml @@ -0,0 +1,110 @@ + <title>Video Capture Interface</title> + + <para>Video capture devices sample an analog video signal and store +the digitized images in memory. Today nearly all devices can capture +at full 25 or 30 frames/second. With this interface applications can +control the capture process and move images from the driver into user +space.</para> + + <para>Conventionally V4L2 video capture devices are accessed through +character device special files named <filename>/dev/video</filename> +and <filename>/dev/video0</filename> to +<filename>/dev/video63</filename> with major number 81 and minor +numbers 0 to 63. <filename>/dev/video</filename> is typically a +symbolic link to the preferred video device. Note the same device +files are used for video output devices.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the video capture interface set the +<constant>V4L2_CAP_VIDEO_CAPTURE</constant> or +<constant>V4L2_CAP_VIDEO_CAPTURE_MPLANE</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. As secondary device functions +they may also support the <link linkend="overlay">video overlay</link> +(<constant>V4L2_CAP_VIDEO_OVERLAY</constant>) and the <link +linkend="raw-vbi">raw VBI capture</link> +(<constant>V4L2_CAP_VBI_CAPTURE</constant>) interface. At least one of +the read/write or streaming I/O methods must be supported. Tuners and +audio inputs are optional.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Video capture devices shall support <link +linkend="audio">audio input</link>, <link +linkend="tuner">tuner</link>, <link linkend="control">controls</link>, +<link linkend="crop">cropping and scaling</link> and <link +linkend="streaming-par">streaming parameter</link> ioctls as needed. +The <link linkend="video">video input</link> and <link +linkend="standard">video standard</link> ioctls must be supported by +all video capture devices.</para> + </section> + + <section> + <title>Image Format Negotiation</title> + + <para>The result of a capture operation is determined by +cropping and image format parameters. The former select an area of the +video picture to capture, the latter how images are stored in memory, +&ie; in RGB or YUV format, the number of bits per pixel or width and +height. Together they also define how images are scaled in the +process.</para> + + <para>As usual these parameters are <emphasis>not</emphasis> reset +at &func-open; time to permit Unix tool chains, programming a device +and then reading from it as if it was a plain file. Well written V4L2 +applications ensure they really get what they want, including cropping +and scaling.</para> + + <para>Cropping initialization at minimum requires to reset the +parameters to defaults. An example is given in <xref +linkend="crop" />.</para> + + <para>To query the current image format applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> or +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant> and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-pix-format; <structfield>pix</structfield> or the +&v4l2-pix-format-mplane; <structfield>pix_mp</structfield> member of the +<structfield>fmt</structfield> union.</para> + + <para>To request different parameters applications set the +<structfield>type</structfield> field of a &v4l2-format; as above and +initialize all fields of the &v4l2-pix-format; +<structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union, or better just modify the +results of <constant>VIDIOC_G_FMT</constant>, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers may +adjust the parameters and finally return the actual parameters as +<constant>VIDIOC_G_FMT</constant> does.</para> + + <para>Like <constant>VIDIOC_S_FMT</constant> the +&VIDIOC-TRY-FMT; ioctl can be used to learn about hardware limitations +without disabling I/O or possibly time consuming hardware +preparations.</para> + + <para>The contents of &v4l2-pix-format; and &v4l2-pix-format-mplane; +are discussed in <xref linkend="pixfmt" />. See also the specification of the +<constant>VIDIOC_G_FMT</constant>, <constant>VIDIOC_S_FMT</constant> +and <constant>VIDIOC_TRY_FMT</constant> ioctls for details. Video +capture devices must implement both the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl, even if +<constant>VIDIOC_S_FMT</constant> ignores all requests and always +returns default parameters as <constant>VIDIOC_G_FMT</constant> does. +<constant>VIDIOC_TRY_FMT</constant> is optional.</para> + </section> + + <section> + <title>Reading Images</title> + + <para>A video capture device may support the <link +linkend="rw">read() function</link> and/or streaming (<link +linkend="mmap">memory mapping</link> or <link +linkend="userp">user pointer</link>) I/O. See <xref +linkend="io" /> for details.</para> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-codec.xml b/Documentation/DocBook/media/v4l/dev-codec.xml new file mode 100644 index 00000000..dca0ecd5 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-codec.xml @@ -0,0 +1,18 @@ + <title>Codec Interface</title> + + <note> + <title>Suspended</title> + + <para>This interface has been be suspended from the V4L2 API +implemented in Linux 2.6 until we have more experience with codec +device interfaces.</para> + </note> + + <para>A V4L2 codec can compress, decompress, transform, or otherwise +convert video data from one format into another format, in memory. +Applications send data to be converted to the driver through a +&func-write; call, and receive the converted data through a +&func-read; call. For efficiency a driver may also support streaming +I/O.</para> + + <para>[to do]</para> diff --git a/Documentation/DocBook/media/v4l/dev-effect.xml b/Documentation/DocBook/media/v4l/dev-effect.xml new file mode 100644 index 00000000..2350a67c --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-effect.xml @@ -0,0 +1,17 @@ + <title>Effect Devices Interface</title> + + <note> + <title>Suspended</title> + + <para>This interface has been be suspended from the V4L2 API +implemented in Linux 2.6 until we have more experience with effect +device interfaces.</para> + </note> + + <para>A V4L2 video effect device can do image effects, filtering, or +combine two or more images or image streams. For example video +transitions or wipes. Applications send data to be processed and +receive the result data either with &func-read; and &func-write; +functions, or through the streaming I/O mechanism.</para> + + <para>[to do]</para> diff --git a/Documentation/DocBook/media/v4l/dev-event.xml b/Documentation/DocBook/media/v4l/dev-event.xml new file mode 100644 index 00000000..19f4becf --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-event.xml @@ -0,0 +1,43 @@ + <title>Event Interface</title> + + <para>The V4L2 event interface provides a means for a user to get + immediately notified on certain conditions taking place on a device. + This might include start of frame or loss of signal events, for + example. Changes in the value or state of a V4L2 control can also be + reported through events. + </para> + + <para>To receive events, the events the user is interested in first must + be subscribed using the &VIDIOC-SUBSCRIBE-EVENT; ioctl. Once an event is + subscribed, the events of subscribed types are dequeueable using the + &VIDIOC-DQEVENT; ioctl. Events may be unsubscribed using + VIDIOC_UNSUBSCRIBE_EVENT ioctl. The special event type V4L2_EVENT_ALL may + be used to unsubscribe all the events the driver supports.</para> + + <para>The event subscriptions and event queues are specific to file + handles. Subscribing an event on one file handle does not affect + other file handles.</para> + + <para>The information on dequeueable events is obtained by using select or + poll system calls on video devices. The V4L2 events use POLLPRI events on + poll system call and exceptions on select system call.</para> + + <para>Starting with kernel 3.1 certain guarantees can be given with + regards to events:<orderedlist> + <listitem> + <para>Each subscribed event has its own internal dedicated event queue. +This means that flooding of one event type will not interfere with other +event types.</para> + </listitem> + <listitem> + <para>If the internal event queue for a particular subscribed event +becomes full, then the oldest event in that queue will be dropped.</para> + </listitem> + <listitem> + <para>Where applicable, certain event types can ensure that the payload +of the oldest event that is about to be dropped will be merged with the payload +of the next oldest event. Thus ensuring that no information is lost, but only an +intermediate step leading up to that information. See the documentation for the +event you want to subscribe to whether this is applicable for that event or not.</para> + </listitem> + </orderedlist></para> diff --git a/Documentation/DocBook/media/v4l/dev-osd.xml b/Documentation/DocBook/media/v4l/dev-osd.xml new file mode 100644 index 00000000..479d9433 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-osd.xml @@ -0,0 +1,156 @@ + <title>Video Output Overlay Interface</title> + <subtitle>Also known as On-Screen Display (OSD)</subtitle> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>Some video output devices can overlay a framebuffer image onto +the outgoing video signal. Applications can set up such an overlay +using this interface, which borrows structures and ioctls of the <link +linkend="overlay">Video Overlay</link> interface.</para> + + <para>The OSD function is accessible through the same character +special file as the <link linkend="capture">Video Output</link> function. +Note the default function of such a <filename>/dev/video</filename> device +is video capturing or output. The OSD function is only available after +calling the &VIDIOC-S-FMT; ioctl.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the <wordasword>Video Output +Overlay</wordasword> interface set the +<constant>V4L2_CAP_VIDEO_OUTPUT_OVERLAY</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl.</para> + </section> + + <section> + <title>Framebuffer</title> + + <para>Contrary to the <wordasword>Video Overlay</wordasword> +interface the framebuffer is normally implemented on the TV card and +not the graphics card. On Linux it is accessible as a framebuffer +device (<filename>/dev/fbN</filename>). Given a V4L2 device, +applications can find the corresponding framebuffer device by calling +the &VIDIOC-G-FBUF; ioctl. It returns, amongst other information, the +physical address of the framebuffer in the +<structfield>base</structfield> field of &v4l2-framebuffer;. The +framebuffer device ioctl <constant>FBIOGET_FSCREENINFO</constant> +returns the same address in the <structfield>smem_start</structfield> +field of struct <structname>fb_fix_screeninfo</structname>. The +<constant>FBIOGET_FSCREENINFO</constant> ioctl and struct +<structname>fb_fix_screeninfo</structname> are defined in the +<filename>linux/fb.h</filename> header file.</para> + + <para>The width and height of the framebuffer depends on the +current video standard. A V4L2 driver may reject attempts to change +the video standard (or any other ioctl which would imply a framebuffer +size change) with an &EBUSY; until all applications closed the +framebuffer device.</para> + + <example> + <title>Finding a framebuffer device for OSD</title> + + <programlisting> +#include <linux/fb.h> + +&v4l2-framebuffer; fbuf; +unsigned int i; +int fb_fd; + +if (-1 == ioctl (fd, VIDIOC_G_FBUF, &fbuf)) { + perror ("VIDIOC_G_FBUF"); + exit (EXIT_FAILURE); +} + +for (i = 0; i > 30; ++i) { + char dev_name[16]; + struct fb_fix_screeninfo si; + + snprintf (dev_name, sizeof (dev_name), "/dev/fb%u", i); + + fb_fd = open (dev_name, O_RDWR); + if (-1 == fb_fd) { + switch (errno) { + case ENOENT: /* no such file */ + case ENXIO: /* no driver */ + continue; + + default: + perror ("open"); + exit (EXIT_FAILURE); + } + } + + if (0 == ioctl (fb_fd, FBIOGET_FSCREENINFO, &si)) { + if (si.smem_start == (unsigned long) fbuf.base) + break; + } else { + /* Apparently not a framebuffer device. */ + } + + close (fb_fd); + fb_fd = -1; +} + +/* fb_fd is the file descriptor of the framebuffer device + for the video output overlay, or -1 if no device was found. */ +</programlisting> + </example> + </section> + + <section> + <title>Overlay Window and Scaling</title> + + <para>The overlay is controlled by source and target rectangles. +The source rectangle selects a subsection of the framebuffer image to +be overlaid, the target rectangle an area in the outgoing video signal +where the image will appear. Drivers may or may not support scaling, +and arbitrary sizes and positions of these rectangles. Further drivers +may support any (or none) of the clipping/blending methods defined for +the <link linkend="overlay">Video Overlay</link> interface.</para> + + <para>A &v4l2-window; defines the size of the source rectangle, +its position in the framebuffer and the clipping/blending method to be +used for the overlay. To get the current parameters applications set +the <structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant> and call the +&VIDIOC-G-FMT; ioctl. The driver fills the +<structname>v4l2_window</structname> substructure named +<structfield>win</structfield>. It is not possible to retrieve a +previously programmed clipping list or bitmap.</para> + + <para>To program the source rectangle applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant>, initialize +the <structfield>win</structfield> substructure and call the +&VIDIOC-S-FMT; ioctl. The driver adjusts the parameters against +hardware limits and returns the actual parameters as +<constant>VIDIOC_G_FMT</constant> does. Like +<constant>VIDIOC_S_FMT</constant>, the &VIDIOC-TRY-FMT; ioctl can be +used to learn about driver capabilities without actually changing +driver state. Unlike <constant>VIDIOC_S_FMT</constant> this also works +after the overlay has been enabled.</para> + + <para>A &v4l2-crop; defines the size and position of the target +rectangle. The scaling factor of the overlay is implied by the width +and height given in &v4l2-window; and &v4l2-crop;. The cropping API +applies to <wordasword>Video Output</wordasword> and <wordasword>Video +Output Overlay</wordasword> devices in the same way as to +<wordasword>Video Capture</wordasword> and <wordasword>Video +Overlay</wordasword> devices, merely reversing the direction of the +data flow. For more information see <xref linkend="crop" />.</para> + </section> + + <section> + <title>Enabling Overlay</title> + + <para>There is no V4L2 ioctl to enable or disable the overlay, +however the framebuffer interface of the driver may support the +<constant>FBIOBLANK</constant> ioctl.</para> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-output.xml b/Documentation/DocBook/media/v4l/dev-output.xml new file mode 100644 index 00000000..9130a3dc --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-output.xml @@ -0,0 +1,106 @@ + <title>Video Output Interface</title> + + <para>Video output devices encode stills or image sequences as +analog video signal. With this interface applications can +control the encoding process and move images from user space to +the driver.</para> + + <para>Conventionally V4L2 video output devices are accessed through +character device special files named <filename>/dev/video</filename> +and <filename>/dev/video0</filename> to +<filename>/dev/video63</filename> with major number 81 and minor +numbers 0 to 63. <filename>/dev/video</filename> is typically a +symbolic link to the preferred video device. Note the same device +files are used for video capture devices.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the video output interface set the +<constant>V4L2_CAP_VIDEO_OUTPUT</constant> or +<constant>V4L2_CAP_VIDEO_OUTPUT_MPLANE</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. As secondary device functions +they may also support the <link linkend="raw-vbi">raw VBI +output</link> (<constant>V4L2_CAP_VBI_OUTPUT</constant>) interface. At +least one of the read/write or streaming I/O methods must be +supported. Modulators and audio outputs are optional.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Video output devices shall support <link +linkend="audio">audio output</link>, <link +linkend="tuner">modulator</link>, <link linkend="control">controls</link>, +<link linkend="crop">cropping and scaling</link> and <link +linkend="streaming-par">streaming parameter</link> ioctls as needed. +The <link linkend="video">video output</link> and <link +linkend="standard">video standard</link> ioctls must be supported by +all video output devices.</para> + </section> + + <section> + <title>Image Format Negotiation</title> + + <para>The output is determined by cropping and image format +parameters. The former select an area of the video picture where the +image will appear, the latter how images are stored in memory, &ie; in +RGB or YUV format, the number of bits per pixel or width and height. +Together they also define how images are scaled in the process.</para> + + <para>As usual these parameters are <emphasis>not</emphasis> reset +at &func-open; time to permit Unix tool chains, programming a device +and then writing to it as if it was a plain file. Well written V4L2 +applications ensure they really get what they want, including cropping +and scaling.</para> + + <para>Cropping initialization at minimum requires to reset the +parameters to defaults. An example is given in <xref +linkend="crop" />.</para> + + <para>To query the current image format applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> or +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant> and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-pix-format; <structfield>pix</structfield> or the +&v4l2-pix-format-mplane; <structfield>pix_mp</structfield> member of the +<structfield>fmt</structfield> union.</para> + + <para>To request different parameters applications set the +<structfield>type</structfield> field of a &v4l2-format; as above and +initialize all fields of the &v4l2-pix-format; +<structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union, or better just modify the +results of <constant>VIDIOC_G_FMT</constant>, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers may +adjust the parameters and finally return the actual parameters as +<constant>VIDIOC_G_FMT</constant> does.</para> + + <para>Like <constant>VIDIOC_S_FMT</constant> the +&VIDIOC-TRY-FMT; ioctl can be used to learn about hardware limitations +without disabling I/O or possibly time consuming hardware +preparations.</para> + + <para>The contents of &v4l2-pix-format; and &v4l2-pix-format-mplane; +are discussed in <xref linkend="pixfmt" />. See also the specification of the +<constant>VIDIOC_G_FMT</constant>, <constant>VIDIOC_S_FMT</constant> +and <constant>VIDIOC_TRY_FMT</constant> ioctls for details. Video +output devices must implement both the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl, even if +<constant>VIDIOC_S_FMT</constant> ignores all requests and always +returns default parameters as <constant>VIDIOC_G_FMT</constant> does. +<constant>VIDIOC_TRY_FMT</constant> is optional.</para> + </section> + + <section> + <title>Writing Images</title> + + <para>A video output device may support the <link +linkend="rw">write() function</link> and/or streaming (<link +linkend="mmap">memory mapping</link> or <link +linkend="userp">user pointer</link>) I/O. See <xref +linkend="io" /> for details.</para> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-overlay.xml b/Documentation/DocBook/media/v4l/dev-overlay.xml new file mode 100644 index 00000000..40d1d768 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-overlay.xml @@ -0,0 +1,371 @@ + <title>Video Overlay Interface</title> + <subtitle>Also known as Framebuffer Overlay or Previewing</subtitle> + + <para>Video overlay devices have the ability to genlock (TV-)video +into the (VGA-)video signal of a graphics card, or to store captured +images directly in video memory of a graphics card, typically with +clipping. This can be considerable more efficient than capturing +images and displaying them by other means. In the old days when only +nuclear power plants needed cooling towers this used to be the only +way to put live video into a window.</para> + + <para>Video overlay devices are accessed through the same character +special files as <link linkend="capture">video capture</link> devices. +Note the default function of a <filename>/dev/video</filename> device +is video capturing. The overlay function is only available after +calling the &VIDIOC-S-FMT; ioctl.</para> + + <para>The driver may support simultaneous overlay and capturing +using the read/write and streaming I/O methods. If so, operation at +the nominal frame rate of the video standard is not guaranteed. Frames +may be directed away from overlay to capture, or one field may be used +for overlay and the other for capture if the capture parameters permit +this.</para> + + <para>Applications should use different file descriptors for +capturing and overlay. This must be supported by all drivers capable +of simultaneous capturing and overlay. Optionally these drivers may +also permit capturing and overlay with a single file descriptor for +compatibility with V4L and earlier versions of V4L2.<footnote> + <para>A common application of two file descriptors is the +XFree86 <link linkend="xvideo">Xv/V4L</link> interface driver and +a V4L2 application. While the X server controls video overlay, the +application can take advantage of memory mapping and DMA.</para> + <para>In the opinion of the designers of this API, no driver +writer taking the efforts to support simultaneous capturing and +overlay will restrict this ability by requiring a single file +descriptor, as in V4L and earlier versions of V4L2. Making this +optional means applications depending on two file descriptors need +backup routines to be compatible with all drivers, which is +considerable more work than using two fds in applications which do +not. Also two fd's fit the general concept of one file descriptor for +each logical stream. Hence as a complexity trade-off drivers +<emphasis>must</emphasis> support two file descriptors and +<emphasis>may</emphasis> support single fd operation.</para> + </footnote></para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the video overlay interface set the +<constant>V4L2_CAP_VIDEO_OVERLAY</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. The overlay I/O method specified +below must be supported. Tuners and audio inputs are optional.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Video overlay devices shall support <link +linkend="audio">audio input</link>, <link +linkend="tuner">tuner</link>, <link linkend="control">controls</link>, +<link linkend="crop">cropping and scaling</link> and <link +linkend="streaming-par">streaming parameter</link> ioctls as needed. +The <link linkend="video">video input</link> and <link +linkend="standard">video standard</link> ioctls must be supported by +all video overlay devices.</para> + </section> + + <section> + <title>Setup</title> + + <para>Before overlay can commence applications must program the +driver with frame buffer parameters, namely the address and size of +the frame buffer and the image format, for example RGB 5:6:5. The +&VIDIOC-G-FBUF; and &VIDIOC-S-FBUF; ioctls are available to get +and set these parameters, respectively. The +<constant>VIDIOC_S_FBUF</constant> ioctl is privileged because it +allows to set up DMA into physical memory, bypassing the memory +protection mechanisms of the kernel. Only the superuser can change the +frame buffer address and size. Users are not supposed to run TV +applications as root or with SUID bit set. A small helper application +with suitable privileges should query the graphics system and program +the V4L2 driver at the appropriate time.</para> + + <para>Some devices add the video overlay to the output signal +of the graphics card. In this case the frame buffer is not modified by +the video device, and the frame buffer address and pixel format are +not needed by the driver. The <constant>VIDIOC_S_FBUF</constant> ioctl +is not privileged. An application can check for this type of device by +calling the <constant>VIDIOC_G_FBUF</constant> ioctl.</para> + + <para>A driver may support any (or none) of five clipping/blending +methods:<orderedlist> + <listitem> + <para>Chroma-keying displays the overlaid image only where +pixels in the primary graphics surface assume a certain color.</para> + </listitem> + <listitem> + <para>A bitmap can be specified where each bit corresponds +to a pixel in the overlaid image. When the bit is set, the +corresponding video pixel is displayed, otherwise a pixel of the +graphics surface.</para> + </listitem> + <listitem> + <para>A list of clipping rectangles can be specified. In +these regions <emphasis>no</emphasis> video is displayed, so the +graphics surface can be seen here.</para> + </listitem> + <listitem> + <para>The framebuffer has an alpha channel that can be used +to clip or blend the framebuffer with the video.</para> + </listitem> + <listitem> + <para>A global alpha value can be specified to blend the +framebuffer contents with video images.</para> + </listitem> + </orderedlist></para> + + <para>When simultaneous capturing and overlay is supported and +the hardware prohibits different image and frame buffer formats, the +format requested first takes precedence. The attempt to capture +(&VIDIOC-S-FMT;) or overlay (&VIDIOC-S-FBUF;) may fail with an +&EBUSY; or return accordingly modified parameters..</para> + </section> + + <section> + <title>Overlay Window</title> + + <para>The overlaid image is determined by cropping and overlay +window parameters. The former select an area of the video picture to +capture, the latter how images are overlaid and clipped. Cropping +initialization at minimum requires to reset the parameters to +defaults. An example is given in <xref linkend="crop" />.</para> + + <para>The overlay window is described by a &v4l2-window;. It +defines the size of the image, its position over the graphics surface +and the clipping to be applied. To get the current parameters +applications set the <structfield>type</structfield> field of a +&v4l2-format; to <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant> and +call the &VIDIOC-G-FMT; ioctl. The driver fills the +<structname>v4l2_window</structname> substructure named +<structfield>win</structfield>. It is not possible to retrieve a +previously programmed clipping list or bitmap.</para> + + <para>To program the overlay window applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, initialize the +<structfield>win</structfield> substructure and call the +&VIDIOC-S-FMT; ioctl. The driver adjusts the parameters against +hardware limits and returns the actual parameters as +<constant>VIDIOC_G_FMT</constant> does. Like +<constant>VIDIOC_S_FMT</constant>, the &VIDIOC-TRY-FMT; ioctl can be +used to learn about driver capabilities without actually changing +driver state. Unlike <constant>VIDIOC_S_FMT</constant> this also works +after the overlay has been enabled.</para> + + <para>The scaling factor of the overlaid image is implied by the +width and height given in &v4l2-window; and the size of the cropping +rectangle. For more information see <xref linkend="crop" />.</para> + + <para>When simultaneous capturing and overlay is supported and +the hardware prohibits different image and window sizes, the size +requested first takes precedence. The attempt to capture or overlay as +well (&VIDIOC-S-FMT;) may fail with an &EBUSY; or return accordingly +modified parameters.</para> + + <table pgwide="1" frame="none" id="v4l2-window"> + <title>struct <structname>v4l2_window</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>w</structfield></entry> + <entry>Size and position of the window relative to the +top, left corner of the frame buffer defined with &VIDIOC-S-FBUF;. The +window can extend the frame buffer width and height, the +<structfield>x</structfield> and <structfield>y</structfield> +coordinates can be negative, and it can lie completely outside the +frame buffer. The driver clips the window accordingly, or if that is +not possible, modifies its size and/or position.</entry> + </row> + <row> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry>Applications set this field to determine which +video field shall be overlaid, typically one of +<constant>V4L2_FIELD_ANY</constant> (0), +<constant>V4L2_FIELD_TOP</constant>, +<constant>V4L2_FIELD_BOTTOM</constant> or +<constant>V4L2_FIELD_INTERLACED</constant>. Drivers may have to choose +a different field order and return the actual setting here.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>chromakey</structfield></entry> + <entry>When chroma-keying has been negotiated with +&VIDIOC-S-FBUF; applications set this field to the desired pixel value +for the chroma key. The format is the same as the pixel format of the +framebuffer (&v4l2-framebuffer; +<structfield>fmt.pixelformat</structfield> field), with bytes in host +order. E. g. for <link +linkend="V4L2-PIX-FMT-BGR32"><constant>V4L2_PIX_FMT_BGR24</constant></link> +the value should be 0xRRGGBB on a little endian, 0xBBGGRR on a big +endian host.</entry> + </row> + <row> + <entry>&v4l2-clip; *</entry> + <entry><structfield>clips</structfield></entry> + <entry>When chroma-keying has <emphasis>not</emphasis> +been negotiated and &VIDIOC-G-FBUF; indicated this capability, +applications can set this field to point to an array of +clipping rectangles.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Like the window coordinates +<structfield>w</structfield>, clipping rectangles are defined relative +to the top, left corner of the frame buffer. However clipping +rectangles must not extend the frame buffer width and height, and they +must not overlap. If possible applications should merge adjacent +rectangles. Whether this must create x-y or y-x bands, or the order of +rectangles, is not defined. When clip lists are not supported the +driver ignores this field. Its contents after calling &VIDIOC-S-FMT; +are undefined.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>clipcount</structfield></entry> + <entry>When the application set the +<structfield>clips</structfield> field, this field must contain the +number of clipping rectangles in the list. When clip lists are not +supported the driver ignores this field, its contents after calling +<constant>VIDIOC_S_FMT</constant> are undefined. When clip lists are +supported but no clipping is desired this field must be set to +zero.</entry> + </row> + <row> + <entry>void *</entry> + <entry><structfield>bitmap</structfield></entry> + <entry>When chroma-keying has +<emphasis>not</emphasis> been negotiated and &VIDIOC-G-FBUF; indicated +this capability, applications can set this field to point to a +clipping bit mask.</entry> + </row> + <row> + <entry spanname="hspan"><para>It must be of the same size +as the window, <structfield>w.width</structfield> and +<structfield>w.height</structfield>. Each bit corresponds to a pixel +in the overlaid image, which is displayed only when the bit is +<emphasis>set</emphasis>. Pixel coordinates translate to bits like: +<programlisting> +((__u8 *) <structfield>bitmap</structfield>)[<structfield>w.width</structfield> * y + x / 8] & (1 << (x & 7))</programlisting></para><para>where <structfield>0</structfield> ≤ x < +<structfield>w.width</structfield> and <structfield>0</structfield> ≤ +y <<structfield>w.height</structfield>.<footnote> + <para>Should we require + <structfield>w.width</structfield> to be a multiple of + eight?</para> + </footnote></para><para>When a clipping +bit mask is not supported the driver ignores this field, its contents +after calling &VIDIOC-S-FMT; are undefined. When a bit mask is supported +but no clipping is desired this field must be set to +<constant>NULL</constant>.</para><para>Applications need not create a +clip list or bit mask. When they pass both, or despite negotiating +chroma-keying, the results are undefined. Regardless of the chosen +method, the clipping abilities of the hardware may be limited in +quantity or quality. The results when these limits are exceeded are +undefined.<footnote> + <para>When the image is written into frame buffer +memory it will be undesirable if the driver clips out less pixels +than expected, because the application and graphics system are not +aware these regions need to be refreshed. The driver should clip out +more pixels or not write the image at all.</para> + </footnote></para></entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>global_alpha</structfield></entry> + <entry>The global alpha value used to blend the +framebuffer with video images, if global alpha blending has been +negotiated (<constant>V4L2_FBUF_FLAG_GLOBAL_ALPHA</constant>, see +&VIDIOC-S-FBUF;, <xref linkend="framebuffer-flags" />).</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Note this field was added in Linux 2.6.23, extending the structure. However +the <link linkend="vidioc-g-fmt">VIDIOC_G/S/TRY_FMT</link> ioctls, +which take a pointer to a <link +linkend="v4l2-format">v4l2_format</link> parent structure with padding +bytes at the end, are not affected.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-clip"> + <title>struct <structname>v4l2_clip</structname><footnote> + <para>The X Window system defines "regions" which are +vectors of struct BoxRec { short x1, y1, x2, y2; } with width = x2 - +x1 and height = y2 - y1, so one cannot pass X11 clip lists +directly.</para> + </footnote></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>c</structfield></entry> + <entry>Coordinates of the clipping rectangle, relative to +the top, left corner of the frame buffer. Only window pixels +<emphasis>outside</emphasis> all clipping rectangles are +displayed.</entry> + </row> + <row> + <entry>&v4l2-clip; *</entry> + <entry><structfield>next</structfield></entry> + <entry>Pointer to the next clipping rectangle, NULL when +this is the last rectangle. Drivers ignore this field, it cannot be +used to pass a linked list of clipping rectangles.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- NB for easier reading this table is duplicated + in the vidioc-cropcap chapter.--> + + <table pgwide="1" frame="none" id="v4l2-rect"> + <title>struct <structname>v4l2_rect</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__s32</entry> + <entry><structfield>left</structfield></entry> + <entry>Horizontal offset of the top, left corner of the +rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>top</structfield></entry> + <entry>Vertical offset of the top, left corner of the +rectangle, in pixels. Offsets increase to the right and down.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the rectangle, in pixels. Width and +height cannot be negative, the fields are signed for hysterical +reasons. <!-- video4linux-list@redhat.com on 22 Oct 2002 subject +"Re:[V4L][patches!] Re:v4l2/kernel-2.5" --></entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>Enabling Overlay</title> + + <para>To start or stop the frame buffer overlay applications call +the &VIDIOC-OVERLAY; ioctl.</para> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-radio.xml b/Documentation/DocBook/media/v4l/dev-radio.xml new file mode 100644 index 00000000..3e6ac73b --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-radio.xml @@ -0,0 +1,49 @@ + <title>Radio Interface</title> + + <para>This interface is intended for AM and FM (analog) radio +receivers and transmitters.</para> + + <para>Conventionally V4L2 radio devices are accessed through +character device special files named <filename>/dev/radio</filename> +and <filename>/dev/radio0</filename> to +<filename>/dev/radio63</filename> with major number 81 and minor +numbers 64 to 127.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the radio interface set the +<constant>V4L2_CAP_RADIO</constant> and +<constant>V4L2_CAP_TUNER</constant> or +<constant>V4L2_CAP_MODULATOR</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. Other combinations of +capability flags are reserved for future extensions.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Radio devices can support <link +linkend="control">controls</link>, and must support the <link +linkend="tuner">tuner or modulator</link> ioctls.</para> + + <para>They do not support the video input or output, audio input +or output, video standard, cropping and scaling, compression and +streaming parameter, or overlay ioctls. All other ioctls and I/O +methods are reserved for future extensions.</para> + </section> + + <section> + <title>Programming</title> + + <para>Radio devices may have a couple audio controls (as discussed +in <xref linkend="control" />) such as a volume control, possibly custom +controls. Further all radio devices have one tuner or modulator (these are +discussed in <xref linkend="tuner" />) with index number zero to select +the radio frequency and to determine if a monaural or FM stereo +program is received/emitted. Drivers switch automatically between AM and FM +depending on the selected frequency. The &VIDIOC-G-TUNER; or +&VIDIOC-G-MODULATOR; ioctl +reports the supported frequency range.</para> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-raw-vbi.xml b/Documentation/DocBook/media/v4l/dev-raw-vbi.xml new file mode 100644 index 00000000..b788c72c --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-raw-vbi.xml @@ -0,0 +1,339 @@ + <title>Raw VBI Data Interface</title> + + <para>VBI is an abbreviation of Vertical Blanking Interval, a gap +in the sequence of lines of an analog video signal. During VBI +no picture information is transmitted, allowing some time while the +electron beam of a cathode ray tube TV returns to the top of the +screen. Using an oscilloscope you will find here the vertical +synchronization pulses and short data packages ASK +modulated<footnote><para>ASK: Amplitude-Shift Keying. A high signal +level represents a '1' bit, a low level a '0' bit.</para></footnote> +onto the video signal. These are transmissions of services such as +Teletext or Closed Caption.</para> + + <para>Subject of this interface type is raw VBI data, as sampled off +a video signal, or to be added to a signal for output. +The data format is similar to uncompressed video images, a number of +lines times a number of samples per line, we call this a VBI image.</para> + + <para>Conventionally V4L2 VBI devices are accessed through character +device special files named <filename>/dev/vbi</filename> and +<filename>/dev/vbi0</filename> to <filename>/dev/vbi31</filename> with +major number 81 and minor numbers 224 to 255. +<filename>/dev/vbi</filename> is typically a symbolic link to the +preferred VBI device. This convention applies to both input and output +devices.</para> + + <para>To address the problems of finding related video and VBI +devices VBI capturing and output is also available as device function +under <filename>/dev/video</filename>. To capture or output raw VBI +data with these devices applications must call the &VIDIOC-S-FMT; +ioctl. Accessed as <filename>/dev/vbi</filename>, raw VBI capturing +or output is the default device function.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the raw VBI capturing or output API set +the <constant>V4L2_CAP_VBI_CAPTURE</constant> or +<constant>V4L2_CAP_VBI_OUTPUT</constant> flags, respectively, in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. At least one of the +read/write, streaming or asynchronous I/O methods must be +supported. VBI devices may or may not have a tuner or modulator.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>VBI devices shall support <link linkend="video">video +input or output</link>, <link linkend="tuner">tuner or +modulator</link>, and <link linkend="control">controls</link> ioctls +as needed. The <link linkend="standard">video standard</link> ioctls provide +information vital to program a VBI device, therefore must be +supported.</para> + </section> + + <section> + <title>Raw VBI Format Negotiation</title> + + <para>Raw VBI sampling abilities can vary, in particular the +sampling frequency. To properly interpret the data V4L2 specifies an +ioctl to query the sampling parameters. Moreover, to allow for some +flexibility applications can also suggest different parameters.</para> + + <para>As usual these parameters are <emphasis>not</emphasis> +reset at &func-open; time to permit Unix tool chains, programming a +device and then reading from it as if it was a plain file. Well +written V4L2 applications should always ensure they really get what +they want, requesting reasonable parameters and then checking if the +actual parameters are suitable.</para> + + <para>To query the current raw VBI capture parameters +applications set the <structfield>type</structfield> field of a +&v4l2-format; to <constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant> or +<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>, and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-vbi-format; <structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union.</para> + + <para>To request different parameters applications set the +<structfield>type</structfield> field of a &v4l2-format; as above and +initialize all fields of the &v4l2-vbi-format; +<structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union, or better just modify the +results of <constant>VIDIOC_G_FMT</constant>, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers return +an &EINVAL; only when the given parameters are ambiguous, otherwise +they modify the parameters according to the hardware capabilites and +return the actual parameters. When the driver allocates resources at +this point, it may return an &EBUSY; to indicate the returned +parameters are valid but the required resources are currently not +available. That may happen for instance when the video and VBI areas +to capture would overlap, or when the driver supports multiple opens +and another process already requested VBI capturing or output. Anyway, +applications must expect other resource allocation points which may +return <errorcode>EBUSY</errorcode>, at the &VIDIOC-STREAMON; ioctl +and the first read(), write() and select() call.</para> + + <para>VBI devices must implement both the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl, even if +<constant>VIDIOC_S_FMT</constant> ignores all requests and always +returns default parameters as <constant>VIDIOC_G_FMT</constant> does. +<constant>VIDIOC_TRY_FMT</constant> is optional.</para> + + <table pgwide="1" frame="none" id="v4l2-vbi-format"> + <title>struct <structname>v4l2_vbi_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>sampling_rate</structfield></entry> + <entry>Samples per second, i. e. unit 1 Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>offset</structfield></entry> + <entry><para>Horizontal offset of the VBI image, +relative to the leading edge of the line synchronization pulse and +counted in samples: The first sample in the VBI image will be located +<structfield>offset</structfield> / +<structfield>sampling_rate</structfield> seconds following the leading +edge. See also <xref linkend="vbi-hsync" />.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>samples_per_line</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>sample_format</structfield></entry> + <entry><para>Defines the sample format as in <xref +linkend="pixfmt" />, a four-character-code.<footnote> + <para>A few devices may be unable to +sample VBI data at all but can extend the video capture window to the +VBI region.</para> + </footnote> Usually this is +<constant>V4L2_PIX_FMT_GREY</constant>, i. e. each sample +consists of 8 bits with lower values oriented towards the black level. +Do not assume any other correlation of values with the signal level. +For example, the MSB does not necessarily indicate if the signal is +'high' or 'low' because 128 may not be the mean value of the +signal. Drivers shall not convert the sample format by software.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>start</structfield>[2]</entry> + <entry>This is the scanning system line number +associated with the first line of the VBI image, of the first and the +second field respectively. See <xref linkend="vbi-525" /> and +<xref linkend="vbi-625" /> for valid values. VBI input drivers can +return start values 0 if the hardware cannot reliable identify +scanning lines, VBI acquisition may not require this +information.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>count</structfield>[2]</entry> + <entry>The number of lines in the first and second +field image, respectively.</entry> + </row> + <row> + <entry spanname="hspan"><para>Drivers should be as +flexibility as possible. For example, it may be possible to extend or +move the VBI capture window down to the picture area, implementing a +'full field mode' to capture data service transmissions embedded in +the picture.</para><para>An application can set the first or second +<structfield>count</structfield> value to zero if no data is required +from the respective field; <structfield>count</structfield>[1] if the +scanning system is progressive, &ie; not interlaced. The +corresponding start value shall be ignored by the application and +driver. Anyway, drivers may not support single field capturing and +return both count values non-zero.</para><para>Both +<structfield>count</structfield> values set to zero, or line numbers +outside the bounds depicted in <xref linkend="vbi-525" /> and <xref + linkend="vbi-625" />, or a field image covering +lines of two fields, are invalid and shall not be returned by the +driver.</para><para>To initialize the <structfield>start</structfield> +and <structfield>count</structfield> fields, applications must first +determine the current video standard selection. The &v4l2-std-id; or +the <structfield>framelines</structfield> field of &v4l2-standard; can +be evaluated for this purpose.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>See <xref linkend="vbifmt-flags" /> below. Currently +only drivers set flags, applications must set this field to +zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>This array is reserved for future extensions. +Drivers and applications must set it to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="vbifmt-flags"> + <title>Raw VBI Format Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_VBI_UNSYNC</constant></entry> + <entry>0x0001</entry> + <entry><para>This flag indicates hardware which does not +properly distinguish between fields. Normally the VBI image stores the +first field (lower scanning line numbers) first in memory. This may be +a top or bottom field depending on the video standard. When this flag +is set the first or second field may be stored first, however the +fields are still in correct temporal order with the older field first +in memory.<footnote> + <para>Most VBI services transmit on both fields, but +some have different semantics depending on the field number. These +cannot be reliable decoded or encoded when +<constant>V4L2_VBI_UNSYNC</constant> is set.</para> + </footnote></para></entry> + </row> + <row> + <entry><constant>V4L2_VBI_INTERLACED</constant></entry> + <entry>0x0002</entry> + <entry>By default the two field images will be passed +sequentially; all lines of the first field followed by all lines of +the second field (compare <xref linkend="field-order" /> +<constant>V4L2_FIELD_SEQ_TB</constant> and +<constant>V4L2_FIELD_SEQ_BT</constant>, whether the top or bottom +field is first in memory depends on the video standard). When this +flag is set, the two fields are interlaced (cf. +<constant>V4L2_FIELD_INTERLACED</constant>). The first line of the +first field followed by the first line of the second field, then the +two second lines, and so on. Such a layout may be necessary when the +hardware has been programmed to capture or output interlaced video +images and is unable to separate the fields for VBI capturing at +the same time. For simplicity setting this flag implies that both +<structfield>count</structfield> values are equal and non-zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <figure id="vbi-hsync"> + <title>Line synchronization</title> + <mediaobject> + <imageobject> + <imagedata fileref="vbi_hsync.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="vbi_hsync.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>Line synchronization diagram</phrase> + </textobject> + </mediaobject> + </figure> + + <figure id="vbi-525"> + <title>ITU-R 525 line numbering (M/NTSC and M/PAL)</title> + <mediaobject> + <imageobject> + <imagedata fileref="vbi_525.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="vbi_525.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>NTSC field synchronization diagram</phrase> + </textobject> + <caption> + <para>(1) For the purpose of this specification field 2 +starts in line 264 and not 263.5 because half line capturing is not +supported.</para> + </caption> + </mediaobject> + </figure> + + <figure id="vbi-625"> + <title>ITU-R 625 line numbering</title> + <mediaobject> + <imageobject> + <imagedata fileref="vbi_625.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="vbi_625.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>PAL/SECAM field synchronization diagram</phrase> + </textobject> + <caption> + <para>(1) For the purpose of this specification field 2 +starts in line 314 and not 313.5 because half line capturing is not +supported.</para> + </caption> + </mediaobject> + </figure> + + <para>Remember the VBI image format depends on the selected +video standard, therefore the application must choose a new standard or +query the current standard first. Attempts to read or write data ahead +of format negotiation, or after switching the video standard which may +invalidate the negotiated VBI parameters, should be refused by the +driver. A format change during active I/O is not permitted.</para> + </section> + + <section> + <title>Reading and writing VBI images</title> + + <para>To assure synchronization with the field number and easier +implementation, the smallest unit of data passed at a time is one +frame, consisting of two fields of VBI images immediately following in +memory.</para> + + <para>The total size of a frame computes as follows:</para> + + <programlisting> +(<structfield>count</structfield>[0] + <structfield>count</structfield>[1]) * +<structfield>samples_per_line</structfield> * sample size in bytes</programlisting> + + <para>The sample size is most likely always one byte, +applications must check the <structfield>sample_format</structfield> +field though, to function properly with other drivers.</para> + + <para>A VBI device may support <link + linkend="rw">read/write</link> and/or streaming (<link + linkend="mmap">memory mapping</link> or <link + linkend="userp">user pointer</link>) I/O. The latter bears the +possibility of synchronizing video and +VBI data by using buffer timestamps.</para> + + <para>Remember the &VIDIOC-STREAMON; ioctl and the first read(), +write() and select() call can be resource allocation points returning +an &EBUSY; if the required hardware resources are temporarily +unavailable, for example the device is already in use by another +process.</para> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-rds.xml b/Documentation/DocBook/media/v4l/dev-rds.xml new file mode 100644 index 00000000..38883a41 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-rds.xml @@ -0,0 +1,196 @@ + <title>RDS Interface</title> + + <para>The Radio Data System transmits supplementary +information in binary format, for example the station name or travel +information, on an inaudible audio subcarrier of a radio program. This +interface is aimed at devices capable of receiving and/or transmitting RDS +information.</para> + + <para>For more information see the core RDS standard <xref linkend="en50067" /> +and the RBDS standard <xref linkend="nrsc4" />.</para> + + <para>Note that the RBDS standard as is used in the USA is almost identical +to the RDS standard. Any RDS decoder/encoder can also handle RBDS. Only some of the +fields have slightly different meanings. See the RBDS standard for more +information.</para> + + <para>The RBDS standard also specifies support for MMBS (Modified Mobile Search). +This is a proprietary format which seems to be discontinued. The RDS interface does not +support this format. Should support for MMBS (or the so-called 'E blocks' in general) +be needed, then please contact the linux-media mailing list: &v4l-ml;.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the RDS capturing API set +the <constant>V4L2_CAP_RDS_CAPTURE</constant> flag in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. Any tuner that supports RDS +will set the <constant>V4L2_TUNER_CAP_RDS</constant> flag in +the <structfield>capability</structfield> field of &v4l2-tuner;. If +the driver only passes RDS blocks without interpreting the data +the <constant>V4L2_TUNER_CAP_RDS_BLOCK_IO</constant> flag has to be +set, see <link linkend="reading-rds-data">Reading RDS data</link>. +For future use the +flag <constant>V4L2_TUNER_CAP_RDS_CONTROLS</constant> has also been +defined. However, a driver for a radio tuner with this capability does +not yet exist, so if you are planning to write such a driver you +should discuss this on the linux-media mailing list: &v4l-ml;.</para> + + <para> Whether an RDS signal is present can be detected by looking +at the <structfield>rxsubchans</structfield> field of &v4l2-tuner;: +the <constant>V4L2_TUNER_SUB_RDS</constant> will be set if RDS data +was detected.</para> + + <para>Devices supporting the RDS output API +set the <constant>V4L2_CAP_RDS_OUTPUT</constant> flag in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. +Any modulator that supports RDS will set the +<constant>V4L2_TUNER_CAP_RDS</constant> flag in the <structfield>capability</structfield> +field of &v4l2-modulator;. +In order to enable the RDS transmission one must set the <constant>V4L2_TUNER_SUB_RDS</constant> +bit in the <structfield>txsubchans</structfield> field of &v4l2-modulator;. +If the driver only passes RDS blocks without interpreting the data +the <constant>V4L2_TUNER_CAP_RDS_BLOCK_IO</constant> flag has to be set. If the +tuner is capable of handling RDS entities like program identification codes and radio +text, the flag <constant>V4L2_TUNER_CAP_RDS_CONTROLS</constant> should be set, +see <link linkend="writing-rds-data">Writing RDS data</link> and +<link linkend="fm-tx-controls">FM Transmitter Control Reference</link>.</para> + </section> + + <section id="reading-rds-data"> + <title>Reading RDS data</title> + + <para>RDS data can be read from the radio device +with the &func-read; function. The data is packed in groups of three bytes.</para> + </section> + + <section id="writing-rds-data"> + <title>Writing RDS data</title> + + <para>RDS data can be written to the radio device +with the &func-write; function. The data is packed in groups of three bytes, +as follows:</para> + </section> + + <section> + <title>RDS datastructures</title> + <table frame="none" pgwide="1" id="v4l2-rds-data"> + <title>struct +<structname>v4l2_rds_data</structname></title> + <tgroup cols="3"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="5*" /> + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>lsb</structfield></entry> + <entry>Least Significant Byte of RDS Block</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>msb</structfield></entry> + <entry>Most Significant Byte of RDS Block</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>block</structfield></entry> + <entry>Block description</entry> + </row> + </tbody> + </tgroup> + </table> + <table frame="none" pgwide="1" id="v4l2-rds-block"> + <title>Block description</title> + <tgroup cols="2"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="5*" /> + <tbody valign="top"> + <row> + <entry>Bits 0-2</entry> + <entry>Block (aka offset) of the received data.</entry> + </row> + <row> + <entry>Bits 3-5</entry> + <entry>Deprecated. Currently identical to bits 0-2. Do not use these bits.</entry> + </row> + <row> + <entry>Bit 6</entry> + <entry>Corrected bit. Indicates that an error was corrected for this data block.</entry> + </row> + <row> + <entry>Bit 7</entry> + <entry>Error bit. Indicates that an uncorrectable error occurred during reception of this block.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-rds-block-codes"> + <title>Block defines</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="5*" /> + <tbody valign="top"> + <row> + <entry>V4L2_RDS_BLOCK_MSK</entry> + <entry> </entry> + <entry>7</entry> + <entry>Mask for bits 0-2 to get the block ID.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_A</entry> + <entry> </entry> + <entry>0</entry> + <entry>Block A.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_B</entry> + <entry> </entry> + <entry>1</entry> + <entry>Block B.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_C</entry> + <entry> </entry> + <entry>2</entry> + <entry>Block C.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_D</entry> + <entry> </entry> + <entry>3</entry> + <entry>Block D.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_C_ALT</entry> + <entry> </entry> + <entry>4</entry> + <entry>Block C'.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_INVALID</entry> + <entry>read-only</entry> + <entry>7</entry> + <entry>An invalid block.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_CORRECTED</entry> + <entry>read-only</entry> + <entry>0x40</entry> + <entry>A bit error was detected but corrected.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_ERROR</entry> + <entry>read-only</entry> + <entry>0x80</entry> + <entry>An uncorrectable error occurred.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml b/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml new file mode 100644 index 00000000..548f8ea2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml @@ -0,0 +1,699 @@ + <title>Sliced VBI Data Interface</title> + + <para>VBI stands for Vertical Blanking Interval, a gap in the +sequence of lines of an analog video signal. During VBI no picture +information is transmitted, allowing some time while the electron beam +of a cathode ray tube TV returns to the top of the screen.</para> + + <para>Sliced VBI devices use hardware to demodulate data transmitted +in the VBI. V4L2 drivers shall <emphasis>not</emphasis> do this by +software, see also the <link linkend="raw-vbi">raw VBI +interface</link>. The data is passed as short packets of fixed size, +covering one scan line each. The number of packets per video frame is +variable.</para> + + <para>Sliced VBI capture and output devices are accessed through the +same character special files as raw VBI devices. When a driver +supports both interfaces, the default function of a +<filename>/dev/vbi</filename> device is <emphasis>raw</emphasis> VBI +capturing or output, and the sliced VBI function is only available +after calling the &VIDIOC-S-FMT; ioctl as defined below. Likewise a +<filename>/dev/video</filename> device may support the sliced VBI API, +however the default function here is video capturing or output. +Different file descriptors must be used to pass raw and sliced VBI +data simultaneously, if this is supported by the driver.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the sliced VBI capturing or output API +set the <constant>V4L2_CAP_SLICED_VBI_CAPTURE</constant> or +<constant>V4L2_CAP_SLICED_VBI_OUTPUT</constant> flag respectively, in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. At least one of the +read/write, streaming or asynchronous <link linkend="io">I/O +methods</link> must be supported. Sliced VBI devices may have a tuner +or modulator.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Sliced VBI devices shall support <link linkend="video">video +input or output</link> and <link linkend="tuner">tuner or +modulator</link> ioctls if they have these capabilities, and they may +support <link linkend="control">control</link> ioctls. The <link +linkend="standard">video standard</link> ioctls provide information +vital to program a sliced VBI device, therefore must be +supported.</para> + </section> + + <section id="sliced-vbi-format-negotitation"> + <title>Sliced VBI Format Negotiation</title> + + <para>To find out which data services are supported by the +hardware applications can call the &VIDIOC-G-SLICED-VBI-CAP; ioctl. +All drivers implementing the sliced VBI interface must support this +ioctl. The results may differ from those of the &VIDIOC-S-FMT; ioctl +when the number of VBI lines the hardware can capture or output per +frame, or the number of services it can identify on a given line are +limited. For example on PAL line 16 the hardware may be able to look +for a VPS or Teletext signal, but not both at the same time.</para> + + <para>To determine the currently selected services applications +set the <structfield>type </structfield> field of &v4l2-format; to +<constant> V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> or <constant> +V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant>, and the &VIDIOC-G-FMT; +ioctl fills the <structfield>fmt.sliced</structfield> member, a +&v4l2-sliced-vbi-format;.</para> + + <para>Applications can request different parameters by +initializing or modifying the <structfield>fmt.sliced</structfield> +member and calling the &VIDIOC-S-FMT; ioctl with a pointer to the +<structname>v4l2_format</structname> structure.</para> + + <para>The sliced VBI API is more complicated than the raw VBI API +because the hardware must be told which VBI service to expect on each +scan line. Not all services may be supported by the hardware on all +lines (this is especially true for VBI output where Teletext is often +unsupported and other services can only be inserted in one specific +line). In many cases, however, it is sufficient to just set the +<structfield>service_set</structfield> field to the required services +and let the driver fill the <structfield>service_lines</structfield> +array according to hardware capabilities. Only if more precise control +is needed should the programmer set the +<structfield>service_lines</structfield> array explicitly.</para> + + <para>The &VIDIOC-S-FMT; ioctl modifies the parameters +according to hardware capabilities. When the driver allocates +resources at this point, it may return an &EBUSY; if the required +resources are temporarily unavailable. Other resource allocation +points which may return <errorcode>EBUSY</errorcode> can be the +&VIDIOC-STREAMON; ioctl and the first &func-read;, &func-write; and +&func-select; call.</para> + + <table frame="none" pgwide="1" id="v4l2-sliced-vbi-format"> + <title>struct +<structname>v4l2_sliced_vbi_format</structname></title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="3*" /> + <colspec colname="c2" colwidth="3*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec namest="c3" nameend="c5" spanname="hspan" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>service_set</structfield></entry> + <entry spanname="hspan"><para>If +<structfield>service_set</structfield> is non-zero when passed with +&VIDIOC-S-FMT; or &VIDIOC-TRY-FMT;, the +<structfield>service_lines</structfield> array will be filled by the +driver according to the services specified in this field. For example, +if <structfield>service_set</structfield> is initialized with +<constant>V4L2_SLICED_TELETEXT_B | V4L2_SLICED_WSS_625</constant>, a +driver for the cx25840 video decoder sets lines 7-22 of both +fields<footnote><para>According to <link +linkend="ets300706">ETS 300 706</link> lines 6-22 of the +first field and lines 5-22 of the second field may carry Teletext +data.</para></footnote> to <constant>V4L2_SLICED_TELETEXT_B</constant> +and line 23 of the first field to +<constant>V4L2_SLICED_WSS_625</constant>. If +<structfield>service_set</structfield> is set to zero, then the values +of <structfield>service_lines</structfield> will be used instead. +</para><para>On return the driver sets this field to the union of all +elements of the returned <structfield>service_lines</structfield> +array. It may contain less services than requested, perhaps just one, +if the hardware cannot handle more services simultaneously. It may be +empty (zero) if none of the requested services are supported by the +hardware.</para></entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>service_lines</structfield>[2][24]</entry> + <entry spanname="hspan"><para>Applications initialize this +array with sets of data services the driver shall look for or insert +on the respective scan line. Subject to hardware capabilities drivers +return the requested set, a subset, which may be just a single +service, or an empty set. When the hardware cannot handle multiple +services on the same line the driver shall choose one. No assumptions +can be made on which service the driver chooses.</para><para>Data +services are defined in <xref linkend="vbi-services2" />. Array indices +map to ITU-R line numbers (see also <xref linkend="vbi-525" /> and <xref + linkend="vbi-625" />) as follows: <!-- No nested +tables, sigh. --></para></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Element</entry> + <entry>525 line systems</entry> + <entry>625 line systems</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][1]</entry> + <entry align="center">1</entry> + <entry align="center">1</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][23]</entry> + <entry align="center">23</entry> + <entry align="center">23</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][1]</entry> + <entry align="center">264</entry> + <entry align="center">314</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][23]</entry> + <entry align="center">286</entry> + <entry align="center">336</entry> + </row> + <!-- End of line numbers table. --> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan">Drivers must set +<structfield>service_lines</structfield>[0][0] and +<structfield>service_lines</structfield>[1][0] to zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>io_size</structfield></entry> + <entry spanname="hspan">Maximum number of bytes passed by +one &func-read; or &func-write; call, and the buffer size in bytes for +the &VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. Drivers set this field to +the size of &v4l2-sliced-vbi-data; times the number of non-zero +elements in the returned <structfield>service_lines</structfield> +array (that is the number of lines potentially carrying data).</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry spanname="hspan">This array is reserved for future +extensions. Applications and drivers must set it to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- See also vidioc-g-sliced-vbi-cap.sgml --> + <table frame="none" pgwide="1" id="vbi-services2"> + <title>Sliced VBI services</title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="2*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec namest="c3" nameend="c5" spanname="rlp" /> + <thead> + <row> + <entry>Symbol</entry> + <entry>Value</entry> + <entry>Reference</entry> + <entry>Lines, usually</entry> + <entry>Payload</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_SLICED_TELETEXT_B</constant> +(Teletext System B)</entry> + <entry>0x0001</entry> + <entry><xref linkend="ets300706" />, <xref linkend="itu653" /></entry> + <entry>PAL/SECAM line 7-22, 320-335 (second field 7-22)</entry> + <entry>Last 42 of the 45 byte Teletext packet, that is +without clock run-in and framing code, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VPS</constant></entry> + <entry>0x0400</entry> + <entry><xref linkend="ets300231" /></entry> + <entry>PAL line 16</entry> + <entry>Byte number 3 to 15 according to Figure 9 of +ETS 300 231, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_CAPTION_525</constant></entry> + <entry>0x1000</entry> + <entry><xref linkend="eia608" /></entry> + <entry>NTSC line 21, 284 (second field 21)</entry> + <entry>Two bytes in transmission order, including parity +bit, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_WSS_625</constant></entry> + <entry>0x4000</entry> + <entry><xref linkend="itu1119" />, <xref linkend="en300294" /></entry> + <entry>PAL/SECAM line 23</entry> + <entry><screen> +Byte 0 1 + msb lsb msb lsb + Bit 7 6 5 4 3 2 1 0 x x 13 12 11 10 9 +</screen></entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_525</constant></entry> + <entry>0x1000</entry> + <entry spanname="rlp">Set of services applicable to 525 +line systems.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_625</constant></entry> + <entry>0x4401</entry> + <entry spanname="rlp">Set of services applicable to 625 +line systems.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Drivers may return an &EINVAL; when applications attempt to +read or write data without prior format negotiation, after switching +the video standard (which may invalidate the negotiated VBI +parameters) and after switching the video input (which may change the +video standard as a side effect). The &VIDIOC-S-FMT; ioctl may return +an &EBUSY; when applications attempt to change the format while i/o is +in progress (between a &VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; call, +and after the first &func-read; or &func-write; call).</para> + </section> + + <section> + <title>Reading and writing sliced VBI data</title> + + <para>A single &func-read; or &func-write; call must pass all data +belonging to one video frame. That is an array of +<structname>v4l2_sliced_vbi_data</structname> structures with one or +more elements and a total size not exceeding +<structfield>io_size</structfield> bytes. Likewise in streaming I/O +mode one buffer of <structfield>io_size</structfield> bytes must +contain data of one video frame. The <structfield>id</structfield> of +unused <structname>v4l2_sliced_vbi_data</structname> elements must be +zero.</para> + + <table frame="none" pgwide="1" id="v4l2-sliced-vbi-data"> + <title>struct +<structname>v4l2_sliced_vbi_data</structname></title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>A flag from <xref linkend="vbi-services" /> +identifying the type of data in this packet. Only a single bit must be +set. When the <structfield>id</structfield> of a captured packet is +zero, the packet is empty and the contents of other fields are +undefined. Applications shall ignore empty packets. When the +<structfield>id</structfield> of a packet for output is zero the +contents of the <structfield>data</structfield> field are undefined +and the driver must no longer insert data on the requested +<structfield>field</structfield> and +<structfield>line</structfield>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>field</structfield></entry> + <entry>The video field number this data has been captured +from, or shall be inserted at. <constant>0</constant> for the first +field, <constant>1</constant> for the second field.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>line</structfield></entry> + <entry>The field (as opposed to frame) line number this +data has been captured from, or shall be inserted at. See <xref + linkend="vbi-525" /> and <xref linkend="vbi-625" /> for valid +values. Sliced VBI capture devices can set the line number of all +packets to <constant>0</constant> if the hardware cannot reliably +identify scan lines. The field number must always be valid.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield></entry> + <entry>This field is reserved for future extensions. +Applications and drivers must set it to zero.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>data</structfield>[48]</entry> + <entry>The packet payload. See <xref + linkend="vbi-services" /> for the contents and number of +bytes passed for each data type. The contents of padding bytes at the +end of this array are undefined, drivers and applications shall ignore +them.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Packets are always passed in ascending line number order, +without duplicate line numbers. The &func-write; function and the +&VIDIOC-QBUF; ioctl must return an &EINVAL; when applications violate +this rule. They must also return an &EINVAL; when applications pass an +incorrect field or line number, or a combination of +<structfield>field</structfield>, <structfield>line</structfield> and +<structfield>id</structfield> which has not been negotiated with the +&VIDIOC-G-FMT; or &VIDIOC-S-FMT; ioctl. When the line numbers are +unknown the driver must pass the packets in transmitted order. The +driver can insert empty packets with <structfield>id</structfield> set +to zero anywhere in the packet array.</para> + + <para>To assure synchronization and to distinguish from frame +dropping, when a captured frame does not carry any of the requested +data services drivers must pass one or more empty packets. When an +application fails to pass VBI data in time for output, the driver +must output the last VPS and WSS packet again, and disable the output +of Closed Caption and Teletext data, or output data which is ignored +by Closed Caption and Teletext decoders.</para> + + <para>A sliced VBI device may support <link +linkend="rw">read/write</link> and/or streaming (<link +linkend="mmap">memory mapping</link> and/or <link linkend="userp">user +pointer</link>) I/O. The latter bears the possibility of synchronizing +video and VBI data by using buffer timestamps.</para> + + </section> + + <section> + <title>Sliced VBI Data in MPEG Streams</title> + + <para>If a device can produce an MPEG output stream, it may be +capable of providing <link +linkend="sliced-vbi-format-negotitation">negotiated sliced VBI +services</link> as data embedded in the MPEG stream. Users or +applications control this sliced VBI data insertion with the <link +linkend="v4l2-mpeg-stream-vbi-fmt">V4L2_CID_MPEG_STREAM_VBI_FMT</link> +control.</para> + + <para>If the driver does not provide the <link +linkend="v4l2-mpeg-stream-vbi-fmt">V4L2_CID_MPEG_STREAM_VBI_FMT</link> +control, or only allows that control to be set to <link +linkend="v4l2-mpeg-stream-vbi-fmt"><constant> +V4L2_MPEG_STREAM_VBI_FMT_NONE</constant></link>, then the device +cannot embed sliced VBI data in the MPEG stream.</para> + + <para>The <link linkend="v4l2-mpeg-stream-vbi-fmt"> +V4L2_CID_MPEG_STREAM_VBI_FMT</link> control does not implicitly set +the device driver to capture nor cease capturing sliced VBI data. The +control only indicates to embed sliced VBI data in the MPEG stream, if +an application has negotiated sliced VBI service be captured.</para> + + <para>It may also be the case that a device can embed sliced VBI +data in only certain types of MPEG streams: for example in an MPEG-2 +PS but not an MPEG-2 TS. In this situation, if sliced VBI data +insertion is requested, the sliced VBI data will be embedded in MPEG +stream types when supported, and silently omitted from MPEG stream +types where sliced VBI data insertion is not supported by the device. +</para> + + <para>The following subsections specify the format of the +embedded sliced VBI data.</para> + + <section> + <title>MPEG Stream Embedded, Sliced VBI Data Format: NONE</title> + <para>The <link linkend="v4l2-mpeg-stream-vbi-fmt"><constant> +V4L2_MPEG_STREAM_VBI_FMT_NONE</constant></link> embedded sliced VBI +format shall be interpreted by drivers as a control to cease +embedding sliced VBI data in MPEG streams. Neither the device nor +driver shall insert "empty" embedded sliced VBI data packets in the +MPEG stream when this format is set. No MPEG stream data structures +are specified for this format.</para> + </section> + + <section> + <title>MPEG Stream Embedded, Sliced VBI Data Format: IVTV</title> + <para>The <link linkend="v4l2-mpeg-stream-vbi-fmt"><constant> +V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant></link> embedded sliced VBI +format, when supported, indicates to the driver to embed up to 36 +lines of sliced VBI data per frame in an MPEG-2 <emphasis>Private +Stream 1 PES</emphasis> packet encapsulated in an MPEG-2 <emphasis> +Program Pack</emphasis> in the MPEG stream.</para> + + <para><emphasis>Historical context</emphasis>: This format +specification originates from a custom, embedded, sliced VBI data +format used by the <filename>ivtv</filename> driver. This format +has already been informally specified in the kernel sources in the +file <filename>Documentation/video4linux/cx2341x/README.vbi</filename> +. The maximum size of the payload and other aspects of this format +are driven by the CX23415 MPEG decoder's capabilities and limitations +with respect to extracting, decoding, and displaying sliced VBI data +embedded within an MPEG stream.</para> + + <para>This format's use is <emphasis>not</emphasis> exclusive to +the <filename>ivtv</filename> driver <emphasis>nor</emphasis> +exclusive to CX2341x devices, as the sliced VBI data packet insertion +into the MPEG stream is implemented in driver software. At least the +<filename>cx18</filename> driver provides sliced VBI data insertion +into an MPEG-2 PS in this format as well.</para> + + <para>The following definitions specify the payload of the +MPEG-2 <emphasis>Private Stream 1 PES</emphasis> packets that contain +sliced VBI data when <link linkend="v4l2-mpeg-stream-vbi-fmt"> +<constant>V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant></link> is set. +(The MPEG-2 <emphasis>Private Stream 1 PES</emphasis> packet header +and encapsulating MPEG-2 <emphasis>Program Pack</emphasis> header are +not detailed here. Please refer to the MPEG-2 specifications for +details on those packet headers.)</para> + + <para>The payload of the MPEG-2 <emphasis>Private Stream 1 PES +</emphasis> packets that contain sliced VBI data is specified by +&v4l2-mpeg-vbi-fmt-ivtv;. The payload is variable +length, depending on the actual number of lines of sliced VBI data +present in a video frame. The payload may be padded at the end with +unspecified fill bytes to align the end of the payload to a 4-byte +boundary. The payload shall never exceed 1552 bytes (2 fields with +18 lines/field with 43 bytes of data/line and a 4 byte magic number). +</para> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-fmt-ivtv"> + <title>struct <structname>v4l2_mpeg_vbi_fmt_ivtv</structname> + </title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>magic</structfield>[4]</entry> + <entry></entry> + <entry>A "magic" constant from <xref + linkend="v4l2-mpeg-vbi-fmt-ivtv-magic" /> that indicates +this is a valid sliced VBI data payload and also indicates which +member of the anonymous union, <structfield>itv0</structfield> or +<structfield>ITV0</structfield>, to use for the payload data.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0"> + <structname>v4l2_mpeg_vbi_itv0</structname></link> + </entry> + <entry><structfield>itv0</structfield></entry> + <entry>The primary form of the sliced VBI data payload +that contains anywhere from 1 to 35 lines of sliced VBI data. +Line masks are provided in this form of the payload indicating +which VBI lines are provided.</entry> + </row> + <row> + <entry></entry> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0-1"> + <structname>v4l2_mpeg_vbi_ITV0</structname></link> + </entry> + <entry><structfield>ITV0</structfield></entry> + <entry>An alternate form of the sliced VBI data payload +used when 36 lines of sliced VBI data are present. No line masks are +provided in this form of the payload; all valid line mask bits are +implcitly set.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-fmt-ivtv-magic"> + <title>Magic Constants for &v4l2-mpeg-vbi-fmt-ivtv; + <structfield>magic</structfield> field</title> + <tgroup cols="3"> + &cs-def; + <thead> + <row> + <entry align="left">Defined Symbol</entry> + <entry align="left">Value</entry> + <entry align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_MAGIC0</constant> + </entry> + <entry>"itv0"</entry> + <entry>Indicates the <structfield>itv0</structfield> +member of the union in &v4l2-mpeg-vbi-fmt-ivtv; is valid.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_MAGIC1</constant> + </entry> + <entry>"ITV0"</entry> + <entry>Indicates the <structfield>ITV0</structfield> +member of the union in &v4l2-mpeg-vbi-fmt-ivtv; is valid and +that 36 lines of sliced VBI data are present.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-itv0"> + <title>struct <structname>v4l2_mpeg_vbi_itv0</structname> + </title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__le32</entry> + <entry><structfield>linemask</structfield>[2]</entry> + <entry><para>Bitmasks indicating the VBI service lines +present. These <structfield>linemask</structfield> values are stored +in little endian byte order in the MPEG stream. Some reference +<structfield>linemask</structfield> bit positions with their +corresponding VBI line number and video field are given below. +b<subscript>0</subscript> indicates the least significant bit of a +<structfield>linemask</structfield> value:<screen> +<structfield>linemask</structfield>[0] b<subscript>0</subscript>: line 6 first field +<structfield>linemask</structfield>[0] b<subscript>17</subscript>: line 23 first field +<structfield>linemask</structfield>[0] b<subscript>18</subscript>: line 6 second field +<structfield>linemask</structfield>[0] b<subscript>31</subscript>: line 19 second field +<structfield>linemask</structfield>[1] b<subscript>0</subscript>: line 20 second field +<structfield>linemask</structfield>[1] b<subscript>3</subscript>: line 23 second field +<structfield>linemask</structfield>[1] b<subscript>4</subscript>-b<subscript>31</subscript>: unused and set to 0</screen></para></entry> + </row> + <row> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0-line"> + <structname>v4l2_mpeg_vbi_itv0_line</structname></link> + </entry> + <entry><structfield>line</structfield>[35]</entry> + <entry>This is a variable length array that holds from 1 +to 35 lines of sliced VBI data. The sliced VBI data lines present +correspond to the bits set in the <structfield>linemask</structfield> +array, starting from b<subscript>0</subscript> of <structfield> +linemask</structfield>[0] up through b<subscript>31</subscript> of +<structfield>linemask</structfield>[0], and from b<subscript>0 +</subscript> of <structfield>linemask</structfield>[1] up through b +<subscript>3</subscript> of <structfield>linemask</structfield>[1]. +<structfield>line</structfield>[0] corresponds to the first bit +found set in the <structfield>linemask</structfield> array, +<structfield>line</structfield>[1] corresponds to the second bit +found set in the <structfield>linemask</structfield> array, etc. +If no <structfield>linemask</structfield> array bits are set, then +<structfield>line</structfield>[0] may contain one line of +unspecified data that should be ignored by applications.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-itv0-1"> + <title>struct <structname>v4l2_mpeg_vbi_ITV0</structname> + </title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0-line"> + <structname>v4l2_mpeg_vbi_itv0_line</structname></link> + </entry> + <entry><structfield>line</structfield>[36]</entry> + <entry>A fixed length array of 36 lines of sliced VBI +data. <structfield>line</structfield>[0] through <structfield>line +</structfield>[17] correspond to lines 6 through 23 of the +first field. <structfield>line</structfield>[18] through +<structfield>line</structfield>[35] corresponds to lines 6 +through 23 of the second field.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-itv0-line"> + <title>struct <structname>v4l2_mpeg_vbi_itv0_line</structname> + </title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>id</structfield></entry> + <entry>A line identifier value from +<xref linkend="ITV0-Line-Identifier-Constants" /> that indicates +the type of sliced VBI data stored on this line.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>data</structfield>[42]</entry> + <entry>The sliced VBI data for the line.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="ITV0-Line-Identifier-Constants"> + <title>Line Identifiers for struct <link + linkend="v4l2-mpeg-vbi-itv0-line"><structname> +v4l2_mpeg_vbi_itv0_line</structname></link> <structfield>id +</structfield> field</title> + <tgroup cols="3"> + &cs-def; + <thead> + <row> + <entry align="left">Defined Symbol</entry> + <entry align="left">Value</entry> + <entry align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_TELETEXT_B</constant> + </entry> + <entry>1</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_CAPTION_525</constant> + </entry> + <entry>4</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_WSS_625</constant> + </entry> + <entry>5</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_VPS</constant> + </entry> + <entry>7</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + </tbody> + </tgroup> + </table> + + </section> + </section> diff --git a/Documentation/DocBook/media/v4l/dev-subdev.xml b/Documentation/DocBook/media/v4l/dev-subdev.xml new file mode 100644 index 00000000..0916a734 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-subdev.xml @@ -0,0 +1,313 @@ + <title>Sub-device Interface</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental">experimental</link> + interface and may change in the future.</para> + </note> + + <para>The complex nature of V4L2 devices, where hardware is often made of + several integrated circuits that need to interact with each other in a + controlled way, leads to complex V4L2 drivers. The drivers usually reflect + the hardware model in software, and model the different hardware components + as software blocks called sub-devices.</para> + + <para>V4L2 sub-devices are usually kernel-only objects. If the V4L2 driver + implements the media device API, they will automatically inherit from media + entities. Applications will be able to enumerate the sub-devices and discover + the hardware topology using the media entities, pads and links enumeration + API.</para> + + <para>In addition to make sub-devices discoverable, drivers can also choose + to make them directly configurable by applications. When both the sub-device + driver and the V4L2 device driver support this, sub-devices will feature a + character device node on which ioctls can be called to + <itemizedlist> + <listitem><para>query, read and write sub-devices controls</para></listitem> + <listitem><para>subscribe and unsubscribe to events and retrieve them</para></listitem> + <listitem><para>negotiate image formats on individual pads</para></listitem> + </itemizedlist> + </para> + + <para>Sub-device character device nodes, conventionally named + <filename>/dev/v4l-subdev*</filename>, use major number 81.</para> + + <section> + <title>Controls</title> + <para>Most V4L2 controls are implemented by sub-device hardware. Drivers + usually merge all controls and expose them through video device nodes. + Applications can control all sub-devices through a single interface.</para> + + <para>Complex devices sometimes implement the same control in different + pieces of hardware. This situation is common in embedded platforms, where + both sensors and image processing hardware implement identical functions, + such as contrast adjustment, white balance or faulty pixels correction. As + the V4L2 controls API doesn't support several identical controls in a single + device, all but one of the identical controls are hidden.</para> + + <para>Applications can access those hidden controls through the sub-device + node with the V4L2 control API described in <xref linkend="control" />. The + ioctls behave identically as when issued on V4L2 device nodes, with the + exception that they deal only with controls implemented in the sub-device. + </para> + + <para>Depending on the driver, those controls might also be exposed through + one (or several) V4L2 device nodes.</para> + </section> + + <section> + <title>Events</title> + <para>V4L2 sub-devices can notify applications of events as described in + <xref linkend="event" />. The API behaves identically as when used on V4L2 + device nodes, with the exception that it only deals with events generated by + the sub-device. Depending on the driver, those events might also be reported + on one (or several) V4L2 device nodes.</para> + </section> + + <section id="pad-level-formats"> + <title>Pad-level Formats</title> + + <warning><para>Pad-level formats are only applicable to very complex device that + need to expose low-level format configuration to user space. Generic V4L2 + applications do <emphasis>not</emphasis> need to use the API described in + this section.</para></warning> + + <note><para>For the purpose of this section, the term + <wordasword>format</wordasword> means the combination of media bus data + format, frame width and frame height.</para></note> + + <para>Image formats are typically negotiated on video capture and output + devices using the <link linkend="crop">cropping and scaling</link> ioctls. + The driver is responsible for configuring every block in the video pipeline + according to the requested format at the pipeline input and/or + output.</para> + + <para>For complex devices, such as often found in embedded systems, + identical image sizes at the output of a pipeline can be achieved using + different hardware configurations. One such example is shown on + <xref linkend="pipeline-scaling" />, where + image scaling can be performed on both the video sensor and the host image + processing hardware.</para> + + <figure id="pipeline-scaling"> + <title>Image Format Negotiation on Pipelines</title> + <mediaobject> + <imageobject> + <imagedata fileref="pipeline.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="pipeline.png" format="PNG" /> + </imageobject> + <textobject> + <phrase>High quality and high speed pipeline configuration</phrase> + </textobject> + </mediaobject> + </figure> + + <para>The sensor scaler is usually of less quality than the host scaler, but + scaling on the sensor is required to achieve higher frame rates. Depending + on the use case (quality vs. speed), the pipeline must be configured + differently. Applications need to configure the formats at every point in + the pipeline explicitly.</para> + + <para>Drivers that implement the <link linkend="media-controller-intro">media + API</link> can expose pad-level image format configuration to applications. + When they do, applications can use the &VIDIOC-SUBDEV-G-FMT; and + &VIDIOC-SUBDEV-S-FMT; ioctls. to negotiate formats on a per-pad basis.</para> + + <para>Applications are responsible for configuring coherent parameters on + the whole pipeline and making sure that connected pads have compatible + formats. The pipeline is checked for formats mismatch at &VIDIOC-STREAMON; + time, and an &EPIPE; is then returned if the configuration is + invalid.</para> + + <para>Pad-level image format configuration support can be tested by calling + the &VIDIOC-SUBDEV-G-FMT; ioctl on pad 0. If the driver returns an &EINVAL; + pad-level format configuration is not supported by the sub-device.</para> + + <section> + <title>Format Negotiation</title> + + <para>Acceptable formats on pads can (and usually do) depend on a number + of external parameters, such as formats on other pads, active links, or + even controls. Finding a combination of formats on all pads in a video + pipeline, acceptable to both application and driver, can't rely on formats + enumeration only. A format negotiation mechanism is required.</para> + + <para>Central to the format negotiation mechanism are the get/set format + operations. When called with the <structfield>which</structfield> argument + set to <constant>V4L2_SUBDEV_FORMAT_TRY</constant>, the + &VIDIOC-SUBDEV-G-FMT; and &VIDIOC-SUBDEV-S-FMT; ioctls operate on a set of + formats parameters that are not connected to the hardware configuration. + Modifying those 'try' formats leaves the device state untouched (this + applies to both the software state stored in the driver and the hardware + state stored in the device itself).</para> + + <para>While not kept as part of the device state, try formats are stored + in the sub-device file handles. A &VIDIOC-SUBDEV-G-FMT; call will return + the last try format set <emphasis>on the same sub-device file + handle</emphasis>. Several applications querying the same sub-device at + the same time will thus not interact with each other.</para> + + <para>To find out whether a particular format is supported by the device, + applications use the &VIDIOC-SUBDEV-S-FMT; ioctl. Drivers verify and, if + needed, change the requested <structfield>format</structfield> based on + device requirements and return the possibly modified value. Applications + can then choose to try a different format or accept the returned value and + continue.</para> + + <para>Formats returned by the driver during a negotiation iteration are + guaranteed to be supported by the device. In particular, drivers guarantee + that a returned format will not be further changed if passed to an + &VIDIOC-SUBDEV-S-FMT; call as-is (as long as external parameters, such as + formats on other pads or links' configuration are not changed).</para> + + <para>Drivers automatically propagate formats inside sub-devices. When a + try or active format is set on a pad, corresponding formats on other pads + of the same sub-device can be modified by the driver. Drivers are free to + modify formats as required by the device. However, they should comply with + the following rules when possible: + <itemizedlist> + <listitem><para>Formats should be propagated from sink pads to source pads. + Modifying a format on a source pad should not modify the format on any + sink pad.</para></listitem> + <listitem><para>Sub-devices that scale frames using variable scaling factors + should reset the scale factors to default values when sink pads formats + are modified. If the 1:1 scaling ratio is supported, this means that + source pads formats should be reset to the sink pads formats.</para></listitem> + </itemizedlist> + </para> + + <para>Formats are not propagated across links, as that would involve + propagating them from one sub-device file handle to another. Applications + must then take care to configure both ends of every link explicitly with + compatible formats. Identical formats on the two ends of a link are + guaranteed to be compatible. Drivers are free to accept different formats + matching device requirements as being compatible.</para> + + <para><xref linkend="sample-pipeline-config" /> + shows a sample configuration sequence for the pipeline described in + <xref linkend="pipeline-scaling" /> (table + columns list entity names and pad numbers).</para> + + <table pgwide="0" frame="none" id="sample-pipeline-config"> + <title>Sample Pipeline Configuration</title> + <tgroup cols="3"> + <colspec colname="what"/> + <colspec colname="sensor-0" /> + <colspec colname="frontend-0" /> + <colspec colname="frontend-1" /> + <colspec colname="scaler-0" /> + <colspec colname="scaler-1" /> + <thead> + <row> + <entry></entry> + <entry>Sensor/0</entry> + <entry>Frontend/0</entry> + <entry>Frontend/1</entry> + <entry>Scaler/0</entry> + <entry>Scaler/1</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry>Initial state</entry> + <entry>2048x1536</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + </row> + <row> + <entry>Configure frontend input</entry> + <entry>2048x1536</entry> + <entry><emphasis>2048x1536</emphasis></entry> + <entry><emphasis>2046x1534</emphasis></entry> + <entry>-</entry> + <entry>-</entry> + </row> + <row> + <entry>Configure scaler input</entry> + <entry>2048x1536</entry> + <entry>2048x1536</entry> + <entry>2046x1534</entry> + <entry><emphasis>2046x1534</emphasis></entry> + <entry><emphasis>2046x1534</emphasis></entry> + </row> + <row> + <entry>Configure scaler output</entry> + <entry>2048x1536</entry> + <entry>2048x1536</entry> + <entry>2046x1534</entry> + <entry>2046x1534</entry> + <entry><emphasis>1280x960</emphasis></entry> + </row> + </tbody> + </tgroup> + </table> + + <para> + <orderedlist> + <listitem><para>Initial state. The sensor output is set to its native 3MP + resolution. Resolutions on the host frontend and scaler input and output + pads are undefined.</para></listitem> + <listitem><para>The application configures the frontend input pad resolution to + 2048x1536. The driver propagates the format to the frontend output pad. + Note that the propagated output format can be different, as in this case, + than the input format, as the hardware might need to crop pixels (for + instance when converting a Bayer filter pattern to RGB or YUV).</para></listitem> + <listitem><para>The application configures the scaler input pad resolution to + 2046x1534 to match the frontend output resolution. The driver propagates + the format to the scaler output pad.</para></listitem> + <listitem><para>The application configures the scaler output pad resolution to + 1280x960.</para></listitem> + </orderedlist> + </para> + + <para>When satisfied with the try results, applications can set the active + formats by setting the <structfield>which</structfield> argument to + <constant>V4L2_SUBDEV_FORMAT_ACTIVE</constant>. Active formats are changed + exactly as try formats by drivers. To avoid modifying the hardware state + during format negotiation, applications should negotiate try formats first + and then modify the active settings using the try formats returned during + the last negotiation iteration. This guarantees that the active format + will be applied as-is by the driver without being modified. + </para> + </section> + + <section> + <title>Cropping and scaling</title> + + <para>Many sub-devices support cropping frames on their input or output + pads (or possible even on both). Cropping is used to select the area of + interest in an image, typically on a video sensor or video decoder. It can + also be used as part of digital zoom implementations to select the area of + the image that will be scaled up.</para> + + <para>Crop settings are defined by a crop rectangle and represented in a + &v4l2-rect; by the coordinates of the top left corner and the rectangle + size. Both the coordinates and sizes are expressed in pixels.</para> + + <para>The crop rectangle is retrieved and set using the + &VIDIOC-SUBDEV-G-CROP; and &VIDIOC-SUBDEV-S-CROP; ioctls. Like for pad + formats, drivers store try and active crop rectangles. The format + negotiation mechanism applies to crop settings as well.</para> + + <para>On input pads, cropping is applied relatively to the current pad + format. The pad format represents the image size as received by the + sub-device from the previous block in the pipeline, and the crop rectangle + represents the sub-image that will be transmitted further inside the + sub-device for processing. The crop rectangle be entirely containted + inside the input image size.</para> + + <para>Input crop rectangle are reset to their default value when the input + image format is modified. Drivers should use the input image size as the + crop rectangle default value, but hardware requirements may prevent this. + </para> + + <para>Cropping behaviour on output pads is not defined.</para> + + </section> + </section> + + &sub-subdev-formats; diff --git a/Documentation/DocBook/media/v4l/dev-teletext.xml b/Documentation/DocBook/media/v4l/dev-teletext.xml new file mode 100644 index 00000000..bd21c64d --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-teletext.xml @@ -0,0 +1,29 @@ + <title>Teletext Interface</title> + + <para>This interface was aimed at devices receiving and demodulating +Teletext data [<xref linkend="ets300706" />, <xref linkend="itu653" />], evaluating the +Teletext packages and storing formatted pages in cache memory. Such +devices are usually implemented as microcontrollers with serial +interface (I<superscript>2</superscript>C) and could be found on old +TV cards, dedicated Teletext decoding cards and home-brew devices +connected to the PC parallel port.</para> + + <para>The Teletext API was designed by Martin Buck. It was defined in +the kernel header file <filename>linux/videotext.h</filename>, the +specification is available from <ulink url="ftp://ftp.gwdg.de/pub/linux/misc/videotext/"> +ftp://ftp.gwdg.de/pub/linux/misc/videotext/</ulink>. (Videotext is the name of +the German public television Teletext service.)</para> + + <para>Eventually the Teletext API was integrated into the V4L API +with character device file names <filename>/dev/vtx0</filename> to +<filename>/dev/vtx31</filename>, device major number 81, minor numbers +192 to 223.</para> + + <para>However, teletext decoders were quickly replaced by more +generic VBI demodulators and those dedicated teletext decoders no longer exist. +For many years the vtx devices were still around, even though nobody used +them. So the decision was made to finally remove support for the Teletext API in +kernel 2.6.37.</para> + + <para>Modern devices all use the <link linkend="raw-vbi">raw</link> or +<link linkend="sliced">sliced</link> VBI API.</para> diff --git a/Documentation/DocBook/media/v4l/driver.xml b/Documentation/DocBook/media/v4l/driver.xml new file mode 100644 index 00000000..eacafe31 --- /dev/null +++ b/Documentation/DocBook/media/v4l/driver.xml @@ -0,0 +1,200 @@ + <title>V4L2 Driver Programming</title> + + <!-- This part defines the interface between the "videodev" + module and individual drivers. --> + + <para>to do</para> +<!-- + <para>V4L2 is a two-layer driver system. The top layer is the "videodev" +kernel module. When videodev initializes it registers as character device +with major number 81, and it registers a set of file operations. All V4L2 +drivers are really clients of videodev, which calls V4L2 drivers through +driver method functions. V4L2 drivers are also written as kernel modules. +After probing the hardware they register one or more devices with +videodev.</para> + + <section id="driver-modules"> + <title>Driver Modules</title> + + <para>V4L2 driver modules must have an initialization function which is +called after the module was loaded into kernel, an exit function whis is +called before the module is removed. When the driver is compiled into the +kernel these functions called at system boot and shutdown time.</para> + + <informalexample> + <programlisting> +#include <linux/module.h> + +/* Export information about this module. For details and other useful + macros see <filename>linux/module.h</filename>. */ +MODULE_DESCRIPTION("my - driver for my hardware"); +MODULE_AUTHOR("Your name here"); +MODULE_LICENSE("GPL"); + +static void +my_module_exit (void) +{ + /* Free all resources allocated by my_module_init(). */ +} + +static int +my_module_init (void) +{ + /* Bind the driver to the supported hardware, see + <link linkend="driver-pci"> and + <link linkend="driver-usb"> for examples. */ + + return 0; /* a negative value on error, 0 on success. */ +} + +/* Export module functions. */ +module_init (my_module_init); +module_exit (my_module_exit); +</programlisting> + </informalexample> + + <para>Users can add parameters when kernel modules are inserted:</para> + + <informalexample> + <programlisting> +include <linux/moduleparam.h> + +static int my_option = 123; +static int my_option_array[47]; + +/* Export the symbol, an int, with access permissions 0664. + See <filename>linux/moduleparam.h</filename> for other types. */ +module_param (my_option, int, 0644); +module_param_array (my_option_array, int, NULL, 0644); + +MODULE_PARM_DESC (my_option, "Does magic things, default 123"); +</programlisting> + </informalexample> + + <para>One parameter should be supported by all V4L2 drivers, the minor +number of the device it will register. Purpose is to predictably link V4L2 +drivers to device nodes if more than one video device is installed. Use the +name of the device node followed by a "_nr" suffix, for example "video_nr" +for <filename>/dev/video</filename>.</para> + + <informalexample> + <programlisting> +/* Minor number of the device, -1 to allocate the first unused. */ +static int video_nr = -1; + +module_param (video_nr, int, 0444); +</programlisting> + </informalexample> + </section> + + <section id="driver-pci"> + <title>PCI Devices</title> + + <para>PCI devices are initialized like this:</para> + + <informalexample> + <programlisting> +typedef struct { + /* State of one physical device. */ +} my_device; + +static int +my_resume (struct pci_dev * pci_dev) +{ + /* Restore the suspended device to working state. */ +} + +static int +my_suspend (struct pci_dev * pci_dev, + pm_message_t state) +{ + /* This function is called before the system goes to sleep. + Stop all DMAs and disable interrupts, then put the device + into a low power state. For details see the kernel + sources under <filename>Documentation/power</filename>. */ + + return 0; /* a negative value on error, 0 on success. */ +} + +static void __devexit +my_remove (struct pci_dev * pci_dev) +{ + my_device *my = pci_get_drvdata (pci_dev); + + /* Describe me. */ +} + +static int __devinit +my_probe (struct pci_dev * pci_dev, + const struct pci_device_id * pci_id) +{ + my_device *my; + + /* Describe me. */ + + /* You can allocate per-device data here and store a pointer + to it in the pci_dev structure. */ + my = ...; + pci_set_drvdata (pci_dev, my); + + return 0; /* a negative value on error, 0 on success. */ +} + +/* A list of supported PCI devices. */ +static struct pci_device_id +my_pci_device_ids [] = { + { PCI_VENDOR_ID_FOO, PCI_DEVICE_ID_BAR, + PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 }, + { 0 } /* end of list */ +}; + +/* Load our module if supported PCI devices are installed. */ +MODULE_DEVICE_TABLE (pci, my_pci_device_ids); + +static struct pci_driver +my_pci_driver = { + .name = "my", + .id_table = my_pci_device_ids, + + .probe = my_probe, + .remove = __devexit_p (my_remove), + + /* Power management functions. */ + .suspend = my_suspend, + .resume = my_resume, +}; + +static void +my_module_exit (void) +{ + pci_unregister_driver (&my_pci_driver); +} + +static int +my_module_init (void) +{ + return pci_register_driver (&my_pci_driver); +} +</programlisting> + </informalexample> + </section> + + <section id="driver-usb"> + <title>USB Devices</title> + <para>to do</para> + </section> + <section id="driver-registering"> + <title>Registering V4L2 Drivers</title> + + <para>After a V4L2 driver probed the hardware it registers one or more +devices with the videodev module.</para> + </section> + <section id="driver-file-ops"> + <title>File Operations</title> + <para>to do</para> + </section> + <section id="driver-internal-api"> + <title>Internal API</title> + <para>to do</para> + </section> +--> diff --git a/Documentation/DocBook/media/v4l/fdl-appendix.xml b/Documentation/DocBook/media/v4l/fdl-appendix.xml new file mode 100644 index 00000000..ae22394b --- /dev/null +++ b/Documentation/DocBook/media/v4l/fdl-appendix.xml @@ -0,0 +1,671 @@ +<!-- + The GNU Free Documentation License 1.1 in DocBook + Markup by Eric Baudais <baudais@okstate.edu> + Maintained by the GNOME Documentation Project + http://live.gnome.org/DocumentationProject + Version: 1.0.1 + Last Modified: Nov 16, 2000 +--> + +<appendix id="fdl"> + <appendixinfo> + <releaseinfo> + Version 1.1, March 2000 + </releaseinfo> + <copyright> + <year>2000</year><holder>Free Software Foundation, Inc.</holder> + </copyright> + <legalnotice id="fdl-legalnotice"> + <para> + <address>Free Software Foundation, Inc. <street>59 Temple Place, + Suite 330</street>, <city>Boston</city>, <state>MA</state> + <postcode>02111-1307</postcode> <country>USA</country></address> + Everyone is permitted to copy and distribute verbatim copies of this + license document, but changing it is not allowed. + </para> + </legalnotice> + </appendixinfo> + <title>GNU Free Documentation License</title> + + <sect1 id="fdl-preamble"> + <title>0. PREAMBLE</title> + <para> + The purpose of this License is to make a manual, textbook, or + other written document <quote>free</quote> in the sense of + freedom: to assure everyone the effective freedom to copy and + redistribute it, with or without modifying it, either + commercially or noncommercially. Secondarily, this License + preserves for the author and publisher a way to get credit for + their work, while not being considered responsible for + modifications made by others. + </para> + + <para> + This License is a kind of <quote>copyleft</quote>, which means + that derivative works of the document must themselves be free in + the same sense. It complements the GNU General Public License, + which is a copyleft license designed for free software. + </para> + + <para> + We have designed this License in order to use it for manuals for + free software, because free software needs free documentation: a + free program should come with manuals providing the same + freedoms that the software does. But this License is not limited + to software manuals; it can be used for any textual work, + regardless of subject matter or whether it is published as a + printed book. We recommend this License principally for works + whose purpose is instruction or reference. + </para> + </sect1> + <sect1 id="fdl-section1"> + <title>1. APPLICABILITY AND DEFINITIONS</title> + <para id="fdl-document"> + This License applies to any manual or other work that contains a + notice placed by the copyright holder saying it can be + distributed under the terms of this License. The + <quote>Document</quote>, below, refers to any such manual or + work. 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These titles must be + distinct from any other section titles. + </para> + + <para> + You may add a section entitled <quote>Endorsements</quote>, + provided it contains nothing but endorsements of your <link + linkend="fdl-modified">Modified Version</link> by various + parties--for example, statements of peer review or that the text + has been approved by an organization as the authoritative + definition of a standard. + </para> + + <para> + You may add a passage of up to five words as a <link + linkend="fdl-cover-texts">Front-Cover Text</link>, and a passage + of up to 25 words as a <link + linkend="fdl-cover-texts">Back-Cover Text</link>, to the end of + the list of <link linkend="fdl-cover-texts">Cover Texts</link> + in the <link linkend="fdl-modified">Modified Version</link>. + Only one passage of Front-Cover Text and one of Back-Cover Text + may be added by (or through arrangements made by) any one + entity. 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COMBINING DOCUMENTS</title> + <para> + You may combine the <link linkend="fdl-document">Document</link> + with other documents released under this License, under the + terms defined in <link linkend="fdl-section4">section 4</link> + above for modified versions, provided that you include in the + combination all of the <link linkend="fdl-invariant">Invariant + Sections</link> of all of the original documents, unmodified, + and list them all as Invariant Sections of your combined work in + its license notice. + </para> + + <para> + The combined work need only contain one copy of this License, + and multiple identical <link linkend="fdl-invariant">Invariant + Sections</link> may be replaced with a single copy. If there are + multiple Invariant Sections with the same name but different + contents, make the title of each such section unique by adding + at the end of it, in parentheses, the name of the original + author or publisher of that section if known, or else a unique + number. 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COLLECTIONS OF DOCUMENTS</title> + <para> + You may make a collection consisting of the <link + linkend="fdl-document">Document</link> and other documents + released under this License, and replace the individual copies + of this License in the various documents with a single copy that + is included in the collection, provided that you follow the + rules of this License for verbatim copying of each of the + documents in all other respects. + </para> + + <para> + You may extract a single document from such a collection, and + dispbibute it individually under this License, provided you + insert a copy of this License into the extracted document, and + follow this License in all other respects regarding verbatim + copying of that document. + </para> + </sect1> + + <sect1 id="fdl-section7"> + <title>7. 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However, + parties who have received copies, or rights, from you under this + License will not have their licenses terminated so long as such + parties remain in full compliance. + </para> + </sect1> + + <sect1 id="fdl-section10"> + <title>10. FUTURE REVISIONS OF THIS LICENSE</title> + <para> + The <ulink type="http" + url="http://www.gnu.org/fsf/fsf.html">Free Software + Foundation</ulink> may publish new, revised versions of the GNU + Free Documentation License from time to time. Such new versions + will be similar in spirit to the present version, but may differ + in detail to address new problems or concerns. See <ulink + type="http" + url="http://www.gnu.org/copyleft">http://www.gnu.org/copyleft/</ulink>. + </para> + + <para> + Each version of the License is given a distinguishing version + number. If the <link linkend="fdl-document">Document</link> + specifies that a particular numbered version of this License + <quote>or any later version</quote> applies to it, you have the + option of following the terms and conditions either of that + specified version or of any later version that has been + published (not as a draft) by the Free Software Foundation. If + the Document does not specify a version number of this License, + you may choose any version ever published (not as a draft) by + the Free Software Foundation. + </para> + </sect1> + + <sect1 id="fdl-using"> + <title>Addendum</title> + <para> + To use this License in a document you have written, include a copy of + the License in the document and put the following copyright and + license notices just after the title page: + </para> + + <blockquote> + <para> + Copyright © YEAR YOUR NAME. + </para> + <para> + Permission is granted to copy, distribute and/or modify this + document under the terms of the GNU Free Documentation + License, Version 1.1 or any later version published by the + Free Software Foundation; with the <link + linkend="fdl-invariant">Invariant Sections</link> being LIST + THEIR TITLES, with the <link + linkend="fdl-cover-texts">Front-Cover Texts</link> being LIST, + and with the <link linkend="fdl-cover-texts">Back-Cover + Texts</link> being LIST. A copy of the license is included in + the section entitled <quote>GNU Free Documentation + License</quote>. + </para> + </blockquote> + + <para> + If you have no <link linkend="fdl-invariant">Invariant + Sections</link>, write <quote>with no Invariant Sections</quote> + instead of saying which ones are invariant. If you have no + <link linkend="fdl-cover-texts">Front-Cover Texts</link>, write + <quote>no Front-Cover Texts</quote> instead of + <quote>Front-Cover Texts being LIST</quote>; likewise for <link + linkend="fdl-cover-texts">Back-Cover Texts</link>. + </para> + + <para> + If your document contains nontrivial examples of program code, + we recommend releasing these examples in parallel under your + choice of free software license, such as the <ulink type="http" + url="http://www.gnu.org/copyleft/gpl.html"> GNU General Public + License</ulink>, to permit their use in free software. + </para> + </sect1> +</appendix> + + + + + + diff --git a/Documentation/DocBook/media/v4l/fieldseq_bt.pdf b/Documentation/DocBook/media/v4l/fieldseq_bt.pdf Binary files differnew file mode 100644 index 00000000..26598b23 --- /dev/null +++ b/Documentation/DocBook/media/v4l/fieldseq_bt.pdf diff --git a/Documentation/DocBook/media/v4l/fieldseq_tb.pdf b/Documentation/DocBook/media/v4l/fieldseq_tb.pdf Binary files differnew file mode 100644 index 00000000..4965b22d --- /dev/null +++ b/Documentation/DocBook/media/v4l/fieldseq_tb.pdf diff --git a/Documentation/DocBook/media/v4l/func-close.xml b/Documentation/DocBook/media/v4l/func-close.xml new file mode 100644 index 00000000..232920d2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-close.xml @@ -0,0 +1,62 @@ +<refentry id="func-close"> + <refmeta> + <refentrytitle>V4L2 close()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-close</refname> + <refpurpose>Close a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>close</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Closes the device. Any I/O in progress is terminated and +resources associated with the file descriptor are freed. However data +format parameters, current input or output, control values or other +properties remain unchanged.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>The function returns <returnvalue>0</returnvalue> on +success, <returnvalue>-1</returnvalue> on failure and the +<varname>errno</varname> is set appropriately. Possible error +codes:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid open file +descriptor.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-ioctl.xml b/Documentation/DocBook/media/v4l/func-ioctl.xml new file mode 100644 index 00000000..4394184a --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-ioctl.xml @@ -0,0 +1,71 @@ +<refentry id="func-ioctl"> + <refmeta> + <refentrytitle>V4L2 ioctl()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-ioctl</refname> + <refpurpose>Program a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <sys/ioctl.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>void *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>V4L2 ioctl request code as defined in the <filename>videodev2.h</filename> header file, for example +VIDIOC_QUERYCAP.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a function parameter, usually a structure.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The <function>ioctl()</function> function is used to program +V4L2 devices. The argument <parameter>fd</parameter> must be an open +file descriptor. An ioctl <parameter>request</parameter> has encoded +in it whether the argument is an input, output or read/write +parameter, and the size of the argument <parameter>argp</parameter> in +bytes. Macros and defines specifying V4L2 ioctl requests are located +in the <filename>videodev2.h</filename> header file. +Applications should use their own copy, not include the version in the +kernel sources on the system they compile on. All V4L2 ioctl requests, +their respective function and parameters are specified in <xref + linkend="user-func" />.</para> + </refsect1> + + <refsect1> + &return-value; + <para>When an ioctl that takes an output or read/write parameter fails, + the parameter remains unmodified.</para> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-mmap.xml b/Documentation/DocBook/media/v4l/func-mmap.xml new file mode 100644 index 00000000..f31ad71b --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-mmap.xml @@ -0,0 +1,183 @@ +<refentry id="func-mmap"> + <refmeta> + <refentrytitle>V4L2 mmap()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-mmap</refname> + <refpurpose>Map device memory into application address space</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo> +#include <unistd.h> +#include <sys/mman.h></funcsynopsisinfo> + <funcprototype> + <funcdef>void *<function>mmap</function></funcdef> + <paramdef>void *<parameter>start</parameter></paramdef> + <paramdef>size_t <parameter>length</parameter></paramdef> + <paramdef>int <parameter>prot</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>off_t <parameter>offset</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + <variablelist> + <varlistentry> + <term><parameter>start</parameter></term> + <listitem> + <para>Map the buffer to this address in the +application's address space. When the <constant>MAP_FIXED</constant> +flag is specified, <parameter>start</parameter> must be a multiple of the +pagesize and mmap will fail when the specified address +cannot be used. Use of this option is discouraged; applications should +just specify a <constant>NULL</constant> pointer here.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>length</parameter></term> + <listitem> + <para>Length of the memory area to map. This must be the +same value as returned by the driver in the &v4l2-buffer; +<structfield>length</structfield> field for the +single-planar API, and the same value as returned by the driver +in the &v4l2-plane; <structfield>length</structfield> field for the +multi-planar API.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>prot</parameter></term> + <listitem> + <para>The <parameter>prot</parameter> argument describes the +desired memory protection. Regardless of the device type and the +direction of data exchange it should be set to +<constant>PROT_READ</constant> | <constant>PROT_WRITE</constant>, +permitting read and write access to image buffers. Drivers should +support at least this combination of flags. Note the Linux +<filename>video-buf</filename> kernel module, which is used by the +bttv, saa7134, saa7146, cx88 and vivi driver supports only +<constant>PROT_READ</constant> | <constant>PROT_WRITE</constant>. When +the driver does not support the desired protection the +<function>mmap()</function> function fails.</para> + <para>Note device memory accesses (⪚ the memory on a +graphics card with video capturing hardware) may incur a performance +penalty compared to main memory accesses, or reads may be +significantly slower than writes or vice versa. Other I/O methods may +be more efficient in this case.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>flags</parameter></term> + <listitem> + <para>The <parameter>flags</parameter> parameter +specifies the type of the mapped object, mapping options and whether +modifications made to the mapped copy of the page are private to the +process or are to be shared with other references.</para> + <para><constant>MAP_FIXED</constant> requests that the +driver selects no other address than the one specified. If the +specified address cannot be used, <function>mmap()</function> will fail. If +<constant>MAP_FIXED</constant> is specified, +<parameter>start</parameter> must be a multiple of the pagesize. Use +of this option is discouraged.</para> + <para>One of the <constant>MAP_SHARED</constant> or +<constant>MAP_PRIVATE</constant> flags must be set. +<constant>MAP_SHARED</constant> allows applications to share the +mapped memory with other (⪚ child-) processes. Note the Linux +<filename>video-buf</filename> module which is used by the bttv, +saa7134, saa7146, cx88 and vivi driver supports only +<constant>MAP_SHARED</constant>. <constant>MAP_PRIVATE</constant> +requests copy-on-write semantics. V4L2 applications should not set the +<constant>MAP_PRIVATE</constant>, <constant>MAP_DENYWRITE</constant>, +<constant>MAP_EXECUTABLE</constant> or <constant>MAP_ANON</constant> +flag.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>offset</parameter></term> + <listitem> + <para>Offset of the buffer in device memory. This must be the +same value as returned by the driver in the &v4l2-buffer; +<structfield>m</structfield> union <structfield>offset</structfield> field for +the single-planar API, and the same value as returned by the driver +in the &v4l2-plane; <structfield>m</structfield> union +<structfield>mem_offset</structfield> field for the multi-planar API.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The <function>mmap()</function> function asks to map +<parameter>length</parameter> bytes starting at +<parameter>offset</parameter> in the memory of the device specified by +<parameter>fd</parameter> into the application address space, +preferably at address <parameter>start</parameter>. This latter +address is a hint only, and is usually specified as 0.</para> + + <para>Suitable length and offset parameters are queried with the +&VIDIOC-QUERYBUF; ioctl. Buffers must be allocated with the +&VIDIOC-REQBUFS; ioctl before they can be queried.</para> + + <para>To unmap buffers the &func-munmap; function is used.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success <function>mmap()</function> returns a pointer to +the mapped buffer. On error <constant>MAP_FAILED</constant> (-1) is +returned, and the <varname>errno</varname> variable is set +appropriately. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid file +descriptor.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is +not open for reading and writing.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>start</parameter> or +<parameter>length</parameter> or <parameter>offset</parameter> are not +suitable. (E. g. they are too large, or not aligned on a +<constant>PAGESIZE</constant> boundary.)</para> + <para>The <parameter>flags</parameter> or +<parameter>prot</parameter> value is not supported.</para> + <para>No buffers have been allocated with the +&VIDIOC-REQBUFS; ioctl.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Not enough physical or virtual memory was available to +complete the request.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-munmap.xml b/Documentation/DocBook/media/v4l/func-munmap.xml new file mode 100644 index 00000000..860d49ca --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-munmap.xml @@ -0,0 +1,76 @@ +<refentry id="func-munmap"> + <refmeta> + <refentrytitle>V4L2 munmap()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-munmap</refname> + <refpurpose>Unmap device memory</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo> +#include <unistd.h> +#include <sys/mman.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>munmap</function></funcdef> + <paramdef>void *<parameter>start</parameter></paramdef> + <paramdef>size_t <parameter>length</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + <refsect1> + <title>Arguments</title> + <variablelist> + <varlistentry> + <term><parameter>start</parameter></term> + <listitem> + <para>Address of the mapped buffer as returned by the +&func-mmap; function.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>length</parameter></term> + <listitem> + <para>Length of the mapped buffer. This must be the same +value as given to <function>mmap()</function> and returned by the +driver in the &v4l2-buffer; <structfield>length</structfield> +field for the single-planar API and in the &v4l2-plane; +<structfield>length</structfield> field for the multi-planar API.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Unmaps a previously with the &func-mmap; function mapped +buffer and frees it, if possible. <!-- ? This function (not freeing) +has no impact on I/O in progress, specifically it does not imply +&VIDIOC-STREAMOFF; to terminate I/O. Unmapped buffers can still be +enqueued, dequeued or queried, they are just not accessible by the +application.--></para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success <function>munmap()</function> returns 0, on +failure -1 and the <varname>errno</varname> variable is set +appropriately:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>start</parameter> or +<parameter>length</parameter> is incorrect, or no buffers have been +mapped yet.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-open.xml b/Documentation/DocBook/media/v4l/func-open.xml new file mode 100644 index 00000000..cf64e207 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-open.xml @@ -0,0 +1,113 @@ +<refentry id="func-open"> + <refmeta> + <refentrytitle>V4L2 open()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-open</refname> + <refpurpose>Open a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <fcntl.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>open</function></funcdef> + <paramdef>const char *<parameter>device_name</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>device_name</parameter></term> + <listitem> + <para>Device to be opened.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>flags</parameter></term> + <listitem> + <para>Open flags. Access mode must be +<constant>O_RDWR</constant>. This is just a technicality, input devices +still support only reading and output devices only writing.</para> + <para>When the <constant>O_NONBLOCK</constant> flag is +given, the read() function and the &VIDIOC-DQBUF; ioctl will return +the &EAGAIN; when no data is available or no buffer is in the driver +outgoing queue, otherwise these functions block until data becomes +available. All V4L2 drivers exchanging data with applications must +support the <constant>O_NONBLOCK</constant> flag.</para> + <para>Other flags have no effect.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1> + <title>Description</title> + + <para>To open a V4L2 device applications call +<function>open()</function> with the desired device name. This +function has no side effects; all data format parameters, current +input or output, control values or other properties remain unchanged. +At the first <function>open()</function> call after loading the driver +they will be reset to default values, drivers are never in an +undefined state.</para> + </refsect1> + <refsect1> + <title>Return Value</title> + + <para>On success <function>open</function> returns the new file +descriptor. On error -1 is returned, and the <varname>errno</varname> +variable is set appropriately. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>The caller has no permission to access the +device.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple opens and the +device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENXIO</errorcode></term> + <listitem> + <para>No device corresponding to this device special file +exists.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Not enough kernel memory was available to complete the +request.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EMFILE</errorcode></term> + <listitem> + <para>The process already has the maximum number of +files open.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENFILE</errorcode></term> + <listitem> + <para>The limit on the total number of files open on the +system has been reached.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-poll.xml b/Documentation/DocBook/media/v4l/func-poll.xml new file mode 100644 index 00000000..85cad8bf --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-poll.xml @@ -0,0 +1,119 @@ +<refentry id="func-poll"> + <refmeta> + <refentrytitle>V4L2 poll()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-poll</refname> + <refpurpose>Wait for some event on a file descriptor</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <sys/poll.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>poll</function></funcdef> + <paramdef>struct pollfd *<parameter>ufds</parameter></paramdef> + <paramdef>unsigned int <parameter>nfds</parameter></paramdef> + <paramdef>int <parameter>timeout</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>With the <function>poll()</function> function applications +can suspend execution until the driver has captured data or is ready +to accept data for output.</para> + + <para>When streaming I/O has been negotiated this function waits +until a buffer has been filled or displayed and can be dequeued with +the &VIDIOC-DQBUF; ioctl. When buffers are already in the outgoing +queue of the driver the function returns immediately.</para> + + <para>On success <function>poll()</function> returns the number of +file descriptors that have been selected (that is, file descriptors +for which the <structfield>revents</structfield> field of the +respective <structname>pollfd</structname> structure is non-zero). +Capture devices set the <constant>POLLIN</constant> and +<constant>POLLRDNORM</constant> flags in the +<structfield>revents</structfield> field, output devices the +<constant>POLLOUT</constant> and <constant>POLLWRNORM</constant> +flags. When the function timed out it returns a value of zero, on +failure it returns <returnvalue>-1</returnvalue> and the +<varname>errno</varname> variable is set appropriately. When the +application did not call &VIDIOC-QBUF; or &VIDIOC-STREAMON; yet the +<function>poll()</function> function succeeds, but sets the +<constant>POLLERR</constant> flag in the +<structfield>revents</structfield> field.</para> + + <para>When use of the <function>read()</function> function has +been negotiated and the driver does not capture yet, the +<function>poll</function> function starts capturing. When that fails +it returns a <constant>POLLERR</constant> as above. Otherwise it waits +until data has been captured and can be read. When the driver captures +continuously (as opposed to, for example, still images) the function +may return immediately.</para> + + <para>When use of the <function>write()</function> function has +been negotiated the <function>poll</function> function just waits +until the driver is ready for a non-blocking +<function>write()</function> call.</para> + + <para>All drivers implementing the <function>read()</function> or +<function>write()</function> function or streaming I/O must also +support the <function>poll()</function> function.</para> + + <para>For more details see the +<function>poll()</function> manual page.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>poll()</function> returns the number +structures which have non-zero <structfield>revents</structfield> +fields, or zero if the call timed out. On error +<returnvalue>-1</returnvalue> is returned, and the +<varname>errno</varname> variable is set appropriately:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para>One or more of the <parameter>ufds</parameter> members +specify an invalid file descriptor.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple read or write +streams and the device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>ufds</parameter> references an inaccessible +memory area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>nfds</parameter> argument is greater +than <constant>OPEN_MAX</constant>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-read.xml b/Documentation/DocBook/media/v4l/func-read.xml new file mode 100644 index 00000000..e218bbfb --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-read.xml @@ -0,0 +1,181 @@ +<refentry id="func-read"> + <refmeta> + <refentrytitle>V4L2 read()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-read</refname> + <refpurpose>Read from a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>ssize_t <function>read</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>void *<parameter>buf</parameter></paramdef> + <paramdef>size_t <parameter>count</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>buf</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>count</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para><function>read()</function> attempts to read up to +<parameter>count</parameter> bytes from file descriptor +<parameter>fd</parameter> into the buffer starting at +<parameter>buf</parameter>. The layout of the data in the buffer is +discussed in the respective device interface section, see ##. If <parameter>count</parameter> is zero, +<function>read()</function> returns zero and has no other results. If +<parameter>count</parameter> is greater than +<constant>SSIZE_MAX</constant>, the result is unspecified. Regardless +of the <parameter>count</parameter> value each +<function>read()</function> call will provide at most one frame (two +fields) worth of data.</para> + + <para>By default <function>read()</function> blocks until data +becomes available. When the <constant>O_NONBLOCK</constant> flag was +given to the &func-open; function it +returns immediately with an &EAGAIN; when no data is available. The +&func-select; or &func-poll; functions +can always be used to suspend execution until data becomes available. All +drivers supporting the <function>read()</function> function must also +support <function>select()</function> and +<function>poll()</function>.</para> + + <para>Drivers can implement read functionality in different +ways, using a single or multiple buffers and discarding the oldest or +newest frames once the internal buffers are filled.</para> + + <para><function>read()</function> never returns a "snapshot" of a +buffer being filled. Using a single buffer the driver will stop +capturing when the application starts reading the buffer until the +read is finished. Thus only the period of the vertical blanking +interval is available for reading, or the capture rate must fall below +the nominal frame rate of the video standard.</para> + +<para>The behavior of +<function>read()</function> when called during the active picture +period or the vertical blanking separating the top and bottom field +depends on the discarding policy. A driver discarding the oldest +frames keeps capturing into an internal buffer, continuously +overwriting the previously, not read frame, and returns the frame +being received at the time of the <function>read()</function> call as +soon as it is complete.</para> + + <para>A driver discarding the newest frames stops capturing until +the next <function>read()</function> call. The frame being received at +<function>read()</function> time is discarded, returning the following +frame instead. Again this implies a reduction of the capture rate to +one half or less of the nominal frame rate. An example of this model +is the video read mode of the bttv driver, initiating a DMA to user +memory when <function>read()</function> is called and returning when +the DMA finished.</para> + + <para>In the multiple buffer model drivers maintain a ring of +internal buffers, automatically advancing to the next free buffer. +This allows continuous capturing when the application can empty the +buffers fast enough. Again, the behavior when the driver runs out of +free buffers depends on the discarding policy.</para> + + <para>Applications can get and set the number of buffers used +internally by the driver with the &VIDIOC-G-PARM; and &VIDIOC-S-PARM; +ioctls. They are optional, however. The discarding policy is not +reported and cannot be changed. For minimum requirements see <xref + linkend="devices" />.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, the number of bytes read is returned. It is not +an error if this number is smaller than the number of bytes requested, +or the amount of data required for one frame. This may happen for +example because <function>read()</function> was interrupted by a +signal. On error, -1 is returned, and the <varname>errno</varname> +variable is set appropriately. In this case the next read will start +at the beginning of a new frame. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>Non-blocking I/O has been selected using +O_NONBLOCK and no data was immediately available for reading.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid file +descriptor or is not open for reading, or the process already has the +maximum number of files open.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple read streams and the +device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>buf</parameter> references an inaccessible +memory area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal before any +data was read.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EIO</errorcode></term> + <listitem> + <para>I/O error. This indicates some hardware problem or a +failure to communicate with a remote device (USB camera etc.).</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <function>read()</function> function is not +supported by this driver, not on this device, or generally not on this +type of device.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-select.xml b/Documentation/DocBook/media/v4l/func-select.xml new file mode 100644 index 00000000..e12a60d9 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-select.xml @@ -0,0 +1,130 @@ +<refentry id="func-select"> + <refmeta> + <refentrytitle>V4L2 select()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-select</refname> + <refpurpose>Synchronous I/O multiplexing</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo> +#include <sys/time.h> +#include <sys/types.h> +#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>select</function></funcdef> + <paramdef>int <parameter>nfds</parameter></paramdef> + <paramdef>fd_set *<parameter>readfds</parameter></paramdef> + <paramdef>fd_set *<parameter>writefds</parameter></paramdef> + <paramdef>fd_set *<parameter>exceptfds</parameter></paramdef> + <paramdef>struct timeval *<parameter>timeout</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>With the <function>select()</function> function applications +can suspend execution until the driver has captured data or is ready +to accept data for output.</para> + + <para>When streaming I/O has been negotiated this function waits +until a buffer has been filled or displayed and can be dequeued with +the &VIDIOC-DQBUF; ioctl. When buffers are already in the outgoing +queue of the driver the function returns immediately.</para> + + <para>On success <function>select()</function> returns the total +number of bits set in the <structname>fd_set</structname>s. When the +function timed out it returns a value of zero. On failure it returns +<returnvalue>-1</returnvalue> and the <varname>errno</varname> +variable is set appropriately. When the application did not call +&VIDIOC-QBUF; or &VIDIOC-STREAMON; yet the +<function>select()</function> function succeeds, setting the bit of +the file descriptor in <parameter>readfds</parameter> or +<parameter>writefds</parameter>, but subsequent &VIDIOC-DQBUF; calls +will fail.<footnote><para>The Linux kernel implements +<function>select()</function> like the &func-poll; function, but +<function>select()</function> cannot return a +<constant>POLLERR</constant>.</para> + </footnote></para> + + <para>When use of the <function>read()</function> function has +been negotiated and the driver does not capture yet, the +<function>select()</function> function starts capturing. When that +fails, <function>select()</function> returns successful and a +subsequent <function>read()</function> call, which also attempts to +start capturing, will return an appropriate error code. When the +driver captures continuously (as opposed to, for example, still +images) and data is already available the +<function>select()</function> function returns immediately.</para> + + <para>When use of the <function>write()</function> function has +been negotiated the <function>select()</function> function just waits +until the driver is ready for a non-blocking +<function>write()</function> call.</para> + + <para>All drivers implementing the <function>read()</function> or +<function>write()</function> function or streaming I/O must also +support the <function>select()</function> function.</para> + + <para>For more details see the <function>select()</function> +manual page.</para> + + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>select()</function> returns the number +of descriptors contained in the three returned descriptor sets, which +will be zero if the timeout expired. On error +<returnvalue>-1</returnvalue> is returned, and the +<varname>errno</varname> variable is set appropriately; the sets and +<parameter>timeout</parameter> are undefined. Possible error codes +are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para>One or more of the file descriptor sets specified a +file descriptor that is not open.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple read or write +streams and the device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para>The <parameter>readfds</parameter>, +<parameter>writefds</parameter>, <parameter>exceptfds</parameter> or +<parameter>timeout</parameter> pointer references an inaccessible memory +area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>nfds</parameter> argument is less than +zero or greater than <constant>FD_SETSIZE</constant>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/func-write.xml b/Documentation/DocBook/media/v4l/func-write.xml new file mode 100644 index 00000000..57520788 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-write.xml @@ -0,0 +1,128 @@ +<refentry id="func-write"> + <refmeta> + <refentrytitle>V4L2 write()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-write</refname> + <refpurpose>Write to a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>ssize_t <function>write</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>void *<parameter>buf</parameter></paramdef> + <paramdef>size_t <parameter>count</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>buf</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>count</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para><function>write()</function> writes up to +<parameter>count</parameter> bytes to the device referenced by the +file descriptor <parameter>fd</parameter> from the buffer starting at +<parameter>buf</parameter>. When the hardware outputs are not active +yet, this function enables them. When <parameter>count</parameter> is +zero, <function>write()</function> returns +<returnvalue>0</returnvalue> without any other effect.</para> + + <para>When the application does not provide more data in time, the +previous video frame, raw VBI image, sliced VPS or WSS data is +displayed again. Sliced Teletext or Closed Caption data is not +repeated, the driver inserts a blank line instead.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, the number of bytes written are returned. Zero +indicates nothing was written. On error, <returnvalue>-1</returnvalue> +is returned, and the <varname>errno</varname> variable is set +appropriately. In this case the next write will start at the beginning +of a new frame. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>Non-blocking I/O has been selected using the <link +linkend="func-open"><constant>O_NONBLOCK</constant></link> flag and no +buffer space was available to write the data immediately.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid file +descriptor or is not open for writing.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple write streams and the +device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>buf</parameter> references an inaccessible +memory area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal before any +data was written.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EIO</errorcode></term> + <listitem> + <para>I/O error. This indicates some hardware problem.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <function>write()</function> function is not +supported by this driver, not on this device, or generally not on this +type of device.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/gen-errors.xml b/Documentation/DocBook/media/v4l/gen-errors.xml new file mode 100644 index 00000000..5bbf3ce1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/gen-errors.xml @@ -0,0 +1,78 @@ +<title>Generic Error Codes</title> + +<table frame="none" pgwide="1" id="gen-errors"> + <title>Generic error codes</title> + <tgroup cols="2"> + &cs-str; + <tbody valign="top"> + <!-- Keep it ordered alphabetically --> + <row> + <entry>EBADF</entry> + <entry>The file descriptor is not a valid.</entry> + </row> + <row> + <entry>EBUSY</entry> + <entry>The ioctl can't be handled because the device is busy. This is + typically return while device is streaming, and an ioctl tried to + change something that would affect the stream, or would require the + usage of a hardware resource that was already allocated. The ioctl + must not be retried without performing another action to fix the + problem first (typically: stop the stream before retrying).</entry> + </row> + <row> + <entry>EFAULT</entry> + <entry>There was a failure while copying data from/to userspace, + probably caused by an invalid pointer reference.</entry> + </row> + <row> + <entry>EINVAL</entry> + <entry>One or more of the ioctl parameters are invalid or out of the + allowed range. This is a widely used error code. See the individual + ioctl requests for specific causes.</entry> + </row> + <row> + <entry>ENODEV</entry> + <entry>Device not found or was removed.</entry> + </row> + <row> + <entry>ENOMEM</entry> + <entry>There's not enough memory to handle the desired operation.</entry> + </row> + <row> + <entry>ENOTTY</entry> + <entry>The ioctl is not supported by the driver, actually meaning that + the required functionality is not available, or the file + descriptor is not for a media device.</entry> + </row> + <row> + <entry>ENOSPC</entry> + <entry>On USB devices, the stream ioctl's can return this error, meaning + that this request would overcommit the usb bandwidth reserved + for periodic transfers (up to 80% of the USB bandwidth).</entry> + </row> + <row> + <entry>ENOSYS or EOPNOTSUPP</entry> + <entry>Function not available for this device (dvb API only. Will likely + be replaced anytime soon by ENOTTY).</entry> + </row> + <row> + <entry>EPERM</entry> + <entry>Permission denied. Can be returned if the device needs write + permission, or some special capabilities is needed + (e. g. root)</entry> + </row> + <row> + <entry>EWOULDBLOCK</entry> + <entry>Operation would block. Used when the ioctl would need to wait + for an event, but the device was opened in non-blocking mode.</entry> + </row> + </tbody> + </tgroup> +</table> + +<para>Note 1: ioctls may return other error codes. Since errors may have side +effects such as a driver reset, applications should abort on unexpected errors. +</para> + +<para>Note 2: Request-specific error codes are listed in the individual +requests descriptions.</para> diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml new file mode 100644 index 00000000..b815929b --- /dev/null +++ b/Documentation/DocBook/media/v4l/io.xml @@ -0,0 +1,1284 @@ + <title>Input/Output</title> + + <para>The V4L2 API defines several different methods to read from or +write to a device. All drivers exchanging data with applications must +support at least one of them.</para> + + <para>The classic I/O method using the <function>read()</function> +and <function>write()</function> function is automatically selected +after opening a V4L2 device. When the driver does not support this +method attempts to read or write will fail at any time.</para> + + <para>Other methods must be negotiated. To select the streaming I/O +method with memory mapped or user buffers applications call the +&VIDIOC-REQBUFS; ioctl. The asynchronous I/O method is not defined +yet.</para> + + <para>Video overlay can be considered another I/O method, although +the application does not directly receive the image data. It is +selected by initiating video overlay with the &VIDIOC-S-FMT; ioctl. +For more information see <xref linkend="overlay" />.</para> + + <para>Generally exactly one I/O method, including overlay, is +associated with each file descriptor. The only exceptions are +applications not exchanging data with a driver ("panel applications", +see <xref linkend="open" />) and drivers permitting simultaneous video capturing +and overlay using the same file descriptor, for compatibility with V4L +and earlier versions of V4L2.</para> + + <para><constant>VIDIOC_S_FMT</constant> and +<constant>VIDIOC_REQBUFS</constant> would permit this to some degree, +but for simplicity drivers need not support switching the I/O method +(after first switching away from read/write) other than by closing +and reopening the device.</para> + + <para>The following sections describe the various I/O methods in +more detail.</para> + + <section id="rw"> + <title>Read/Write</title> + + <para>Input and output devices support the +<function>read()</function> and <function>write()</function> function, +respectively, when the <constant>V4L2_CAP_READWRITE</constant> flag in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set.</para> + + <para>Drivers may need the CPU to copy the data, but they may also +support DMA to or from user memory, so this I/O method is not +necessarily less efficient than other methods merely exchanging buffer +pointers. It is considered inferior though because no meta-information +like frame counters or timestamps are passed. This information is +necessary to recognize frame dropping and to synchronize with other +data streams. However this is also the simplest I/O method, requiring +little or no setup to exchange data. It permits command line stunts +like this (the <application>vidctrl</application> tool is +fictitious):</para> + + <informalexample> + <screen> +> vidctrl /dev/video --input=0 --format=YUYV --size=352x288 +> dd if=/dev/video of=myimage.422 bs=202752 count=1 +</screen> + </informalexample> + + <para>To read from the device applications use the +&func-read; function, to write the &func-write; function. +Drivers must implement one I/O method if they +exchange data with applications, but it need not be this.<footnote> + <para>It would be desirable if applications could depend on +drivers supporting all I/O interfaces, but as much as the complex +memory mapping I/O can be inadequate for some devices we have no +reason to require this interface, which is most useful for simple +applications capturing still images.</para> + </footnote> When reading or writing is supported, the driver +must also support the &func-select; and &func-poll; +function.<footnote> + <para>At the driver level <function>select()</function> and +<function>poll()</function> are the same, and +<function>select()</function> is too important to be optional.</para> + </footnote></para> + </section> + + <section id="mmap"> + <title>Streaming I/O (Memory Mapping)</title> + + <para>Input and output devices support this I/O method when the +<constant>V4L2_CAP_STREAMING</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set. There are two +streaming methods, to determine if the memory mapping flavor is +supported applications must call the &VIDIOC-REQBUFS; ioctl.</para> + + <para>Streaming is an I/O method where only pointers to buffers +are exchanged between application and driver, the data itself is not +copied. Memory mapping is primarily intended to map buffers in device +memory into the application's address space. Device memory can be for +example the video memory on a graphics card with a video capture +add-on. However, being the most efficient I/O method available for a +long time, many other drivers support streaming as well, allocating +buffers in DMA-able main memory.</para> + + <para>A driver can support many sets of buffers. Each set is +identified by a unique buffer type value. The sets are independent and +each set can hold a different type of data. To access different sets +at the same time different file descriptors must be used.<footnote> + <para>One could use one file descriptor and set the buffer +type field accordingly when calling &VIDIOC-QBUF; etc., but it makes +the <function>select()</function> function ambiguous. We also like the +clean approach of one file descriptor per logical stream. Video +overlay for example is also a logical stream, although the CPU is not +needed for continuous operation.</para> + </footnote></para> + + <para>To allocate device buffers applications call the +&VIDIOC-REQBUFS; ioctl with the desired number of buffers and buffer +type, for example <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>. +This ioctl can also be used to change the number of buffers or to free +the allocated memory, provided none of the buffers are still +mapped.</para> + + <para>Before applications can access the buffers they must map +them into their address space with the &func-mmap; function. The +location of the buffers in device memory can be determined with the +&VIDIOC-QUERYBUF; ioctl. In the single-planar API case, the +<structfield>m.offset</structfield> and <structfield>length</structfield> +returned in a &v4l2-buffer; are passed as sixth and second parameter to the +<function>mmap()</function> function. When using the multi-planar API, +struct &v4l2-buffer; contains an array of &v4l2-plane; structures, each +containing its own <structfield>m.offset</structfield> and +<structfield>length</structfield>. When using the multi-planar API, every +plane of every buffer has to be mapped separately, so the number of +calls to &func-mmap; should be equal to number of buffers times number of +planes in each buffer. The offset and length values must not be modified. +Remember, the buffers are allocated in physical memory, as opposed to virtual +memory, which can be swapped out to disk. Applications should free the buffers +as soon as possible with the &func-munmap; function.</para> + + <example> + <title>Mapping buffers in the single-planar API</title> + <programlisting> +&v4l2-requestbuffers; reqbuf; +struct { + void *start; + size_t length; +} *buffers; +unsigned int i; + +memset(&reqbuf, 0, sizeof(reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +reqbuf.memory = V4L2_MEMORY_MMAP; +reqbuf.count = 20; + +if (-1 == ioctl (fd, &VIDIOC-REQBUFS;, &reqbuf)) { + if (errno == EINVAL) + printf("Video capturing or mmap-streaming is not supported\n"); + else + perror("VIDIOC_REQBUFS"); + + exit(EXIT_FAILURE); +} + +/* We want at least five buffers. */ + +if (reqbuf.count < 5) { + /* You may need to free the buffers here. */ + printf("Not enough buffer memory\n"); + exit(EXIT_FAILURE); +} + +buffers = calloc(reqbuf.count, sizeof(*buffers)); +assert(buffers != NULL); + +for (i = 0; i < reqbuf.count; i++) { + &v4l2-buffer; buffer; + + memset(&buffer, 0, sizeof(buffer)); + buffer.type = reqbuf.type; + buffer.memory = V4L2_MEMORY_MMAP; + buffer.index = i; + + if (-1 == ioctl (fd, &VIDIOC-QUERYBUF;, &buffer)) { + perror("VIDIOC_QUERYBUF"); + exit(EXIT_FAILURE); + } + + buffers[i].length = buffer.length; /* remember for munmap() */ + + buffers[i].start = mmap(NULL, buffer.length, + PROT_READ | PROT_WRITE, /* recommended */ + MAP_SHARED, /* recommended */ + fd, buffer.m.offset); + + if (MAP_FAILED == buffers[i].start) { + /* If you do not exit here you should unmap() and free() + the buffers mapped so far. */ + perror("mmap"); + exit(EXIT_FAILURE); + } +} + +/* Cleanup. */ + +for (i = 0; i < reqbuf.count; i++) + munmap(buffers[i].start, buffers[i].length); + </programlisting> + </example> + + <example> + <title>Mapping buffers in the multi-planar API</title> + <programlisting> +&v4l2-requestbuffers; reqbuf; +/* Our current format uses 3 planes per buffer */ +#define FMT_NUM_PLANES = 3 + +struct { + void *start[FMT_NUM_PLANES]; + size_t length[FMT_NUM_PLANES]; +} *buffers; +unsigned int i, j; + +memset(&reqbuf, 0, sizeof(reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE; +reqbuf.memory = V4L2_MEMORY_MMAP; +reqbuf.count = 20; + +if (ioctl(fd, &VIDIOC-REQBUFS;, &reqbuf) < 0) { + if (errno == EINVAL) + printf("Video capturing or mmap-streaming is not supported\n"); + else + perror("VIDIOC_REQBUFS"); + + exit(EXIT_FAILURE); +} + +/* We want at least five buffers. */ + +if (reqbuf.count < 5) { + /* You may need to free the buffers here. */ + printf("Not enough buffer memory\n"); + exit(EXIT_FAILURE); +} + +buffers = calloc(reqbuf.count, sizeof(*buffers)); +assert(buffers != NULL); + +for (i = 0; i < reqbuf.count; i++) { + &v4l2-buffer; buffer; + &v4l2-plane; planes[FMT_NUM_PLANES]; + + memset(&buffer, 0, sizeof(buffer)); + buffer.type = reqbuf.type; + buffer.memory = V4L2_MEMORY_MMAP; + buffer.index = i; + /* length in struct v4l2_buffer in multi-planar API stores the size + * of planes array. */ + buffer.length = FMT_NUM_PLANES; + buffer.m.planes = planes; + + if (ioctl(fd, &VIDIOC-QUERYBUF;, &buffer) < 0) { + perror("VIDIOC_QUERYBUF"); + exit(EXIT_FAILURE); + } + + /* Every plane has to be mapped separately */ + for (j = 0; j < FMT_NUM_PLANES; j++) { + buffers[i].length[j] = buffer.m.planes[j].length; /* remember for munmap() */ + + buffers[i].start[j] = mmap(NULL, buffer.m.planes[j].length, + PROT_READ | PROT_WRITE, /* recommended */ + MAP_SHARED, /* recommended */ + fd, buffer.m.planes[j].m.offset); + + if (MAP_FAILED == buffers[i].start[j]) { + /* If you do not exit here you should unmap() and free() + the buffers and planes mapped so far. */ + perror("mmap"); + exit(EXIT_FAILURE); + } + } +} + +/* Cleanup. */ + +for (i = 0; i < reqbuf.count; i++) + for (j = 0; j < FMT_NUM_PLANES; j++) + munmap(buffers[i].start[j], buffers[i].length[j]); + </programlisting> + </example> + + <para>Conceptually streaming drivers maintain two buffer queues, an incoming +and an outgoing queue. They separate the synchronous capture or output +operation locked to a video clock from the application which is +subject to random disk or network delays and preemption by +other processes, thereby reducing the probability of data loss. +The queues are organized as FIFOs, buffers will be +output in the order enqueued in the incoming FIFO, and were +captured in the order dequeued from the outgoing FIFO.</para> + + <para>The driver may require a minimum number of buffers enqueued +at all times to function, apart of this no limit exists on the number +of buffers applications can enqueue in advance, or dequeue and +process. They can also enqueue in a different order than buffers have +been dequeued, and the driver can <emphasis>fill</emphasis> enqueued +<emphasis>empty</emphasis> buffers in any order. <footnote> + <para>Random enqueue order permits applications processing +images out of order (such as video codecs) to return buffers earlier, +reducing the probability of data loss. Random fill order allows +drivers to reuse buffers on a LIFO-basis, taking advantage of caches +holding scatter-gather lists and the like.</para> + </footnote> The index number of a buffer (&v4l2-buffer; +<structfield>index</structfield>) plays no role here, it only +identifies the buffer.</para> + + <para>Initially all mapped buffers are in dequeued state, +inaccessible by the driver. For capturing applications it is customary +to first enqueue all mapped buffers, then to start capturing and enter +the read loop. Here the application waits until a filled buffer can be +dequeued, and re-enqueues the buffer when the data is no longer +needed. Output applications fill and enqueue buffers, when enough +buffers are stacked up the output is started with +<constant>VIDIOC_STREAMON</constant>. In the write loop, when +the application runs out of free buffers, it must wait until an empty +buffer can be dequeued and reused.</para> + + <para>To enqueue and dequeue a buffer applications use the +&VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. The status of a buffer being +mapped, enqueued, full or empty can be determined at any time using the +&VIDIOC-QUERYBUF; ioctl. Two methods exist to suspend execution of the +application until one or more buffers can be dequeued. By default +<constant>VIDIOC_DQBUF</constant> blocks when no buffer is in the +outgoing queue. When the <constant>O_NONBLOCK</constant> flag was +given to the &func-open; function, <constant>VIDIOC_DQBUF</constant> +returns immediately with an &EAGAIN; when no buffer is available. The +&func-select; or &func-poll; function are always available.</para> + + <para>To start and stop capturing or output applications call the +&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctl. Note +<constant>VIDIOC_STREAMOFF</constant> removes all buffers from both +queues as a side effect. Since there is no notion of doing anything +"now" on a multitasking system, if an application needs to synchronize +with another event it should examine the &v4l2-buffer; +<structfield>timestamp</structfield> of captured buffers, or set the +field before enqueuing buffers for output.</para> + + <para>Drivers implementing memory mapping I/O must +support the <constant>VIDIOC_REQBUFS</constant>, +<constant>VIDIOC_QUERYBUF</constant>, +<constant>VIDIOC_QBUF</constant>, <constant>VIDIOC_DQBUF</constant>, +<constant>VIDIOC_STREAMON</constant> and +<constant>VIDIOC_STREAMOFF</constant> ioctl, the +<function>mmap()</function>, <function>munmap()</function>, +<function>select()</function> and <function>poll()</function> +function.<footnote> + <para>At the driver level <function>select()</function> and +<function>poll()</function> are the same, and +<function>select()</function> is too important to be optional. The +rest should be evident.</para> + </footnote></para> + + <para>[capture example]</para> + + </section> + + <section id="userp"> + <title>Streaming I/O (User Pointers)</title> + + <para>Input and output devices support this I/O method when the +<constant>V4L2_CAP_STREAMING</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set. If the particular user +pointer method (not only memory mapping) is supported must be +determined by calling the &VIDIOC-REQBUFS; ioctl.</para> + + <para>This I/O method combines advantages of the read/write and +memory mapping methods. Buffers (planes) are allocated by the application +itself, and can reside for example in virtual or shared memory. Only +pointers to data are exchanged, these pointers and meta-information +are passed in &v4l2-buffer; (or in &v4l2-plane; in the multi-planar API case). +The driver must be switched into user pointer I/O mode by calling the +&VIDIOC-REQBUFS; with the desired buffer type. No buffers (planes) are allocated +beforehand, consequently they are not indexed and cannot be queried like mapped +buffers with the <constant>VIDIOC_QUERYBUF</constant> ioctl.</para> + + <example> + <title>Initiating streaming I/O with user pointers</title> + + <programlisting> +&v4l2-requestbuffers; reqbuf; + +memset (&reqbuf, 0, sizeof (reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +reqbuf.memory = V4L2_MEMORY_USERPTR; + +if (ioctl (fd, &VIDIOC-REQBUFS;, &reqbuf) == -1) { + if (errno == EINVAL) + printf ("Video capturing or user pointer streaming is not supported\n"); + else + perror ("VIDIOC_REQBUFS"); + + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <para>Buffer (plane) addresses and sizes are passed on the fly with the +&VIDIOC-QBUF; ioctl. Although buffers are commonly cycled, +applications can pass different addresses and sizes at each +<constant>VIDIOC_QBUF</constant> call. If required by the hardware the +driver swaps memory pages within physical memory to create a +continuous area of memory. This happens transparently to the +application in the virtual memory subsystem of the kernel. When buffer +pages have been swapped out to disk they are brought back and finally +locked in physical memory for DMA.<footnote> + <para>We expect that frequently used buffers are typically not +swapped out. Anyway, the process of swapping, locking or generating +scatter-gather lists may be time consuming. The delay can be masked by +the depth of the incoming buffer queue, and perhaps by maintaining +caches assuming a buffer will be soon enqueued again. On the other +hand, to optimize memory usage drivers can limit the number of buffers +locked in advance and recycle the most recently used buffers first. Of +course, the pages of empty buffers in the incoming queue need not be +saved to disk. Output buffers must be saved on the incoming and +outgoing queue because an application may share them with other +processes.</para> + </footnote></para> + + <para>Filled or displayed buffers are dequeued with the +&VIDIOC-DQBUF; ioctl. The driver can unlock the memory pages at any +time between the completion of the DMA and this ioctl. The memory is +also unlocked when &VIDIOC-STREAMOFF; is called, &VIDIOC-REQBUFS;, or +when the device is closed. Applications must take care not to free +buffers without dequeuing. For once, the buffers remain locked until +further, wasting physical memory. Second the driver will not be +notified when the memory is returned to the application's free list +and subsequently reused for other purposes, possibly completing the +requested DMA and overwriting valuable data.</para> + + <para>For capturing applications it is customary to enqueue a +number of empty buffers, to start capturing and enter the read loop. +Here the application waits until a filled buffer can be dequeued, and +re-enqueues the buffer when the data is no longer needed. Output +applications fill and enqueue buffers, when enough buffers are stacked +up output is started. In the write loop, when the application +runs out of free buffers it must wait until an empty buffer can be +dequeued and reused. Two methods exist to suspend execution of the +application until one or more buffers can be dequeued. By default +<constant>VIDIOC_DQBUF</constant> blocks when no buffer is in the +outgoing queue. When the <constant>O_NONBLOCK</constant> flag was +given to the &func-open; function, <constant>VIDIOC_DQBUF</constant> +returns immediately with an &EAGAIN; when no buffer is available. The +&func-select; or &func-poll; function are always available.</para> + + <para>To start and stop capturing or output applications call the +&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctl. Note +<constant>VIDIOC_STREAMOFF</constant> removes all buffers from both +queues and unlocks all buffers as a side effect. Since there is no +notion of doing anything "now" on a multitasking system, if an +application needs to synchronize with another event it should examine +the &v4l2-buffer; <structfield>timestamp</structfield> of captured +buffers, or set the field before enqueuing buffers for output.</para> + + <para>Drivers implementing user pointer I/O must +support the <constant>VIDIOC_REQBUFS</constant>, +<constant>VIDIOC_QBUF</constant>, <constant>VIDIOC_DQBUF</constant>, +<constant>VIDIOC_STREAMON</constant> and +<constant>VIDIOC_STREAMOFF</constant> ioctl, the +<function>select()</function> and <function>poll()</function> function.<footnote> + <para>At the driver level <function>select()</function> and +<function>poll()</function> are the same, and +<function>select()</function> is too important to be optional. The +rest should be evident.</para> + </footnote></para> + </section> + + <section id="async"> + <title>Asynchronous I/O</title> + + <para>This method is not defined yet.</para> + </section> + + <section id="buffer"> + <title>Buffers</title> + + <para>A buffer contains data exchanged by application and +driver using one of the Streaming I/O methods. In the multi-planar API, the +data is held in planes, while the buffer structure acts as a container +for the planes. Only pointers to buffers (planes) are exchanged, the data +itself is not copied. These pointers, together with meta-information like +timestamps or field parity, are stored in a struct +<structname>v4l2_buffer</structname>, argument to +the &VIDIOC-QUERYBUF;, &VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. +In the multi-planar API, some plane-specific members of struct +<structname>v4l2_buffer</structname>, such as pointers and sizes for each +plane, are stored in struct <structname>v4l2_plane</structname> instead. +In that case, struct <structname>v4l2_buffer</structname> contains an array of +plane structures.</para> + + <para>Nominally timestamps refer to the first data byte transmitted. +In practice however the wide range of hardware covered by the V4L2 API +limits timestamp accuracy. Often an interrupt routine will +sample the system clock shortly after the field or frame was stored +completely in memory. So applications must expect a constant +difference up to one field or frame period plus a small (few scan +lines) random error. The delay and error can be much +larger due to compression or transmission over an external bus when +the frames are not properly stamped by the sender. This is frequently +the case with USB cameras. Here timestamps refer to the instant the +field or frame was received by the driver, not the capture time. These +devices identify by not enumerating any video standards, see <xref +linkend="standard" />.</para> + + <para>Similar limitations apply to output timestamps. Typically +the video hardware locks to a clock controlling the video timing, the +horizontal and vertical synchronization pulses. At some point in the +line sequence, possibly the vertical blanking, an interrupt routine +samples the system clock, compares against the timestamp and programs +the hardware to repeat the previous field or frame, or to display the +buffer contents.</para> + + <para>Apart of limitations of the video device and natural +inaccuracies of all clocks, it should be noted system time itself is +not perfectly stable. It can be affected by power saving cycles, +warped to insert leap seconds, or even turned back or forth by the +system administrator affecting long term measurements. <footnote> + <para>Since no other Linux multimedia +API supports unadjusted time it would be foolish to introduce here. We +must use a universally supported clock to synchronize different media, +hence time of day.</para> + </footnote></para> + + <table frame="none" pgwide="1" id="v4l2-buffer"> + <title>struct <structname>v4l2_buffer</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry></entry> + <entry>Number of the buffer, set by the application. This +field is only used for <link linkend="mmap">memory mapping</link> I/O +and can range from zero to the number of buffers allocated +with the &VIDIOC-REQBUFS; ioctl (&v4l2-requestbuffers; <structfield>count</structfield>) minus one.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>Type of the buffer, same as &v4l2-format; +<structfield>type</structfield> or &v4l2-requestbuffers; +<structfield>type</structfield>, set by the application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>bytesused</structfield></entry> + <entry></entry> + <entry>The number of bytes occupied by the data in the +buffer. It depends on the negotiated data format and may change with +each buffer for compressed variable size data like JPEG images. +Drivers must set this field when <structfield>type</structfield> +refers to an input stream, applications when an output stream.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry>Flags set by the application or driver, see <xref +linkend="buffer-flags" />.</entry> + </row> + <row> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry></entry> + <entry>Indicates the field order of the image in the +buffer, see <xref linkend="v4l2-field" />. This field is not used when +the buffer contains VBI data. Drivers must set it when +<structfield>type</structfield> refers to an input stream, +applications when an output stream.</entry> + </row> + <row> + <entry>struct timeval</entry> + <entry><structfield>timestamp</structfield></entry> + <entry></entry> + <entry><para>For input streams this is the +system time (as returned by the <function>gettimeofday()</function> +function) when the first data byte was captured. For output streams +the data will not be displayed before this time, secondary to the +nominal frame rate determined by the current video standard in +enqueued order. Applications can for example zero this field to +display frames as soon as possible. The driver stores the time at +which the first data byte was actually sent out in the +<structfield>timestamp</structfield> field. This permits +applications to monitor the drift between the video and system +clock.</para></entry> + </row> + <row> + <entry>&v4l2-timecode;</entry> + <entry><structfield>timecode</structfield></entry> + <entry></entry> + <entry>When <structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> and the +<constant>V4L2_BUF_FLAG_TIMECODE</constant> flag is set in +<structfield>flags</structfield>, this structure contains a frame +timecode. In <link linkend="v4l2-field">V4L2_FIELD_ALTERNATE</link> +mode the top and bottom field contain the same timecode. +Timecodes are intended to help video editing and are typically recorded on +video tapes, but also embedded in compressed formats like MPEG. This +field is independent of the <structfield>timestamp</structfield> and +<structfield>sequence</structfield> fields.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>sequence</structfield></entry> + <entry></entry> + <entry>Set by the driver, counting the frames in the +sequence.</entry> + </row> + <row> + <entry spanname="hspan"><para>In <link +linkend="v4l2-field">V4L2_FIELD_ALTERNATE</link> mode the top and +bottom field have the same sequence number. The count starts at zero +and includes dropped or repeated frames. A dropped frame was received +by an input device but could not be stored due to lack of free buffer +space. A repeated frame was displayed again by an output device +because the application did not pass new data in +time.</para><para>Note this may count the frames received +e.g. over USB, without taking into account the frames dropped by the +remote hardware due to limited compression throughput or bus +bandwidth. These devices identify by not enumerating any video +standards, see <xref linkend="standard" />.</para></entry> + </row> + <row> + <entry>&v4l2-memory;</entry> + <entry><structfield>memory</structfield></entry> + <entry></entry> + <entry>This field must be set by applications and/or drivers +in accordance with the selected I/O method.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>m</structfield></entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>offset</structfield></entry> + <entry>For the single-planar API and when +<structfield>memory</structfield> is <constant>V4L2_MEMORY_MMAP</constant> this +is the offset of the buffer from the start of the device memory. The value is +returned by the driver and apart of serving as parameter to the &func-mmap; +function not useful for applications. See <xref linkend="mmap" /> for details + </entry> + </row> + <row> + <entry></entry> + <entry>unsigned long</entry> + <entry><structfield>userptr</structfield></entry> + <entry>For the single-planar API and when +<structfield>memory</structfield> is <constant>V4L2_MEMORY_USERPTR</constant> +this is a pointer to the buffer (casted to unsigned long type) in virtual +memory, set by the application. See <xref linkend="userp" /> for details. + </entry> + </row> + <row> + <entry></entry> + <entry>struct v4l2_plane</entry> + <entry><structfield>*planes</structfield></entry> + <entry>When using the multi-planar API, contains a userspace pointer + to an array of &v4l2-plane;. The size of the array should be put + in the <structfield>length</structfield> field of this + <structname>v4l2_buffer</structname> structure.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>length</structfield></entry> + <entry></entry> + <entry>Size of the buffer (not the payload) in bytes for the + single-planar API. For the multi-planar API should contain the + number of elements in the <structfield>planes</structfield> array. + </entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>input</structfield></entry> + <entry></entry> + <entry>Some video capture drivers support rapid and +synchronous video input changes, a function useful for example in +video surveillance applications. For this purpose applications set the +<constant>V4L2_BUF_FLAG_INPUT</constant> flag, and this field to the +number of a video input as in &v4l2-input; field +<structfield>index</structfield>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield></entry> + <entry></entry> + <entry>A place holder for future extensions and custom +(driver defined) buffer types +<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher. Applications +should set this to 0.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-plane"> + <title>struct <structname>v4l2_plane</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>bytesused</structfield></entry> + <entry></entry> + <entry>The number of bytes occupied by data in the plane + (its payload).</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>length</structfield></entry> + <entry></entry> + <entry>Size in bytes of the plane (not its payload).</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>m</structfield></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>mem_offset</structfield></entry> + <entry>When the memory type in the containing &v4l2-buffer; is + <constant>V4L2_MEMORY_MMAP</constant>, this is the value that + should be passed to &func-mmap;, similar to the + <structfield>offset</structfield> field in &v4l2-buffer;.</entry> + </row> + <row> + <entry></entry> + <entry>__unsigned long</entry> + <entry><structfield>userptr</structfield></entry> + <entry>When the memory type in the containing &v4l2-buffer; is + <constant>V4L2_MEMORY_USERPTR</constant>, this is a userspace + pointer to the memory allocated for this plane by an application. + </entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>data_offset</structfield></entry> + <entry></entry> + <entry>Offset in bytes to video data in the plane, if applicable. + </entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[11]</structfield></entry> + <entry></entry> + <entry>Reserved for future use. Should be zeroed by an + application.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-buf-type"> + <title>enum v4l2_buf_type</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant></entry> + <entry>1</entry> + <entry>Buffer of a single-planar video capture stream, see <xref + linkend="capture" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant> + </entry> + <entry>9</entry> + <entry>Buffer of a multi-planar video capture stream, see <xref + linkend="capture" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant></entry> + <entry>2</entry> + <entry>Buffer of a single-planar video output stream, see <xref + linkend="output" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant> + </entry> + <entry>10</entry> + <entry>Buffer of a multi-planar video output stream, see <xref + linkend="output" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant></entry> + <entry>3</entry> + <entry>Buffer for video overlay, see <xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant></entry> + <entry>4</entry> + <entry>Buffer of a raw VBI capture stream, see <xref + linkend="raw-vbi" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant></entry> + <entry>5</entry> + <entry>Buffer of a raw VBI output stream, see <xref + linkend="raw-vbi" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant></entry> + <entry>6</entry> + <entry>Buffer of a sliced VBI capture stream, see <xref + linkend="sliced" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant></entry> + <entry>7</entry> + <entry>Buffer of a sliced VBI output stream, see <xref + linkend="sliced" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant></entry> + <entry>8</entry> + <entry>Buffer for video output overlay (OSD), see <xref + linkend="osd" />. Status: <link +linkend="experimental">Experimental</link>.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_PRIVATE</constant></entry> + <entry>0x80</entry> + <entry>This and higher values are reserved for custom +(driver defined) buffer types.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="buffer-flags"> + <title>Buffer Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_BUF_FLAG_MAPPED</constant></entry> + <entry>0x0001</entry> + <entry>The buffer resides in device memory and has been mapped +into the application's address space, see <xref linkend="mmap" /> for details. +Drivers set or clear this flag when the +<link linkend="vidioc-querybuf">VIDIOC_QUERYBUF</link>, <link + linkend="vidioc-qbuf">VIDIOC_QBUF</link> or <link + linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl is called. Set by the driver.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_QUEUED</constant></entry> + <entry>0x0002</entry> + <entry>Internally drivers maintain two buffer queues, an +incoming and outgoing queue. When this flag is set, the buffer is +currently on the incoming queue. It automatically moves to the +outgoing queue after the buffer has been filled (capture devices) or +displayed (output devices). Drivers set or clear this flag when the +<constant>VIDIOC_QUERYBUF</constant> ioctl is called. After +(successful) calling the <constant>VIDIOC_QBUF </constant>ioctl it is +always set and after <constant>VIDIOC_DQBUF</constant> always +cleared.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_DONE</constant></entry> + <entry>0x0004</entry> + <entry>When this flag is set, the buffer is currently on +the outgoing queue, ready to be dequeued from the driver. Drivers set +or clear this flag when the <constant>VIDIOC_QUERYBUF</constant> ioctl +is called. After calling the <constant>VIDIOC_QBUF</constant> or +<constant>VIDIOC_DQBUF</constant> it is always cleared. Of course a +buffer cannot be on both queues at the same time, the +<constant>V4L2_BUF_FLAG_QUEUED</constant> and +<constant>V4L2_BUF_FLAG_DONE</constant> flag are mutually exclusive. +They can be both cleared however, then the buffer is in "dequeued" +state, in the application domain to say so.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_ERROR</constant></entry> + <entry>0x0040</entry> + <entry>When this flag is set, the buffer has been dequeued + successfully, although the data might have been corrupted. + This is recoverable, streaming may continue as normal and + the buffer may be reused normally. + Drivers set this flag when the <constant>VIDIOC_DQBUF</constant> + ioctl is called.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_KEYFRAME</constant></entry> + <entry>0x0008</entry> + <entry>Drivers set or clear this flag when calling the +<constant>VIDIOC_DQBUF</constant> ioctl. It may be set by video +capture devices when the buffer contains a compressed image which is a +key frame (or field), &ie; can be decompressed on its own.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_PFRAME</constant></entry> + <entry>0x0010</entry> + <entry>Similar to <constant>V4L2_BUF_FLAG_KEYFRAME</constant> +this flags predicted frames or fields which contain only differences to a +previous key frame.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_BFRAME</constant></entry> + <entry>0x0020</entry> + <entry>Similar to <constant>V4L2_BUF_FLAG_PFRAME</constant> + this is a bidirectional predicted frame or field. [ooc tbd]</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_TIMECODE</constant></entry> + <entry>0x0100</entry> + <entry>The <structfield>timecode</structfield> field is valid. +Drivers set or clear this flag when the <constant>VIDIOC_DQBUF</constant> +ioctl is called.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_INPUT</constant></entry> + <entry>0x0200</entry> + <entry>The <structfield>input</structfield> field is valid. +Applications set or clear this flag before calling the +<constant>VIDIOC_QBUF</constant> ioctl.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_PREPARED</constant></entry> + <entry>0x0400</entry> + <entry>The buffer has been prepared for I/O and can be queued by the +application. Drivers set or clear this flag when the +<link linkend="vidioc-querybuf">VIDIOC_QUERYBUF</link>, <link + linkend="vidioc-qbuf">VIDIOC_PREPARE_BUF</link>, <link + linkend="vidioc-qbuf">VIDIOC_QBUF</link> or <link + linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl is called.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_NO_CACHE_INVALIDATE</constant></entry> + <entry>0x0400</entry> + <entry>Caches do not have to be invalidated for this buffer. +Typically applications shall use this flag if the data captured in the buffer +is not going to be touched by the CPU, instead the buffer will, probably, be +passed on to a DMA-capable hardware unit for further processing or output. +</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_NO_CACHE_CLEAN</constant></entry> + <entry>0x0800</entry> + <entry>Caches do not have to be cleaned for this buffer. +Typically applications shall use this flag for output buffers if the data +in this buffer has not been created by the CPU but by some DMA-capable unit, +in which case caches have not been used.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-memory"> + <title>enum v4l2_memory</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_MEMORY_MMAP</constant></entry> + <entry>1</entry> + <entry>The buffer is used for <link linkend="mmap">memory +mapping</link> I/O.</entry> + </row> + <row> + <entry><constant>V4L2_MEMORY_USERPTR</constant></entry> + <entry>2</entry> + <entry>The buffer is used for <link linkend="userp">user +pointer</link> I/O.</entry> + </row> + <row> + <entry><constant>V4L2_MEMORY_OVERLAY</constant></entry> + <entry>3</entry> + <entry>[to do]</entry> + </row> + </tbody> + </tgroup> + </table> + + <section> + <title>Timecodes</title> + + <para>The <structname>v4l2_timecode</structname> structure is +designed to hold a <xref linkend="smpte12m" /> or similar timecode. +(struct <structname>timeval</structname> timestamps are stored in +&v4l2-buffer; field <structfield>timestamp</structfield>.)</para> + + <table frame="none" pgwide="1" id="v4l2-timecode"> + <title>struct <structname>v4l2_timecode</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Frame rate the timecodes are based on, see <xref + linkend="timecode-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Timecode flags, see <xref linkend="timecode-flags" />.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>frames</structfield></entry> + <entry>Frame count, 0 ... 23/24/29/49/59, depending on the + type of timecode.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>seconds</structfield></entry> + <entry>Seconds count, 0 ... 59. This is a binary, not BCD number.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>minutes</structfield></entry> + <entry>Minutes count, 0 ... 59. This is a binary, not BCD number.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>hours</structfield></entry> + <entry>Hours count, 0 ... 29. This is a binary, not BCD number.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>userbits</structfield>[4]</entry> + <entry>The "user group" bits from the timecode.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="timecode-type"> + <title>Timecode Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TC_TYPE_24FPS</constant></entry> + <entry>1</entry> + <entry>24 frames per second, i. e. film.</entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_25FPS</constant></entry> + <entry>2</entry> + <entry>25 frames per second, &ie; PAL or SECAM video.</entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_30FPS</constant></entry> + <entry>3</entry> + <entry>30 frames per second, &ie; NTSC video.</entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_50FPS</constant></entry> + <entry>4</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_60FPS</constant></entry> + <entry>5</entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="timecode-flags"> + <title>Timecode Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TC_FLAG_DROPFRAME</constant></entry> + <entry>0x0001</entry> + <entry>Indicates "drop frame" semantics for counting frames +in 29.97 fps material. When set, frame numbers 0 and 1 at the start of +each minute, except minutes 0, 10, 20, 30, 40, 50 are omitted from the +count.</entry> + </row> + <row> + <entry><constant>V4L2_TC_FLAG_COLORFRAME</constant></entry> + <entry>0x0002</entry> + <entry>The "color frame" flag.</entry> + </row> + <row> + <entry><constant>V4L2_TC_USERBITS_field</constant></entry> + <entry>0x000C</entry> + <entry>Field mask for the "binary group flags".</entry> + </row> + <row> + <entry><constant>V4L2_TC_USERBITS_USERDEFINED</constant></entry> + <entry>0x0000</entry> + <entry>Unspecified format.</entry> + </row> + <row> + <entry><constant>V4L2_TC_USERBITS_8BITCHARS</constant></entry> + <entry>0x0008</entry> + <entry>8-bit ISO characters.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + </section> + + <section id="field-order"> + <title>Field Order</title> + + <para>We have to distinguish between progressive and interlaced +video. Progressive video transmits all lines of a video image +sequentially. Interlaced video divides an image into two fields, +containing only the odd and even lines of the image, respectively. +Alternating the so called odd and even field are transmitted, and due +to a small delay between fields a cathode ray TV displays the lines +interleaved, yielding the original frame. This curious technique was +invented because at refresh rates similar to film the image would +fade out too quickly. Transmitting fields reduces the flicker without +the necessity of doubling the frame rate and with it the bandwidth +required for each channel.</para> + + <para>It is important to understand a video camera does not expose +one frame at a time, merely transmitting the frames separated into +fields. The fields are in fact captured at two different instances in +time. An object on screen may well move between one field and the +next. For applications analysing motion it is of paramount importance +to recognize which field of a frame is older, the <emphasis>temporal +order</emphasis>.</para> + + <para>When the driver provides or accepts images field by field +rather than interleaved, it is also important applications understand +how the fields combine to frames. We distinguish between top (aka odd) and +bottom (aka even) fields, the <emphasis>spatial order</emphasis>: The first line +of the top field is the first line of an interlaced frame, the first +line of the bottom field is the second line of that frame.</para> + + <para>However because fields were captured one after the other, +arguing whether a frame commences with the top or bottom field is +pointless. Any two successive top and bottom, or bottom and top fields +yield a valid frame. Only when the source was progressive to begin +with, ⪚ when transferring film to video, two fields may come from +the same frame, creating a natural order.</para> + + <para>Counter to intuition the top field is not necessarily the +older field. Whether the older field contains the top or bottom lines +is a convention determined by the video standard. Hence the +distinction between temporal and spatial order of fields. The diagrams +below should make this clearer.</para> + + <para>All video capture and output devices must report the current +field order. Some drivers may permit the selection of a different +order, to this end applications initialize the +<structfield>field</structfield> field of &v4l2-pix-format; before +calling the &VIDIOC-S-FMT; ioctl. If this is not desired it should +have the value <constant>V4L2_FIELD_ANY</constant> (0).</para> + + <table frame="none" pgwide="1" id="v4l2-field"> + <title>enum v4l2_field</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FIELD_ANY</constant></entry> + <entry>0</entry> + <entry>Applications request this field order when any +one of the <constant>V4L2_FIELD_NONE</constant>, +<constant>V4L2_FIELD_TOP</constant>, +<constant>V4L2_FIELD_BOTTOM</constant>, or +<constant>V4L2_FIELD_INTERLACED</constant> formats is acceptable. +Drivers choose depending on hardware capabilities or e. g. the +requested image size, and return the actual field order. &v4l2-buffer; +<structfield>field</structfield> can never be +<constant>V4L2_FIELD_ANY</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_NONE</constant></entry> + <entry>1</entry> + <entry>Images are in progressive format, not interlaced. +The driver may also indicate this order when it cannot distinguish +between <constant>V4L2_FIELD_TOP</constant> and +<constant>V4L2_FIELD_BOTTOM</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_TOP</constant></entry> + <entry>2</entry> + <entry>Images consist of the top (aka odd) field only.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_BOTTOM</constant></entry> + <entry>3</entry> + <entry>Images consist of the bottom (aka even) field only. +Applications may wish to prevent a device from capturing interlaced +images because they will have "comb" or "feathering" artefacts around +moving objects.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_INTERLACED</constant></entry> + <entry>4</entry> + <entry>Images contain both fields, interleaved line by +line. The temporal order of the fields (whether the top or bottom +field is first transmitted) depends on the current video standard. +M/NTSC transmits the bottom field first, all other standards the top +field first.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_SEQ_TB</constant></entry> + <entry>5</entry> + <entry>Images contain both fields, the top field lines +are stored first in memory, immediately followed by the bottom field +lines. Fields are always stored in temporal order, the older one first +in memory. Image sizes refer to the frame, not fields.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_SEQ_BT</constant></entry> + <entry>6</entry> + <entry>Images contain both fields, the bottom field +lines are stored first in memory, immediately followed by the top +field lines. Fields are always stored in temporal order, the older one +first in memory. Image sizes refer to the frame, not fields.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_ALTERNATE</constant></entry> + <entry>7</entry> + <entry>The two fields of a frame are passed in separate +buffers, in temporal order, &ie; the older one first. To indicate the field +parity (whether the current field is a top or bottom field) the driver +or application, depending on data direction, must set &v4l2-buffer; +<structfield>field</structfield> to +<constant>V4L2_FIELD_TOP</constant> or +<constant>V4L2_FIELD_BOTTOM</constant>. Any two successive fields pair +to build a frame. If fields are successive, without any dropped fields +between them (fields can drop individually), can be determined from +the &v4l2-buffer; <structfield>sequence</structfield> field. Image +sizes refer to the frame, not fields. This format cannot be selected +when using the read/write I/O method.<!-- Where it's indistinguishable +from V4L2_FIELD_SEQ_*. --></entry> + </row> + <row> + <entry><constant>V4L2_FIELD_INTERLACED_TB</constant></entry> + <entry>8</entry> + <entry>Images contain both fields, interleaved line by +line, top field first. The top field is transmitted first.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_INTERLACED_BT</constant></entry> + <entry>9</entry> + <entry>Images contain both fields, interleaved line by +line, top field first. The bottom field is transmitted first.</entry> + </row> + </tbody> + </tgroup> + </table> + + <figure id="fieldseq-tb"> + <title>Field Order, Top Field First Transmitted</title> + <mediaobject> + <imageobject> + <imagedata fileref="fieldseq_tb.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="fieldseq_tb.gif" format="GIF" /> + </imageobject> + </mediaobject> + </figure> + + <figure id="fieldseq-bt"> + <title>Field Order, Bottom Field First Transmitted</title> + <mediaobject> + <imageobject> + <imagedata fileref="fieldseq_bt.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="fieldseq_bt.gif" format="GIF" /> + </imageobject> + </mediaobject> + </figure> + </section> diff --git a/Documentation/DocBook/media/v4l/keytable.c.xml b/Documentation/DocBook/media/v4l/keytable.c.xml new file mode 100644 index 00000000..d53254a3 --- /dev/null +++ b/Documentation/DocBook/media/v4l/keytable.c.xml @@ -0,0 +1,172 @@ +<programlisting> +/* keytable.c - This program allows checking/replacing keys at IR + + Copyright (C) 2006-2009 Mauro Carvalho Chehab <mchehab@infradead.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + */ + +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <linux/input.h> +#include <sys/ioctl.h> + +#include "parse.h" + +void prtcode (int *codes) +{ + struct parse_key *p; + + for (p=keynames;p->name!=NULL;p++) { + if (p->value == (unsigned)codes[1]) { + printf("scancode 0x%04x = %s (0x%02x)\n", codes[0], p->name, codes[1]); + return; + } + } + + if (isprint (codes[1])) + printf("scancode %d = '%c' (0x%02x)\n", codes[0], codes[1], codes[1]); + else + printf("scancode %d = 0x%02x\n", codes[0], codes[1]); +} + +int parse_code(char *string) +{ + struct parse_key *p; + + for (p=keynames;p->name!=NULL;p++) { + if (!strcasecmp(p->name, string)) { + return p->value; + } + } + return -1; +} + +int main (int argc, char *argv[]) +{ + int fd; + unsigned int i, j; + int codes[2]; + + if (argc<2 || argc>4) { + printf ("usage: %s <device> to get table; or\n" + " %s <device> <scancode> <keycode>\n" + " %s <device> <keycode_file>\n",*argv,*argv,*argv); + return -1; + } + + if ((fd = open(argv[1], O_RDONLY)) < 0) { + perror("Couldn't open input device"); + return(-1); + } + + if (argc==4) { + int value; + + value=parse_code(argv[3]); + + if (value==-1) { + value = strtol(argv[3], NULL, 0); + if (errno) + perror("value"); + } + + codes [0] = (unsigned) strtol(argv[2], NULL, 0); + codes [1] = (unsigned) value; + + if(ioctl(fd, EVIOCSKEYCODE, codes)) + perror ("EVIOCSKEYCODE"); + + if(ioctl(fd, EVIOCGKEYCODE, codes)==0) + prtcode(codes); + return 0; + } + + if (argc==3) { + FILE *fin; + int value; + char *scancode, *keycode, s[2048]; + + fin=fopen(argv[2],"r"); + if (fin==NULL) { + perror ("opening keycode file"); + return -1; + } + + /* Clears old table */ + for (j = 0; j < 256; j++) { + for (i = 0; i < 256; i++) { + codes[0] = (j << 8) | i; + codes[1] = KEY_RESERVED; + ioctl(fd, EVIOCSKEYCODE, codes); + } + } + + while (fgets(s,sizeof(s),fin)) { + scancode=strtok(s,"\n\t =:"); + if (!scancode) { + perror ("parsing input file scancode"); + return -1; + } + if (!strcasecmp(scancode, "scancode")) { + scancode = strtok(NULL,"\n\t =:"); + if (!scancode) { + perror ("parsing input file scancode"); + return -1; + } + } + + keycode=strtok(NULL,"\n\t =:("); + if (!keycode) { + perror ("parsing input file keycode"); + return -1; + } + + // printf ("parsing %s=%s:", scancode, keycode); + value=parse_code(keycode); + // printf ("\tvalue=%d\n",value); + + if (value==-1) { + value = strtol(keycode, NULL, 0); + if (errno) + perror("value"); + } + + codes [0] = (unsigned) strtol(scancode, NULL, 0); + codes [1] = (unsigned) value; + + // printf("\t%04x=%04x\n",codes[0], codes[1]); + if(ioctl(fd, EVIOCSKEYCODE, codes)) { + fprintf(stderr, "Setting scancode 0x%04x with 0x%04x via ",codes[0], codes[1]); + perror ("EVIOCSKEYCODE"); + } + + if(ioctl(fd, EVIOCGKEYCODE, codes)==0) + prtcode(codes); + } + return 0; + } + + /* Get scancode table */ + for (j = 0; j < 256; j++) { + for (i = 0; i < 256; i++) { + codes[0] = (j << 8) | i; + if (!ioctl(fd, EVIOCGKEYCODE, codes) && codes[1] != KEY_RESERVED) + prtcode(codes); + } + } + return 0; +} + +</programlisting> diff --git a/Documentation/DocBook/media/v4l/libv4l.xml b/Documentation/DocBook/media/v4l/libv4l.xml new file mode 100644 index 00000000..d3b71e20 --- /dev/null +++ b/Documentation/DocBook/media/v4l/libv4l.xml @@ -0,0 +1,160 @@ +<title>Libv4l Userspace Library</title> +<section id="libv4l-introduction"> + <title>Introduction</title> + + <para>libv4l is a collection of libraries which adds a thin abstraction +layer on top of video4linux2 devices. The purpose of this (thin) layer +is to make it easy for application writers to support a wide variety of +devices without having to write separate code for different devices in the +same class.</para> +<para>An example of using libv4l is provided by +<link linkend='v4l2grab-example'>v4l2grab</link>. +</para> + + <para>libv4l consists of 3 different libraries:</para> + <section> + <title>libv4lconvert</title> + + <para>libv4lconvert is a library that converts several +different pixelformats found in V4L2 drivers into a few common RGB and +YUY formats.</para> + <para>It currently accepts the following V4L2 driver formats: +<link linkend="V4L2-PIX-FMT-BGR24"><constant>V4L2_PIX_FMT_BGR24</constant></link>, +<link linkend="V4L2-PIX-FMT-HM12"><constant>V4L2_PIX_FMT_HM12</constant></link>, +<link linkend="V4L2-PIX-FMT-JPEG"><constant>V4L2_PIX_FMT_JPEG</constant></link>, +<link linkend="V4L2-PIX-FMT-MJPEG"><constant>V4L2_PIX_FMT_MJPEG</constant></link>, +<link linkend="V4L2-PIX-FMT-MR97310A"><constant>V4L2_PIX_FMT_MR97310A</constant></link>, +<link linkend="V4L2-PIX-FMT-OV511"><constant>V4L2_PIX_FMT_OV511</constant></link>, +<link linkend="V4L2-PIX-FMT-OV518"><constant>V4L2_PIX_FMT_OV518</constant></link>, +<link linkend="V4L2-PIX-FMT-PAC207"><constant>V4L2_PIX_FMT_PAC207</constant></link>, +<link linkend="V4L2-PIX-FMT-PJPG"><constant>V4L2_PIX_FMT_PJPG</constant></link>, +<link linkend="V4L2-PIX-FMT-RGB24"><constant>V4L2_PIX_FMT_RGB24</constant></link>, +<link linkend="V4L2-PIX-FMT-SBGGR8"><constant>V4L2_PIX_FMT_SBGGR8</constant></link>, +<link linkend="V4L2-PIX-FMT-SGBRG8"><constant>V4L2_PIX_FMT_SGBRG8</constant></link>, +<link linkend="V4L2-PIX-FMT-SGRBG8"><constant>V4L2_PIX_FMT_SGRBG8</constant></link>, +<link linkend="V4L2-PIX-FMT-SN9C10X"><constant>V4L2_PIX_FMT_SN9C10X</constant></link>, +<link linkend="V4L2-PIX-FMT-SN9C20X-I420"><constant>V4L2_PIX_FMT_SN9C20X_I420</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA501"><constant>V4L2_PIX_FMT_SPCA501</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA505"><constant>V4L2_PIX_FMT_SPCA505</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA508"><constant>V4L2_PIX_FMT_SPCA508</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA561"><constant>V4L2_PIX_FMT_SPCA561</constant></link>, +<link linkend="V4L2-PIX-FMT-SQ905C"><constant>V4L2_PIX_FMT_SQ905C</constant></link>, +<constant>V4L2_PIX_FMT_SRGGB8</constant>, +<link linkend="V4L2-PIX-FMT-UYVY"><constant>V4L2_PIX_FMT_UYVY</constant></link>, +<link linkend="V4L2-PIX-FMT-YUV420"><constant>V4L2_PIX_FMT_YUV420</constant></link>, +<link linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link>, +<link linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link>, +and <link linkend="V4L2-PIX-FMT-YVYU"><constant>V4L2_PIX_FMT_YVYU</constant></link>. +</para> + <para>Later on libv4lconvert was expanded to also be able to do +various video processing functions to improve webcam video quality. +The video processing is split in to 2 parts: libv4lconvert/control and +libv4lconvert/processing.</para> + + <para>The control part is used to offer video controls which can +be used to control the video processing functions made available by + libv4lconvert/processing. These controls are stored application wide +(until reboot) by using a persistent shared memory object.</para> + + <para>libv4lconvert/processing offers the actual video +processing functionality.</para> + </section> + <section> + <title>libv4l1</title> + <para>This library offers functions that can be used to quickly +make v4l1 applications work with v4l2 devices. These functions work exactly +like the normal open/close/etc, except that libv4l1 does full emulation of +the v4l1 api on top of v4l2 drivers, in case of v4l1 drivers it +will just pass calls through.</para> + <para>Since those functions are emulations of the old V4L1 API, +it shouldn't be used for new applications.</para> + </section> + <section> + <title>libv4l2</title> + <para>This library should be used for all modern V4L2 +applications.</para> + <para>It provides handles to call V4L2 open/ioctl/close/poll +methods. Instead of just providing the raw output of the device, it enhances +the calls in the sense that it will use libv4lconvert to provide more video +formats and to enhance the image quality.</para> + <para>In most cases, libv4l2 just passes the calls directly +through to the v4l2 driver, intercepting the calls to +<link linkend='vidioc-g-fmt'><constant>VIDIOC_TRY_FMT</constant></link>, +<link linkend='vidioc-g-fmt'><constant>VIDIOC_G_FMT</constant></link> +<link linkend='vidioc-g-fmt'><constant>VIDIOC_S_FMT</constant></link> +<link linkend='vidioc-enum-framesizes'><constant>VIDIOC_ENUM_FRAMESIZES</constant></link> +and <link linkend='vidioc-enum-frameintervals'><constant>VIDIOC_ENUM_FRAMEINTERVALS</constant></link> +in order to emulate the formats +<link linkend="V4L2-PIX-FMT-BGR24"><constant>V4L2_PIX_FMT_BGR24</constant></link>, +<link linkend="V4L2-PIX-FMT-RGB24"><constant>V4L2_PIX_FMT_RGB24</constant></link>, +<link linkend="V4L2-PIX-FMT-YUV420"><constant>V4L2_PIX_FMT_YUV420</constant></link>, +and <link linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link>, +if they aren't available in the driver. +<link linkend='vidioc-enum-fmt'><constant>VIDIOC_ENUM_FMT</constant></link> +keeps enumerating the hardware supported formats, plus the emulated formats +offered by libv4l at the end. +</para> + <section id="libv4l-ops"> + <title>Libv4l device control functions</title> + <para>The common file operation methods are provided by +libv4l.</para> + <para>Those functions operate just like glibc +open/close/dup/ioctl/read/mmap/munmap:</para> +<itemizedlist><listitem> + <para>int v4l2_open(const char *file, int oflag, +...) - +operates like the standard <link linkend='func-open'>open()</link> function. +</para></listitem><listitem> + <para>int v4l2_close(int fd) - +operates like the standard <link linkend='func-close'>close()</link> function. +</para></listitem><listitem> + <para>int v4l2_dup(int fd) - +operates like the standard dup() function, duplicating a file handler. +</para></listitem><listitem> + <para>int v4l2_ioctl (int fd, unsigned long int request, ...) - +operates like the standard <link linkend='func-ioctl'>ioctl()</link> function. +</para></listitem><listitem> + <para>int v4l2_read (int fd, void* buffer, size_t n) - +operates like the standard <link linkend='func-read'>read()</link> function. +</para></listitem><listitem> + <para>void v4l2_mmap(void *start, size_t length, int prot, int flags, int fd, int64_t offset); - +operates like the standard <link linkend='func-mmap'>mmap()</link> function. +</para></listitem><listitem> + <para>int v4l2_munmap(void *_start, size_t length); - +operates like the standard <link linkend='func-munmap'>munmap()</link> function. +</para></listitem> +</itemizedlist> + <para>Those functions provide additional control:</para> +<itemizedlist><listitem> + <para>int v4l2_fd_open(int fd, int v4l2_flags) - +opens an already opened fd for further use through v4l2lib and possibly +modify libv4l2's default behavior through the v4l2_flags argument. +Currently, v4l2_flags can be <constant>V4L2_DISABLE_CONVERSION</constant>, +to disable format conversion. +</para></listitem><listitem> + <para>int v4l2_set_control(int fd, int cid, int value) - +This function takes a value of 0 - 65535, and then scales that range to +the actual range of the given v4l control id, and then if the cid exists +and is not locked sets the cid to the scaled value. +</para></listitem><listitem> + <para>int v4l2_get_control(int fd, int cid) - +This function returns a value of 0 - 65535, scaled to from the actual range +of the given v4l control id. when the cid does not exist, could not be +accessed for some reason, or some error occurred 0 is returned. +</para></listitem> +</itemizedlist> + </section> + </section> + <section> + + <title>v4l1compat.so wrapper library</title> + + <para>This library intercepts calls to +open/close/ioctl/mmap/mmunmap operations and redirects them to the libv4l +counterparts, by using LD_PRELOAD=/usr/lib/v4l1compat.so. It also +emulates V4L1 calls via V4L2 API.</para> + <para>It allows usage of binary legacy applications that +still don't use libv4l.</para> + </section> + +</section> diff --git a/Documentation/DocBook/media/v4l/lirc_device_interface.xml b/Documentation/DocBook/media/v4l/lirc_device_interface.xml new file mode 100644 index 00000000..8d7eb6bf --- /dev/null +++ b/Documentation/DocBook/media/v4l/lirc_device_interface.xml @@ -0,0 +1,253 @@ +<section id="lirc_dev"> +<title>LIRC Device Interface</title> + + +<section id="lirc_dev_intro"> +<title>Introduction</title> + +<para>The LIRC device interface is a bi-directional interface for +transporting raw IR data between userspace and kernelspace. Fundamentally, +it is just a chardev (/dev/lircX, for X = 0, 1, 2, ...), with a number +of standard struct file_operations defined on it. With respect to +transporting raw IR data to and fro, the essential fops are read, write +and ioctl.</para> + +<para>Example dmesg output upon a driver registering w/LIRC:</para> + <blockquote> + <para>$ dmesg |grep lirc_dev</para> + <para>lirc_dev: IR Remote Control driver registered, major 248</para> + <para>rc rc0: lirc_dev: driver ir-lirc-codec (mceusb) registered at minor = 0</para> + </blockquote> + +<para>What you should see for a chardev:</para> + <blockquote> + <para>$ ls -l /dev/lirc*</para> + <para>crw-rw---- 1 root root 248, 0 Jul 2 22:20 /dev/lirc0</para> + </blockquote> +</section> + +<section id="lirc_read"> +<title>LIRC read fop</title> + +<para>The lircd userspace daemon reads raw IR data from the LIRC chardev. The +exact format of the data depends on what modes a driver supports, and what +mode has been selected. lircd obtains supported modes and sets the active mode +via the ioctl interface, detailed at <xref linkend="lirc_ioctl"/>. The generally +preferred mode is LIRC_MODE_MODE2, in which packets containing an int value +describing an IR signal are read from the chardev.</para> + +<para>See also <ulink url="http://www.lirc.org/html/technical.html">http://www.lirc.org/html/technical.html</ulink> for more info.</para> +</section> + +<section id="lirc_write"> +<title>LIRC write fop</title> + +<para>The data written to the chardev is a pulse/space sequence of integer +values. Pulses and spaces are only marked implicitly by their position. The +data must start and end with a pulse, therefore, the data must always include +an uneven number of samples. The write function must block until the data has +been transmitted by the hardware.</para> +</section> + +<section id="lirc_ioctl"> +<title>LIRC ioctl fop</title> + +<para>The LIRC device's ioctl definition is bound by the ioctl function +definition of struct file_operations, leaving us with an unsigned int +for the ioctl command and an unsigned long for the arg. For the purposes +of ioctl portability across 32-bit and 64-bit, these values are capped +to their 32-bit sizes.</para> + +<para>The following ioctls can be used to change specific hardware settings. +In general each driver should have a default set of settings. The driver +implementation is expected to re-apply the default settings when the device +is closed by user-space, so that every application opening the device can rely +on working with the default settings initially.</para> + +<variablelist> + <varlistentry> + <term>LIRC_GET_FEATURES</term> + <listitem> + <para>Obviously, get the underlying hardware device's features. If a driver + does not announce support of certain features, calling of the corresponding + ioctls is undefined.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_SEND_MODE</term> + <listitem> + <para>Get supported transmit mode. Only LIRC_MODE_PULSE is supported by lircd.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_REC_MODE</term> + <listitem> + <para>Get supported receive modes. Only LIRC_MODE_MODE2 and LIRC_MODE_LIRCCODE + are supported by lircd.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_SEND_CARRIER</term> + <listitem> + <para>Get carrier frequency (in Hz) currently used for transmit.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_REC_CARRIER</term> + <listitem> + <para>Get carrier frequency (in Hz) currently used for IR reception.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_{G,S}ET_{SEND,REC}_DUTY_CYCLE</term> + <listitem> + <para>Get/set the duty cycle (from 0 to 100) of the carrier signal. Currently, + no special meaning is defined for 0 or 100, but this could be used to switch + off carrier generation in the future, so these values should be reserved.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_REC_RESOLUTION</term> + <listitem> + <para>Some receiver have maximum resolution which is defined by internal + sample rate or data format limitations. E.g. it's common that signals can + only be reported in 50 microsecond steps. This integer value is used by + lircd to automatically adjust the aeps tolerance value in the lircd + config file.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_M{IN,AX}_TIMEOUT</term> + <listitem> + <para>Some devices have internal timers that can be used to detect when + there's no IR activity for a long time. This can help lircd in detecting + that a IR signal is finished and can speed up the decoding process. + Returns an integer value with the minimum/maximum timeout that can be + set. Some devices have a fixed timeout, in that case both ioctls will + return the same value even though the timeout cannot be changed.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_M{IN,AX}_FILTER_{PULSE,SPACE}</term> + <listitem> + <para>Some devices are able to filter out spikes in the incoming signal + using given filter rules. These ioctls return the hardware capabilities + that describe the bounds of the possible filters. Filter settings depend + on the IR protocols that are expected. lircd derives the settings from + all protocols definitions found in its config file.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_GET_LENGTH</term> + <listitem> + <para>Retrieves the code length in bits (only for LIRC_MODE_LIRCCODE). + Reads on the device must be done in blocks matching the bit count. + The bit could should be rounded up so that it matches full bytes.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_{SEND,REC}_MODE</term> + <listitem> + <para>Set send/receive mode. Largely obsolete for send, as only + LIRC_MODE_PULSE is supported.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_{SEND,REC}_CARRIER</term> + <listitem> + <para>Set send/receive carrier (in Hz).</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_TRANSMITTER_MASK</term> + <listitem> + <para>This enables the given set of transmitters. The first transmitter + is encoded by the least significant bit, etc. When an invalid bit mask + is given, i.e. a bit is set, even though the device does not have so many + transitters, then this ioctl returns the number of available transitters + and does nothing otherwise.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_REC_TIMEOUT</term> + <listitem> + <para>Sets the integer value for IR inactivity timeout (cf. + LIRC_GET_MIN_TIMEOUT and LIRC_GET_MAX_TIMEOUT). A value of 0 (if + supported by the hardware) disables all hardware timeouts and data should + be reported as soon as possible. If the exact value cannot be set, then + the next possible value _greater_ than the given value should be set.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_REC_TIMEOUT_REPORTS</term> + <listitem> + <para>Enable (1) or disable (0) timeout reports in LIRC_MODE_MODE2. By + default, timeout reports should be turned off.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_REC_FILTER_{,PULSE,SPACE}</term> + <listitem> + <para>Pulses/spaces shorter than this are filtered out by hardware. If + filters cannot be set independently for pulse/space, the corresponding + ioctls must return an error and LIRC_SET_REC_FILTER shall be used instead.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_MEASURE_CARRIER_MODE</term> + <listitem> + <para>Enable (1)/disable (0) measure mode. If enabled, from the next key + press on, the driver will send LIRC_MODE2_FREQUENCY packets. By default + this should be turned off.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_REC_{DUTY_CYCLE,CARRIER}_RANGE</term> + <listitem> + <para>To set a range use LIRC_SET_REC_DUTY_CYCLE_RANGE/LIRC_SET_REC_CARRIER_RANGE + with the lower bound first and later LIRC_SET_REC_DUTY_CYCLE/LIRC_SET_REC_CARRIER + with the upper bound.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_NOTIFY_DECODE</term> + <listitem> + <para>This ioctl is called by lircd whenever a successful decoding of an + incoming IR signal could be done. This can be used by supporting hardware + to give visual feedback to the user e.g. by flashing a LED.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SETUP_{START,END}</term> + <listitem> + <para>Setting of several driver parameters can be optimized by encapsulating + the according ioctl calls with LIRC_SETUP_START/LIRC_SETUP_END. When a + driver receives a LIRC_SETUP_START ioctl it can choose to not commit + further setting changes to the hardware until a LIRC_SETUP_END is received. + But this is open to the driver implementation and every driver must also + handle parameter changes which are not encapsulated by LIRC_SETUP_START + and LIRC_SETUP_END. Drivers can also choose to ignore these ioctls.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>LIRC_SET_WIDEBAND_RECEIVER</term> + <listitem> + <para>Some receivers are equipped with special wide band receiver which is intended + to be used to learn output of existing remote. + Calling that ioctl with (1) will enable it, and with (0) disable it. + This might be useful of receivers that have otherwise narrow band receiver + that prevents them to be used with some remotes. + Wide band receiver might also be more precise + On the other hand its disadvantage it usually reduced range of reception. + Note: wide band receiver might be implictly enabled if you enable + carrier reports. In that case it will be disabled as soon as you disable + carrier reports. Trying to disable wide band receiver while carrier + reports are active will do nothing.</para> + </listitem> + </varlistentry> +</variablelist> +<section id="lirc_dev_errors"> + &return-value; +</section> +</section> +</section> diff --git a/Documentation/DocBook/media/v4l/media-controller.xml b/Documentation/DocBook/media/v4l/media-controller.xml new file mode 100644 index 00000000..873ac3a6 --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-controller.xml @@ -0,0 +1,89 @@ +<partinfo> + <authorgroup> + <author> + <firstname>Laurent</firstname> + <surname>Pinchart</surname> + <affiliation><address><email>laurent.pinchart@ideasonboard.com</email></address></affiliation> + <contrib>Initial version.</contrib> + </author> + </authorgroup> + <copyright> + <year>2010</year> + <holder>Laurent Pinchart</holder> + </copyright> + + <revhistory> + <!-- Put document revisions here, newest first. --> + <revision> + <revnumber>1.0.0</revnumber> + <date>2010-11-10</date> + <authorinitials>lp</authorinitials> + <revremark>Initial revision</revremark> + </revision> + </revhistory> +</partinfo> + +<title>Media Controller API</title> + +<chapter id="media_controller"> + <title>Media Controller</title> + + <section id="media-controller-intro"> + <title>Introduction</title> + <para>Media devices increasingly handle multiple related functions. Many USB + cameras include microphones, video capture hardware can also output video, + or SoC camera interfaces also perform memory-to-memory operations similar to + video codecs.</para> + <para>Independent functions, even when implemented in the same hardware, can + be modelled as separate devices. A USB camera with a microphone will be + presented to userspace applications as V4L2 and ALSA capture devices. The + devices' relationships (when using a webcam, end-users shouldn't have to + manually select the associated USB microphone), while not made available + directly to applications by the drivers, can usually be retrieved from + sysfs.</para> + <para>With more and more advanced SoC devices being introduced, the current + approach will not scale. Device topologies are getting increasingly complex + and can't always be represented by a tree structure. Hardware blocks are + shared between different functions, creating dependencies between seemingly + unrelated devices.</para> + <para>Kernel abstraction APIs such as V4L2 and ALSA provide means for + applications to access hardware parameters. As newer hardware expose an + increasingly high number of those parameters, drivers need to guess what + applications really require based on limited information, thereby + implementing policies that belong to userspace.</para> + <para>The media controller API aims at solving those problems.</para> + </section> + + <section id="media-controller-model"> + <title>Media device model</title> + <para>Discovering a device internal topology, and configuring it at runtime, + is one of the goals of the media controller API. To achieve this, hardware + devices are modelled as an oriented graph of building blocks called entities + connected through pads.</para> + <para>An entity is a basic media hardware or software building block. It can + correspond to a large variety of logical blocks such as physical hardware + devices (CMOS sensor for instance), logical hardware devices (a building + block in a System-on-Chip image processing pipeline), DMA channels or + physical connectors.</para> + <para>A pad is a connection endpoint through which an entity can interact + with other entities. Data (not restricted to video) produced by an entity + flows from the entity's output to one or more entity inputs. Pads should not + be confused with physical pins at chip boundaries.</para> + <para>A link is a point-to-point oriented connection between two pads, + either on the same entity or on different entities. Data flows from a source + pad to a sink pad.</para> + </section> +</chapter> + +<appendix id="media-user-func"> + <title>Function Reference</title> + <!-- Keep this alphabetically sorted. --> + &sub-media-func-open; + &sub-media-func-close; + &sub-media-func-ioctl; + <!-- All ioctls go here. --> + &sub-media-ioc-device-info; + &sub-media-ioc-enum-entities; + &sub-media-ioc-enum-links; + &sub-media-ioc-setup-link; +</appendix> diff --git a/Documentation/DocBook/media/v4l/media-func-close.xml b/Documentation/DocBook/media/v4l/media-func-close.xml new file mode 100644 index 00000000..be149c80 --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-func-close.xml @@ -0,0 +1,59 @@ +<refentry id="media-func-close"> + <refmeta> + <refentrytitle>media close()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>media-close</refname> + <refpurpose>Close a media device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>close</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Closes the media device. Resources associated with the file descriptor + are freed. The device configuration remain unchanged.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para><function>close</function> returns 0 on success. On error, -1 is + returned, and <varname>errno</varname> is set appropriately. Possible error + codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid open file descriptor. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/media-func-ioctl.xml b/Documentation/DocBook/media/v4l/media-func-ioctl.xml new file mode 100644 index 00000000..39478d0f --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-func-ioctl.xml @@ -0,0 +1,73 @@ +<refentry id="media-func-ioctl"> + <refmeta> + <refentrytitle>media ioctl()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>media-ioctl</refname> + <refpurpose>Control a media device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <sys/ioctl.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>void *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>Media ioctl request code as defined in the media.h header file, + for example MEDIA_IOC_SETUP_LINK.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a request-specific structure.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + <para>The <function>ioctl()</function> function manipulates media device + parameters. The argument <parameter>fd</parameter> must be an open file + descriptor.</para> + <para>The ioctl <parameter>request</parameter> code specifies the media + function to be called. It has encoded in it whether the argument is an + input, output or read/write parameter, and the size of the argument + <parameter>argp</parameter> in bytes.</para> + <para>Macros and structures definitions specifying media ioctl requests and + their parameters are located in the media.h header file. All media ioctl + requests, their respective function and parameters are specified in + <xref linkend="media-user-func" />.</para> + </refsect1> + + <refsect1> + &return-value; + + <para>Request-specific error codes are listed in the + individual requests descriptions.</para> + <para>When an ioctl that takes an output or read/write parameter fails, + the parameter remains unmodified.</para> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/media-func-open.xml b/Documentation/DocBook/media/v4l/media-func-open.xml new file mode 100644 index 00000000..f7df034d --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-func-open.xml @@ -0,0 +1,94 @@ +<refentry id="media-func-open"> + <refmeta> + <refentrytitle>media open()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>media-open</refname> + <refpurpose>Open a media device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <fcntl.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>open</function></funcdef> + <paramdef>const char *<parameter>device_name</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>device_name</parameter></term> + <listitem> + <para>Device to be opened.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>flags</parameter></term> + <listitem> + <para>Open flags. Access mode must be either <constant>O_RDONLY</constant> + or <constant>O_RDWR</constant>. Other flags have no effect.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1> + <title>Description</title> + <para>To open a media device applications call <function>open()</function> + with the desired device name. The function has no side effects; the device + configuration remain unchanged.</para> + <para>When the device is opened in read-only mode, attemps to modify its + configuration will result in an error, and <varname>errno</varname> will be + set to <errorcode>EBADF</errorcode>.</para> + </refsect1> + <refsect1> + <title>Return Value</title> + + <para><function>open</function> returns the new file descriptor on success. + On error, -1 is returned, and <varname>errno</varname> is set appropriately. + Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>The requested access to the file is not allowed.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EMFILE</errorcode></term> + <listitem> + <para>The process already has the maximum number of files open. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENFILE</errorcode></term> + <listitem> + <para>The system limit on the total number of open files has been + reached.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Insufficient kernel memory was available.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENXIO</errorcode></term> + <listitem> + <para>No device corresponding to this device special file exists. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/media-ioc-device-info.xml b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml new file mode 100644 index 00000000..2ce52141 --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml @@ -0,0 +1,132 @@ +<refentry id="media-ioc-device-info"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_DEVICE_INFO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_DEVICE_INFO</refname> + <refpurpose>Query device information</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct media_device_info *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>File descriptor returned by + <link linkend='media-func-open'><function>open()</function></link>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>MEDIA_IOC_DEVICE_INFO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>All media devices must support the <constant>MEDIA_IOC_DEVICE_INFO</constant> + ioctl. To query device information, applications call the ioctl with a + pointer to a &media-device-info;. The driver fills the structure and returns + the information to the application. + The ioctl never fails.</para> + + <table pgwide="1" frame="none" id="media-device-info"> + <title>struct <structname>media_device_info</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>char</entry> + <entry><structfield>driver</structfield>[16]</entry> + <entry><para>Name of the driver implementing the media API as a + NUL-terminated ASCII string. The driver version is stored in the + <structfield>driver_version</structfield> field.</para> + <para>Driver specific applications can use this information to + verify the driver identity. It is also useful to work around + known bugs, or to identify drivers in error reports.</para></entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>model</structfield>[32]</entry> + <entry>Device model name as a NUL-terminated UTF-8 string. The + device version is stored in the <structfield>device_version</structfield> + field and is not be appended to the model name.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>serial</structfield>[40]</entry> + <entry>Serial number as a NUL-terminated ASCII string.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>bus_info</structfield>[32]</entry> + <entry>Location of the device in the system as a NUL-terminated + ASCII string. This includes the bus type name (PCI, USB, ...) and a + bus-specific identifier.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>media_version</structfield></entry> + <entry>Media API version, formatted with the + <constant>KERNEL_VERSION()</constant> macro.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>hw_revision</structfield></entry> + <entry>Hardware device revision in a driver-specific format.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>media_version</structfield></entry> + <entry>Media device driver version, formatted with the + <constant>KERNEL_VERSION()</constant> macro. Together with the + <structfield>driver</structfield> field this identifies a particular + driver.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[31]</entry> + <entry>Reserved for future extensions. Drivers and applications must + set this array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + <para>The <structfield>serial</structfield> and <structfield>bus_info</structfield> + fields can be used to distinguish between multiple instances of otherwise + identical hardware. The serial number takes precedence when provided and can + be assumed to be unique. If the serial number is an empty string, the + <structfield>bus_info</structfield> field can be used instead. The + <structfield>bus_info</structfield> field is guaranteed to be unique, but + can vary across reboots or device unplug/replug.</para> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml b/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml new file mode 100644 index 00000000..576b68b3 --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml @@ -0,0 +1,308 @@ +<refentry id="media-ioc-enum-entities"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_ENUM_ENTITIES</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_ENUM_ENTITIES</refname> + <refpurpose>Enumerate entities and their properties</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct media_entity_desc *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>File descriptor returned by + <link linkend='media-func-open'><function>open()</function></link>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>MEDIA_IOC_ENUM_ENTITIES</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + <para>To query the attributes of an entity, applications set the id field + of a &media-entity-desc; structure and call the MEDIA_IOC_ENUM_ENTITIES + ioctl with a pointer to this structure. The driver fills the rest of the + structure or returns an &EINVAL; when the id is invalid.</para> + <para>Entities can be enumerated by or'ing the id with the + <constant>MEDIA_ENT_ID_FLAG_NEXT</constant> flag. The driver will return + information about the entity with the smallest id strictly larger than the + requested one ('next entity'), or the &EINVAL; if there is none.</para> + <para>Entity IDs can be non-contiguous. Applications must + <emphasis>not</emphasis> try to enumerate entities by calling + MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error.</para> + <para>Two or more entities that share a common non-zero + <structfield>group_id</structfield> value are considered as logically + grouped. Groups are used to report + <itemizedlist> + <listitem><para>ALSA, VBI and video nodes that carry the same media + stream</para></listitem> + <listitem><para>lens and flash controllers associated with a sensor</para></listitem> + </itemizedlist> + </para> + + <table pgwide="1" frame="none" id="media-entity-desc"> + <title>struct <structname>media_entity_desc</structname></title> + <tgroup cols="5"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <colspec colname="c5" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity id, set by the application. When the id is or'ed with + <constant>MEDIA_ENT_ID_FLAG_NEXT</constant>, the driver clears the + flag and returns the first entity with a larger id.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry></entry> + <entry></entry> + <entry>Entity name as an UTF-8 NULL-terminated string.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity type, see <xref linkend="media-entity-type" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>revision</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity revision in a driver/hardware specific format.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity flags, see <xref linkend="media-entity-flag" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>group_id</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity group ID</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>pads</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Number of pads</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>links</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Total number of outbound links. Inbound links are not counted + in this field.</entry> + </row> + <row> + <entry>union</entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>v4l</structfield></entry> + <entry></entry> + <entry>Valid for V4L sub-devices and nodes only.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>major</structfield></entry> + <entry>V4L device node major number. For V4L sub-devices with no + device node, set by the driver to 0.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>minor</structfield></entry> + <entry>V4L device node minor number. For V4L sub-devices with no + device node, set by the driver to 0.</entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>fb</structfield></entry> + <entry></entry> + <entry>Valid for frame buffer nodes only.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>major</structfield></entry> + <entry>Frame buffer device node major number.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>minor</structfield></entry> + <entry>Frame buffer device node minor number.</entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>alsa</structfield></entry> + <entry></entry> + <entry>Valid for ALSA devices only.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>card</structfield></entry> + <entry>ALSA card number</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>device</structfield></entry> + <entry>ALSA device number</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>subdevice</structfield></entry> + <entry>ALSA sub-device number</entry> + </row> + <row> + <entry></entry> + <entry>int</entry> + <entry><structfield>dvb</structfield></entry> + <entry></entry> + <entry>DVB card number</entry> + </row> + <row> + <entry></entry> + <entry>__u8</entry> + <entry><structfield>raw</structfield>[180]</entry> + <entry></entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-entity-type"> + <title>Media entity types</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE</constant></entry> + <entry>Unknown device node</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_V4L</constant></entry> + <entry>V4L video, radio or vbi device node</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_FB</constant></entry> + <entry>Frame buffer device node</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_ALSA</constant></entry> + <entry>ALSA card</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_DVB</constant></entry> + <entry>DVB card</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV</constant></entry> + <entry>Unknown V4L sub-device</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_SENSOR</constant></entry> + <entry>Video sensor</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_FLASH</constant></entry> + <entry>Flash controller</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_LENS</constant></entry> + <entry>Lens controller</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-entity-flag"> + <title>Media entity flags</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_ENT_FL_DEFAULT</constant></entry> + <entry>Default entity for its type. Used to discover the default + audio, VBI and video devices, the default camera sensor, ...</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &media-entity-desc; <structfield>id</structfield> references + a non-existing entity.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml new file mode 100644 index 00000000..355df43b --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml @@ -0,0 +1,207 @@ +<refentry id="media-ioc-enum-links"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_ENUM_LINKS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_ENUM_LINKS</refname> + <refpurpose>Enumerate all pads and links for a given entity</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct media_links_enum *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>File descriptor returned by + <link linkend='media-func-open'><function>open()</function></link>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>MEDIA_IOC_ENUM_LINKS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To enumerate pads and/or links for a given entity, applications set + the entity field of a &media-links-enum; structure and initialize the + &media-pad-desc; and &media-link-desc; structure arrays pointed by the + <structfield>pads</structfield> and <structfield>links</structfield> fields. + They then call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this + structure.</para> + <para>If the <structfield>pads</structfield> field is not NULL, the driver + fills the <structfield>pads</structfield> array with information about the + entity's pads. The array must have enough room to store all the entity's + pads. The number of pads can be retrieved with the &MEDIA-IOC-ENUM-ENTITIES; + ioctl.</para> + <para>If the <structfield>links</structfield> field is not NULL, the driver + fills the <structfield>links</structfield> array with information about the + entity's outbound links. The array must have enough room to store all the + entity's outbound links. The number of outbound links can be retrieved with + the &MEDIA-IOC-ENUM-ENTITIES; ioctl.</para> + <para>Only forward links that originate at one of the entity's source pads + are returned during the enumeration process.</para> + + <table pgwide="1" frame="none" id="media-links-enum"> + <title>struct <structname>media_links_enum</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>entity</structfield></entry> + <entry>Entity id, set by the application.</entry> + </row> + <row> + <entry>struct &media-pad-desc;</entry> + <entry>*<structfield>pads</structfield></entry> + <entry>Pointer to a pads array allocated by the application. Ignored + if NULL.</entry> + </row> + <row> + <entry>struct &media-link-desc;</entry> + <entry>*<structfield>links</structfield></entry> + <entry>Pointer to a links array allocated by the application. Ignored + if NULL.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="media-pad-desc"> + <title>struct <structname>media_pad_desc</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>entity</structfield></entry> + <entry>ID of the entity this pad belongs to.</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>index</structfield></entry> + <entry>0-based pad index.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Pad flags, see <xref linkend="media-pad-flag" /> for more details.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-pad-flag"> + <title>Media pad flags</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_PAD_FL_SINK</constant></entry> + <entry>Input pad, relative to the entity. Input pads sink data and + are targets of links.</entry> + </row> + <row> + <entry><constant>MEDIA_PAD_FL_SOURCE</constant></entry> + <entry>Output pad, relative to the entity. Output pads source data + and are origins of links.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="media-link-desc"> + <title>struct <structname>media_link_desc</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>struct &media-pad-desc;</entry> + <entry><structfield>source</structfield></entry> + <entry>Pad at the origin of this link.</entry> + </row> + <row> + <entry>struct &media-pad-desc;</entry> + <entry><structfield>sink</structfield></entry> + <entry>Pad at the target of this link.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Link flags, see <xref linkend="media-link-flag" /> for more details.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-link-flag"> + <title>Media link flags</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_LNK_FL_ENABLED</constant></entry> + <entry>The link is enabled and can be used to transfer media data. + When two or more links target a sink pad, only one of them can be + enabled at a time.</entry> + </row> + <row> + <entry><constant>MEDIA_LNK_FL_IMMUTABLE</constant></entry> + <entry>The link enabled state can't be modified at runtime. An + immutable link is always enabled.</entry> + </row> + <row> + <entry><constant>MEDIA_LNK_FL_DYNAMIC</constant></entry> + <entry>The link enabled state can be modified during streaming. This + flag is set by drivers and is read-only for applications.</entry> + </row> + </tbody> + </tgroup> + </table> + <para>One and only one of <constant>MEDIA_PAD_FL_SINK</constant> and + <constant>MEDIA_PAD_FL_SOURCE</constant> must be set for every pad.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &media-links-enum; <structfield>id</structfield> references + a non-existing entity.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml b/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml new file mode 100644 index 00000000..fc2e522e --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml @@ -0,0 +1,84 @@ +<refentry id="media-ioc-setup-link"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_SETUP_LINK</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_SETUP_LINK</refname> + <refpurpose>Modify the properties of a link</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct media_link_desc *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>File descriptor returned by + <link linkend='media-func-open'><function>open()</function></link>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>MEDIA_IOC_SETUP_LINK</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To change link properties applications fill a &media-link-desc; with + link identification information (source and sink pad) and the new requested + link flags. They then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to + that structure.</para> + <para>The only configurable property is the <constant>ENABLED</constant> + link flag to enable/disable a link. Links marked with the + <constant>IMMUTABLE</constant> link flag can not be enabled or disabled. + </para> + <para>Link configuration has no side effect on other links. If an enabled + link at the sink pad prevents the link from being enabled, the driver + returns with an &EBUSY;.</para> + <para>Only links marked with the <constant>DYNAMIC</constant> link flag can + be enabled/disabled while streaming media data. Attempting to enable or + disable a streaming non-dynamic link will return an &EBUSY;.</para> + <para>If the specified link can't be found the driver returns with an + &EINVAL;.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &media-link-desc; references a non-existing link, or the + link is immutable and an attempt to modify its configuration was made. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pipeline.pdf b/Documentation/DocBook/media/v4l/pipeline.pdf Binary files differnew file mode 100644 index 00000000..ee3e37f0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pipeline.pdf diff --git a/Documentation/DocBook/media/v4l/pixfmt-grey.xml b/Documentation/DocBook/media/v4l/pixfmt-grey.xml new file mode 100644 index 00000000..bee970d3 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-grey.xml @@ -0,0 +1,62 @@ + <refentry id="V4L2-PIX-FMT-GREY"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_GREY ('GREY')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_GREY</constant></refname> + <refpurpose>Grey-scale image</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a grey-scale image. It is really a degenerate +Y'CbCr format which simply contains no Cb or Cr data.</para> + + <example> + <title><constant>V4L2_PIX_FMT_GREY</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-m420.xml b/Documentation/DocBook/media/v4l/pixfmt-m420.xml new file mode 100644 index 00000000..aadae92c --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-m420.xml @@ -0,0 +1,139 @@ + <refentry id="V4L2-PIX-FMT-M420"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_M420 ('M420')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_M420</constant></refname> + <refpurpose>Format with ½ horizontal and vertical chroma + resolution, also known as YUV 4:2:0. Hybrid plane line-interleaved + layout.</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>M420 is a YUV format with ½ horizontal and vertical chroma + subsampling (YUV 4:2:0). Pixels are organized as interleaved luma and + chroma planes. Two lines of luma data are followed by one line of chroma + data.</para> + <para>The luma plane has one byte per pixel. The chroma plane contains + interleaved CbCr pixels subsampled by ½ in the horizontal and + vertical directions. Each CbCr pair belongs to four pixels. For example, +Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to +Y'<subscript>00</subscript>, Y'<subscript>01</subscript>, +Y'<subscript>10</subscript>, Y'<subscript>11</subscript>.</para> + + <para>All line lengths are identical: if the Y lines include pad bytes + so do the CbCr lines.</para> + + <example> + <title><constant>V4L2_PIX_FMT_M420</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv12.xml b/Documentation/DocBook/media/v4l/pixfmt-nv12.xml new file mode 100644 index 00000000..84dd4fd7 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv12.xml @@ -0,0 +1,143 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-NV12"><constant>V4L2_PIX_FMT_NV12</constant></refname> + <refname id="V4L2-PIX-FMT-NV21"><constant>V4L2_PIX_FMT_NV21</constant></refname> + <refpurpose>Formats with ½ horizontal and vertical +chroma resolution, also known as YUV 4:2:0. One luminance and one +chrominance plane with alternating chroma samples as opposed to +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are two-plane versions of the YUV 4:2:0 format. +The three components are separated into two sub-images or planes. The +Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_NV12</constant>, a combined CbCr plane +immediately follows the Y plane in memory. The CbCr plane is the same +width, in bytes, as the Y plane (and of the image), but is half as +tall in pixels. Each CbCr pair belongs to four pixels. For example, +Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to +Y'<subscript>00</subscript>, Y'<subscript>01</subscript>, +Y'<subscript>10</subscript>, Y'<subscript>11</subscript>. +<constant>V4L2_PIX_FMT_NV21</constant> is the same except the Cb and +Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para> + + <para>If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_NV12</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv12m.xml b/Documentation/DocBook/media/v4l/pixfmt-nv12m.xml new file mode 100644 index 00000000..5274c24d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv12m.xml @@ -0,0 +1,146 @@ + <refentry id="V4L2-PIX-FMT-NV12M"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_NV12M ('NM12')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname> <constant>V4L2_PIX_FMT_NV12M</constant></refname> + <refpurpose>Variation of <constant>V4L2_PIX_FMT_NV12</constant> with planes + non contiguous in memory. </refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a multi-planar, two-plane version of the YUV 4:2:0 format. +The three components are separated into two sub-images or planes. +<constant>V4L2_PIX_FMT_NV12M</constant> differs from <constant>V4L2_PIX_FMT_NV12 +</constant> in that the two planes are non-contiguous in memory, i.e. the chroma +plane do not necessarily immediately follows the luma plane. +The luminance data occupies the first plane. The Y plane has one byte per pixel. +In the second plane there is a chrominance data with alternating chroma samples. +The CbCr plane is the same width, in bytes, as the Y plane (and of the image), +but is half as tall in pixels. Each CbCr pair belongs to four pixels. For example, +Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to +Y'<subscript>00</subscript>, Y'<subscript>01</subscript>, +Y'<subscript>10</subscript>, Y'<subscript>11</subscript>. </para> + + <para><constant>V4L2_PIX_FMT_NV12M</constant> is intended to be +used only in drivers and applications that support the multi-planar API, +described in <xref linkend="planar-apis"/>. </para> + + <para>If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_NV12M</constant> 4 × 4 pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start0 + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start0 + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start0 + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start0 + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>start1 + 0:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start1 + 4:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv12mt.xml b/Documentation/DocBook/media/v4l/pixfmt-nv12mt.xml new file mode 100644 index 00000000..2f82b1da --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv12mt.xml @@ -0,0 +1,66 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_NV12MT ('TM12')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-NV12MT"><constant>V4L2_PIX_FMT_NV12MT +</constant></refname> + <refpurpose>Formats with ½ horizontal and vertical +chroma resolution. This format has two planes - one for luminance and one for +chrominance. Chroma samples are interleaved. The difference to +<constant>V4L2_PIX_FMT_NV12</constant> is the memory layout. Pixels are +grouped in macroblocks of 64x32 size. The order of macroblocks in memory is +also not standard. + </refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is the two-plane versions of the YUV 4:2:0 format where data +is grouped into 64x32 macroblocks. The three components are separated into two +sub-images or planes. The Y plane has one byte per pixel and pixels are grouped +into 64x32 macroblocks. The CbCr plane has the same width, in bytes, as the Y +plane (and the image), but is half as tall in pixels. The chroma plane is also +grouped into 64x32 macroblocks.</para> + <para>Width of the buffer has to be aligned to the multiple of 128, and +height alignment is 32. Every four adjactent buffers - two horizontally and two +vertically are grouped together and are located in memory in Z or flipped Z +order. </para> + <para>Layout of macroblocks in memory is presented in the following +figure.</para> + <para><figure id="nv12mt"> + <title><constant>V4L2_PIX_FMT_NV12MT</constant> macroblock Z shape +memory layout</title> + <mediaobject> + <imageobject> + <imagedata fileref="nv12mt.gif" format="GIF" /> + </imageobject> + </mediaobject> + </figure> + The requirement that width is multiple of 128 is implemented because, +the Z shape cannot be cut in half horizontally. In case the vertical resolution +of macroblocks is odd then the last row of macroblocks is arranged in a linear +order. </para> + <para>In case of chroma the layout is identical. Cb and Cr samples are +interleaved. Height of the buffer is aligned to 32. + </para> + <example> + <title>Memory layout of macroblocks in <constant>V4L2_PIX_FMT_NV12 +</constant> format pixel image - extreme case</title> + <para> + <figure id="nv12mt_ex"> + <title>Example <constant>V4L2_PIX_FMT_NV12MT</constant> memory +layout of macroblocks</title> + <mediaobject> + <imageobject> + <imagedata fileref="nv12mt_example.gif" format="GIF" /> + </imageobject> + </mediaobject> + </figure> + Memory layout of macroblocks of <constant>V4L2_PIX_FMT_NV12MT +</constant> format in most extreme case. + </para> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv16.xml b/Documentation/DocBook/media/v4l/pixfmt-nv16.xml new file mode 100644 index 00000000..8ae1f8a8 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv16.xml @@ -0,0 +1,166 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_NV16 ('NV16'), V4L2_PIX_FMT_NV61 ('NV61')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-NV16"><constant>V4L2_PIX_FMT_NV16</constant></refname> + <refname id="V4L2-PIX-FMT-NV61"><constant>V4L2_PIX_FMT_NV61</constant></refname> + <refpurpose>Formats with ½ horizontal +chroma resolution, also known as YUV 4:2:2. One luminance and one +chrominance plane with alternating chroma samples as opposed to +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are two-plane versions of the YUV 4:2:2 format. +The three components are separated into two sub-images or planes. The +Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_NV16</constant>, a combined CbCr plane +immediately follows the Y plane in memory. The CbCr plane is the same +width and height, in bytes, as the Y plane (and of the image). +Each CbCr pair belongs to two pixels. For example, +Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to +Y'<subscript>00</subscript>, Y'<subscript>01</subscript>. +<constant>V4L2_PIX_FMT_NV61</constant> is the same except the Cb and +Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para> + + <para>If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_NV16</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 28:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv24.xml b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml new file mode 100644 index 00000000..fb255f2c --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml @@ -0,0 +1,121 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_NV24 ('NV24'), V4L2_PIX_FMT_NV42 ('NV42')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-NV24"><constant>V4L2_PIX_FMT_NV24</constant></refname> + <refname id="V4L2-PIX-FMT-NV42"><constant>V4L2_PIX_FMT_NV42</constant></refname> + <refpurpose>Formats with full horizontal and vertical +chroma resolutions, also known as YUV 4:4:4. One luminance and one +chrominance plane with alternating chroma samples as opposed to +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are two-plane versions of the YUV 4:4:4 format. The three + components are separated into two sub-images or planes. The Y plane is + first, with each Y sample stored in one byte per pixel. For + <constant>V4L2_PIX_FMT_NV24</constant>, a combined CbCr plane + immediately follows the Y plane in memory. The CbCr plane has the same + width and height, in pixels, as the Y plane (and the image). Each line + contains one CbCr pair per pixel, with each Cb and Cr sample stored in + one byte. <constant>V4L2_PIX_FMT_NV42</constant> is the same except that + the Cb and Cr samples are swapped, the CrCb plane starts with a Cr + sample.</para> + + <para>If the Y plane has pad bytes after each row, then the CbCr plane + has twice as many pad bytes after its rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_NV24</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Cb<subscript>02</subscript></entry> + <entry>Cr<subscript>02</subscript></entry> + <entry>Cb<subscript>03</subscript></entry> + <entry>Cr<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Cb<subscript>12</subscript></entry> + <entry>Cr<subscript>12</subscript></entry> + <entry>Cb<subscript>13</subscript></entry> + <entry>Cr<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 32:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Cb<subscript>22</subscript></entry> + <entry>Cr<subscript>22</subscript></entry> + <entry>Cb<subscript>23</subscript></entry> + <entry>Cr<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 40:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Cb<subscript>32</subscript></entry> + <entry>Cr<subscript>32</subscript></entry> + <entry>Cb<subscript>33</subscript></entry> + <entry>Cr<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml new file mode 100644 index 00000000..166c8d65 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml @@ -0,0 +1,935 @@ +<refentry id="packed-rgb"> + <refmeta> + <refentrytitle>Packed RGB formats</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname>Packed RGB formats</refname> + <refpurpose>Packed RGB formats</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These formats are designed to match the pixel formats of +typical PC graphics frame buffers. They occupy 8, 16, 24 or 32 bits +per pixel. These are all packed-pixel formats, meaning all the data +for a pixel lie next to each other in memory.</para> + + <para>When one of these formats is used, drivers shall report the +colorspace <constant>V4L2_COLORSPACE_SRGB</constant>.</para> + + <table pgwide="1" frame="none" id="rgb-formats"> + <title>Packed RGB Image Formats</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <colspec colnum="13" colname="b17" align="center" /> + <colspec colnum="14" colname="b16" align="center" /> + <colspec colnum="15" colname="b15" align="center" /> + <colspec colnum="16" colname="b14" align="center" /> + <colspec colnum="17" colname="b13" align="center" /> + <colspec colnum="18" colname="b12" align="center" /> + <colspec colnum="19" colname="b11" align="center" /> + <colspec colnum="20" colname="b10" align="center" /> + + <colspec colnum="22" colname="b27" align="center" /> + <colspec colnum="23" colname="b26" align="center" /> + <colspec colnum="24" colname="b25" align="center" /> + <colspec colnum="25" colname="b24" align="center" /> + <colspec colnum="26" colname="b23" align="center" /> + <colspec colnum="27" colname="b22" align="center" /> + <colspec colnum="28" colname="b21" align="center" /> + <colspec colnum="29" colname="b20" align="center" /> + + <colspec colnum="31" colname="b37" align="center" /> + <colspec colnum="32" colname="b36" align="center" /> + <colspec colnum="33" colname="b35" align="center" /> + <colspec colnum="34" colname="b34" align="center" /> + <colspec colnum="35" colname="b33" align="center" /> + <colspec colnum="36" colname="b32" align="center" /> + <colspec colnum="37" colname="b31" align="center" /> + <colspec colnum="38" colname="b30" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0 in memory</entry> + <entry spanname="b1">Byte 1</entry> + <entry spanname="b2">Byte 2</entry> + <entry spanname="b3">Byte 3</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-RGB332"> + <entry><constant>V4L2_PIX_FMT_RGB332</constant></entry> + <entry>'RGB1'</entry> + <entry></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB444"> + <entry><constant>V4L2_PIX_FMT_RGB444</constant></entry> + <entry>'R444'</entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB555"> + <entry><constant>V4L2_PIX_FMT_RGB555</constant></entry> + <entry>'RGBO'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>a</entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB565"> + <entry><constant>V4L2_PIX_FMT_RGB565</constant></entry> + <entry>'RGBP'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB555X"> + <entry><constant>V4L2_PIX_FMT_RGB555X</constant></entry> + <entry>'RGBQ'</entry> + <entry></entry> + <entry>a</entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB565X"> + <entry><constant>V4L2_PIX_FMT_RGB565X</constant></entry> + <entry>'RGBR'</entry> + <entry></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-BGR666"> + <entry><constant>V4L2_PIX_FMT_BGR666</constant></entry> + <entry>'BGRH'</entry> + <entry></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + </row> + <row id="V4L2-PIX-FMT-BGR24"> + <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> + <entry>'BGR3'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB24"> + <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> + <entry>'RGB3'</entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-BGR32"> + <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> + <entry>'BGR4'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB32"> + <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> + <entry>'RGB4'</entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Bit 7 is the most significant bit. The value of a = alpha +bits is undefined when reading from the driver, ignored when writing +to the driver, except when alpha blending has been negotiated for a +<link linkend="overlay">Video Overlay</link> or <link linkend="osd"> +Video Output Overlay</link> or when alpha component has been configured +for a <link linkend="capture">Video Capture</link> by means of <link +linkend="v4l2-alpha-component"> <constant>V4L2_CID_ALPHA_COMPONENT +</constant> </link> control.</para> + + <example> + <title><constant>V4L2_PIX_FMT_BGR24</constant> 4 × 4 pixel +image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="13" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00</subscript></entry> + <entry>G<subscript>00</subscript></entry> + <entry>R<subscript>00</subscript></entry> + <entry>B<subscript>01</subscript></entry> + <entry>G<subscript>01</subscript></entry> + <entry>R<subscript>01</subscript></entry> + <entry>B<subscript>02</subscript></entry> + <entry>G<subscript>02</subscript></entry> + <entry>R<subscript>02</subscript></entry> + <entry>B<subscript>03</subscript></entry> + <entry>G<subscript>03</subscript></entry> + <entry>R<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>B<subscript>10</subscript></entry> + <entry>G<subscript>10</subscript></entry> + <entry>R<subscript>10</subscript></entry> + <entry>B<subscript>11</subscript></entry> + <entry>G<subscript>11</subscript></entry> + <entry>R<subscript>11</subscript></entry> + <entry>B<subscript>12</subscript></entry> + <entry>G<subscript>12</subscript></entry> + <entry>R<subscript>12</subscript></entry> + <entry>B<subscript>13</subscript></entry> + <entry>G<subscript>13</subscript></entry> + <entry>R<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>B<subscript>20</subscript></entry> + <entry>G<subscript>20</subscript></entry> + <entry>R<subscript>20</subscript></entry> + <entry>B<subscript>21</subscript></entry> + <entry>G<subscript>21</subscript></entry> + <entry>R<subscript>21</subscript></entry> + <entry>B<subscript>22</subscript></entry> + <entry>G<subscript>22</subscript></entry> + <entry>R<subscript>22</subscript></entry> + <entry>B<subscript>23</subscript></entry> + <entry>G<subscript>23</subscript></entry> + <entry>R<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 36:</entry> + <entry>B<subscript>30</subscript></entry> + <entry>G<subscript>30</subscript></entry> + <entry>R<subscript>30</subscript></entry> + <entry>B<subscript>31</subscript></entry> + <entry>G<subscript>31</subscript></entry> + <entry>R<subscript>31</subscript></entry> + <entry>B<subscript>32</subscript></entry> + <entry>G<subscript>32</subscript></entry> + <entry>R<subscript>32</subscript></entry> + <entry>B<subscript>33</subscript></entry> + <entry>G<subscript>33</subscript></entry> + <entry>R<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + + <important> + <para>Drivers may interpret these formats differently.</para> + </important> + + <para>Some RGB formats above are uncommon and were probably +defined in error. Drivers may interpret them as in <xref + linkend="rgb-formats-corrected" />.</para> + + <table pgwide="1" frame="none" id="rgb-formats-corrected"> + <title>Packed RGB Image Formats (corrected)</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <colspec colnum="13" colname="b17" align="center" /> + <colspec colnum="14" colname="b16" align="center" /> + <colspec colnum="15" colname="b15" align="center" /> + <colspec colnum="16" colname="b14" align="center" /> + <colspec colnum="17" colname="b13" align="center" /> + <colspec colnum="18" colname="b12" align="center" /> + <colspec colnum="19" colname="b11" align="center" /> + <colspec colnum="20" colname="b10" align="center" /> + + <colspec colnum="22" colname="b27" align="center" /> + <colspec colnum="23" colname="b26" align="center" /> + <colspec colnum="24" colname="b25" align="center" /> + <colspec colnum="25" colname="b24" align="center" /> + <colspec colnum="26" colname="b23" align="center" /> + <colspec colnum="27" colname="b22" align="center" /> + <colspec colnum="28" colname="b21" align="center" /> + <colspec colnum="29" colname="b20" align="center" /> + + <colspec colnum="31" colname="b37" align="center" /> + <colspec colnum="32" colname="b36" align="center" /> + <colspec colnum="33" colname="b35" align="center" /> + <colspec colnum="34" colname="b34" align="center" /> + <colspec colnum="35" colname="b33" align="center" /> + <colspec colnum="36" colname="b32" align="center" /> + <colspec colnum="37" colname="b31" align="center" /> + <colspec colnum="38" colname="b30" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0 in memory</entry> + <entry spanname="b1">Byte 1</entry> + <entry spanname="b2">Byte 2</entry> + <entry spanname="b3">Byte 3</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row><!-- id="V4L2-PIX-FMT-RGB332" --> + <entry><constant>V4L2_PIX_FMT_RGB332</constant></entry> + <entry>'RGB1'</entry> + <entry></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB444" --> + <entry><constant>V4L2_PIX_FMT_RGB444</constant></entry> + <entry>'R444'</entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB555" --> + <entry><constant>V4L2_PIX_FMT_RGB555</constant></entry> + <entry>'RGBO'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a</entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB565" --> + <entry><constant>V4L2_PIX_FMT_RGB565</constant></entry> + <entry>'RGBP'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB555X" --> + <entry><constant>V4L2_PIX_FMT_RGB555X</constant></entry> + <entry>'RGBQ'</entry> + <entry></entry> + <entry>a</entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB565X" --> + <entry><constant>V4L2_PIX_FMT_RGB565X</constant></entry> + <entry>'RGBR'</entry> + <entry></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-BGR666" --> + <entry><constant>V4L2_PIX_FMT_BGR666</constant></entry> + <entry>'BGRH'</entry> + <entry></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-BGR24" --> + <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> + <entry>'BGR3'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB24" --> + <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> + <entry>'RGB3'</entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-BGR32" --> + <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> + <entry>'BGR4'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB32" --> + <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> + <entry>'RGB4'</entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + + <para>A test utility to determine which RGB formats a driver +actually supports is available from the LinuxTV v4l-dvb repository. +See &v4l-dvb; for access instructions.</para> + + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-packed-yuv.xml b/Documentation/DocBook/media/v4l/pixfmt-packed-yuv.xml new file mode 100644 index 00000000..33fa5a47 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-packed-yuv.xml @@ -0,0 +1,236 @@ +<refentry id="packed-yuv"> + <refmeta> + <refentrytitle>Packed YUV formats</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname>Packed YUV formats</refname> + <refpurpose>Packed YUV formats</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>Similar to the packed RGB formats these formats store +the Y, Cb and Cr component of each pixel in one 16 or 32 bit +word.</para> + + <table pgwide="1" frame="none"> + <title>Packed YUV Image Formats</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <colspec colnum="13" colname="b17" align="center" /> + <colspec colnum="14" colname="b16" align="center" /> + <colspec colnum="15" colname="b15" align="center" /> + <colspec colnum="16" colname="b14" align="center" /> + <colspec colnum="17" colname="b13" align="center" /> + <colspec colnum="18" colname="b12" align="center" /> + <colspec colnum="19" colname="b11" align="center" /> + <colspec colnum="20" colname="b10" align="center" /> + + <colspec colnum="22" colname="b27" align="center" /> + <colspec colnum="23" colname="b26" align="center" /> + <colspec colnum="24" colname="b25" align="center" /> + <colspec colnum="25" colname="b24" align="center" /> + <colspec colnum="26" colname="b23" align="center" /> + <colspec colnum="27" colname="b22" align="center" /> + <colspec colnum="28" colname="b21" align="center" /> + <colspec colnum="29" colname="b20" align="center" /> + + <colspec colnum="31" colname="b37" align="center" /> + <colspec colnum="32" colname="b36" align="center" /> + <colspec colnum="33" colname="b35" align="center" /> + <colspec colnum="34" colname="b34" align="center" /> + <colspec colnum="35" colname="b33" align="center" /> + <colspec colnum="36" colname="b32" align="center" /> + <colspec colnum="37" colname="b31" align="center" /> + <colspec colnum="38" colname="b30" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0 in memory</entry> + <entry spanname="b1">Byte 1</entry> + <entry spanname="b2">Byte 2</entry> + <entry spanname="b3">Byte 3</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-YUV444"> + <entry><constant>V4L2_PIX_FMT_YUV444</constant></entry> + <entry>'Y444'</entry> + <entry></entry> + <entry>Cb<subscript>3</subscript></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + </row> + + <row id="V4L2-PIX-FMT-YUV555"> + <entry><constant>V4L2_PIX_FMT_YUV555</constant></entry> + <entry>'YUVO'</entry> + <entry></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry>Cr<subscript>4</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + <entry></entry> + <entry>a</entry> + <entry>Y'<subscript>4</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + <entry>Cb<subscript>4</subscript></entry> + <entry>Cb<subscript>3</subscript></entry> + </row> + + <row id="V4L2-PIX-FMT-YUV565"> + <entry><constant>V4L2_PIX_FMT_YUV565</constant></entry> + <entry>'YUVP'</entry> + <entry></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry>Cr<subscript>4</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + <entry></entry> + <entry>Y'<subscript>4</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + <entry>Cb<subscript>5</subscript></entry> + <entry>Cb<subscript>4</subscript></entry> + <entry>Cb<subscript>3</subscript></entry> + </row> + + <row id="V4L2-PIX-FMT-YUV32"> + <entry><constant>V4L2_PIX_FMT_YUV32</constant></entry> + <entry>'YUV4'</entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry></entry> + <entry>Y'<subscript>7</subscript></entry> + <entry>Y'<subscript>6</subscript></entry> + <entry>Y'<subscript>5</subscript></entry> + <entry>Y'<subscript>4</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + <entry></entry> + <entry>Cb<subscript>7</subscript></entry> + <entry>Cb<subscript>6</subscript></entry> + <entry>Cb<subscript>5</subscript></entry> + <entry>Cb<subscript>4</subscript></entry> + <entry>Cb<subscript>3</subscript></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry></entry> + <entry>Cr<subscript>7</subscript></entry> + <entry>Cr<subscript>6</subscript></entry> + <entry>Cr<subscript>5</subscript></entry> + <entry>Cr<subscript>4</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Bit 7 is the most significant bit. The value of a = alpha +bits is undefined when reading from the driver, ignored when writing +to the driver, except when alpha blending has been negotiated for a +<link linkend="overlay">Video Overlay</link> or <link +linkend="osd">Video Output Overlay</link>.</para> + + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-sbggr16.xml b/Documentation/DocBook/media/v4l/pixfmt-sbggr16.xml new file mode 100644 index 00000000..6494b05d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sbggr16.xml @@ -0,0 +1,83 @@ +<refentry id="V4L2-PIX-FMT-SBGGR16"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SBGGR16 ('BYR2')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SBGGR16</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This format is similar to <link +linkend="V4L2-PIX-FMT-SBGGR8"> +<constant>V4L2_PIX_FMT_SBGGR8</constant></link>, except each pixel has +a depth of 16 bits. The least significant byte is stored at lower +memory addresses (little-endian). Note the actual sampling precision +may be lower than 16 bits, for example 10 bits per pixel with values +in range 0 to 1023.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SBGGR16</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00low</subscript></entry> + <entry>B<subscript>00high</subscript></entry> + <entry>G<subscript>01low</subscript></entry> + <entry>G<subscript>01high</subscript></entry> + <entry>B<subscript>02low</subscript></entry> + <entry>B<subscript>02high</subscript></entry> + <entry>G<subscript>03low</subscript></entry> + <entry>G<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>10low</subscript></entry> + <entry>G<subscript>10high</subscript></entry> + <entry>R<subscript>11low</subscript></entry> + <entry>R<subscript>11high</subscript></entry> + <entry>G<subscript>12low</subscript></entry> + <entry>G<subscript>12high</subscript></entry> + <entry>R<subscript>13low</subscript></entry> + <entry>R<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>B<subscript>20low</subscript></entry> + <entry>B<subscript>20high</subscript></entry> + <entry>G<subscript>21low</subscript></entry> + <entry>G<subscript>21high</subscript></entry> + <entry>B<subscript>22low</subscript></entry> + <entry>B<subscript>22high</subscript></entry> + <entry>G<subscript>23low</subscript></entry> + <entry>G<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>G<subscript>30low</subscript></entry> + <entry>G<subscript>30high</subscript></entry> + <entry>R<subscript>31low</subscript></entry> + <entry>R<subscript>31high</subscript></entry> + <entry>G<subscript>32low</subscript></entry> + <entry>G<subscript>32high</subscript></entry> + <entry>R<subscript>33low</subscript></entry> + <entry>R<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-sbggr8.xml b/Documentation/DocBook/media/v4l/pixfmt-sbggr8.xml new file mode 100644 index 00000000..5eaf2b42 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sbggr8.xml @@ -0,0 +1,67 @@ + <refentry id="V4L2-PIX-FMT-SBGGR8"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SBGGR8 ('BA81')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SBGGR8</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a blue and green value, the second row of a green and +red value. This scheme repeats to the right and down for every two +columns and rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SBGGR8</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00</subscript></entry> + <entry>G<subscript>01</subscript></entry> + <entry>B<subscript>02</subscript></entry> + <entry>G<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>G<subscript>10</subscript></entry> + <entry>R<subscript>11</subscript></entry> + <entry>G<subscript>12</subscript></entry> + <entry>R<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>B<subscript>20</subscript></entry> + <entry>G<subscript>21</subscript></entry> + <entry>B<subscript>22</subscript></entry> + <entry>G<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>G<subscript>30</subscript></entry> + <entry>R<subscript>31</subscript></entry> + <entry>G<subscript>32</subscript></entry> + <entry>R<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-sgbrg8.xml b/Documentation/DocBook/media/v4l/pixfmt-sgbrg8.xml new file mode 100644 index 00000000..fee65dca --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sgbrg8.xml @@ -0,0 +1,67 @@ + <refentry id="V4L2-PIX-FMT-SGBRG8"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SGBRG8 ('GBRG')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SGBRG8</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a green and blue value, the second row of a red and +green value. This scheme repeats to the right and down for every two +columns and rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SGBRG8</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>G<subscript>00</subscript></entry> + <entry>B<subscript>01</subscript></entry> + <entry>G<subscript>02</subscript></entry> + <entry>B<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>R<subscript>10</subscript></entry> + <entry>G<subscript>11</subscript></entry> + <entry>R<subscript>12</subscript></entry> + <entry>G<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>20</subscript></entry> + <entry>B<subscript>21</subscript></entry> + <entry>G<subscript>22</subscript></entry> + <entry>B<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>R<subscript>30</subscript></entry> + <entry>G<subscript>31</subscript></entry> + <entry>R<subscript>32</subscript></entry> + <entry>G<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml b/Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml new file mode 100644 index 00000000..19727ab4 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml @@ -0,0 +1,67 @@ + <refentry id="V4L2-PIX-FMT-SGRBG8"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SGRBG8 ('GRBG')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SGRBG8</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a green and blue value, the second row of a red and +green value. This scheme repeats to the right and down for every two +columns and rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SGRBG8</constant> 4 × +4 pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>G<subscript>00</subscript></entry> + <entry>R<subscript>01</subscript></entry> + <entry>G<subscript>02</subscript></entry> + <entry>R<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>R<subscript>10</subscript></entry> + <entry>B<subscript>11</subscript></entry> + <entry>R<subscript>12</subscript></entry> + <entry>B<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>20</subscript></entry> + <entry>R<subscript>21</subscript></entry> + <entry>G<subscript>22</subscript></entry> + <entry>R<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>R<subscript>30</subscript></entry> + <entry>B<subscript>31</subscript></entry> + <entry>R<subscript>32</subscript></entry> + <entry>B<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-srggb10.xml b/Documentation/DocBook/media/v4l/pixfmt-srggb10.xml new file mode 100644 index 00000000..7b274092 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-srggb10.xml @@ -0,0 +1,90 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SRGGB10 ('RG10'), + V4L2_PIX_FMT_SGRBG10 ('BA10'), + V4L2_PIX_FMT_SGBRG10 ('GB10'), + V4L2_PIX_FMT_SBGGR10 ('BG10'), + </refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-SRGGB10"><constant>V4L2_PIX_FMT_SRGGB10</constant></refname> + <refname id="V4L2-PIX-FMT-SGRBG10"><constant>V4L2_PIX_FMT_SGRBG10</constant></refname> + <refname id="V4L2-PIX-FMT-SGBRG10"><constant>V4L2_PIX_FMT_SGBRG10</constant></refname> + <refname id="V4L2-PIX-FMT-SBGGR10"><constant>V4L2_PIX_FMT_SBGGR10</constant></refname> + <refpurpose>10-bit Bayer formats expanded to 16 bits</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>The following four pixel formats are raw sRGB / Bayer formats with +10 bits per colour. Each colour component is stored in a 16-bit word, with 6 +unused high bits filled with zeros. Each n-pixel row contains n/2 green samples +and n/2 blue or red samples, with alternating red and blue rows. Bytes are +stored in memory in little endian order. They are conventionally described +as GRGR... BGBG..., RGRG... GBGB..., etc. Below is an example of one of these +formats</para> + + <example> + <title><constant>V4L2_PIX_FMT_SBGGR10</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte, high 6 bits in high bytes are 0. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00low</subscript></entry> + <entry>B<subscript>00high</subscript></entry> + <entry>G<subscript>01low</subscript></entry> + <entry>G<subscript>01high</subscript></entry> + <entry>B<subscript>02low</subscript></entry> + <entry>B<subscript>02high</subscript></entry> + <entry>G<subscript>03low</subscript></entry> + <entry>G<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>10low</subscript></entry> + <entry>G<subscript>10high</subscript></entry> + <entry>R<subscript>11low</subscript></entry> + <entry>R<subscript>11high</subscript></entry> + <entry>G<subscript>12low</subscript></entry> + <entry>G<subscript>12high</subscript></entry> + <entry>R<subscript>13low</subscript></entry> + <entry>R<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>B<subscript>20low</subscript></entry> + <entry>B<subscript>20high</subscript></entry> + <entry>G<subscript>21low</subscript></entry> + <entry>G<subscript>21high</subscript></entry> + <entry>B<subscript>22low</subscript></entry> + <entry>B<subscript>22high</subscript></entry> + <entry>G<subscript>23low</subscript></entry> + <entry>G<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>G<subscript>30low</subscript></entry> + <entry>G<subscript>30high</subscript></entry> + <entry>R<subscript>31low</subscript></entry> + <entry>R<subscript>31high</subscript></entry> + <entry>G<subscript>32low</subscript></entry> + <entry>G<subscript>32high</subscript></entry> + <entry>R<subscript>33low</subscript></entry> + <entry>R<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-srggb12.xml b/Documentation/DocBook/media/v4l/pixfmt-srggb12.xml new file mode 100644 index 00000000..9ba4fb69 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-srggb12.xml @@ -0,0 +1,90 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SRGGB12 ('RG12'), + V4L2_PIX_FMT_SGRBG12 ('BA12'), + V4L2_PIX_FMT_SGBRG12 ('GB12'), + V4L2_PIX_FMT_SBGGR12 ('BG12'), + </refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-SRGGB12"><constant>V4L2_PIX_FMT_SRGGB12</constant></refname> + <refname id="V4L2-PIX-FMT-SGRBG12"><constant>V4L2_PIX_FMT_SGRBG12</constant></refname> + <refname id="V4L2-PIX-FMT-SGBRG12"><constant>V4L2_PIX_FMT_SGBRG12</constant></refname> + <refname id="V4L2-PIX-FMT-SBGGR12"><constant>V4L2_PIX_FMT_SBGGR12</constant></refname> + <refpurpose>12-bit Bayer formats expanded to 16 bits</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>The following four pixel formats are raw sRGB / Bayer formats with +12 bits per colour. Each colour component is stored in a 16-bit word, with 6 +unused high bits filled with zeros. Each n-pixel row contains n/2 green samples +and n/2 blue or red samples, with alternating red and blue rows. Bytes are +stored in memory in little endian order. They are conventionally described +as GRGR... BGBG..., RGRG... GBGB..., etc. Below is an example of one of these +formats</para> + + <example> + <title><constant>V4L2_PIX_FMT_SBGGR12</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte, high 6 bits in high bytes are 0. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00low</subscript></entry> + <entry>B<subscript>00high</subscript></entry> + <entry>G<subscript>01low</subscript></entry> + <entry>G<subscript>01high</subscript></entry> + <entry>B<subscript>02low</subscript></entry> + <entry>B<subscript>02high</subscript></entry> + <entry>G<subscript>03low</subscript></entry> + <entry>G<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>10low</subscript></entry> + <entry>G<subscript>10high</subscript></entry> + <entry>R<subscript>11low</subscript></entry> + <entry>R<subscript>11high</subscript></entry> + <entry>G<subscript>12low</subscript></entry> + <entry>G<subscript>12high</subscript></entry> + <entry>R<subscript>13low</subscript></entry> + <entry>R<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>B<subscript>20low</subscript></entry> + <entry>B<subscript>20high</subscript></entry> + <entry>G<subscript>21low</subscript></entry> + <entry>G<subscript>21high</subscript></entry> + <entry>B<subscript>22low</subscript></entry> + <entry>B<subscript>22high</subscript></entry> + <entry>G<subscript>23low</subscript></entry> + <entry>G<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>G<subscript>30low</subscript></entry> + <entry>G<subscript>30high</subscript></entry> + <entry>R<subscript>31low</subscript></entry> + <entry>R<subscript>31high</subscript></entry> + <entry>G<subscript>32low</subscript></entry> + <entry>G<subscript>32high</subscript></entry> + <entry>R<subscript>33low</subscript></entry> + <entry>R<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-srggb8.xml b/Documentation/DocBook/media/v4l/pixfmt-srggb8.xml new file mode 100644 index 00000000..2570e3be --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-srggb8.xml @@ -0,0 +1,67 @@ + <refentry id="V4L2-PIX-FMT-SRGGB8"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SRGGB8 ('RGGB')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SRGGB8</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a red and green value, the second row of a green and +blue value. This scheme repeats to the right and down for every two +columns and rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SRGGB8</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>R<subscript>00</subscript></entry> + <entry>G<subscript>01</subscript></entry> + <entry>R<subscript>02</subscript></entry> + <entry>G<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>G<subscript>10</subscript></entry> + <entry>B<subscript>11</subscript></entry> + <entry>G<subscript>12</subscript></entry> + <entry>B<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>R<subscript>20</subscript></entry> + <entry>G<subscript>21</subscript></entry> + <entry>R<subscript>22</subscript></entry> + <entry>G<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>G<subscript>30</subscript></entry> + <entry>B<subscript>31</subscript></entry> + <entry>G<subscript>32</subscript></entry> + <entry>B<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-uyvy.xml b/Documentation/DocBook/media/v4l/pixfmt-uyvy.xml new file mode 100644 index 00000000..b1f6801a --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-uyvy.xml @@ -0,0 +1,120 @@ + <refentry id="V4L2-PIX-FMT-UYVY"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_UYVY ('UYVY')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_UYVY</constant></refname> + <refpurpose>Variation of +<constant>V4L2_PIX_FMT_YUYV</constant> with different order of samples +in memory</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component.</para> + + <example> + <title><constant>V4L2_PIX_FMT_UYVY</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-vyuy.xml b/Documentation/DocBook/media/v4l/pixfmt-vyuy.xml new file mode 100644 index 00000000..82803408 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-vyuy.xml @@ -0,0 +1,120 @@ + <refentry id="V4L2-PIX-FMT-VYUY"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_VYUY ('VYUY')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_VYUY</constant></refname> + <refpurpose>Variation of +<constant>V4L2_PIX_FMT_YUYV</constant> with different order of samples +in memory</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component.</para> + + <example> + <title><constant>V4L2_PIX_FMT_VYUY</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-y10.xml b/Documentation/DocBook/media/v4l/pixfmt-y10.xml new file mode 100644 index 00000000..d065043d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y10.xml @@ -0,0 +1,79 @@ +<refentry id="V4L2-PIX-FMT-Y10"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_Y10 ('Y10 ')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_Y10</constant></refname> + <refpurpose>Grey-scale image</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a grey-scale image with a depth of 10 bits per pixel. Pixels +are stored in 16-bit words with unused high bits padded with 0. The least +significant byte is stored at lower memory addresses (little-endian).</para> + + <example> + <title><constant>V4L2_PIX_FMT_Y10</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00low</subscript></entry> + <entry>Y'<subscript>00high</subscript></entry> + <entry>Y'<subscript>01low</subscript></entry> + <entry>Y'<subscript>01high</subscript></entry> + <entry>Y'<subscript>02low</subscript></entry> + <entry>Y'<subscript>02high</subscript></entry> + <entry>Y'<subscript>03low</subscript></entry> + <entry>Y'<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10low</subscript></entry> + <entry>Y'<subscript>10high</subscript></entry> + <entry>Y'<subscript>11low</subscript></entry> + <entry>Y'<subscript>11high</subscript></entry> + <entry>Y'<subscript>12low</subscript></entry> + <entry>Y'<subscript>12high</subscript></entry> + <entry>Y'<subscript>13low</subscript></entry> + <entry>Y'<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20low</subscript></entry> + <entry>Y'<subscript>20high</subscript></entry> + <entry>Y'<subscript>21low</subscript></entry> + <entry>Y'<subscript>21high</subscript></entry> + <entry>Y'<subscript>22low</subscript></entry> + <entry>Y'<subscript>22high</subscript></entry> + <entry>Y'<subscript>23low</subscript></entry> + <entry>Y'<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30low</subscript></entry> + <entry>Y'<subscript>30high</subscript></entry> + <entry>Y'<subscript>31low</subscript></entry> + <entry>Y'<subscript>31high</subscript></entry> + <entry>Y'<subscript>32low</subscript></entry> + <entry>Y'<subscript>32high</subscript></entry> + <entry>Y'<subscript>33low</subscript></entry> + <entry>Y'<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-y10b.xml b/Documentation/DocBook/media/v4l/pixfmt-y10b.xml new file mode 100644 index 00000000..adb0ad80 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y10b.xml @@ -0,0 +1,43 @@ +<refentry id="V4L2-PIX-FMT-Y10BPACK"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_Y10BPACK ('Y10B')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_Y10BPACK</constant></refname> + <refpurpose>Grey-scale image as a bit-packed array</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a packed grey-scale image format with a depth of 10 bits per + pixel. Pixels are stored in a bit-packed array of 10bit bits per pixel, + with no padding between them and with the most significant bits coming + first from the left.</para> + + <example> + <title><constant>V4L2_PIX_FMT_Y10BPACK</constant> 4 pixel data stream taking 5 bytes</title> + + <formalpara> + <title>Bit-packed representation</title> + <para>pixels cross the byte boundary and have a ratio of 5 bytes for each 4 + pixels. + <informaltable frame="all"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>Y'<subscript>00[9:2]</subscript></entry> + <entry>Y'<subscript>00[1:0]</subscript>Y'<subscript>01[9:4]</subscript></entry> + <entry>Y'<subscript>01[3:0]</subscript>Y'<subscript>02[9:6]</subscript></entry> + <entry>Y'<subscript>02[5:0]</subscript>Y'<subscript>03[9:8]</subscript></entry> + <entry>Y'<subscript>03[7:0]</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-y12.xml b/Documentation/DocBook/media/v4l/pixfmt-y12.xml new file mode 100644 index 00000000..ff417b85 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y12.xml @@ -0,0 +1,79 @@ +<refentry id="V4L2-PIX-FMT-Y12"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_Y12 ('Y12 ')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_Y12</constant></refname> + <refpurpose>Grey-scale image</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a grey-scale image with a depth of 12 bits per pixel. Pixels +are stored in 16-bit words with unused high bits padded with 0. The least +significant byte is stored at lower memory addresses (little-endian).</para> + + <example> + <title><constant>V4L2_PIX_FMT_Y12</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00low</subscript></entry> + <entry>Y'<subscript>00high</subscript></entry> + <entry>Y'<subscript>01low</subscript></entry> + <entry>Y'<subscript>01high</subscript></entry> + <entry>Y'<subscript>02low</subscript></entry> + <entry>Y'<subscript>02high</subscript></entry> + <entry>Y'<subscript>03low</subscript></entry> + <entry>Y'<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10low</subscript></entry> + <entry>Y'<subscript>10high</subscript></entry> + <entry>Y'<subscript>11low</subscript></entry> + <entry>Y'<subscript>11high</subscript></entry> + <entry>Y'<subscript>12low</subscript></entry> + <entry>Y'<subscript>12high</subscript></entry> + <entry>Y'<subscript>13low</subscript></entry> + <entry>Y'<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20low</subscript></entry> + <entry>Y'<subscript>20high</subscript></entry> + <entry>Y'<subscript>21low</subscript></entry> + <entry>Y'<subscript>21high</subscript></entry> + <entry>Y'<subscript>22low</subscript></entry> + <entry>Y'<subscript>22high</subscript></entry> + <entry>Y'<subscript>23low</subscript></entry> + <entry>Y'<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30low</subscript></entry> + <entry>Y'<subscript>30high</subscript></entry> + <entry>Y'<subscript>31low</subscript></entry> + <entry>Y'<subscript>31high</subscript></entry> + <entry>Y'<subscript>32low</subscript></entry> + <entry>Y'<subscript>32high</subscript></entry> + <entry>Y'<subscript>33low</subscript></entry> + <entry>Y'<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-y16.xml b/Documentation/DocBook/media/v4l/pixfmt-y16.xml new file mode 100644 index 00000000..ff4f727d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y16.xml @@ -0,0 +1,81 @@ +<refentry id="V4L2-PIX-FMT-Y16"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_Y16 ('Y16 ')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_Y16</constant></refname> + <refpurpose>Grey-scale image</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a grey-scale image with a depth of 16 bits per +pixel. The least significant byte is stored at lower memory addresses +(little-endian). Note the actual sampling precision may be lower than +16 bits, for example 10 bits per pixel with values in range 0 to +1023.</para> + + <example> + <title><constant>V4L2_PIX_FMT_Y16</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00low</subscript></entry> + <entry>Y'<subscript>00high</subscript></entry> + <entry>Y'<subscript>01low</subscript></entry> + <entry>Y'<subscript>01high</subscript></entry> + <entry>Y'<subscript>02low</subscript></entry> + <entry>Y'<subscript>02high</subscript></entry> + <entry>Y'<subscript>03low</subscript></entry> + <entry>Y'<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10low</subscript></entry> + <entry>Y'<subscript>10high</subscript></entry> + <entry>Y'<subscript>11low</subscript></entry> + <entry>Y'<subscript>11high</subscript></entry> + <entry>Y'<subscript>12low</subscript></entry> + <entry>Y'<subscript>12high</subscript></entry> + <entry>Y'<subscript>13low</subscript></entry> + <entry>Y'<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20low</subscript></entry> + <entry>Y'<subscript>20high</subscript></entry> + <entry>Y'<subscript>21low</subscript></entry> + <entry>Y'<subscript>21high</subscript></entry> + <entry>Y'<subscript>22low</subscript></entry> + <entry>Y'<subscript>22high</subscript></entry> + <entry>Y'<subscript>23low</subscript></entry> + <entry>Y'<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30low</subscript></entry> + <entry>Y'<subscript>30high</subscript></entry> + <entry>Y'<subscript>31low</subscript></entry> + <entry>Y'<subscript>31high</subscript></entry> + <entry>Y'<subscript>32low</subscript></entry> + <entry>Y'<subscript>32high</subscript></entry> + <entry>Y'<subscript>33low</subscript></entry> + <entry>Y'<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-y41p.xml b/Documentation/DocBook/media/v4l/pixfmt-y41p.xml new file mode 100644 index 00000000..98dcb91d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y41p.xml @@ -0,0 +1,149 @@ + <refentry id="V4L2-PIX-FMT-Y41P"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_Y41P ('Y41P')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_Y41P</constant></refname> + <refpurpose>Format with ¼ horizontal chroma +resolution, also known as YUV 4:1:1</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each 12 bytes is eight pixels. In the +twelve bytes are two CbCr pairs and eight Y's. The first CbCr pair +goes with the first four Y's, and the second CbCr pair goes with the +other four Y's. The Cb and Cr components have one fourth the +horizontal resolution of the Y component.</para> + + <para>Do not confuse this format with <link +linkend="V4L2-PIX-FMT-YUV411P"><constant>V4L2_PIX_FMT_YUV411P</constant></link>. +Y41P is derived from "YUV 4:1:1 <emphasis>packed</emphasis>", while +YUV411P stands for "YUV 4:1:1 <emphasis>planar</emphasis>".</para> + + <example> + <title><constant>V4L2_PIX_FMT_Y41P</constant> 8 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="13" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + <entry>Y'<subscript>04</subscript></entry> + <entry>Y'<subscript>05</subscript></entry> + <entry>Y'<subscript>06</subscript></entry> + <entry>Y'<subscript>07</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + <entry>Y'<subscript>14</subscript></entry> + <entry>Y'<subscript>15</subscript></entry> + <entry>Y'<subscript>16</subscript></entry> + <entry>Y'<subscript>17</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + <entry>Y'<subscript>24</subscript></entry> + <entry>Y'<subscript>25</subscript></entry> + <entry>Y'<subscript>26</subscript></entry> + <entry>Y'<subscript>27</subscript></entry> + </row> + <row> + <entry>start + 36:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + <entry>Y'<subscript>34</subscript></entry> + <entry>Y'<subscript>35</subscript></entry> + <entry>Y'<subscript>36</subscript></entry> + <entry>Y'<subscript>37</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="15" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry><entry></entry> + <entry>4</entry><entry></entry><entry>5</entry><entry></entry> + <entry>6</entry><entry></entry><entry>7</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv410.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv410.xml new file mode 100644 index 00000000..0869dce5 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv410.xml @@ -0,0 +1,133 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YVU410 ('YVU9'), V4L2_PIX_FMT_YUV410 ('YUV9')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-YVU410"><constant>V4L2_PIX_FMT_YVU410</constant></refname> + <refname id="V4L2-PIX-FMT-YUV410"><constant>V4L2_PIX_FMT_YUV410</constant></refname> + <refpurpose>Planar formats with ¼ horizontal and +vertical chroma resolution, also known as YUV 4:1:0</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are planar formats, as opposed to a packed format. +The three components are separated into three sub-images or planes. +The Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_YVU410</constant>, the Cr plane immediately +follows the Y plane in memory. The Cr plane is ¼ the width and +¼ the height of the Y plane (and of the image). Each Cr belongs +to 16 pixels, a four-by-four square of the image. Following the Cr +plane is the Cb plane, just like the Cr plane. +<constant>V4L2_PIX_FMT_YUV410</constant> is the same, except the Cb +plane comes first, then the Cr plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have ¼ as many pad bytes after their rows. In +other words, four Cx rows (including padding) are exactly as long as +one Y row (including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YVU410</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cr<subscript>00</subscript></entry> + </row> + <row> + <entry>start + 17:</entry> + <entry>Cb<subscript>00</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry></entry><entry></entry><entry>C</entry> + <entry></entry><entry></entry><entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml new file mode 100644 index 00000000..086dc731 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml @@ -0,0 +1,147 @@ + <refentry id="V4L2-PIX-FMT-YUV411P"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YUV411P ('411P')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YUV411P</constant></refname> + <refpurpose>Format with ¼ horizontal chroma resolution, +also known as YUV 4:1:1. Planar layout as opposed to +<constant>V4L2_PIX_FMT_Y41P</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This format is not commonly used. This is a planar +format similar to the 4:2:2 planar format except with half as many +chroma. The three components are separated into three sub-images or +planes. The Y plane is first. The Y plane has one byte per pixel. The +Cb plane immediately follows the Y plane in memory. The Cb plane is +¼ the width of the Y plane (and of the image). Each Cb belongs +to 4 pixels all on the same row. For example, +Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, +Y'<subscript>01</subscript>, Y'<subscript>02</subscript> and +Y'<subscript>03</subscript>. Following the Cb plane is the Cr plane, +just like the Cb plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have ¼ as many pad bytes after their rows. In +other words, four C x rows (including padding) is exactly as long as +one Y row (including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YUV411P</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + </row> + <row> + <entry>start + 17:</entry> + <entry>Cb<subscript>10</subscript></entry> + </row> + <row> + <entry>start + 18:</entry> + <entry>Cb<subscript>20</subscript></entry> + </row> + <row> + <entry>start + 19:</entry> + <entry>Cb<subscript>30</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cr<subscript>00</subscript></entry> + </row> + <row> + <entry>start + 21:</entry> + <entry>Cr<subscript>10</subscript></entry> + </row> + <row> + <entry>start + 22:</entry> + <entry>Cr<subscript>20</subscript></entry> + </row> + <row> + <entry>start + 23:</entry> + <entry>Cr<subscript>30</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv420.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv420.xml new file mode 100644 index 00000000..48649fac --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv420.xml @@ -0,0 +1,149 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YVU420 ('YV12'), V4L2_PIX_FMT_YUV420 ('YU12')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></refname> + <refname id="V4L2-PIX-FMT-YUV420"><constant>V4L2_PIX_FMT_YUV420</constant></refname> + <refpurpose>Planar formats with ½ horizontal and +vertical chroma resolution, also known as YUV 4:2:0</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are planar formats, as opposed to a packed format. +The three components are separated into three sub- images or planes. +The Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_YVU420</constant>, the Cr plane immediately +follows the Y plane in memory. The Cr plane is half the width and half +the height of the Y plane (and of the image). Each Cr belongs to four +pixels, a two-by-two square of the image. For example, +Cr<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, +Y'<subscript>01</subscript>, Y'<subscript>10</subscript>, and +Y'<subscript>11</subscript>. Following the Cr plane is the Cb plane, +just like the Cr plane. <constant>V4L2_PIX_FMT_YUV420</constant> is +the same except the Cb plane comes first, then the Cr plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YVU420</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 18:</entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 22:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml new file mode 100644 index 00000000..60308f1e --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml @@ -0,0 +1,154 @@ + <refentry id="V4L2-PIX-FMT-YUV420M"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YUV420M ('YM12')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname> <constant>V4L2_PIX_FMT_YUV420M</constant></refname> + <refpurpose>Variation of <constant>V4L2_PIX_FMT_YUV420</constant> + with planes non contiguous in memory. </refpurpose> + </refnamediv> + + <refsect1> + <title>Description</title> + + <para>This is a multi-planar format, as opposed to a packed format. +The three components are separated into three sub- images or planes. + +The Y plane is first. The Y plane has one byte per pixel. The Cb data +constitutes the second plane which is half the width and half +the height of the Y plane (and of the image). Each Cb belongs to four +pixels, a two-by-two square of the image. For example, +Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, +Y'<subscript>01</subscript>, Y'<subscript>10</subscript>, and +Y'<subscript>11</subscript>. The Cr data, just like the Cb plane, is +in the third plane. </para> + + <para>If the Y plane has pad bytes after each row, then the Cb +and Cr planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding).</para> + + <para><constant>V4L2_PIX_FMT_NV12M</constant> is intended to be +used only in drivers and applications that support the multi-planar API, +described in <xref linkend="planar-apis"/>. </para> + + <example> + <title><constant>V4L2_PIX_FMT_YVU420M</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start0 + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start0 + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start0 + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start0 + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row><entry></entry></row> + <row> + <entry>start1 + 0:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + </row> + <row> + <entry>start1 + 2:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + </row> + <row><entry></entry></row> + <row> + <entry>start2 + 0:</entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start2 + 2:</entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv422p.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv422p.xml new file mode 100644 index 00000000..4ce6463f --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv422p.xml @@ -0,0 +1,153 @@ + <refentry id="V4L2-PIX-FMT-YUV422P"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YUV422P ('422P')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YUV422P</constant></refname> + <refpurpose>Format with ½ horizontal chroma resolution, +also known as YUV 4:2:2. Planar layout as opposed to +<constant>V4L2_PIX_FMT_YUYV</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This format is not commonly used. This is a planar +version of the YUYV format. The three components are separated into +three sub-images or planes. The Y plane is first. The Y plane has one +byte per pixel. The Cb plane immediately follows the Y plane in +memory. The Cb plane is half the width of the Y plane (and of the +image). Each Cb belongs to two pixels. For example, +Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, +Y'<subscript>01</subscript>. Following the Cb plane is the Cr plane, +just like the Cb plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YUV422P</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 18:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 22:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 26:</entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 28:</entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 30:</entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuyv.xml b/Documentation/DocBook/media/v4l/pixfmt-yuyv.xml new file mode 100644 index 00000000..58384092 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuyv.xml @@ -0,0 +1,120 @@ + <refentry id="V4L2-PIX-FMT-YUYV"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YUYV ('YUYV')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YUYV</constant></refname> + <refpurpose>Packed format with ½ horizontal chroma +resolution, also known as YUV 4:2:2</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y component. +<constant>V4L2_PIX_FMT_YUYV </constant> is known in the Windows +environment as YUY2.</para> + + <example> + <title><constant>V4L2_PIX_FMT_YUYV</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt-yvyu.xml b/Documentation/DocBook/media/v4l/pixfmt-yvyu.xml new file mode 100644 index 00000000..bfffdc76 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yvyu.xml @@ -0,0 +1,120 @@ + <refentry id="V4L2-PIX-FMT-YVYU"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YVYU ('YVYU')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YVYU</constant></refname> + <refpurpose>Variation of +<constant>V4L2_PIX_FMT_YUYV</constant> with different order of samples +in memory</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component.</para> + + <example> + <title><constant>V4L2_PIX_FMT_YVYU</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml new file mode 100644 index 00000000..31eaae24 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -0,0 +1,1005 @@ + <title>Image Formats</title> + + <para>The V4L2 API was primarily designed for devices exchanging +image data with applications. The +<structname>v4l2_pix_format</structname> and <structname>v4l2_pix_format_mplane +</structname> structures define the format and layout of an image in memory. +The former is used with the single-planar API, while the latter is used with the +multi-planar version (see <xref linkend="planar-apis"/>). Image formats are +negotiated with the &VIDIOC-S-FMT; ioctl. (The explanations here focus on video +capturing and output, for overlay frame buffer formats see also +&VIDIOC-G-FBUF;.)</para> + +<section> + <title>Single-planar format structure</title> + <table pgwide="1" frame="none" id="v4l2-pix-format"> + <title>struct <structname>v4l2_pix_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Image width in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Image height in pixels.</entry> + </row> + <row> + <entry spanname="hspan">Applications set these fields to +request an image size, drivers return the closest possible values. In +case of planar formats the <structfield>width</structfield> and +<structfield>height</structfield> applies to the largest plane. To +avoid ambiguities drivers must return values rounded up to a multiple +of the scale factor of any smaller planes. For example when the image +format is YUV 4:2:0, <structfield>width</structfield> and +<structfield>height</structfield> must be multiples of two.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry>The pixel format or type of compression, set by the +application. This is a little endian <link +linkend="v4l2-fourcc">four character code</link>. V4L2 defines +standard RGB formats in <xref linkend="rgb-formats" />, YUV formats in <xref +linkend="yuv-formats" />, and reserved codes in <xref +linkend="reserved-formats" /></entry> + </row> + <row> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry>Video images are typically interlaced. Applications +can request to capture or output only the top or bottom field, or both +fields interlaced or sequentially stored in one buffer or alternating +in separate buffers. Drivers return the actual field order selected. +For details see <xref linkend="field-order" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>bytesperline</structfield></entry> + <entry>Distance in bytes between the leftmost pixels in two +adjacent lines.</entry> + </row> + <row> + <entry spanname="hspan"><para>Both applications and drivers +can set this field to request padding bytes at the end of each line. +Drivers however may ignore the value requested by the application, +returning <structfield>width</structfield> times bytes per pixel or a +larger value required by the hardware. That implies applications can +just set this field to zero to get a reasonable +default.</para><para>Video hardware may access padding bytes, +therefore they must reside in accessible memory. Consider cases where +padding bytes after the last line of an image cross a system page +boundary. Input devices may write padding bytes, the value is +undefined. Output devices ignore the contents of padding +bytes.</para><para>When the image format is planar the +<structfield>bytesperline</structfield> value applies to the largest +plane and is divided by the same factor as the +<structfield>width</structfield> field for any smaller planes. For +example the Cb and Cr planes of a YUV 4:2:0 image have half as many +padding bytes following each line as the Y plane. To avoid ambiguities +drivers must return a <structfield>bytesperline</structfield> value +rounded up to a multiple of the scale factor.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>sizeimage</structfield></entry> + <entry>Size in bytes of the buffer to hold a complete image, +set by the driver. Usually this is +<structfield>bytesperline</structfield> times +<structfield>height</structfield>. When the image consists of variable +length compressed data this is the maximum number of bytes required to +hold an image.</entry> + </row> + <row> + <entry>&v4l2-colorspace;</entry> + <entry><structfield>colorspace</structfield></entry> + <entry>This information supplements the +<structfield>pixelformat</structfield> and must be set by the driver, +see <xref linkend="colorspaces" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>priv</structfield></entry> + <entry>Reserved for custom (driver defined) additional +information about formats. When not used drivers and applications must +set this field to zero.</entry> + </row> + </tbody> + </tgroup> + </table> +</section> + +<section> + <title>Multi-planar format structures</title> + <para>The <structname>v4l2_plane_pix_format</structname> structures define + size and layout for each of the planes in a multi-planar format. + The <structname>v4l2_pix_format_mplane</structname> structure contains + information common to all planes (such as image width and height) and + an array of <structname>v4l2_plane_pix_format</structname> structures, + describing all planes of that format.</para> + <table pgwide="1" frame="none" id="v4l2-plane-pix-format"> + <title>struct <structname>v4l2_plane_pix_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>sizeimage</structfield></entry> + <entry>Maximum size in bytes required for image data in this plane. + </entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>bytesperline</structfield></entry> + <entry>Distance in bytes between the leftmost pixels in two adjacent + lines.</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>reserved[7]</structfield></entry> + <entry>Reserved for future extensions. Should be zeroed by the + application.</entry> + </row> + </tbody> + </tgroup> + </table> + <table pgwide="1" frame="none" id="v4l2-pix-format-mplane"> + <title>struct <structname>v4l2_pix_format_mplane</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Image width in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Image height in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry>The pixel format. Both single- and multi-planar four character +codes can be used.</entry> + </row> + <row> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry>See &v4l2-pix-format;.</entry> + </row> + <row> + <entry>&v4l2-colorspace;</entry> + <entry><structfield>colorspace</structfield></entry> + <entry>See &v4l2-pix-format;.</entry> + </row> + <row> + <entry>&v4l2-plane-pix-format;</entry> + <entry><structfield>plane_fmt[VIDEO_MAX_PLANES]</structfield></entry> + <entry>An array of structures describing format of each plane this + pixel format consists of. The number of valid entries in this array + has to be put in the <structfield>num_planes</structfield> + field.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>num_planes</structfield></entry> + <entry>Number of planes (i.e. separate memory buffers) for this format + and the number of valid entries in the + <structfield>plane_fmt</structfield> array.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>reserved[11]</structfield></entry> + <entry>Reserved for future extensions. Should be zeroed by the + application.</entry> + </row> + </tbody> + </tgroup> + </table> +</section> + + <section> + <title>Standard Image Formats</title> + + <para>In order to exchange images between drivers and +applications, it is necessary to have standard image data formats +which both sides will interpret the same way. V4L2 includes several +such formats, and this section is intended to be an unambiguous +specification of the standard image data formats in V4L2.</para> + + <para>V4L2 drivers are not limited to these formats, however. +Driver-specific formats are possible. In that case the application may +depend on a codec to convert images to one of the standard formats +when needed. But the data can still be stored and retrieved in the +proprietary format. For example, a device may support a proprietary +compressed format. Applications can still capture and save the data in +the compressed format, saving much disk space, and later use a codec +to convert the images to the X Windows screen format when the video is +to be displayed.</para> + + <para>Even so, ultimately, some standard formats are needed, so +the V4L2 specification would not be complete without well-defined +standard formats.</para> + + <para>The V4L2 standard formats are mainly uncompressed formats. The +pixels are always arranged in memory from left to right, and from top +to bottom. The first byte of data in the image buffer is always for +the leftmost pixel of the topmost row. Following that is the pixel +immediately to its right, and so on until the end of the top row of +pixels. Following the rightmost pixel of the row there may be zero or +more bytes of padding to guarantee that each row of pixel data has a +certain alignment. Following the pad bytes, if any, is data for the +leftmost pixel of the second row from the top, and so on. The last row +has just as many pad bytes after it as the other rows.</para> + + <para>In V4L2 each format has an identifier which looks like +<constant>PIX_FMT_XXX</constant>, defined in the <link +linkend="videodev">videodev.h</link> header file. These identifiers +represent <link linkend="v4l2-fourcc">four character (FourCC) codes</link> +which are also listed below, however they are not the same as those +used in the Windows world.</para> + + <para>For some formats, data is stored in separate, discontiguous +memory buffers. Those formats are identified by a separate set of FourCC codes +and are referred to as "multi-planar formats". For example, a YUV422 frame is +normally stored in one memory buffer, but it can also be placed in two or three +separate buffers, with Y component in one buffer and CbCr components in another +in the 2-planar version or with each component in its own buffer in the +3-planar case. Those sub-buffers are referred to as "planes".</para> + </section> + + <section id="colorspaces"> + <title>Colorspaces</title> + + <para>[intro]</para> + + <!-- See proposal by Billy Biggs, video4linux-list@redhat.com +on 11 Oct 2002, subject: "Re: [V4L] Re: v4l2 api", and +http://vektor.theorem.ca/graphics/ycbcr/ and +http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html --> + + <para> + <variablelist> + <varlistentry> + <term>Gamma Correction</term> + <listitem> + <para>[to do]</para> + <para>E'<subscript>R</subscript> = f(R)</para> + <para>E'<subscript>G</subscript> = f(G)</para> + <para>E'<subscript>B</subscript> = f(B)</para> + </listitem> + </varlistentry> + <varlistentry> + <term>Construction of luminance and color-difference +signals</term> + <listitem> + <para>[to do]</para> + <para>E'<subscript>Y</subscript> = +Coeff<subscript>R</subscript> E'<subscript>R</subscript> ++ Coeff<subscript>G</subscript> E'<subscript>G</subscript> ++ Coeff<subscript>B</subscript> E'<subscript>B</subscript></para> + <para>(E'<subscript>R</subscript> - E'<subscript>Y</subscript>) = E'<subscript>R</subscript> +- Coeff<subscript>R</subscript> E'<subscript>R</subscript> +- Coeff<subscript>G</subscript> E'<subscript>G</subscript> +- Coeff<subscript>B</subscript> E'<subscript>B</subscript></para> + <para>(E'<subscript>B</subscript> - E'<subscript>Y</subscript>) = E'<subscript>B</subscript> +- Coeff<subscript>R</subscript> E'<subscript>R</subscript> +- Coeff<subscript>G</subscript> E'<subscript>G</subscript> +- Coeff<subscript>B</subscript> E'<subscript>B</subscript></para> + </listitem> + </varlistentry> + <varlistentry> + <term>Re-normalized color-difference signals</term> + <listitem> + <para>The color-difference signals are scaled back to unity +range [-0.5;+0.5]:</para> + <para>K<subscript>B</subscript> = 0.5 / (1 - Coeff<subscript>B</subscript>)</para> + <para>K<subscript>R</subscript> = 0.5 / (1 - Coeff<subscript>R</subscript>)</para> + <para>P<subscript>B</subscript> = +K<subscript>B</subscript> (E'<subscript>B</subscript> - E'<subscript>Y</subscript>) = + 0.5 (Coeff<subscript>R</subscript> / Coeff<subscript>B</subscript>) E'<subscript>R</subscript> ++ 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>B</subscript>) E'<subscript>G</subscript> ++ 0.5 E'<subscript>B</subscript></para> + <para>P<subscript>R</subscript> = +K<subscript>R</subscript> (E'<subscript>R</subscript> - E'<subscript>Y</subscript>) = + 0.5 E'<subscript>R</subscript> ++ 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>R</subscript>) E'<subscript>G</subscript> ++ 0.5 (Coeff<subscript>B</subscript> / Coeff<subscript>R</subscript>) E'<subscript>B</subscript></para> + </listitem> + </varlistentry> + <varlistentry> + <term>Quantization</term> + <listitem> + <para>[to do]</para> + <para>Y' = (Lum. Levels - 1) · E'<subscript>Y</subscript> + Lum. Offset</para> + <para>C<subscript>B</subscript> = (Chrom. Levels - 1) +· P<subscript>B</subscript> + Chrom. Offset</para> + <para>C<subscript>R</subscript> = (Chrom. Levels - 1) +· P<subscript>R</subscript> + Chrom. Offset</para> + <para>Rounding to the nearest integer and clamping to the range +[0;255] finally yields the digital color components Y'CbCr +stored in YUV images.</para> + </listitem> + </varlistentry> + </variablelist> + </para> + + <example> + <title>ITU-R Rec. BT.601 color conversion</title> + + <para>Forward Transformation</para> + + <programlisting> +int ER, EG, EB; /* gamma corrected RGB input [0;255] */ +int Y1, Cb, Cr; /* output [0;255] */ + +double r, g, b; /* temporaries */ +double y1, pb, pr; + +int +clamp (double x) +{ + int r = x; /* round to nearest */ + + if (r < 0) return 0; + else if (r > 255) return 255; + else return r; +} + +r = ER / 255.0; +g = EG / 255.0; +b = EB / 255.0; + +y1 = 0.299 * r + 0.587 * g + 0.114 * b; +pb = -0.169 * r - 0.331 * g + 0.5 * b; +pr = 0.5 * r - 0.419 * g - 0.081 * b; + +Y1 = clamp (219 * y1 + 16); +Cb = clamp (224 * pb + 128); +Cr = clamp (224 * pr + 128); + +/* or shorter */ + +y1 = 0.299 * ER + 0.587 * EG + 0.114 * EB; + +Y1 = clamp ( (219 / 255.0) * y1 + 16); +Cb = clamp (((224 / 255.0) / (2 - 2 * 0.114)) * (EB - y1) + 128); +Cr = clamp (((224 / 255.0) / (2 - 2 * 0.299)) * (ER - y1) + 128); + </programlisting> + + <para>Inverse Transformation</para> + + <programlisting> +int Y1, Cb, Cr; /* gamma pre-corrected input [0;255] */ +int ER, EG, EB; /* output [0;255] */ + +double r, g, b; /* temporaries */ +double y1, pb, pr; + +int +clamp (double x) +{ + int r = x; /* round to nearest */ + + if (r < 0) return 0; + else if (r > 255) return 255; + else return r; +} + +y1 = (255 / 219.0) * (Y1 - 16); +pb = (255 / 224.0) * (Cb - 128); +pr = (255 / 224.0) * (Cr - 128); + +r = 1.0 * y1 + 0 * pb + 1.402 * pr; +g = 1.0 * y1 - 0.344 * pb - 0.714 * pr; +b = 1.0 * y1 + 1.772 * pb + 0 * pr; + +ER = clamp (r * 255); /* [ok? one should prob. limit y1,pb,pr] */ +EG = clamp (g * 255); +EB = clamp (b * 255); + </programlisting> + </example> + + <table pgwide="1" id="v4l2-colorspace" orient="land"> + <title>enum v4l2_colorspace</title> + <tgroup cols="11" align="center"> + <colspec align="left" /> + <colspec align="center" /> + <colspec align="left" /> + <colspec colname="cr" /> + <colspec colname="cg" /> + <colspec colname="cb" /> + <colspec colname="wp" /> + <colspec colname="gc" /> + <colspec colname="lum" /> + <colspec colname="qy" /> + <colspec colname="qc" /> + <spanspec namest="cr" nameend="cb" spanname="chrom" /> + <spanspec namest="qy" nameend="qc" spanname="quant" /> + <spanspec namest="lum" nameend="qc" spanname="spam" /> + <thead> + <row> + <entry morerows="1">Identifier</entry> + <entry morerows="1">Value</entry> + <entry morerows="1">Description</entry> + <entry spanname="chrom">Chromaticities<footnote> + <para>The coordinates of the color primaries are +given in the CIE system (1931)</para> + </footnote></entry> + <entry morerows="1">White Point</entry> + <entry morerows="1">Gamma Correction</entry> + <entry morerows="1">Luminance E'<subscript>Y</subscript></entry> + <entry spanname="quant">Quantization</entry> + </row> + <row> + <entry>Red</entry> + <entry>Green</entry> + <entry>Blue</entry> + <entry>Y'</entry> + <entry>Cb, Cr</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_COLORSPACE_SMPTE170M</constant></entry> + <entry>1</entry> + <entry>NTSC/PAL according to <xref linkend="smpte170m" />, +<xref linkend="itu601" /></entry> + <entry>x = 0.630, y = 0.340</entry> + <entry>x = 0.310, y = 0.595</entry> + <entry>x = 0.155, y = 0.070</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4.5 I for I ≤0.018, +1.099 I<superscript>0.45</superscript> - 0.099 for 0.018 < I</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_SMPTE240M</constant></entry> + <entry>2</entry> + <entry>1125-Line (US) HDTV, see <xref +linkend="smpte240m" /></entry> + <entry>x = 0.630, y = 0.340</entry> + <entry>x = 0.310, y = 0.595</entry> + <entry>x = 0.155, y = 0.070</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4 I for I ≤0.0228, +1.1115 I<superscript>0.45</superscript> - 0.1115 for 0.0228 < I</entry> + <entry>0.212 E'<subscript>R</subscript> ++ 0.701 E'<subscript>G</subscript> ++ 0.087 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_REC709</constant></entry> + <entry>3</entry> + <entry>HDTV and modern devices, see <xref +linkend="itu709" /></entry> + <entry>x = 0.640, y = 0.330</entry> + <entry>x = 0.300, y = 0.600</entry> + <entry>x = 0.150, y = 0.060</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4.5 I for I ≤0.018, +1.099 I<superscript>0.45</superscript> - 0.099 for 0.018 < I</entry> + <entry>0.2125 E'<subscript>R</subscript> ++ 0.7154 E'<subscript>G</subscript> ++ 0.0721 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_BT878</constant></entry> + <entry>4</entry> + <entry>Broken Bt878 extents<footnote> + <para>The ubiquitous Bt878 video capture chip +quantizes E'<subscript>Y</subscript> to 238 levels, yielding a range +of Y' = 16 … 253, unlike Rec. 601 Y' = 16 … +235. This is not a typo in the Bt878 documentation, it has been +implemented in silicon. The chroma extents are unclear.</para> + </footnote>, <xref linkend="itu601" /></entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry><emphasis>237</emphasis> E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128 (probably)</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_470_SYSTEM_M</constant></entry> + <entry>5</entry> + <entry>M/NTSC<footnote> + <para>No identifier exists for M/PAL which uses +the chromaticities of M/NTSC, the remaining parameters are equal to B and +G/PAL.</para> + </footnote> according to <xref linkend="itu470" />, <xref + linkend="itu601" /></entry> + <entry>x = 0.67, y = 0.33</entry> + <entry>x = 0.21, y = 0.71</entry> + <entry>x = 0.14, y = 0.08</entry> + <entry>x = 0.310, y = 0.316, Illuminant C</entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant></entry> + <entry>6</entry> + <entry>625-line PAL and SECAM systems according to <xref +linkend="itu470" />, <xref linkend="itu601" /></entry> + <entry>x = 0.64, y = 0.33</entry> + <entry>x = 0.29, y = 0.60</entry> + <entry>x = 0.15, y = 0.06</entry> + <entry>x = 0.313, y = 0.329, +Illuminant D<subscript>65</subscript></entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_JPEG</constant></entry> + <entry>7</entry> + <entry>JPEG Y'CbCr, see <xref linkend="jfif" />, <xref linkend="itu601" /></entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>256 E'<subscript>Y</subscript> + 16<footnote> + <para>Note JFIF quantizes +Y'P<subscript>B</subscript>P<subscript>R</subscript> in range [0;+1] and +[-0.5;+0.5] to <emphasis>257</emphasis> levels, however Y'CbCr signals +are still clamped to [0;255].</para> + </footnote></entry> + <entry>256 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_SRGB</constant></entry> + <entry>8</entry> + <entry>[?]</entry> + <entry>x = 0.640, y = 0.330</entry> + <entry>x = 0.300, y = 0.600</entry> + <entry>x = 0.150, y = 0.060</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4.5 I for I ≤0.018, +1.099 I<superscript>0.45</superscript> - 0.099 for 0.018 < I</entry> + <entry spanname="spam">n/a</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section id="pixfmt-indexed"> + <title>Indexed Format</title> + + <para>In this format each pixel is represented by an 8 bit index +into a 256 entry ARGB palette. It is intended for <link +linkend="osd">Video Output Overlays</link> only. There are no ioctls to +access the palette, this must be done with ioctls of the Linux framebuffer API.</para> + + <table pgwide="0" frame="none"> + <title>Indexed Image Format</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-PAL8"> + <entry><constant>V4L2_PIX_FMT_PAL8</constant></entry> + <entry>'PAL8'</entry> + <entry></entry> + <entry>i<subscript>7</subscript></entry> + <entry>i<subscript>6</subscript></entry> + <entry>i<subscript>5</subscript></entry> + <entry>i<subscript>4</subscript></entry> + <entry>i<subscript>3</subscript></entry> + <entry>i<subscript>2</subscript></entry> + <entry>i<subscript>1</subscript></entry> + <entry>i<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section id="pixfmt-rgb"> + <title>RGB Formats</title> + + &sub-packed-rgb; + &sub-sbggr8; + &sub-sgbrg8; + &sub-sgrbg8; + &sub-srggb8; + &sub-sbggr16; + &sub-srggb10; + &sub-srggb12; + </section> + + <section id="yuv-formats"> + <title>YUV Formats</title> + + <para>YUV is the format native to TV broadcast and composite video +signals. It separates the brightness information (Y) from the color +information (U and V or Cb and Cr). The color information consists of +red and blue <emphasis>color difference</emphasis> signals, this way +the green component can be reconstructed by subtracting from the +brightness component. See <xref linkend="colorspaces" /> for conversion +examples. YUV was chosen because early television would only transmit +brightness information. To add color in a way compatible with existing +receivers a new signal carrier was added to transmit the color +difference signals. Secondary in the YUV format the U and V components +usually have lower resolution than the Y component. This is an analog +video compression technique taking advantage of a property of the +human visual system, being more sensitive to brightness +information.</para> + + &sub-packed-yuv; + &sub-grey; + &sub-y10; + &sub-y12; + &sub-y10b; + &sub-y16; + &sub-yuyv; + &sub-uyvy; + &sub-yvyu; + &sub-vyuy; + &sub-y41p; + &sub-yuv420; + &sub-yuv420m; + &sub-yuv410; + &sub-yuv422p; + &sub-yuv411p; + &sub-nv12; + &sub-nv12m; + &sub-nv12mt; + &sub-nv16; + &sub-nv24; + &sub-m420; + </section> + + <section> + <title>Compressed Formats</title> + + <table pgwide="1" frame="none" id="compressed-formats"> + <title>Compressed Image Formats</title> + <tgroup cols="3" align="left"> + &cs-def; + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry>Details</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-JPEG"> + <entry><constant>V4L2_PIX_FMT_JPEG</constant></entry> + <entry>'JPEG'</entry> + <entry>TBD. See also &VIDIOC-G-JPEGCOMP;, + &VIDIOC-S-JPEGCOMP;.</entry> + </row> + <row id="V4L2-PIX-FMT-MPEG"> + <entry><constant>V4L2_PIX_FMT_MPEG</constant></entry> + <entry>'MPEG'</entry> + <entry>MPEG multiplexed stream. The actual format is determined by +extended control <constant>V4L2_CID_MPEG_STREAM_TYPE</constant>, see +<xref linkend="mpeg-control-id" />.</entry> + </row> + <row id="V4L2-PIX-FMT-H264"> + <entry><constant>V4L2_PIX_FMT_H264</constant></entry> + <entry>'H264'</entry> + <entry>H264 video elementary stream with start codes.</entry> + </row> + <row id="V4L2-PIX-FMT-H264-NO-SC"> + <entry><constant>V4L2_PIX_FMT_H264_NO_SC</constant></entry> + <entry>'AVC1'</entry> + <entry>H264 video elementary stream without start codes.</entry> + </row> + <row id="V4L2-PIX-FMT-H263"> + <entry><constant>V4L2_PIX_FMT_H263</constant></entry> + <entry>'H263'</entry> + <entry>H263 video elementary stream.</entry> + </row> + <row id="V4L2-PIX-FMT-MPEG1"> + <entry><constant>V4L2_PIX_FMT_MPEG1</constant></entry> + <entry>'MPG1'</entry> + <entry>MPEG1 video elementary stream.</entry> + </row> + <row id="V4L2-PIX-FMT-MPEG2"> + <entry><constant>V4L2_PIX_FMT_MPEG2</constant></entry> + <entry>'MPG2'</entry> + <entry>MPEG2 video elementary stream.</entry> + </row> + <row id="V4L2-PIX-FMT-MPEG4"> + <entry><constant>V4L2_PIX_FMT_MPEG4</constant></entry> + <entry>'MPG4'</entry> + <entry>MPEG4 video elementary stream.</entry> + </row> + <row id="V4L2-PIX-FMT-XVID"> + <entry><constant>V4L2_PIX_FMT_XVID</constant></entry> + <entry>'XVID'</entry> + <entry>Xvid video elementary stream.</entry> + </row> + <row id="V4L2-PIX-FMT-VC1-ANNEX-G"> + <entry><constant>V4L2_PIX_FMT_VC1_ANNEX_G</constant></entry> + <entry>'VC1G'</entry> + <entry>VC1, SMPTE 421M Annex G compliant stream.</entry> + </row> + <row id="V4L2-PIX-FMT-VC1-ANNEX-L"> + <entry><constant>V4L2_PIX_FMT_VC1_ANNEX_L</constant></entry> + <entry>'VC1L'</entry> + <entry>VC1, SMPTE 421M Annex L compliant stream.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section id="pixfmt-reserved"> + <title>Reserved Format Identifiers</title> + + <para>These formats are not defined by this specification, they +are just listed for reference and to avoid naming conflicts. If you +want to register your own format, send an e-mail to the linux-media mailing +list &v4l-ml; for inclusion in the <filename>videodev2.h</filename> +file. If you want to share your format with other developers add a +link to your documentation and send a copy to the linux-media mailing list +for inclusion in this section. If you think your format should be listed +in a standard format section please make a proposal on the linux-media mailing +list.</para> + + <table pgwide="1" frame="none" id="reserved-formats"> + <title>Reserved Image Formats</title> + <tgroup cols="3" align="left"> + &cs-def; + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry>Details</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-DV"> + <entry><constant>V4L2_PIX_FMT_DV</constant></entry> + <entry>'dvsd'</entry> + <entry>unknown</entry> + </row> + <row id="V4L2-PIX-FMT-ET61X251"> + <entry><constant>V4L2_PIX_FMT_ET61X251</constant></entry> + <entry>'E625'</entry> + <entry>Compressed format of the ET61X251 driver.</entry> + </row> + <row id="V4L2-PIX-FMT-HI240"> + <entry><constant>V4L2_PIX_FMT_HI240</constant></entry> + <entry>'HI24'</entry> + <entry><para>8 bit RGB format used by the BTTV driver.</para></entry> + </row> + <row id="V4L2-PIX-FMT-HM12"> + <entry><constant>V4L2_PIX_FMT_HM12</constant></entry> + <entry>'HM12'</entry> + <entry><para>YUV 4:2:0 format used by the +IVTV driver, <ulink url="http://www.ivtvdriver.org/"> +http://www.ivtvdriver.org/</ulink></para><para>The format is documented in the +kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.hm12</filename> +</para></entry> + </row> + <row id="V4L2-PIX-FMT-CPIA1"> + <entry><constant>V4L2_PIX_FMT_CPIA1</constant></entry> + <entry>'CPIA'</entry> + <entry>YUV format used by the gspca cpia1 driver.</entry> + </row> + <row id="V4L2-PIX-FMT-JPGL"> + <entry><constant>V4L2_PIX_FMT_JPGL</constant></entry> + <entry>'JPGL'</entry> + <entry>JPEG-Light format (Pegasus Lossless JPEG) + used in Divio webcams NW 80x.</entry> + </row> + <row id="V4L2-PIX-FMT-SPCA501"> + <entry><constant>V4L2_PIX_FMT_SPCA501</constant></entry> + <entry>'S501'</entry> + <entry>YUYV per line used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SPCA505"> + <entry><constant>V4L2_PIX_FMT_SPCA505</constant></entry> + <entry>'S505'</entry> + <entry>YYUV per line used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SPCA508"> + <entry><constant>V4L2_PIX_FMT_SPCA508</constant></entry> + <entry>'S508'</entry> + <entry>YUVY per line used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SPCA561"> + <entry><constant>V4L2_PIX_FMT_SPCA561</constant></entry> + <entry>'S561'</entry> + <entry>Compressed GBRG Bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SGRBG10DPCM8"> + <entry><constant>V4L2_PIX_FMT_SGRBG10DPCM8</constant></entry> + <entry>'DB10'</entry> + <entry>10 bit raw Bayer DPCM compressed to 8 bits.</entry> + </row> + <row id="V4L2-PIX-FMT-PAC207"> + <entry><constant>V4L2_PIX_FMT_PAC207</constant></entry> + <entry>'P207'</entry> + <entry>Compressed BGGR Bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-MR97310A"> + <entry><constant>V4L2_PIX_FMT_MR97310A</constant></entry> + <entry>'M310'</entry> + <entry>Compressed BGGR Bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-JL2005BCD"> + <entry><constant>V4L2_PIX_FMT_JL2005BCD</constant></entry> + <entry>'JL20'</entry> + <entry>JPEG compressed RGGB Bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-OV511"> + <entry><constant>V4L2_PIX_FMT_OV511</constant></entry> + <entry>'O511'</entry> + <entry>OV511 JPEG format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-OV518"> + <entry><constant>V4L2_PIX_FMT_OV518</constant></entry> + <entry>'O518'</entry> + <entry>OV518 JPEG format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-PJPG"> + <entry><constant>V4L2_PIX_FMT_PJPG</constant></entry> + <entry>'PJPG'</entry> + <entry>Pixart 73xx JPEG format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SE401"> + <entry><constant>V4L2_PIX_FMT_SE401</constant></entry> + <entry>'S401'</entry> + <entry>Compressed RGB format used by the gspca se401 driver</entry> + </row> + <row id="V4L2-PIX-FMT-SQ905C"> + <entry><constant>V4L2_PIX_FMT_SQ905C</constant></entry> + <entry>'905C'</entry> + <entry>Compressed RGGB bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-MJPEG"> + <entry><constant>V4L2_PIX_FMT_MJPEG</constant></entry> + <entry>'MJPG'</entry> + <entry>Compressed format used by the Zoran driver</entry> + </row> + <row id="V4L2-PIX-FMT-PWC1"> + <entry><constant>V4L2_PIX_FMT_PWC1</constant></entry> + <entry>'PWC1'</entry> + <entry>Compressed format of the PWC driver.</entry> + </row> + <row id="V4L2-PIX-FMT-PWC2"> + <entry><constant>V4L2_PIX_FMT_PWC2</constant></entry> + <entry>'PWC2'</entry> + <entry>Compressed format of the PWC driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SN9C10X"> + <entry><constant>V4L2_PIX_FMT_SN9C10X</constant></entry> + <entry>'S910'</entry> + <entry>Compressed format of the SN9C102 driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SN9C20X-I420"> + <entry><constant>V4L2_PIX_FMT_SN9C20X_I420</constant></entry> + <entry>'S920'</entry> + <entry>YUV 4:2:0 format of the gspca sn9c20x driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SN9C2028"> + <entry><constant>V4L2_PIX_FMT_SN9C2028</constant></entry> + <entry>'SONX'</entry> + <entry>Compressed GBRG bayer format of the gspca sn9c2028 driver.</entry> + </row> + <row id="V4L2-PIX-FMT-STV0680"> + <entry><constant>V4L2_PIX_FMT_STV0680</constant></entry> + <entry>'S680'</entry> + <entry>Bayer format of the gspca stv0680 driver.</entry> + </row> + <row id="V4L2-PIX-FMT-WNVA"> + <entry><constant>V4L2_PIX_FMT_WNVA</constant></entry> + <entry>'WNVA'</entry> + <entry><para>Used by the Winnov Videum driver, <ulink +url="http://www.thedirks.org/winnov/"> +http://www.thedirks.org/winnov/</ulink></para></entry> + </row> + <row id="V4L2-PIX-FMT-TM6000"> + <entry><constant>V4L2_PIX_FMT_TM6000</constant></entry> + <entry>'TM60'</entry> + <entry><para>Used by Trident tm6000</para></entry> + </row> + <row id="V4L2-PIX-FMT-CIT-YYVYUY"> + <entry><constant>V4L2_PIX_FMT_CIT_YYVYUY</constant></entry> + <entry>'CITV'</entry> + <entry><para>Used by xirlink CIT, found at IBM webcams.</para> + <para>Uses one line of Y then 1 line of VYUY</para> + </entry> + </row> + <row id="V4L2-PIX-FMT-KONICA420"> + <entry><constant>V4L2_PIX_FMT_KONICA420</constant></entry> + <entry>'KONI'</entry> + <entry><para>Used by Konica webcams.</para> + <para>YUV420 planar in blocks of 256 pixels.</para> + </entry> + </row> + <row id="V4L2-PIX-FMT-YYUV"> + <entry><constant>V4L2_PIX_FMT_YYUV</constant></entry> + <entry>'YYUV'</entry> + <entry>unknown</entry> + </row> + <row id="V4L2-PIX-FMT-Y4"> + <entry><constant>V4L2_PIX_FMT_Y4</constant></entry> + <entry>'Y04 '</entry> + <entry>Old 4-bit greyscale format. Only the least significant 4 bits of each byte are used, +the other bits are set to 0.</entry> + </row> + <row id="V4L2-PIX-FMT-Y6"> + <entry><constant>V4L2_PIX_FMT_Y6</constant></entry> + <entry>'Y06 '</entry> + <entry>Old 6-bit greyscale format. Only the least significant 6 bits of each byte are used, +the other bits are set to 0.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> diff --git a/Documentation/DocBook/media/v4l/planar-apis.xml b/Documentation/DocBook/media/v4l/planar-apis.xml new file mode 100644 index 00000000..878ce204 --- /dev/null +++ b/Documentation/DocBook/media/v4l/planar-apis.xml @@ -0,0 +1,62 @@ +<section id="planar-apis"> + <title>Single- and multi-planar APIs</title> + + <para>Some devices require data for each input or output video frame + to be placed in discontiguous memory buffers. In such cases, one + video frame has to be addressed using more than one memory address, i.e. one + pointer per "plane". A plane is a sub-buffer of the current frame. For + examples of such formats see <xref linkend="pixfmt" />.</para> + + <para>Initially, V4L2 API did not support multi-planar buffers and a set of + extensions has been introduced to handle them. Those extensions constitute + what is being referred to as the "multi-planar API".</para> + + <para>Some of the V4L2 API calls and structures are interpreted differently, + depending on whether single- or multi-planar API is being used. An application + can choose whether to use one or the other by passing a corresponding buffer + type to its ioctl calls. Multi-planar versions of buffer types are suffixed + with an `_MPLANE' string. For a list of available multi-planar buffer types + see &v4l2-buf-type;. + </para> + + <section> + <title>Multi-planar formats</title> + <para>Multi-planar API introduces new multi-planar formats. Those formats + use a separate set of FourCC codes. It is important to distinguish between + the multi-planar API and a multi-planar format. Multi-planar API calls can + handle all single-planar formats as well (as long as they are passed in + multi-planar API structures), while the single-planar API cannot + handle multi-planar formats.</para> + </section> + + <section> + <title>Calls that distinguish between single and multi-planar APIs</title> + <variablelist> + <varlistentry> + <term>&VIDIOC-QUERYCAP;</term> + <listitem><para>Two additional multi-planar capabilities are added. They can + be set together with non-multi-planar ones for devices that handle + both single- and multi-planar formats.</para></listitem> + </varlistentry> + <varlistentry> + <term>&VIDIOC-G-FMT;, &VIDIOC-S-FMT;, &VIDIOC-TRY-FMT;</term> + <listitem><para>New structures for describing multi-planar formats are added: + &v4l2-pix-format-mplane; and &v4l2-plane-pix-format;. Drivers may + define new multi-planar formats, which have distinct FourCC codes from + the existing single-planar ones.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>&VIDIOC-QBUF;, &VIDIOC-DQBUF;, &VIDIOC-QUERYBUF;</term> + <listitem><para>A new &v4l2-plane; structure for describing planes is added. + Arrays of this structure are passed in the new + <structfield>m.planes</structfield> field of &v4l2-buffer;.</para> + </listitem> + </varlistentry> + <varlistentry> + <term>&VIDIOC-REQBUFS;</term> + <listitem><para>Will allocate multi-planar buffers as requested.</para></listitem> + </varlistentry> + </variablelist> + </section> +</section> diff --git a/Documentation/DocBook/media/v4l/remote_controllers.xml b/Documentation/DocBook/media/v4l/remote_controllers.xml new file mode 100644 index 00000000..160e464d --- /dev/null +++ b/Documentation/DocBook/media/v4l/remote_controllers.xml @@ -0,0 +1,177 @@ +<title>Remote Controllers</title> +<section id="Remote_controllers_Intro"> +<title>Introduction</title> + +<para>Currently, most analog and digital devices have a Infrared input for remote controllers. Each +manufacturer has their own type of control. It is not rare for the same manufacturer to ship different +types of controls, depending on the device.</para> +<para>Unfortunately, for several years, there was no effort to create uniform IR keycodes for +different devices. This caused the same IR keyname to be mapped completely differently on +different IR devices. This resulted that the same IR keyname to be mapped completely different on +different IR's. Due to that, V4L2 API now specifies a standard for mapping Media keys on IR.</para> +<para>This standard should be used by both V4L/DVB drivers and userspace applications</para> +<para>The modules register the remote as keyboard within the linux input layer. This means that the IR key strokes will look like normal keyboard key strokes (if CONFIG_INPUT_KEYBOARD is enabled). Using the event devices (CONFIG_INPUT_EVDEV) it is possible for applications to access the remote via /dev/input/event devices.</para> + +<table pgwide="1" frame="none" id="rc_standard_keymap"> +<title>IR default keymapping</title> +<tgroup cols="3"> +&cs-str; +<tbody valign="top"> +<row> +<entry>Key code</entry> +<entry>Meaning</entry> +<entry>Key examples on IR</entry> +</row> + +<row><entry><emphasis role="bold">Numeric keys</emphasis></entry></row> + +<row><entry><constant>KEY_0</constant></entry><entry>Keyboard digit 0</entry><entry>0</entry></row> +<row><entry><constant>KEY_1</constant></entry><entry>Keyboard digit 1</entry><entry>1</entry></row> +<row><entry><constant>KEY_2</constant></entry><entry>Keyboard digit 2</entry><entry>2</entry></row> +<row><entry><constant>KEY_3</constant></entry><entry>Keyboard digit 3</entry><entry>3</entry></row> +<row><entry><constant>KEY_4</constant></entry><entry>Keyboard digit 4</entry><entry>4</entry></row> +<row><entry><constant>KEY_5</constant></entry><entry>Keyboard digit 5</entry><entry>5</entry></row> +<row><entry><constant>KEY_6</constant></entry><entry>Keyboard digit 6</entry><entry>6</entry></row> +<row><entry><constant>KEY_7</constant></entry><entry>Keyboard digit 7</entry><entry>7</entry></row> +<row><entry><constant>KEY_8</constant></entry><entry>Keyboard digit 8</entry><entry>8</entry></row> +<row><entry><constant>KEY_9</constant></entry><entry>Keyboard digit 9</entry><entry>9</entry></row> + +<row><entry><emphasis role="bold">Movie play control</emphasis></entry></row> + +<row><entry><constant>KEY_FORWARD</constant></entry><entry>Instantly advance in time</entry><entry>>> / FORWARD</entry></row> +<row><entry><constant>KEY_BACK</constant></entry><entry>Instantly go back in time</entry><entry><<< / BACK</entry></row> +<row><entry><constant>KEY_FASTFORWARD</constant></entry><entry>Play movie faster</entry><entry>>>> / FORWARD</entry></row> +<row><entry><constant>KEY_REWIND</constant></entry><entry>Play movie back</entry><entry>REWIND / BACKWARD</entry></row> +<row><entry><constant>KEY_NEXT</constant></entry><entry>Select next chapter / sub-chapter / interval</entry><entry>NEXT / SKIP</entry></row> +<row><entry><constant>KEY_PREVIOUS</constant></entry><entry>Select previous chapter / sub-chapter / interval</entry><entry><< / PREV / PREVIOUS</entry></row> +<row><entry><constant>KEY_AGAIN</constant></entry><entry>Repeat the video or a video interval</entry><entry>REPEAT / LOOP / RECALL</entry></row> +<row><entry><constant>KEY_PAUSE</constant></entry><entry>Pause sroweam</entry><entry>PAUSE / FREEZE</entry></row> +<row><entry><constant>KEY_PLAY</constant></entry><entry>Play movie at the normal timeshift</entry><entry>NORMAL TIMESHIFT / LIVE / ></entry></row> +<row><entry><constant>KEY_PLAYPAUSE</constant></entry><entry>Alternate between play and pause</entry><entry>PLAY / PAUSE</entry></row> +<row><entry><constant>KEY_STOP</constant></entry><entry>Stop sroweam</entry><entry>STOP</entry></row> +<row><entry><constant>KEY_RECORD</constant></entry><entry>Start/stop recording sroweam</entry><entry>CAPTURE / REC / RECORD/PAUSE</entry></row> +<row><entry><constant>KEY_CAMERA</constant></entry><entry>Take a picture of the image</entry><entry>CAMERA ICON / CAPTURE / SNAPSHOT</entry></row> +<row><entry><constant>KEY_SHUFFLE</constant></entry><entry>Enable shuffle mode</entry><entry>SHUFFLE</entry></row> +<row><entry><constant>KEY_TIME</constant></entry><entry>Activate time shift mode</entry><entry>TIME SHIFT</entry></row> +<row><entry><constant>KEY_TITLE</constant></entry><entry>Allow changing the chapter</entry><entry>CHAPTER</entry></row> +<row><entry><constant>KEY_SUBTITLE</constant></entry><entry>Allow changing the subtitle</entry><entry>SUBTITLE</entry></row> + +<row><entry><emphasis role="bold">Image control</emphasis></entry></row> + +<row><entry><constant>KEY_BRIGHTNESSDOWN</constant></entry><entry>Decrease Brightness</entry><entry>BRIGHTNESS DECREASE</entry></row> +<row><entry><constant>KEY_BRIGHTNESSUP</constant></entry><entry>Increase Brightness</entry><entry>BRIGHTNESS INCREASE</entry></row> + +<row><entry><constant>KEY_ANGLE</constant></entry><entry>Switch video camera angle (on videos with more than one angle stored)</entry><entry>ANGLE / SWAP</entry></row> +<row><entry><constant>KEY_EPG</constant></entry><entry>Open the Elecrowonic Play Guide (EPG)</entry><entry>EPG / GUIDE</entry></row> +<row><entry><constant>KEY_TEXT</constant></entry><entry>Activate/change closed caption mode</entry><entry>CLOSED CAPTION/TELETEXT / DVD TEXT / TELETEXT / TTX</entry></row> + +<row><entry><emphasis role="bold">Audio control</emphasis></entry></row> + +<row><entry><constant>KEY_AUDIO</constant></entry><entry>Change audio source</entry><entry>AUDIO SOURCE / AUDIO / MUSIC</entry></row> +<row><entry><constant>KEY_MUTE</constant></entry><entry>Mute/unmute audio</entry><entry>MUTE / DEMUTE / UNMUTE</entry></row> +<row><entry><constant>KEY_VOLUMEDOWN</constant></entry><entry>Decrease volume</entry><entry>VOLUME- / VOLUME DOWN</entry></row> +<row><entry><constant>KEY_VOLUMEUP</constant></entry><entry>Increase volume</entry><entry>VOLUME+ / VOLUME UP</entry></row> +<row><entry><constant>KEY_MODE</constant></entry><entry>Change sound mode</entry><entry>MONO/STEREO</entry></row> +<row><entry><constant>KEY_LANGUAGE</constant></entry><entry>Select Language</entry><entry>1ST / 2ND LANGUAGE / DVD LANG / MTS/SAP / MTS SEL</entry></row> + +<row><entry><emphasis role="bold">Channel control</emphasis></entry></row> + +<row><entry><constant>KEY_CHANNEL</constant></entry><entry>Go to the next favorite channel</entry><entry>ALT / CHANNEL / CH SURFING / SURF / FAV</entry></row> +<row><entry><constant>KEY_CHANNELDOWN</constant></entry><entry>Decrease channel sequencially</entry><entry>CHANNEL - / CHANNEL DOWN / DOWN</entry></row> +<row><entry><constant>KEY_CHANNELUP</constant></entry><entry>Increase channel sequencially</entry><entry>CHANNEL + / CHANNEL UP / UP</entry></row> +<row><entry><constant>KEY_DIGITS</constant></entry><entry>Use more than one digit for channel</entry><entry>PLUS / 100/ 1xx / xxx / -/-- / Single Double Triple Digit</entry></row> +<row><entry><constant>KEY_SEARCH</constant></entry><entry>Start channel autoscan</entry><entry>SCAN / AUTOSCAN</entry></row> + +<row><entry><emphasis role="bold">Colored keys</emphasis></entry></row> + +<row><entry><constant>KEY_BLUE</constant></entry><entry>IR Blue key</entry><entry>BLUE</entry></row> +<row><entry><constant>KEY_GREEN</constant></entry><entry>IR Green Key</entry><entry>GREEN</entry></row> +<row><entry><constant>KEY_RED</constant></entry><entry>IR Red key</entry><entry>RED</entry></row> +<row><entry><constant>KEY_YELLOW</constant></entry><entry>IR Yellow key</entry><entry> YELLOW</entry></row> + +<row><entry><emphasis role="bold">Media selection</emphasis></entry></row> + +<row><entry><constant>KEY_CD</constant></entry><entry>Change input source to Compact Disc</entry><entry>CD</entry></row> +<row><entry><constant>KEY_DVD</constant></entry><entry>Change input to DVD</entry><entry>DVD / DVD MENU</entry></row> +<row><entry><constant>KEY_EJECTCLOSECD</constant></entry><entry>Open/close the CD/DVD player</entry><entry>-> ) / CLOSE / OPEN</entry></row> + +<row><entry><constant>KEY_MEDIA</constant></entry><entry>Turn on/off Media application</entry><entry>PC/TV / TURN ON/OFF APP</entry></row> +<row><entry><constant>KEY_PC</constant></entry><entry>Selects from TV to PC</entry><entry>PC</entry></row> +<row><entry><constant>KEY_RADIO</constant></entry><entry>Put into AM/FM radio mode</entry><entry>RADIO / TV/FM / TV/RADIO / FM / FM/RADIO</entry></row> +<row><entry><constant>KEY_TV</constant></entry><entry>Select tv mode</entry><entry>TV / LIVE TV</entry></row> +<row><entry><constant>KEY_TV2</constant></entry><entry>Select Cable mode</entry><entry>AIR/CBL</entry></row> +<row><entry><constant>KEY_VCR</constant></entry><entry>Select VCR mode</entry><entry>VCR MODE / DTR</entry></row> +<row><entry><constant>KEY_VIDEO</constant></entry><entry>Alternate between input modes</entry><entry>SOURCE / SELECT / DISPLAY / SWITCH INPUTS / VIDEO</entry></row> + +<row><entry><emphasis role="bold">Power control</emphasis></entry></row> + +<row><entry><constant>KEY_POWER</constant></entry><entry>Turn on/off computer</entry><entry>SYSTEM POWER / COMPUTER POWER</entry></row> +<row><entry><constant>KEY_POWER2</constant></entry><entry>Turn on/off application</entry><entry>TV ON/OFF / POWER</entry></row> +<row><entry><constant>KEY_SLEEP</constant></entry><entry>Activate sleep timer</entry><entry>SLEEP / SLEEP TIMER</entry></row> +<row><entry><constant>KEY_SUSPEND</constant></entry><entry>Put computer into suspend mode</entry><entry>STANDBY / SUSPEND</entry></row> + +<row><entry><emphasis role="bold">Window control</emphasis></entry></row> + +<row><entry><constant>KEY_CLEAR</constant></entry><entry>Stop sroweam and return to default input video/audio</entry><entry>CLEAR / RESET / BOSS KEY</entry></row> +<row><entry><constant>KEY_CYCLEWINDOWS</constant></entry><entry>Minimize windows and move to the next one</entry><entry>ALT-TAB / MINIMIZE / DESKTOP</entry></row> +<row><entry><constant>KEY_FAVORITES</constant></entry><entry>Open the favorites sroweam window</entry><entry>TV WALL / Favorites</entry></row> +<row><entry><constant>KEY_MENU</constant></entry><entry>Call application menu</entry><entry>2ND CONTROLS (USA: MENU) / DVD/MENU / SHOW/HIDE CTRL</entry></row> +<row><entry><constant>KEY_NEW</constant></entry><entry>Open/Close Picture in Picture</entry><entry>PIP</entry></row> +<row><entry><constant>KEY_OK</constant></entry><entry>Send a confirmation code to application</entry><entry>OK / ENTER / RETURN</entry></row> +<row><entry><constant>KEY_SCREEN</constant></entry><entry>Select screen aspect ratio</entry><entry>4:3 16:9 SELECT</entry></row> +<row><entry><constant>KEY_ZOOM</constant></entry><entry>Put device into zoom/full screen mode</entry><entry>ZOOM / FULL SCREEN / ZOOM+ / HIDE PANNEL / SWITCH</entry></row> + +<row><entry><emphasis role="bold">Navigation keys</emphasis></entry></row> + +<row><entry><constant>KEY_ESC</constant></entry><entry>Cancel current operation</entry><entry>CANCEL / BACK</entry></row> +<row><entry><constant>KEY_HELP</constant></entry><entry>Open a Help window</entry><entry>HELP</entry></row> +<row><entry><constant>KEY_HOMEPAGE</constant></entry><entry>Navigate to Homepage</entry><entry>HOME</entry></row> +<row><entry><constant>KEY_INFO</constant></entry><entry>Open On Screen Display</entry><entry>DISPLAY INFORMATION / OSD</entry></row> +<row><entry><constant>KEY_WWW</constant></entry><entry>Open the default browser</entry><entry>WEB</entry></row> +<row><entry><constant>KEY_UP</constant></entry><entry>Up key</entry><entry>UP</entry></row> +<row><entry><constant>KEY_DOWN</constant></entry><entry>Down key</entry><entry>DOWN</entry></row> +<row><entry><constant>KEY_LEFT</constant></entry><entry>Left key</entry><entry>LEFT</entry></row> +<row><entry><constant>KEY_RIGHT</constant></entry><entry>Right key</entry><entry>RIGHT</entry></row> + +<row><entry><emphasis role="bold">Miscellaneous keys</emphasis></entry></row> + +<row><entry><constant>KEY_DOT</constant></entry><entry>Return a dot</entry><entry>.</entry></row> +<row><entry><constant>KEY_FN</constant></entry><entry>Select a function</entry><entry>FUNCTION</entry></row> + +</tbody> +</tgroup> +</table> + +<para>It should be noticed that, sometimes, there some fundamental missing keys at some cheaper IR's. Due to that, it is recommended to:</para> + +<table pgwide="1" frame="none" id="rc_keymap_notes"> +<title>Notes</title> +<tgroup cols="1"> +&cs-str; +<tbody valign="top"> +<row> +<entry>On simpler IR's, without separate channel keys, you need to map UP as <constant>KEY_CHANNELUP</constant></entry> +</row><row> +<entry>On simpler IR's, without separate channel keys, you need to map DOWN as <constant>KEY_CHANNELDOWN</constant></entry> +</row><row> +<entry>On simpler IR's, without separate volume keys, you need to map LEFT as <constant>KEY_VOLUMEDOWN</constant></entry> +</row><row> +<entry>On simpler IR's, without separate volume keys, you need to map RIGHT as <constant>KEY_VOLUMEUP</constant></entry> +</row> +</tbody> +</tgroup> +</table> + +</section> + +<section id="Remote_controllers_table_change"> +<title>Changing default Remote Controller mappings</title> +<para>The event interface provides two ioctls to be used against +the /dev/input/event device, to allow changing the default +keymapping.</para> + +<para>This program demonstrates how to replace the keymap tables.</para> +&sub-keytable-c; +</section> + +&sub-lirc_device_interface; diff --git a/Documentation/DocBook/media/v4l/selection-api.xml b/Documentation/DocBook/media/v4l/selection-api.xml new file mode 100644 index 00000000..b299e477 --- /dev/null +++ b/Documentation/DocBook/media/v4l/selection-api.xml @@ -0,0 +1,325 @@ +<section id="selection-api"> + + <title>Experimental API for cropping, composing and scaling</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <section> + <title>Introduction</title> + +<para>Some video capture devices can sample a subsection of a picture and +shrink or enlarge it to an image of arbitrary size. Next, the devices can +insert the image into larger one. Some video output devices can crop part of an +input image, scale it up or down and insert it at an arbitrary scan line and +horizontal offset into a video signal. We call these abilities cropping, +scaling and composing.</para> + +<para>On a video <emphasis>capture</emphasis> device the source is a video +signal, and the cropping target determine the area actually sampled. The sink +is an image stored in a memory buffer. The composing area specifies which part +of the buffer is actually written to by the hardware. </para> + +<para>On a video <emphasis>output</emphasis> device the source is an image in a +memory buffer, and the cropping target is a part of an image to be shown on a +display. The sink is the display or the graphics screen. The application may +select the part of display where the image should be displayed. The size and +position of such a window is controlled by the compose target.</para> + +<para>Rectangles for all cropping and composing targets are defined even if the +device does supports neither cropping nor composing. Their size and position +will be fixed in such a case. If the device does not support scaling then the +cropping and composing rectangles have the same size.</para> + + </section> + + <section> + <title>Selection targets</title> + + <figure id="sel-targets-capture"> + <title>Cropping and composing targets</title> + <mediaobject> + <imageobject> + <imagedata fileref="selection.png" format="PNG" /> + </imageobject> + <textobject> + <phrase>Targets used by a cropping, composing and scaling + process</phrase> + </textobject> + </mediaobject> + </figure> + +For complete list of the available selection targets see table <xref +linkend="v4l2-sel-target"/> + + </section> + + <section> + + <title>Configuration</title> + +<para>Applications can use the <link linkend="vidioc-g-selection">selection +API</link> to select an area in a video signal or a buffer, and to query for +default settings and hardware limits.</para> + +<para>Video hardware can have various cropping, composing and scaling +limitations. It may only scale up or down, support only discrete scaling +factors, or have different scaling abilities in the horizontal and vertical +directions. Also it may not support scaling at all. At the same time the +cropping/composing rectangles may have to be aligned, and both the source and +the sink may have arbitrary upper and lower size limits. Therefore, as usual, +drivers are expected to adjust the requested parameters and return the actual +values selected. An application can control the rounding behaviour using <link +linkend="v4l2-sel-flags"> constraint flags </link>.</para> + + <section> + + <title>Configuration of video capture</title> + +<para>See figure <xref linkend="sel-targets-capture" /> for examples of the +selection targets available for a video capture device. It is recommended to +configure the cropping targets before to the composing targets.</para> + +<para>The range of coordinates of the top left corner, width and height of +areas that can be sampled is given by the <constant> V4L2_SEL_TGT_CROP_BOUNDS +</constant> target. It is recommended for the driver developers to put the +top/left corner at position <constant> (0,0) </constant>. The rectangle's +coordinates are expressed in pixels.</para> + +<para>The top left corner, width and height of the source rectangle, that is +the area actually sampled, is given by the <constant> V4L2_SEL_TGT_CROP_ACTIVE +</constant> target. It uses the same coordinate system as <constant> +V4L2_SEL_TGT_CROP_BOUNDS </constant>. The active cropping area must lie +completely inside the capture boundaries. The driver may further adjust the +requested size and/or position according to hardware limitations.</para> + +<para>Each capture device has a default source rectangle, given by the +<constant> V4L2_SEL_TGT_CROP_DEFAULT </constant> target. This rectangle shall +over what the driver writer considers the complete picture. Drivers shall set +the active crop rectangle to the default when the driver is first loaded, but +not later.</para> + +<para>The composing targets refer to a memory buffer. The limits of composing +coordinates are obtained using <constant> V4L2_SEL_TGT_COMPOSE_BOUNDS +</constant>. All coordinates are expressed in pixels. The rectangle's top/left +corner must be located at position <constant> (0,0) </constant>. The width and +height are equal to the image size set by <constant> VIDIOC_S_FMT </constant>. +</para> + +<para>The part of a buffer into which the image is inserted by the hardware is +controlled by the <constant> V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> target. +The rectangle's coordinates are also expressed in the same coordinate system as +the bounds rectangle. The composing rectangle must lie completely inside bounds +rectangle. The driver must adjust the composing rectangle to fit to the +bounding limits. Moreover, the driver can perform other adjustments according +to hardware limitations. The application can control rounding behaviour using +<link linkend="v4l2-sel-flags"> constraint flags </link>.</para> + +<para>For capture devices the default composing rectangle is queried using +<constant> V4L2_SEL_TGT_COMPOSE_DEFAULT </constant>. It is usually equal to the +bounding rectangle.</para> + +<para>The part of a buffer that is modified by the hardware is given by +<constant> V4L2_SEL_TGT_COMPOSE_PADDED </constant>. It contains all pixels +defined using <constant> V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> plus all +padding data modified by hardware during insertion process. All pixels outside +this rectangle <emphasis>must not</emphasis> be changed by the hardware. The +content of pixels that lie inside the padded area but outside active area is +undefined. The application can use the padded and active rectangles to detect +where the rubbish pixels are located and remove them if needed.</para> + + </section> + + <section> + + <title>Configuration of video output</title> + +<para>For output devices targets and ioctls are used similarly to the video +capture case. The <emphasis> composing </emphasis> rectangle refers to the +insertion of an image into a video signal. The cropping rectangles refer to a +memory buffer. It is recommended to configure the composing targets before to +the cropping targets.</para> + +<para>The cropping targets refer to the memory buffer that contains an image to +be inserted into a video signal or graphical screen. The limits of cropping +coordinates are obtained using <constant> V4L2_SEL_TGT_CROP_BOUNDS </constant>. +All coordinates are expressed in pixels. The top/left corner is always point +<constant> (0,0) </constant>. The width and height is equal to the image size +specified using <constant> VIDIOC_S_FMT </constant> ioctl.</para> + +<para>The top left corner, width and height of the source rectangle, that is +the area from which image date are processed by the hardware, is given by the +<constant> V4L2_SEL_TGT_CROP_ACTIVE </constant>. Its coordinates are expressed +in in the same coordinate system as the bounds rectangle. The active cropping +area must lie completely inside the crop boundaries and the driver may further +adjust the requested size and/or position according to hardware +limitations.</para> + +<para>For output devices the default cropping rectangle is queried using +<constant> V4L2_SEL_TGT_CROP_DEFAULT </constant>. It is usually equal to the +bounding rectangle.</para> + +<para>The part of a video signal or graphics display where the image is +inserted by the hardware is controlled by <constant> +V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> target. The rectangle's coordinates +are expressed in pixels. The composing rectangle must lie completely inside the +bounds rectangle. The driver must adjust the area to fit to the bounding +limits. Moreover, the driver can perform other adjustments according to +hardware limitations. </para> + +<para>The device has a default composing rectangle, given by the <constant> +V4L2_SEL_TGT_COMPOSE_DEFAULT </constant> target. This rectangle shall cover what +the driver writer considers the complete picture. It is recommended for the +driver developers to put the top/left corner at position <constant> (0,0) +</constant>. Drivers shall set the active composing rectangle to the default +one when the driver is first loaded.</para> + +<para>The devices may introduce additional content to video signal other than +an image from memory buffers. It includes borders around an image. However, +such a padded area is driver-dependent feature not covered by this document. +Driver developers are encouraged to keep padded rectangle equal to active one. +The padded target is accessed by the <constant> V4L2_SEL_TGT_COMPOSE_PADDED +</constant> identifier. It must contain all pixels from the <constant> +V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> target.</para> + + </section> + + <section> + + <title>Scaling control</title> + +<para>An application can detect if scaling is performed by comparing the width +and the height of rectangles obtained using <constant> V4L2_SEL_TGT_CROP_ACTIVE +</constant> and <constant> V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> targets. If +these are not equal then the scaling is applied. The application can compute +the scaling ratios using these values.</para> + + </section> + + </section> + + <section> + + <title>Comparison with old cropping API</title> + +<para>The selection API was introduced to cope with deficiencies of previous +<link linkend="crop"> API </link>, that was designed to control simple capture +devices. Later the cropping API was adopted by video output drivers. The ioctls +are used to select a part of the display were the video signal is inserted. It +should be considered as an API abuse because the described operation is +actually the composing. The selection API makes a clear distinction between +composing and cropping operations by setting the appropriate targets. The V4L2 +API lacks any support for composing to and cropping from an image inside a +memory buffer. The application could configure a capture device to fill only a +part of an image by abusing V4L2 API. Cropping a smaller image from a larger +one is achieved by setting the field <structfield> +&v4l2-pix-format;::bytesperline </structfield>. Introducing an image offsets +could be done by modifying field <structfield> &v4l2-buffer;::m:userptr +</structfield> before calling <constant> VIDIOC_QBUF </constant>. Those +operations should be avoided because they are not portable (endianness), and do +not work for macroblock and Bayer formats and mmap buffers. The selection API +deals with configuration of buffer cropping/composing in a clear, intuitive and +portable way. Next, with the selection API the concepts of the padded target +and constraints flags are introduced. Finally, <structname> &v4l2-crop; +</structname> and <structname> &v4l2-cropcap; </structname> have no reserved +fields. Therefore there is no way to extend their functionality. The new +<structname> &v4l2-selection; </structname> provides a lot of place for future +extensions. Driver developers are encouraged to implement only selection API. +The former cropping API would be simulated using the new one. </para> + + </section> + + <section> + <title>Examples</title> + <example> + <title>Resetting the cropping parameters</title> + + <para>(A video capture device is assumed; change <constant> +V4L2_BUF_TYPE_VIDEO_CAPTURE </constant> for other devices; change target to +<constant> V4L2_SEL_TGT_COMPOSE_* </constant> family to configure composing +area)</para> + + <programlisting> + + &v4l2-selection; sel = { + .type = V4L2_BUF_TYPE_VIDEO_CAPTURE, + .target = V4L2_SEL_TGT_CROP_DEFAULT, + }; + ret = ioctl(fd, &VIDIOC-G-SELECTION;, &sel); + if (ret) + exit(-1); + sel.target = V4L2_SEL_TGT_CROP_ACTIVE; + ret = ioctl(fd, &VIDIOC-S-SELECTION;, &sel); + if (ret) + exit(-1); + + </programlisting> + </example> + + <example> + <title>Simple downscaling</title> + <para>Setting a composing area on output of size of <emphasis> at most +</emphasis> half of limit placed at a center of a display.</para> + <programlisting> + + &v4l2-selection; sel = { + .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, + .target = V4L2_SEL_TGT_COMPOSE_BOUNDS, + }; + struct v4l2_rect r; + + ret = ioctl(fd, &VIDIOC-G-SELECTION;, &sel); + if (ret) + exit(-1); + /* setting smaller compose rectangle */ + r.width = sel.r.width / 2; + r.height = sel.r.height / 2; + r.left = sel.r.width / 4; + r.top = sel.r.height / 4; + sel.r = r; + sel.target = V4L2_SEL_TGT_COMPOSE_ACTIVE; + sel.flags = V4L2_SEL_FLAG_LE; + ret = ioctl(fd, &VIDIOC-S-SELECTION;, &sel); + if (ret) + exit(-1); + + </programlisting> + </example> + + <example> + <title>Querying for scaling factors</title> + <para>A video output device is assumed; change <constant> +V4L2_BUF_TYPE_VIDEO_OUTPUT </constant> for other devices</para> + <programlisting> + + &v4l2-selection; compose = { + .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, + .target = V4L2_SEL_TGT_COMPOSE_ACTIVE, + }; + &v4l2-selection; crop = { + .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, + .target = V4L2_SEL_TGT_CROP_ACTIVE, + }; + double hscale, vscale; + + ret = ioctl(fd, &VIDIOC-G-SELECTION;, &compose); + if (ret) + exit(-1); + ret = ioctl(fd, &VIDIOC-G-SELECTION;, &crop); + if (ret) + exit(-1); + + /* computing scaling factors */ + hscale = (double)compose.r.width / crop.r.width; + vscale = (double)compose.r.height / crop.r.height; + + </programlisting> + </example> + + </section> + +</section> diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml b/Documentation/DocBook/media/v4l/subdev-formats.xml new file mode 100644 index 00000000..49c532eb --- /dev/null +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml @@ -0,0 +1,2569 @@ +<section id="v4l2-mbus-format"> + <title>Media Bus Formats</title> + + <table pgwide="1" frame="none" id="v4l2-mbus-framefmt"> + <title>struct <structname>v4l2_mbus_framefmt</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Image width, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Image height, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>code</structfield></entry> + <entry>Format code, from &v4l2-mbus-pixelcode;.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>field</structfield></entry> + <entry>Field order, from &v4l2-field;. See + <xref linkend="field-order" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>colorspace</structfield></entry> + <entry>Image colorspace, from &v4l2-colorspace;. See + <xref linkend="colorspaces" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[7]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <section id="v4l2-mbus-pixelcode"> + <title>Media Bus Pixel Codes</title> + + <para>The media bus pixel codes describe image formats as flowing over + physical busses (both between separate physical components and inside SoC + devices). This should not be confused with the V4L2 pixel formats that + describe, using four character codes, image formats as stored in memory. + </para> + + <para>While there is a relationship between image formats on busses and + image formats in memory (a raw Bayer image won't be magically converted to + JPEG just by storing it to memory), there is no one-to-one correspondance + between them.</para> + + <section> + <title>Packed RGB Formats</title> + + <para>Those formats transfer pixel data as red, green and blue components. + The format code is made of the following information. + <itemizedlist> + <listitem><para>The red, green and blue components order code, as encoded in a + pixel sample. Possible values are RGB and BGR.</para></listitem> + <listitem><para>The number of bits per component, for each component. The values + can be different for all components. Common values are 555 and 565.</para> + </listitem> + <listitem><para>The number of bus samples per pixel. Pixels that are wider than + the bus width must be transferred in multiple samples. Common values are + 1 and 2.</para></listitem> + <listitem><para>The bus width.</para></listitem> + <listitem><para>For formats where the total number of bits per pixel is smaller + than the number of bus samples per pixel times the bus width, a padding + value stating if the bytes are padded in their most high order bits + (PADHI) or low order bits (PADLO).</para></listitem> + <listitem><para>For formats where the number of bus samples per pixel is larger + than 1, an endianness value stating if the pixel is transferred MSB first + (BE) or LSB first (LE).</para></listitem> + </itemizedlist> + </para> + + <para>For instance, a format where pixels are encoded as 5-bits red, 5-bits + green and 5-bit blue values padded on the high bit, transferred as 2 8-bit + samples per pixel with the most significant bits (padding, red and half of + the green value) transferred first will be named + <constant>V4L2_MBUS_FMT_RGB555_2X8_PADHI_BE</constant>. + </para> + + <para>The following tables list existing packet RGB formats.</para> + + <table pgwide="0" frame="none" id="v4l2-mbus-pixelcode-rgb"> + <title>RGB formats</title> + <tgroup cols="11"> + <colspec colname="id" align="left" /> + <colspec colname="code" align="center"/> + <colspec colname="bit" /> + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry></entry> + <entry spanname="b0">Data organization</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-MBUS-FMT-RGB444-2X8-PADHI-BE"> + <entry>V4L2_MBUS_FMT_RGB444_2X8_PADHI_BE</entry> + <entry>0x1001</entry> + <entry></entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-RGB444-2X8-PADHI-LE"> + <entry>V4L2_MBUS_FMT_RGB444_2X8_PADHI_LE</entry> + <entry>0x1002</entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-RGB555-2X8-PADHI-BE"> + <entry>V4L2_MBUS_FMT_RGB555_2X8_PADHI_BE</entry> + <entry>0x1003</entry> + <entry></entry> + <entry>0</entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-RGB555-2X8-PADHI-LE"> + <entry>V4L2_MBUS_FMT_RGB555_2X8_PADHI_LE</entry> + <entry>0x1004</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>0</entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-BGR565-2X8-BE"> + <entry>V4L2_MBUS_FMT_BGR565_2X8_BE</entry> + <entry>0x1005</entry> + <entry></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-BGR565-2X8-LE"> + <entry>V4L2_MBUS_FMT_BGR565_2X8_LE</entry> + <entry>0x1006</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-RGB565-2X8-BE"> + <entry>V4L2_MBUS_FMT_RGB565_2X8_BE</entry> + <entry>0x1007</entry> + <entry></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-RGB565-2X8-LE"> + <entry>V4L2_MBUS_FMT_RGB565_2X8_LE</entry> + <entry>0x1008</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>Bayer Formats</title> + + <para>Those formats transfer pixel data as red, green and blue components. + The format code is made of the following information. + <itemizedlist> + <listitem><para>The red, green and blue components order code, as encoded in a + pixel sample. The possible values are shown in <xref + linkend="bayer-patterns" />.</para></listitem> + <listitem><para>The number of bits per pixel component. All components are + transferred on the same number of bits. Common values are 8, 10 and 12.</para> + </listitem> + <listitem><para>If the pixel components are DPCM-compressed, a mention of the + DPCM compression and the number of bits per compressed pixel component.</para> + </listitem> + <listitem><para>The number of bus samples per pixel. Pixels that are wider than + the bus width must be transferred in multiple samples. Common values are + 1 and 2.</para></listitem> + <listitem><para>The bus width.</para></listitem> + <listitem><para>For formats where the total number of bits per pixel is smaller + than the number of bus samples per pixel times the bus width, a padding + value stating if the bytes are padded in their most high order bits + (PADHI) or low order bits (PADLO).</para></listitem> + <listitem><para>For formats where the number of bus samples per pixel is larger + than 1, an endianness value stating if the pixel is transferred MSB first + (BE) or LSB first (LE).</para></listitem> + </itemizedlist> + </para> + + <para>For instance, a format with uncompressed 10-bit Bayer components + arranged in a red, green, green, blue pattern transferred as 2 8-bit + samples per pixel with the least significant bits transferred first will + be named <constant>V4L2_MBUS_FMT_SRGGB10_2X8_PADHI_LE</constant>. + </para> + + <figure id="bayer-patterns"> + <title>Bayer Patterns</title> + <mediaobject> + <imageobject> + <imagedata fileref="bayer.png" format="PNG" /> + </imageobject> + <textobject> + <phrase>Bayer filter color patterns</phrase> + </textobject> + </mediaobject> + </figure> + + <para>The following table lists existing packet Bayer formats. The data + organization is given as an example for the first pixel only.</para> + + <table pgwide="0" frame="none" id="v4l2-mbus-pixelcode-bayer"> + <title>Bayer Formats</title> + <tgroup cols="15"> + <colspec colname="id" align="left" /> + <colspec colname="code" align="center"/> + <colspec colname="bit" /> + <colspec colnum="4" colname="b11" align="center" /> + <colspec colnum="5" colname="b10" align="center" /> + <colspec colnum="6" colname="b09" align="center" /> + <colspec colnum="7" colname="b08" align="center" /> + <colspec colnum="8" colname="b07" align="center" /> + <colspec colnum="9" colname="b06" align="center" /> + <colspec colnum="10" colname="b05" align="center" /> + <colspec colnum="11" colname="b04" align="center" /> + <colspec colnum="12" colname="b03" align="center" /> + <colspec colnum="13" colname="b02" align="center" /> + <colspec colnum="14" colname="b01" align="center" /> + <colspec colnum="15" colname="b00" align="center" /> + <spanspec namest="b11" nameend="b00" spanname="b0" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry></entry> + <entry spanname="b0">Data organization</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Bit</entry> + <entry>11</entry> + <entry>10</entry> + <entry>9</entry> + <entry>8</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-MBUS-FMT-SBGGR8-1X8"> + <entry>V4L2_MBUS_FMT_SBGGR8_1X8</entry> + <entry>0x3001</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGBRG8-1X8"> + <entry>V4L2_MBUS_FMT_SGBRG8_1X8</entry> + <entry>0x3013</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGRBG8-1X8"> + <entry>V4L2_MBUS_FMT_SGRBG8_1X8</entry> + <entry>0x3002</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SRGGB8-1X8"> + <entry>V4L2_MBUS_FMT_SRGGB8_1X8</entry> + <entry>0x3014</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SBGGR10-DPCM8-1X8"> + <entry>V4L2_MBUS_FMT_SBGGR10_DPCM8_1X8</entry> + <entry>0x300b</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGBRG10-DPCM8-1X8"> + <entry>V4L2_MBUS_FMT_SGBRG10_DPCM8_1X8</entry> + <entry>0x300c</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGRBG10-DPCM8-1X8"> + <entry>V4L2_MBUS_FMT_SGRBG10_DPCM8_1X8</entry> + <entry>0x3009</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SRGGB10-DPCM8-1X8"> + <entry>V4L2_MBUS_FMT_SRGGB10_DPCM8_1X8</entry> + <entry>0x300d</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SBGGR10-2X8-PADHI-BE"> + <entry>V4L2_MBUS_FMT_SBGGR10_2X8_PADHI_BE</entry> + <entry>0x3003</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>b<subscript>9</subscript></entry> + <entry>b<subscript>8</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SBGGR10-2X8-PADHI-LE"> + <entry>V4L2_MBUS_FMT_SBGGR10_2X8_PADHI_LE</entry> + <entry>0x3004</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>b<subscript>9</subscript></entry> + <entry>b<subscript>8</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SBGGR10-2X8-PADLO-BE"> + <entry>V4L2_MBUS_FMT_SBGGR10_2X8_PADLO_BE</entry> + <entry>0x3005</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>9</subscript></entry> + <entry>b<subscript>8</subscript></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + </row> + <row id="V4L2-MBUS-FMT-SBGGR10-2X8-PADLO-LE"> + <entry>V4L2_MBUS_FMT_SBGGR10_2X8_PADLO_LE</entry> + <entry>0x3006</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>9</subscript></entry> + <entry>b<subscript>8</subscript></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SBGGR10-1X10"> + <entry>V4L2_MBUS_FMT_SBGGR10_1X10</entry> + <entry>0x3007</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>b<subscript>9</subscript></entry> + <entry>b<subscript>8</subscript></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGBRG10-1X10"> + <entry>V4L2_MBUS_FMT_SGBRG10_1X10</entry> + <entry>0x300e</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>g<subscript>9</subscript></entry> + <entry>g<subscript>8</subscript></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGRBG10-1X10"> + <entry>V4L2_MBUS_FMT_SGRBG10_1X10</entry> + <entry>0x300a</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>g<subscript>9</subscript></entry> + <entry>g<subscript>8</subscript></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SRGGB10-1X10"> + <entry>V4L2_MBUS_FMT_SRGGB10_1X10</entry> + <entry>0x300f</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>r<subscript>9</subscript></entry> + <entry>r<subscript>8</subscript></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SBGGR12-1X12"> + <entry>V4L2_MBUS_FMT_SBGGR12_1X12</entry> + <entry>0x3008</entry> + <entry></entry> + <entry>b<subscript>11</subscript></entry> + <entry>b<subscript>10</subscript></entry> + <entry>b<subscript>9</subscript></entry> + <entry>b<subscript>8</subscript></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGBRG12-1X12"> + <entry>V4L2_MBUS_FMT_SGBRG12_1X12</entry> + <entry>0x3010</entry> + <entry></entry> + <entry>g<subscript>11</subscript></entry> + <entry>g<subscript>10</subscript></entry> + <entry>g<subscript>9</subscript></entry> + <entry>g<subscript>8</subscript></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SGRBG12-1X12"> + <entry>V4L2_MBUS_FMT_SGRBG12_1X12</entry> + <entry>0x3011</entry> + <entry></entry> + <entry>g<subscript>11</subscript></entry> + <entry>g<subscript>10</subscript></entry> + <entry>g<subscript>9</subscript></entry> + <entry>g<subscript>8</subscript></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-SRGGB12-1X12"> + <entry>V4L2_MBUS_FMT_SRGGB12_1X12</entry> + <entry>0x3012</entry> + <entry></entry> + <entry>r<subscript>11</subscript></entry> + <entry>r<subscript>10</subscript></entry> + <entry>r<subscript>9</subscript></entry> + <entry>r<subscript>8</subscript></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>Packed YUV Formats</title> + + <para>Those data formats transfer pixel data as (possibly downsampled) Y, U + and V components. The format code is made of the following information. + <itemizedlist> + <listitem><para>The Y, U and V components order code, as transferred on the + bus. Possible values are YUYV, UYVY, YVYU and VYUY.</para></listitem> + <listitem><para>The number of bits per pixel component. All components are + transferred on the same number of bits. Common values are 8, 10 and 12.</para> + </listitem> + <listitem><para>The number of bus samples per pixel. Pixels that are wider than + the bus width must be transferred in multiple samples. Common values are + 1, 1.5 (encoded as 1_5) and 2.</para></listitem> + <listitem><para>The bus width. When the bus width is larger than the number of + bits per pixel component, several components are packed in a single bus + sample. The components are ordered as specified by the order code, with + components on the left of the code transferred in the high order bits. + Common values are 8 and 16.</para> + </listitem> + </itemizedlist> + </para> + + <para>For instance, a format where pixels are encoded as 8-bit YUV values + downsampled to 4:2:2 and transferred as 2 8-bit bus samples per pixel in the + U, Y, V, Y order will be named <constant>V4L2_MBUS_FMT_UYVY8_2X8</constant>. + </para> + + <para>The following table lisst existing packet YUV formats.</para> + + <table pgwide="0" frame="none" id="v4l2-mbus-pixelcode-yuv8"> + <title>YUV Formats</title> + <tgroup cols="23"> + <colspec colname="id" align="left" /> + <colspec colname="code" align="center"/> + <colspec colname="bit" /> + <colspec colnum="4" colname="b19" align="center" /> + <colspec colnum="5" colname="b18" align="center" /> + <colspec colnum="6" colname="b17" align="center" /> + <colspec colnum="7" colname="b16" align="center" /> + <colspec colnum="8" colname="b15" align="center" /> + <colspec colnum="9" colname="b14" align="center" /> + <colspec colnum="10" colname="b13" align="center" /> + <colspec colnum="11" colname="b12" align="center" /> + <colspec colnum="12" colname="b11" align="center" /> + <colspec colnum="13" colname="b10" align="center" /> + <colspec colnum="14" colname="b09" align="center" /> + <colspec colnum="15" colname="b08" align="center" /> + <colspec colnum="16" colname="b07" align="center" /> + <colspec colnum="17" colname="b06" align="center" /> + <colspec colnum="18" colname="b05" align="center" /> + <colspec colnum="19" colname="b04" align="center" /> + <colspec colnum="20" colname="b03" align="center" /> + <colspec colnum="21" colname="b02" align="center" /> + <colspec colnum="22" colname="b01" align="center" /> + <colspec colnum="23" colname="b00" align="center" /> + <spanspec namest="b19" nameend="b00" spanname="b0" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry></entry> + <entry spanname="b0">Data organization</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Bit</entry> + <entry>19</entry> + <entry>18</entry> + <entry>17</entry> + <entry>16</entry> + <entry>15</entry> + <entry>14</entry> + <entry>13</entry> + <entry>12</entry> + <entry>11</entry> + <entry>10</entry> + <entry>9</entry> + <entry>8</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-MBUS-FMT-Y8-1X8"> + <entry>V4L2_MBUS_FMT_Y8_1X8</entry> + <entry>0x2001</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-UYVY8-1_5X8"> + <entry>V4L2_MBUS_FMT_UYVY8_1_5X8</entry> + <entry>0x2002</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-VYUY8-1_5X8"> + <entry>V4L2_MBUS_FMT_VYUY8_1_5X8</entry> + <entry>0x2003</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-YUYV8-1_5X8"> + <entry>V4L2_MBUS_FMT_YUYV8_1_5X8</entry> + <entry>0x2004</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + 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<entry>v<subscript>8</subscript></entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-YVYU10-2X10"> + <entry>V4L2_MBUS_FMT_YVYU10_2X10</entry> + <entry>0x200c</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>9</subscript></entry> + <entry>y<subscript>8</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>v<subscript>9</subscript></entry> + <entry>v<subscript>8</subscript></entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>9</subscript></entry> + <entry>y<subscript>8</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>u<subscript>9</subscript></entry> + <entry>u<subscript>8</subscript></entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-Y12-1X12"> + <entry>V4L2_MBUS_FMT_Y12_1X12</entry> + <entry>0x2013</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>11</subscript></entry> + <entry>y<subscript>10</subscript></entry> + <entry>y<subscript>9</subscript></entry> + <entry>y<subscript>8</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-UYVY8-1X16"> + <entry>V4L2_MBUS_FMT_UYVY8_1X16</entry> + <entry>0x200f</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-VYUY8-1X16"> + <entry>V4L2_MBUS_FMT_VYUY8_1X16</entry> + <entry>0x2010</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-YUYV8-1X16"> + <entry>V4L2_MBUS_FMT_YUYV8_1X16</entry> + <entry>0x2011</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-YVYU8-1X16"> + <entry>V4L2_MBUS_FMT_YVYU8_1X16</entry> + <entry>0x2012</entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>-</entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-YUYV10-1X20"> + <entry>V4L2_MBUS_FMT_YUYV10_1X20</entry> + <entry>0x200d</entry> + <entry></entry> + <entry>y<subscript>9</subscript></entry> + <entry>y<subscript>8</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>u<subscript>9</subscript></entry> + <entry>u<subscript>8</subscript></entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>y<subscript>9</subscript></entry> + <entry>y<subscript>8</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>v<subscript>9</subscript></entry> + <entry>v<subscript>8</subscript></entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row id="V4L2-MBUS-FMT-YVYU10-1X20"> + <entry>V4L2_MBUS_FMT_YVYU10_1X20</entry> + <entry>0x200e</entry> + <entry></entry> + <entry>y<subscript>9</subscript></entry> + <entry>y<subscript>8</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>v<subscript>9</subscript></entry> + <entry>v<subscript>8</subscript></entry> + <entry>v<subscript>7</subscript></entry> + <entry>v<subscript>6</subscript></entry> + <entry>v<subscript>5</subscript></entry> + <entry>v<subscript>4</subscript></entry> + <entry>v<subscript>3</subscript></entry> + <entry>v<subscript>2</subscript></entry> + <entry>v<subscript>1</subscript></entry> + <entry>v<subscript>0</subscript></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>y<subscript>9</subscript></entry> + <entry>y<subscript>8</subscript></entry> + <entry>y<subscript>7</subscript></entry> + <entry>y<subscript>6</subscript></entry> + <entry>y<subscript>5</subscript></entry> + <entry>y<subscript>4</subscript></entry> + <entry>y<subscript>3</subscript></entry> + <entry>y<subscript>2</subscript></entry> + <entry>y<subscript>1</subscript></entry> + <entry>y<subscript>0</subscript></entry> + <entry>u<subscript>9</subscript></entry> + <entry>u<subscript>8</subscript></entry> + <entry>u<subscript>7</subscript></entry> + <entry>u<subscript>6</subscript></entry> + <entry>u<subscript>5</subscript></entry> + <entry>u<subscript>4</subscript></entry> + <entry>u<subscript>3</subscript></entry> + <entry>u<subscript>2</subscript></entry> + <entry>u<subscript>1</subscript></entry> + <entry>u<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>JPEG Compressed Formats</title> + + <para>Those data formats consist of an ordered sequence of 8-bit bytes + obtained from JPEG compression process. Additionally to the + <constant>_JPEG</constant> postfix the format code is made of + the following information. + <itemizedlist> + <listitem><para>The number of bus samples per entropy encoded byte.</para></listitem> + <listitem><para>The bus width.</para></listitem> + </itemizedlist> + </para> + + <para>For instance, for a JPEG baseline process and an 8-bit bus width + the format will be named <constant>V4L2_MBUS_FMT_JPEG_1X8</constant>. + </para> + + <para>The following table lists existing JPEG compressed formats.</para> + + <table pgwide="0" frame="none" id="v4l2-mbus-pixelcode-jpeg"> + <title>JPEG Formats</title> + <tgroup cols="3"> + <colspec colname="id" align="left" /> + <colspec colname="code" align="left"/> + <colspec colname="remarks" align="left"/> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry>Remarks</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-MBUS-FMT-JPEG-1X8"> + <entry>V4L2_MBUS_FMT_JPEG_1X8</entry> + <entry>0x4001</entry> + <entry>Besides of its usage for the parallel bus this format is + recommended for transmission of JPEG data over MIPI CSI bus + using the User Defined 8-bit Data types. + </entry> + </row> + </tbody> + </tgroup> + </table> + </section> + </section> +</section> diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml new file mode 100644 index 00000000..8ae38876 --- /dev/null +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -0,0 +1,575 @@ + <partinfo> + <authorgroup> + <author> + <firstname>Michael</firstname> + <surname>Schimek</surname> + <othername role="mi">H</othername> + <affiliation> + <address> + <email>mschimek@gmx.at</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Bill</firstname> + <surname>Dirks</surname> + <!-- Commented until Bill opts in to be spammed. + <affiliation> + <address> + <email>bill@thedirks.org</email> + </address> + </affiliation> --> + <contrib>Original author of the V4L2 API and +documentation.</contrib> + </author> + + <author> + <firstname>Hans</firstname> + <surname>Verkuil</surname> + <contrib>Designed and documented the VIDIOC_LOG_STATUS ioctl, +the extended control ioctls and major parts of the sliced VBI +API.</contrib> + <affiliation> + <address> + <email>hverkuil@xs4all.nl</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Martin</firstname> + <surname>Rubli</surname> + <!-- + <affiliation> + <address> + <email>martin_rubli@logitech.com</email> + </address> + </affiliation> --> + <contrib>Designed and documented the VIDIOC_ENUM_FRAMESIZES +and VIDIOC_ENUM_FRAMEINTERVALS ioctls.</contrib> + </author> + + <author> + <firstname>Andy</firstname> + <surname>Walls</surname> + <contrib>Documented the fielded V4L2_MPEG_STREAM_VBI_FMT_IVTV +MPEG stream embedded, sliced VBI data format in this specification. +</contrib> + <affiliation> + <address> + <email>awalls@md.metrocast.net</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Mauro</firstname> + <surname>Carvalho Chehab</surname> + <contrib>Documented libv4l, designed and added v4l2grab example, +Remote Controller chapter.</contrib> + <affiliation> + <address> + <email>mchehab@redhat.com</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Muralidharan</firstname> + <surname>Karicheri</surname> + <contrib>Documented the Digital Video timings API.</contrib> + <affiliation> + <address> + <email>m-karicheri2@ti.com</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Pawel</firstname> + <surname>Osciak</surname> + <contrib>Designed and documented the multi-planar API.</contrib> + <affiliation> + <address> + <email>pawel AT osciak.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>1999</year> + <year>2000</year> + <year>2001</year> + <year>2002</year> + <year>2003</year> + <year>2004</year> + <year>2005</year> + <year>2006</year> + <year>2007</year> + <year>2008</year> + <year>2009</year> + <year>2010</year> + <year>2011</year> + <holder>Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin +Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab, + Pawel Osciak</holder> + </copyright> + <legalnotice> + <para>Except when explicitly stated as GPL, programming examples within + this part can be used and distributed without restrictions.</para> + </legalnotice> + <revhistory> + <!-- Put document revisions here, newest first. --> + <!-- API revisions (changes and additions of defines, enums, +structs, ioctls) must be noted in more detail in the history chapter +(compat.xml), along with the possible impact on existing drivers and +applications. --> + + <revision> + <revnumber>3.4</revnumber> + <date>2012-01-25</date> + <authorinitials>sn</authorinitials> + <revremark>Added <link linkend="jpeg-controls">JPEG compression + control class.</link> + </revremark> + </revision> + + <revision> + <revnumber>3.3</revnumber> + <date>2012-01-11</date> + <authorinitials>hv</authorinitials> + <revremark>Added device_caps field to struct v4l2_capabilities.</revremark> + </revision> + + <revision> + <revnumber>3.2</revnumber> + <date>2011-08-26</date> + <authorinitials>hv</authorinitials> + <revremark>Added V4L2_CTRL_FLAG_VOLATILE.</revremark> + </revision> + + <revision> + <revnumber>3.1</revnumber> + <date>2011-06-27</date> + <authorinitials>mcc, po, hv</authorinitials> + <revremark>Documented that VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one. + Standardize an error code for invalid ioctl. + Added V4L2_CTRL_TYPE_BITMASK.</revremark> + </revision> + + <revision> + <revnumber>2.6.39</revnumber> + <date>2011-03-01</date> + <authorinitials>mcc, po</authorinitials> + <revremark>Removed VIDIOC_*_OLD from videodev2.h header and update it to reflect latest changes. Added the <link linkend="planar-apis">multi-planar API</link>.</revremark> + </revision> + + <revision> + <revnumber>2.6.37</revnumber> + <date>2010-08-06</date> + <authorinitials>hv</authorinitials> + <revremark>Removed obsolete vtx (videotext) API.</revremark> + </revision> + + <revision> + <revnumber>2.6.33</revnumber> + <date>2009-12-03</date> + <authorinitials>mk</authorinitials> + <revremark>Added documentation for the Digital Video timings API.</revremark> + </revision> + + <revision> + <revnumber>2.6.32</revnumber> + <date>2009-08-31</date> + <authorinitials>mcc</authorinitials> + <revremark>Now, revisions will match the kernel version where +the V4L2 API changes will be used by the Linux Kernel. +Also added Remote Controller chapter.</revremark> + </revision> + + <revision> + <revnumber>0.29</revnumber> + <date>2009-08-26</date> + <authorinitials>ev</authorinitials> + <revremark>Added documentation for string controls and for FM Transmitter controls.</revremark> + </revision> + + <revision> + <revnumber>0.28</revnumber> + <date>2009-08-26</date> + <authorinitials>gl</authorinitials> + <revremark>Added V4L2_CID_BAND_STOP_FILTER documentation.</revremark> + </revision> + + <revision> + <revnumber>0.27</revnumber> + <date>2009-08-15</date> + <authorinitials>mcc</authorinitials> + <revremark>Added libv4l and Remote Controller documentation; +added v4l2grab and keytable application examples.</revremark> + </revision> + + <revision> + <revnumber>0.26</revnumber> + <date>2009-07-23</date> + <authorinitials>hv</authorinitials> + <revremark>Finalized the RDS capture API. Added modulator and RDS encoder +capabilities. Added support for string controls.</revremark> + </revision> + + <revision> + <revnumber>0.25</revnumber> + <date>2009-01-18</date> + <authorinitials>hv</authorinitials> + <revremark>Added pixel formats VYUY, NV16 and NV61, and changed +the debug ioctls VIDIOC_DBG_G/S_REGISTER and VIDIOC_DBG_G_CHIP_IDENT. +Added camera controls V4L2_CID_ZOOM_ABSOLUTE, V4L2_CID_ZOOM_RELATIVE, +V4L2_CID_ZOOM_CONTINUOUS and V4L2_CID_PRIVACY.</revremark> + </revision> + + <revision> + <revnumber>0.24</revnumber> + <date>2008-03-04</date> + <authorinitials>mhs</authorinitials> + <revremark>Added pixel formats Y16 and SBGGR16, new controls +and a camera controls class. Removed VIDIOC_G/S_MPEGCOMP.</revremark> + </revision> + + <revision> + <revnumber>0.23</revnumber> + <date>2007-08-30</date> + <authorinitials>mhs</authorinitials> + <revremark>Fixed a typo in VIDIOC_DBG_G/S_REGISTER. +Clarified the byte order of packed pixel formats.</revremark> + </revision> + + <revision> + <revnumber>0.22</revnumber> + <date>2007-08-29</date> + <authorinitials>mhs</authorinitials> + <revremark>Added the Video Output Overlay interface, new MPEG +controls, V4L2_FIELD_INTERLACED_TB and V4L2_FIELD_INTERLACED_BT, +VIDIOC_DBG_G/S_REGISTER, VIDIOC_(TRY_)ENCODER_CMD, +VIDIOC_G_CHIP_IDENT, VIDIOC_G_ENC_INDEX, new pixel formats. +Clarifications in the cropping chapter, about RGB pixel formats, the +mmap(), poll(), select(), read() and write() functions. Typographical +fixes.</revremark> + </revision> + + <revision> + <revnumber>0.21</revnumber> + <date>2006-12-19</date> + <authorinitials>mhs</authorinitials> + <revremark>Fixed a link in the VIDIOC_G_EXT_CTRLS section.</revremark> + </revision> + + <revision> + <revnumber>0.20</revnumber> + <date>2006-11-24</date> + <authorinitials>mhs</authorinitials> + <revremark>Clarified the purpose of the audioset field in +struct v4l2_input and v4l2_output.</revremark> + </revision> + + <revision> + <revnumber>0.19</revnumber> + <date>2006-10-19</date> + <authorinitials>mhs</authorinitials> + <revremark>Documented V4L2_PIX_FMT_RGB444.</revremark> + </revision> + + <revision> + <revnumber>0.18</revnumber> + <date>2006-10-18</date> + <authorinitials>mhs</authorinitials> + <revremark>Added the description of extended controls by Hans +Verkuil. Linked V4L2_PIX_FMT_MPEG to V4L2_CID_MPEG_STREAM_TYPE.</revremark> + </revision> + + <revision> + <revnumber>0.17</revnumber> + <date>2006-10-12</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected V4L2_PIX_FMT_HM12 description.</revremark> + </revision> + + <revision> + <revnumber>0.16</revnumber> + <date>2006-10-08</date> + <authorinitials>mhs</authorinitials> + <revremark>VIDIOC_ENUM_FRAMESIZES and +VIDIOC_ENUM_FRAMEINTERVALS are now part of the API.</revremark> + </revision> + + <revision> + <revnumber>0.15</revnumber> + <date>2006-09-23</date> + <authorinitials>mhs</authorinitials> + <revremark>Cleaned up the bibliography, added BT.653 and +BT.1119. capture.c/start_capturing() for user pointer I/O did not +initialize the buffer index. Documented the V4L MPEG and MJPEG +VID_TYPEs and V4L2_PIX_FMT_SBGGR8. Updated the list of reserved pixel +formats. See the history chapter for API changes.</revremark> + </revision> + + <revision> + <revnumber>0.14</revnumber> + <date>2006-09-14</date> + <authorinitials>mr</authorinitials> + <revremark>Added VIDIOC_ENUM_FRAMESIZES and +VIDIOC_ENUM_FRAMEINTERVALS proposal for frame format enumeration of +digital devices.</revremark> + </revision> + + <revision> + <revnumber>0.13</revnumber> + <date>2006-04-07</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected the description of struct v4l2_window +clips. New V4L2_STD_ and V4L2_TUNER_MODE_LANG1_LANG2 +defines.</revremark> + </revision> + + <revision> + <revnumber>0.12</revnumber> + <date>2006-02-03</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected the description of struct +v4l2_captureparm and v4l2_outputparm.</revremark> + </revision> + + <revision> + <revnumber>0.11</revnumber> + <date>2006-01-27</date> + <authorinitials>mhs</authorinitials> + <revremark>Improved the description of struct +v4l2_tuner.</revremark> + </revision> + + <revision> + <revnumber>0.10</revnumber> + <date>2006-01-10</date> + <authorinitials>mhs</authorinitials> + <revremark>VIDIOC_G_INPUT and VIDIOC_S_PARM +clarifications.</revremark> + </revision> + + <revision> + <revnumber>0.9</revnumber> + <date>2005-11-27</date> + <authorinitials>mhs</authorinitials> + <revremark>Improved the 525 line numbering diagram. Hans +Verkuil and I rewrote the sliced VBI section. He also contributed a +VIDIOC_LOG_STATUS page. Fixed VIDIOC_S_STD call in the video standard +selection example. Various updates.</revremark> + </revision> + + <revision> + <revnumber>0.8</revnumber> + <date>2004-10-04</date> + <authorinitials>mhs</authorinitials> + <revremark>Somehow a piece of junk slipped into the capture +example, removed.</revremark> + </revision> + + <revision> + <revnumber>0.7</revnumber> + <date>2004-09-19</date> + <authorinitials>mhs</authorinitials> + <revremark>Fixed video standard selection, control +enumeration, downscaling and aspect example. Added read and user +pointer i/o to video capture example.</revremark> + </revision> + + <revision> + <revnumber>0.6</revnumber> + <date>2004-08-01</date> + <authorinitials>mhs</authorinitials> + <revremark>v4l2_buffer changes, added video capture example, +various corrections.</revremark> + </revision> + + <revision> + <revnumber>0.5</revnumber> + <date>2003-11-05</date> + <authorinitials>mhs</authorinitials> + <revremark>Pixel format erratum.</revremark> + </revision> + + <revision> + <revnumber>0.4</revnumber> + <date>2003-09-17</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected source and Makefile to generate a PDF. +SGML fixes. Added latest API changes. Closed gaps in the history +chapter.</revremark> + </revision> + + <revision> + <revnumber>0.3</revnumber> + <date>2003-02-05</date> + <authorinitials>mhs</authorinitials> + <revremark>Another draft, more corrections.</revremark> + </revision> + + <revision> + <revnumber>0.2</revnumber> + <date>2003-01-15</date> + <authorinitials>mhs</authorinitials> + <revremark>Second draft, with corrections pointed out by Gerd +Knorr.</revremark> + </revision> + + <revision> + <revnumber>0.1</revnumber> + <date>2002-12-01</date> + <authorinitials>mhs</authorinitials> + <revremark>First draft, based on documentation by Bill Dirks +and discussions on the V4L mailing list.</revremark> + </revision> + </revhistory> +</partinfo> + +<title>Video for Linux Two API Specification</title> + <subtitle>Revision 3.3</subtitle> + + <chapter id="common"> + &sub-common; + </chapter> + + <chapter id="pixfmt"> + &sub-pixfmt; + </chapter> + + <chapter id="io"> + &sub-io; + </chapter> + + <chapter id="devices"> + <title>Interfaces</title> + + <section id="capture"> &sub-dev-capture; </section> + <section id="overlay"> &sub-dev-overlay; </section> + <section id="output"> &sub-dev-output; </section> + <section id="osd"> &sub-dev-osd; </section> + <section id="codec"> &sub-dev-codec; </section> + <section id="effect"> &sub-dev-effect; </section> + <section id="raw-vbi"> &sub-dev-raw-vbi; </section> + <section id="sliced"> &sub-dev-sliced-vbi; </section> + <section id="ttx"> &sub-dev-teletext; </section> + <section id="radio"> &sub-dev-radio; </section> + <section id="rds"> &sub-dev-rds; </section> + <section id="event"> &sub-dev-event; </section> + <section id="subdev"> &sub-dev-subdev; </section> + </chapter> + + <chapter id="driver"> + &sub-driver; + </chapter> + + <chapter id="libv4l"> + &sub-libv4l; + </chapter> + + <chapter id="compat"> + &sub-compat; + </chapter> + + <appendix id="user-func"> + <title>Function Reference</title> + + <!-- Keep this alphabetically sorted. --> + + &sub-close; + &sub-ioctl; + <!-- All ioctls go here. --> + &sub-create-bufs; + &sub-cropcap; + &sub-dbg-g-chip-ident; + &sub-dbg-g-register; + &sub-decoder-cmd; + &sub-dqevent; + &sub-encoder-cmd; + &sub-enumaudio; + &sub-enumaudioout; + &sub-enum-dv-presets; + &sub-enum-fmt; + &sub-enum-framesizes; + &sub-enum-frameintervals; + &sub-enuminput; + &sub-enumoutput; + &sub-enumstd; + &sub-g-audio; + &sub-g-audioout; + &sub-g-crop; + &sub-g-ctrl; + &sub-g-dv-preset; + &sub-g-dv-timings; + &sub-g-enc-index; + &sub-g-ext-ctrls; + &sub-g-fbuf; + &sub-g-fmt; + &sub-g-frequency; + &sub-g-input; + &sub-g-jpegcomp; + &sub-g-modulator; + &sub-g-output; + &sub-g-parm; + &sub-g-priority; + &sub-g-selection; + &sub-g-sliced-vbi-cap; + &sub-g-std; + &sub-g-tuner; + &sub-log-status; + &sub-overlay; + &sub-qbuf; + &sub-querybuf; + &sub-querycap; + &sub-queryctrl; + &sub-query-dv-preset; + &sub-querystd; + &sub-prepare-buf; + &sub-reqbufs; + &sub-s-hw-freq-seek; + &sub-streamon; + &sub-subdev-enum-frame-interval; + &sub-subdev-enum-frame-size; + &sub-subdev-enum-mbus-code; + &sub-subdev-g-crop; + &sub-subdev-g-fmt; + &sub-subdev-g-frame-interval; + &sub-subscribe-event; + <!-- End of ioctls. --> + &sub-mmap; + &sub-munmap; + &sub-open; + &sub-poll; + &sub-read; + &sub-select; + &sub-write; + </appendix> + + <appendix id="videodev"> + <title>Video For Linux Two Header File</title> + &sub-videodev2-h; + </appendix> + + <appendix id="capture-example"> + <title>Video Capture Example</title> + &sub-capture-c; + </appendix> + + <appendix id="v4l2grab-example"> + <title>Video Grabber example using libv4l</title> + <para>This program demonstrates how to grab V4L2 images in ppm format by +using libv4l handlers. The advantage is that this grabber can potentially work +with any V4L2 driver.</para> + &sub-v4l2grab-c; + </appendix> + + &sub-media-indices; + + &sub-biblio; + diff --git a/Documentation/DocBook/media/v4l/v4l2grab.c.xml b/Documentation/DocBook/media/v4l/v4l2grab.c.xml new file mode 100644 index 00000000..bed12e40 --- /dev/null +++ b/Documentation/DocBook/media/v4l/v4l2grab.c.xml @@ -0,0 +1,164 @@ +<programlisting> +/* V4L2 video picture grabber + Copyright (C) 2009 Mauro Carvalho Chehab <mchehab@infradead.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <errno.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/mman.h> +#include <linux/videodev2.h> +#include "../libv4l/include/libv4l2.h" + +#define CLEAR(x) memset(&(x), 0, sizeof(x)) + +struct buffer { + void *start; + size_t length; +}; + +static void xioctl(int fh, int request, void *arg) +{ + int r; + + do { + r = v4l2_ioctl(fh, request, arg); + } while (r == -1 && ((errno == EINTR) || (errno == EAGAIN))); + + if (r == -1) { + fprintf(stderr, "error %d, %s\n", errno, strerror(errno)); + exit(EXIT_FAILURE); + } +} + +int main(int argc, char **argv) +{ + struct <link linkend="v4l2-format">v4l2_format</link> fmt; + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req; + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + fd_set fds; + struct timeval tv; + int r, fd = -1; + unsigned int i, n_buffers; + char *dev_name = "/dev/video0"; + char out_name[256]; + FILE *fout; + struct buffer *buffers; + + fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0); + if (fd < 0) { + perror("Cannot open device"); + exit(EXIT_FAILURE); + } + + CLEAR(fmt); + fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + fmt.fmt.pix.width = 640; + fmt.fmt.pix.height = 480; + fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24; + fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; + xioctl(fd, VIDIOC_S_FMT, &fmt); + if (fmt.fmt.pix.pixelformat != V4L2_PIX_FMT_RGB24) { + printf("Libv4l didn't accept RGB24 format. Can't proceed.\n"); + exit(EXIT_FAILURE); + } + if ((fmt.fmt.pix.width != 640) || (fmt.fmt.pix.height != 480)) + printf("Warning: driver is sending image at %dx%d\n", + fmt.fmt.pix.width, fmt.fmt.pix.height); + + CLEAR(req); + req.count = 2; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_MMAP; + xioctl(fd, VIDIOC_REQBUFS, &req); + + buffers = calloc(req.count, sizeof(*buffers)); + for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = n_buffers; + + xioctl(fd, VIDIOC_QUERYBUF, &buf); + + buffers[n_buffers].length = buf.length; + buffers[n_buffers].start = v4l2_mmap(NULL, buf.length, + PROT_READ | PROT_WRITE, MAP_SHARED, + fd, buf.m.offset); + + if (MAP_FAILED == buffers[n_buffers].start) { + perror("mmap"); + exit(EXIT_FAILURE); + } + } + + for (i = 0; i < n_buffers; ++i) { + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = i; + xioctl(fd, VIDIOC_QBUF, &buf); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + + xioctl(fd, VIDIOC_STREAMON, &type); + for (i = 0; i < 20; i++) { + do { + FD_ZERO(&fds); + FD_SET(fd, &fds); + + /* Timeout. */ + tv.tv_sec = 2; + tv.tv_usec = 0; + + r = select(fd + 1, &fds, NULL, NULL, &tv); + } while ((r == -1 && (errno = EINTR))); + if (r == -1) { + perror("select"); + return errno; + } + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + xioctl(fd, VIDIOC_DQBUF, &buf); + + sprintf(out_name, "out%03d.ppm", i); + fout = fopen(out_name, "w"); + if (!fout) { + perror("Cannot open image"); + exit(EXIT_FAILURE); + } + fprintf(fout, "P6\n%d %d 255\n", + fmt.fmt.pix.width, fmt.fmt.pix.height); + fwrite(buffers[buf.index].start, buf.bytesused, 1, fout); + fclose(fout); + + xioctl(fd, VIDIOC_QBUF, &buf); + } + + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + xioctl(fd, VIDIOC_STREAMOFF, &type); + for (i = 0; i < n_buffers; ++i) + v4l2_munmap(buffers[i].start, buffers[i].length); + v4l2_close(fd); + + return 0; +} +</programlisting> diff --git a/Documentation/DocBook/media/v4l/vbi_525.pdf b/Documentation/DocBook/media/v4l/vbi_525.pdf Binary files differnew file mode 100644 index 00000000..9e72c25b --- /dev/null +++ b/Documentation/DocBook/media/v4l/vbi_525.pdf diff --git a/Documentation/DocBook/media/v4l/vbi_625.pdf b/Documentation/DocBook/media/v4l/vbi_625.pdf Binary files differnew file mode 100644 index 00000000..765235e3 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vbi_625.pdf diff --git a/Documentation/DocBook/media/v4l/vbi_hsync.pdf b/Documentation/DocBook/media/v4l/vbi_hsync.pdf Binary files differnew file mode 100644 index 00000000..200b6681 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vbi_hsync.pdf diff --git a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml new file mode 100644 index 00000000..73ae8a6c --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml @@ -0,0 +1,139 @@ +<refentry id="vidioc-create-bufs"> + <refmeta> + <refentrytitle>ioctl VIDIOC_CREATE_BUFS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_CREATE_BUFS</refname> + <refpurpose>Create buffers for Memory Mapped or User Pointer I/O</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_create_buffers *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_CREATE_BUFS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl is used to create buffers for <link linkend="mmap">memory +mapped</link> or <link linkend="userp">user pointer</link> +I/O. It can be used as an alternative or in addition to the +<constant>VIDIOC_REQBUFS</constant> ioctl, when a tighter control over buffers +is required. This ioctl can be called multiple times to create buffers of +different sizes.</para> + + <para>To allocate device buffers applications initialize relevant fields of +the <structname>v4l2_create_buffers</structname> structure. They set the +<structfield>type</structfield> field in the +<structname>v4l2_format</structname> structure, embedded in this +structure, to the respective stream or buffer type. +<structfield>count</structfield> must be set to the number of required buffers. +<structfield>memory</structfield> specifies the required I/O method. The +<structfield>format</structfield> field shall typically be filled in using +either the <constant>VIDIOC_TRY_FMT</constant> or +<constant>VIDIOC_G_FMT</constant> ioctl(). Additionally, applications can adjust +<structfield>sizeimage</structfield> fields to fit their specific needs. The +<structfield>reserved</structfield> array must be zeroed.</para> + + <para>When the ioctl is called with a pointer to this structure the driver +will attempt to allocate up to the requested number of buffers and store the +actual number allocated and the starting index in the +<structfield>count</structfield> and the <structfield>index</structfield> fields +respectively. On return <structfield>count</structfield> can be smaller than +the number requested. The driver may also increase buffer sizes if required, +however, it will not update <structfield>sizeimage</structfield> field values. +The user has to use <constant>VIDIOC_QUERYBUF</constant> to retrieve that +information.</para> + + <table pgwide="1" frame="none" id="v4l2-create-buffers"> + <title>struct <structname>v4l2_create_buffers</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>The starting buffer index, returned by the driver.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>count</structfield></entry> + <entry>The number of buffers requested or granted.</entry> + </row> + <row> + <entry>&v4l2-memory;</entry> + <entry><structfield>memory</structfield></entry> + <entry>Applications set this field to +<constant>V4L2_MEMORY_MMAP</constant> or +<constant>V4L2_MEMORY_USERPTR</constant>.</entry> + </row> + <row> + <entry>&v4l2-format;</entry> + <entry><structfield>format</structfield></entry> + <entry>Filled in by the application, preserved by the driver.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[8]</entry> + <entry>A place holder for future extensions.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>No memory to allocate buffers for <link linkend="mmap">memory +mapped</link> I/O.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer type (<structfield>type</structfield> field) or the +requested I/O method (<structfield>memory</structfield>) is not +supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-cropcap.xml b/Documentation/DocBook/media/v4l/vidioc-cropcap.xml new file mode 100644 index 00000000..b4f2f255 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-cropcap.xml @@ -0,0 +1,165 @@ +<refentry id="vidioc-cropcap"> + <refmeta> + <refentrytitle>ioctl VIDIOC_CROPCAP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_CROPCAP</refname> + <refpurpose>Information about the video cropping and scaling abilities</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_cropcap +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_CROPCAP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Applications use this function to query the cropping +limits, the pixel aspect of images and to calculate scale factors. +They set the <structfield>type</structfield> field of a v4l2_cropcap +structure to the respective buffer (stream) type and call the +<constant>VIDIOC_CROPCAP</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure. The results are +constant except when switching the video standard. Remember this +switch can occur implicit when switching the video input or +output.</para> + + <table pgwide="1" frame="none" id="v4l2-cropcap"> + <title>struct <structname>v4l2_cropcap</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, set by the application. +Only these types are valid here: +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver +defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> +and higher.</entry> + </row> + <row> + <entry>struct <link linkend="v4l2-rect-crop">v4l2_rect</link></entry> + <entry><structfield>bounds</structfield></entry> + <entry>Defines the window within capturing or output is +possible, this may exclude for example the horizontal and vertical +blanking areas. The cropping rectangle cannot exceed these limits. +Width and height are defined in pixels, the driver writer is free to +choose origin and units of the coordinate system in the analog +domain.</entry> + </row> + <row> + <entry>struct <link linkend="v4l2-rect-crop">v4l2_rect</link></entry> + <entry><structfield>defrect</structfield></entry> + <entry>Default cropping rectangle, it shall cover the +"whole picture". Assuming pixel aspect 1/1 this could be for example a +640 × 480 rectangle for NTSC, a +768 × 576 rectangle for PAL and SECAM centered over +the active picture area. The same co-ordinate system as for + <structfield>bounds</structfield> is used.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>pixelaspect</structfield></entry> + <entry><para>This is the pixel aspect (y / x) when no +scaling is applied, the ratio of the actual sampling +frequency and the frequency required to get square +pixels.</para><para>When cropping coordinates refer to square pixels, +the driver sets <structfield>pixelaspect</structfield> to 1/1. Other +common values are 54/59 for PAL and SECAM, 11/10 for NTSC sampled +according to [<xref linkend="itu601" />].</para></entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- NB this table is duplicated in the overlay chapter. --> + + <table pgwide="1" frame="none" id="v4l2-rect-crop"> + <title>struct <structname>v4l2_rect</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__s32</entry> + <entry><structfield>left</structfield></entry> + <entry>Horizontal offset of the top, left corner of the +rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>top</structfield></entry> + <entry>Vertical offset of the top, left corner of the +rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the rectangle, in pixels. Width +and height cannot be negative, the fields are signed for +hysterical reasons. <!-- video4linux-list@redhat.com +on 22 Oct 2002 subject "Re:[V4L][patches!] Re:v4l2/kernel-2.5" --> +</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-cropcap; <structfield>type</structfield> is +invalid. This is not permitted for video capture, output and overlay devices, +which must support <constant>VIDIOC_CROPCAP</constant>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml new file mode 100644 index 00000000..4ecd9668 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml @@ -0,0 +1,266 @@ +<refentry id="vidioc-dbg-g-chip-ident"> + <refmeta> + <refentrytitle>ioctl VIDIOC_DBG_G_CHIP_IDENT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_DBG_G_CHIP_IDENT</refname> + <refpurpose>Identify the chips on a TV card</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dbg_chip_ident +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_DBG_G_CHIP_IDENT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link +linkend="experimental">experimental</link> interface and may change in +the future.</para> + </note> + + <para>For driver debugging purposes this ioctl allows test +applications to query the driver about the chips present on the TV +card. Regular applications must not use it. When you found a chip +specific bug, please contact the linux-media mailing list (&v4l-ml;) +so it can be fixed.</para> + + <para>To query the driver applications must initialize the +<structfield>match.type</structfield> and +<structfield>match.addr</structfield> or <structfield>match.name</structfield> +fields of a &v4l2-dbg-chip-ident; +and call <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> with a pointer to +this structure. On success the driver stores information about the +selected chip in the <structfield>ident</structfield> and +<structfield>revision</structfield> fields. On failure the structure +remains unchanged.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_HOST</constant>, +<structfield>match.addr</structfield> selects the nth non-&i2c; chip +on the TV card. You can enumerate all chips by starting at zero and +incrementing <structfield>match.addr</structfield> by one until +<constant>VIDIOC_DBG_G_CHIP_IDENT</constant> fails with an &EINVAL;. +The number zero always selects the host chip, ⪚ the chip connected +to the PCI or USB bus.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant>, +<structfield>match.name</structfield> contains the I2C driver name. +For instance +<constant>"saa7127"</constant> will match any chip +supported by the saa7127 driver, regardless of its &i2c; bus address. +When multiple chips supported by the same driver are present, the +ioctl will return <constant>V4L2_IDENT_AMBIGUOUS</constant> in the +<structfield>ident</structfield> field.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_ADDR</constant>, +<structfield>match.addr</structfield> selects a chip by its 7 bit +&i2c; bus address.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_AC97</constant>, +<structfield>match.addr</structfield> selects the nth AC97 chip +on the TV card. You can enumerate all chips by starting at zero and +incrementing <structfield>match.addr</structfield> by one until +<constant>VIDIOC_DBG_G_CHIP_IDENT</constant> fails with an &EINVAL;.</para> + + <para>On success, the <structfield>ident</structfield> field will +contain a chip ID from the Linux +<filename>media/v4l2-chip-ident.h</filename> header file, and the +<structfield>revision</structfield> field will contain a driver +specific value, or zero if no particular revision is associated with +this chip.</para> + + <para>When the driver could not identify the selected chip, +<structfield>ident</structfield> will contain +<constant>V4L2_IDENT_UNKNOWN</constant>. When no chip matched +the ioctl will succeed but the +<structfield>ident</structfield> field will contain +<constant>V4L2_IDENT_NONE</constant>. If multiple chips matched, +<structfield>ident</structfield> will contain +<constant>V4L2_IDENT_AMBIGUOUS</constant>. In all these cases the +<structfield>revision</structfield> field remains unchanged.</para> + + <para>This ioctl is optional, not all drivers may support it. It +was introduced in Linux 2.6.21, but the API was changed to the +one described here in 2.6.29.</para> + + <para>We recommended the <application>v4l2-dbg</application> +utility over calling this ioctl directly. It is available from the +LinuxTV v4l-dvb repository; see <ulink +url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for +access instructions.</para> + + <!-- Note for convenience vidioc-dbg-g-register.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="ident-v4l2-dbg-match"> + <title>struct <structname>v4l2_dbg_match</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>See <xref linkend="ident-chip-match-types" /> for a list of +possible types.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>addr</structfield></entry> + <entry>Match a chip by this number, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + <row> + <entry></entry> + <entry>char</entry> + <entry><structfield>name[32]</structfield></entry> + <entry>Match a chip by this name, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-dbg-chip-ident"> + <title>struct <structname>v4l2_dbg_chip_ident</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>struct v4l2_dbg_match</entry> + <entry><structfield>match</structfield></entry> + <entry>How to match the chip, see <xref linkend="ident-v4l2-dbg-match" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>ident</structfield></entry> + <entry>A chip identifier as defined in the Linux +<filename>media/v4l2-chip-ident.h</filename> header file, or one of +the values from <xref linkend="chip-ids" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>revision</structfield></entry> + <entry>A chip revision, chip and driver specific.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Note for convenience vidioc-dbg-g-register.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="ident-chip-match-types"> + <title>Chip Match Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CHIP_MATCH_HOST</constant></entry> + <entry>0</entry> + <entry>Match the nth chip on the card, zero for the + host chip. Does not match &i2c; chips.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant></entry> + <entry>1</entry> + <entry>Match an &i2c; chip by its driver name.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_ADDR</constant></entry> + <entry>2</entry> + <entry>Match a chip by its 7 bit &i2c; bus address.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry> + <entry>3</entry> + <entry>Match the nth anciliary AC97 chip.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- This is an anonymous enum in media/v4l2-chip-ident.h. --> + <table pgwide="1" frame="none" id="chip-ids"> + <title>Chip Identifiers</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_IDENT_NONE</constant></entry> + <entry>0</entry> + <entry>No chip matched.</entry> + </row> + <row> + <entry><constant>V4L2_IDENT_AMBIGUOUS</constant></entry> + <entry>1</entry> + <entry>Multiple chips matched.</entry> + </row> + <row> + <entry><constant>V4L2_IDENT_UNKNOWN</constant></entry> + <entry>2</entry> + <entry>A chip is present at this address, but the driver +could not identify it.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>match_type</structfield> is invalid.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml b/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml new file mode 100644 index 00000000..a44aebc7 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml @@ -0,0 +1,258 @@ +<refentry id="vidioc-dbg-g-register"> + <refmeta> + <refentrytitle>ioctl VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_DBG_G_REGISTER</refname> + <refname>VIDIOC_DBG_S_REGISTER</refname> + <refpurpose>Read or write hardware registers</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dbg_register *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_dbg_register +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>For driver debugging purposes these ioctls allow test +applications to access hardware registers directly. Regular +applications must not use them.</para> + + <para>Since writing or even reading registers can jeopardize the +system security, its stability and damage the hardware, both ioctls +require superuser privileges. Additionally the Linux kernel must be +compiled with the <constant>CONFIG_VIDEO_ADV_DEBUG</constant> option +to enable these ioctls.</para> + + <para>To write a register applications must initialize all fields +of a &v4l2-dbg-register; and call +<constant>VIDIOC_DBG_S_REGISTER</constant> with a pointer to this +structure. The <structfield>match.type</structfield> and +<structfield>match.addr</structfield> or <structfield>match.name</structfield> +fields select a chip on the TV +card, the <structfield>reg</structfield> field specifies a register +number and the <structfield>val</structfield> field the value to be +written into the register.</para> + + <para>To read a register applications must initialize the +<structfield>match.type</structfield>, +<structfield>match.chip</structfield> or <structfield>match.name</structfield> and +<structfield>reg</structfield> fields, and call +<constant>VIDIOC_DBG_G_REGISTER</constant> with a pointer to this +structure. On success the driver stores the register value in the +<structfield>val</structfield> field. On failure the structure remains +unchanged.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_HOST</constant>, +<structfield>match.addr</structfield> selects the nth non-&i2c; chip +on the TV card. The number zero always selects the host chip, ⪚ the +chip connected to the PCI or USB bus. You can find out which chips are +present with the &VIDIOC-DBG-G-CHIP-IDENT; ioctl.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant>, +<structfield>match.name</structfield> contains the I2C driver name. +For instance +<constant>"saa7127"</constant> will match any chip +supported by the saa7127 driver, regardless of its &i2c; bus address. +When multiple chips supported by the same driver are present, the +effect of these ioctls is undefined. Again with the +&VIDIOC-DBG-G-CHIP-IDENT; ioctl you can find out which &i2c; chips are +present.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_ADDR</constant>, +<structfield>match.addr</structfield> selects a chip by its 7 bit &i2c; +bus address.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_AC97</constant>, +<structfield>match.addr</structfield> selects the nth AC97 chip +on the TV card.</para> + + <note> + <title>Success not guaranteed</title> + + <para>Due to a flaw in the Linux &i2c; bus driver these ioctls may +return successfully without actually reading or writing a register. To +catch the most likely failure we recommend a &VIDIOC-DBG-G-CHIP-IDENT; +call confirming the presence of the selected &i2c; chip.</para> + </note> + + <para>These ioctls are optional, not all drivers may support them. +However when a driver supports these ioctls it must also support +&VIDIOC-DBG-G-CHIP-IDENT;. Conversely it may support +<constant>VIDIOC_DBG_G_CHIP_IDENT</constant> but not these ioctls.</para> + + <para><constant>VIDIOC_DBG_G_REGISTER</constant> and +<constant>VIDIOC_DBG_S_REGISTER</constant> were introduced in Linux +2.6.21, but their API was changed to the one described here in kernel 2.6.29.</para> + + <para>We recommended the <application>v4l2-dbg</application> +utility over calling these ioctls directly. It is available from the +LinuxTV v4l-dvb repository; see <ulink +url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for +access instructions.</para> + + <!-- Note for convenience vidioc-dbg-g-chip-ident.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="v4l2-dbg-match"> + <title>struct <structname>v4l2_dbg_match</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>See <xref linkend="ident-chip-match-types" /> for a list of +possible types.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>addr</structfield></entry> + <entry>Match a chip by this number, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + <row> + <entry></entry> + <entry>char</entry> + <entry><structfield>name[32]</structfield></entry> + <entry>Match a chip by this name, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + </tbody> + </tgroup> + </table> + + + <table pgwide="1" frame="none" id="v4l2-dbg-register"> + <title>struct <structname>v4l2_dbg_register</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>struct v4l2_dbg_match</entry> + <entry><structfield>match</structfield></entry> + <entry>How to match the chip, see <xref linkend="v4l2-dbg-match" />.</entry> + </row> + <row> + <entry>__u64</entry> + <entry><structfield>reg</structfield></entry> + <entry>A register number.</entry> + </row> + <row> + <entry>__u64</entry> + <entry><structfield>val</structfield></entry> + <entry>The value read from, or to be written into the +register.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Note for convenience vidioc-dbg-g-chip-ident.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="chip-match-types"> + <title>Chip Match Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CHIP_MATCH_HOST</constant></entry> + <entry>0</entry> + <entry>Match the nth chip on the card, zero for the + host chip. Does not match &i2c; chips.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant></entry> + <entry>1</entry> + <entry>Match an &i2c; chip by its driver name.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_ADDR</constant></entry> + <entry>2</entry> + <entry>Match a chip by its 7 bit &i2c; bus address.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry> + <entry>3</entry> + <entry>Match the nth anciliary AC97 chip.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EPERM</errorcode></term> + <listitem> + <para>Insufficient permissions. Root privileges are required +to execute these ioctls.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml new file mode 100644 index 00000000..74b87f6e --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml @@ -0,0 +1,256 @@ +<refentry id="vidioc-decoder-cmd"> + <refmeta> + <refentrytitle>ioctl VIDIOC_DECODER_CMD, VIDIOC_TRY_DECODER_CMD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_DECODER_CMD</refname> + <refname>VIDIOC_TRY_DECODER_CMD</refname> + <refpurpose>Execute an decoder command</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_decoder_cmd *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_DECODER_CMD, VIDIOC_TRY_DECODER_CMD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>These ioctls control an audio/video (usually MPEG-) decoder. +<constant>VIDIOC_DECODER_CMD</constant> sends a command to the +decoder, <constant>VIDIOC_TRY_DECODER_CMD</constant> can be used to +try a command without actually executing it. To send a command applications +must initialize all fields of a &v4l2-decoder-cmd; and call +<constant>VIDIOC_DECODER_CMD</constant> or <constant>VIDIOC_TRY_DECODER_CMD</constant> +with a pointer to this structure.</para> + + <para>The <structfield>cmd</structfield> field must contain the +command code. Some commands use the <structfield>flags</structfield> field for +additional information. +</para> + + <para>A <function>write</function>() or &VIDIOC-STREAMON; call sends an implicit +START command to the decoder if it has not been started yet. +</para> + + <para>A <function>close</function>() or &VIDIOC-STREAMOFF; call of a streaming +file descriptor sends an implicit immediate STOP command to the decoder, and all +buffered data is discarded.</para> + + <para>These ioctls are optional, not all drivers may support +them. They were introduced in Linux 3.3.</para> + + <table pgwide="1" frame="none" id="v4l2-decoder-cmd"> + <title>struct <structname>v4l2_decoder_cmd</structname></title> + <tgroup cols="5"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>cmd</structfield></entry> + <entry></entry> + <entry></entry> + <entry>The decoder command, see <xref linkend="decoder-cmds" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Flags to go with the command. If no flags are defined for +this command, drivers and applications must set this field to zero.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + <entry></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>start</structfield></entry> + <entry></entry> + <entry>Structure containing additional data for the +<constant>V4L2_DEC_CMD_START</constant> command.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__s32</entry> + <entry><structfield>speed</structfield></entry> + <entry>Playback speed and direction. The playback speed is defined as +<structfield>speed</structfield>/1000 of the normal speed. So 1000 is normal playback. +Negative numbers denote reverse playback, so -1000 does reverse playback at normal +speed. Speeds -1, 0 and 1 have special meanings: speed 0 is shorthand for 1000 +(normal playback). A speed of 1 steps just one frame forward, a speed of -1 steps +just one frame back. + </entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>format</structfield></entry> + <entry>Format restrictions. This field is set by the driver, not the +application. Possible values are <constant>V4L2_DEC_START_FMT_NONE</constant> if +there are no format restrictions or <constant>V4L2_DEC_START_FMT_GOP</constant> +if the decoder operates on full GOPs (<wordasword>Group Of Pictures</wordasword>). +This is usually the case for reverse playback: the decoder needs full GOPs, which +it can then play in reverse order. So to implement reverse playback the application +must feed the decoder the last GOP in the video file, then the GOP before that, etc. etc. + </entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>stop</structfield></entry> + <entry></entry> + <entry>Structure containing additional data for the +<constant>V4L2_DEC_CMD_STOP</constant> command.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u64</entry> + <entry><structfield>pts</structfield></entry> + <entry>Stop playback at this <structfield>pts</structfield> or immediately +if the playback is already past that timestamp. Leave to 0 if you want to stop after the +last frame was decoded. + </entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>raw</structfield></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>data</structfield>[16]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="decoder-cmds"> + <title>Decoder Commands</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_DEC_CMD_START</constant></entry> + <entry>0</entry> + <entry>Start the decoder. When the decoder is already +running or paused, this command will just change the playback speed. +That means that calling <constant>V4L2_DEC_CMD_START</constant> when +the decoder was paused will <emphasis>not</emphasis> resume the decoder. +You have to explicitly call <constant>V4L2_DEC_CMD_RESUME</constant> for that. +This command has one flag: +<constant>V4L2_DEC_CMD_START_MUTE_AUDIO</constant>. If set, then audio will +be muted when playing back at a non-standard speed. + </entry> + </row> + <row> + <entry><constant>V4L2_DEC_CMD_STOP</constant></entry> + <entry>1</entry> + <entry>Stop the decoder. When the decoder is already stopped, +this command does nothing. This command has two flags: +if <constant>V4L2_DEC_CMD_STOP_TO_BLACK</constant> is set, then the decoder will +set the picture to black after it stopped decoding. Otherwise the last image will +repeat. If <constant>V4L2_DEC_CMD_STOP_IMMEDIATELY</constant> is set, then the decoder +stops immediately (ignoring the <structfield>pts</structfield> value), otherwise it +will keep decoding until timestamp >= pts or until the last of the pending data from +its internal buffers was decoded. +</entry> + </row> + <row> + <entry><constant>V4L2_DEC_CMD_PAUSE</constant></entry> + <entry>2</entry> + <entry>Pause the decoder. When the decoder has not been +started yet, the driver will return an &EPERM;. When the decoder is +already paused, this command does nothing. This command has one flag: +if <constant>V4L2_DEC_CMD_PAUSE_TO_BLACK</constant> is set, then set the +decoder output to black when paused. +</entry> + </row> + <row> + <entry><constant>V4L2_DEC_CMD_RESUME</constant></entry> + <entry>3</entry> + <entry>Resume decoding after a PAUSE command. When the +decoder has not been started yet, the driver will return an &EPERM;. +When the decoder is already running, this command does nothing. No +flags are defined for this command.</entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>cmd</structfield> field is invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EPERM</errorcode></term> + <listitem> + <para>The application sent a PAUSE or RESUME command when +the decoder was not running.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml new file mode 100644 index 00000000..e8714aa1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml @@ -0,0 +1,271 @@ +<refentry id="vidioc-dqevent"> + <refmeta> + <refentrytitle>ioctl VIDIOC_DQEVENT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_DQEVENT</refname> + <refpurpose>Dequeue event</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_event +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_DQEVENT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Dequeue an event from a video device. No input is required + for this ioctl. All the fields of the &v4l2-event; structure are + filled by the driver. The file handle will also receive exceptions + which the application may get by e.g. using the select system + call.</para> + + <table frame="none" pgwide="1" id="v4l2-event"> + <title>struct <structname>v4l2_event</structname></title> + <tgroup cols="4"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>Type of the event.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>u</structfield></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-event-vsync;</entry> + <entry><structfield>vsync</structfield></entry> + <entry>Event data for event V4L2_EVENT_VSYNC. + </entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-event-ctrl;</entry> + <entry><structfield>ctrl</structfield></entry> + <entry>Event data for event V4L2_EVENT_CTRL. + </entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-event-frame-sync;</entry> + <entry><structfield>frame</structfield></entry> + <entry>Event data for event V4L2_EVENT_FRAME_SYNC.</entry> + </row> + <row> + <entry></entry> + <entry>__u8</entry> + <entry><structfield>data</structfield>[64]</entry> + <entry>Event data. Defined by the event type. The union + should be used to define easily accessible type for + events.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pending</structfield></entry> + <entry></entry> + <entry>Number of pending events excluding this one.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>sequence</structfield></entry> + <entry></entry> + <entry>Event sequence number. The sequence number is + incremented for every subscribed event that takes place. + If sequence numbers are not contiguous it means that + events have been lost. + </entry> + </row> + <row> + <entry>struct timespec</entry> + <entry><structfield>timestamp</structfield></entry> + <entry></entry> + <entry>Event timestamp.</entry> + </row> + <row> + <entry>u32</entry> + <entry><structfield>id</structfield></entry> + <entry></entry> + <entry>The ID associated with the event source. If the event does not + have an associated ID (this depends on the event type), then this + is 0.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[8]</entry> + <entry></entry> + <entry>Reserved for future extensions. Drivers must set + the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-event-vsync"> + <title>struct <structname>v4l2_event_vsync</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>field</structfield></entry> + <entry>The upcoming field. See &v4l2-field;.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-event-ctrl"> + <title>struct <structname>v4l2_event_ctrl</structname></title> + <tgroup cols="4"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>changes</structfield></entry> + <entry></entry> + <entry>A bitmask that tells what has changed. See <xref linkend="changes-flags" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>The type of the control. See &v4l2-ctrl-type;.</entry> + </row> + <row> + <entry>union (anonymous)</entry> + <entry></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>__s32</entry> + <entry><structfield>value</structfield></entry> + <entry>The 32-bit value of the control for 32-bit control types. + This is 0 for string controls since the value of a string + cannot be passed using &VIDIOC-DQEVENT;.</entry> + </row> + <row> + <entry></entry> + <entry>__s64</entry> + <entry><structfield>value64</structfield></entry> + <entry>The 64-bit value of the control for 64-bit control types.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry>The control flags. See <xref linkend="control-flags" />.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>minimum</structfield></entry> + <entry></entry> + <entry>The minimum value of the control. See &v4l2-queryctrl;.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>maximum</structfield></entry> + <entry></entry> + <entry>The maximum value of the control. See &v4l2-queryctrl;.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>step</structfield></entry> + <entry></entry> + <entry>The step value of the control. See &v4l2-queryctrl;.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>default_value</structfield></entry> + <entry></entry> + <entry>The default value value of the control. See &v4l2-queryctrl;.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-event-frame-sync"> + <title>struct <structname>v4l2_event_frame_sync</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>frame_sequence</structfield></entry> + <entry> + The sequence number of the frame being received. + </entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="changes-flags"> + <title>Changes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_EVENT_CTRL_CH_VALUE</constant></entry> + <entry>0x0001</entry> + <entry>This control event was triggered because the value of the control + changed. Special case: if a button control is pressed, then this + event is sent as well, even though there is not explicit value + associated with a button control.</entry> + </row> + <row> + <entry><constant>V4L2_EVENT_CTRL_CH_FLAGS</constant></entry> + <entry>0x0002</entry> + <entry>This control event was triggered because the control flags + changed.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml new file mode 100644 index 00000000..f431b3ba --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml @@ -0,0 +1,196 @@ +<refentry id="vidioc-encoder-cmd"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENCODER_CMD</refname> + <refname>VIDIOC_TRY_ENCODER_CMD</refname> + <refpurpose>Execute an encoder command</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_encoder_cmd *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>These ioctls control an audio/video (usually MPEG-) encoder. +<constant>VIDIOC_ENCODER_CMD</constant> sends a command to the +encoder, <constant>VIDIOC_TRY_ENCODER_CMD</constant> can be used to +try a command without actually executing it.</para> + + <para>To send a command applications must initialize all fields of a + &v4l2-encoder-cmd; and call + <constant>VIDIOC_ENCODER_CMD</constant> or + <constant>VIDIOC_TRY_ENCODER_CMD</constant> with a pointer to this + structure.</para> + + <para>The <structfield>cmd</structfield> field must contain the +command code. The <structfield>flags</structfield> field is currently +only used by the STOP command and contains one bit: If the +<constant>V4L2_ENC_CMD_STOP_AT_GOP_END</constant> flag is set, +encoding will continue until the end of the current <wordasword>Group +Of Pictures</wordasword>, otherwise it will stop immediately.</para> + + <para>A <function>read</function>() or &VIDIOC-STREAMON; call sends an implicit +START command to the encoder if it has not been started yet. After a STOP command, +<function>read</function>() calls will read the remaining data +buffered by the driver. When the buffer is empty, +<function>read</function>() will return zero and the next +<function>read</function>() call will restart the encoder.</para> + + <para>A <function>close</function>() or &VIDIOC-STREAMOFF; call of a streaming +file descriptor sends an implicit immediate STOP to the encoder, and all buffered +data is discarded.</para> + + <para>These ioctls are optional, not all drivers may support +them. They were introduced in Linux 2.6.21.</para> + + <table pgwide="1" frame="none" id="v4l2-encoder-cmd"> + <title>struct <structname>v4l2_encoder_cmd</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>cmd</structfield></entry> + <entry>The encoder command, see <xref linkend="encoder-cmds" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Flags to go with the command, see <xref + linkend="encoder-flags" />. If no flags are defined for +this command, drivers and applications must set this field to +zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>data</structfield>[8]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="encoder-cmds"> + <title>Encoder Commands</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_ENC_CMD_START</constant></entry> + <entry>0</entry> + <entry>Start the encoder. When the encoder is already +running or paused, this command does nothing. No flags are defined for +this command.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_CMD_STOP</constant></entry> + <entry>1</entry> + <entry>Stop the encoder. When the +<constant>V4L2_ENC_CMD_STOP_AT_GOP_END</constant> flag is set, +encoding will continue until the end of the current <wordasword>Group +Of Pictures</wordasword>, otherwise encoding will stop immediately. +When the encoder is already stopped, this command does +nothing.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_CMD_PAUSE</constant></entry> + <entry>2</entry> + <entry>Pause the encoder. When the encoder has not been +started yet, the driver will return an &EPERM;. When the encoder is +already paused, this command does nothing. No flags are defined for +this command.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_CMD_RESUME</constant></entry> + <entry>3</entry> + <entry>Resume encoding after a PAUSE command. When the +encoder has not been started yet, the driver will return an &EPERM;. +When the encoder is already running, this command does nothing. No +flags are defined for this command.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="encoder-flags"> + <title>Encoder Command Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_ENC_CMD_STOP_AT_GOP_END</constant></entry> + <entry>0x0001</entry> + <entry>Stop encoding at the end of the current <wordasword>Group Of +Pictures</wordasword>, rather than immediately.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>cmd</structfield> field is invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EPERM</errorcode></term> + <listitem> + <para>The application sent a PAUSE or RESUME command when +the encoder was not running.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml b/Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml new file mode 100644 index 00000000..0be17c23 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml @@ -0,0 +1,230 @@ +<refentry id="vidioc-enum-dv-presets"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUM_DV_PRESETS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUM_DV_PRESETS</refname> + <refpurpose>Enumerate supported Digital Video presets</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dv_enum_preset *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUM_DV_PRESETS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a DV preset, applications initialize the +<structfield>index</structfield> field and zero the reserved array of &v4l2-dv-enum-preset; +and call the <constant>VIDIOC_ENUM_DV_PRESETS</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all DV Presets supported, +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>. Drivers may enumerate a +different set of DV presets after switching the video input or +output.</para> + + <table pgwide="1" frame="none" id="v4l2-dv-enum-preset"> + <title>struct <structname>v4l2_dv_enum_presets</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the DV preset, set by the +application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>preset</structfield></entry> + <entry>This field identifies one of the DV preset values listed in <xref linkend="v4l2-dv-presets-vals"/>.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[24]</entry> + <entry>Name of the preset, a NUL-terminated ASCII string, for example: "720P-60", "1080I-60". This information is +intended for the user.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the active video in pixels for the DV preset.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the active video in lines for the DV preset.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-dv-presets-vals"> + <title>struct <structname>DV Presets</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>Preset</entry> + <entry>Preset value</entry> + <entry>Description</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry>V4L2_DV_INVALID</entry> + <entry>0</entry> + <entry>Invalid preset value.</entry> + </row> + <row> + <entry>V4L2_DV_480P59_94</entry> + <entry>1</entry> + <entry>720x480 progressive video at 59.94 fps as per BT.1362.</entry> + </row> + <row> + <entry>V4L2_DV_576P50</entry> + <entry>2</entry> + <entry>720x576 progressive video at 50 fps as per BT.1362.</entry> + </row> + <row> + <entry>V4L2_DV_720P24</entry> + <entry>3</entry> + <entry>1280x720 progressive video at 24 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_720P25</entry> + <entry>4</entry> + <entry>1280x720 progressive video at 25 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_720P30</entry> + <entry>5</entry> + <entry>1280x720 progressive video at 30 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_720P50</entry> + <entry>6</entry> + <entry>1280x720 progressive video at 50 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_720P59_94</entry> + <entry>7</entry> + <entry>1280x720 progressive video at 59.94 fps as per SMPTE 274M.</entry> + </row> + <row> + <entry>V4L2_DV_720P60</entry> + <entry>8</entry> + <entry>1280x720 progressive video at 60 fps as per SMPTE 274M/296M.</entry> + </row> + <row> + <entry>V4L2_DV_1080I29_97</entry> + <entry>9</entry> + <entry>1920x1080 interlaced video at 29.97 fps as per BT.1120/SMPTE 274M.</entry> + </row> + <row> + <entry>V4L2_DV_1080I30</entry> + <entry>10</entry> + <entry>1920x1080 interlaced video at 30 fps as per BT.1120/SMPTE 274M.</entry> + </row> + <row> + <entry>V4L2_DV_1080I25</entry> + <entry>11</entry> + <entry>1920x1080 interlaced video at 25 fps as per BT.1120.</entry> + </row> + <row> + <entry>V4L2_DV_1080I50</entry> + <entry>12</entry> + <entry>1920x1080 interlaced video at 50 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_1080I60</entry> + <entry>13</entry> + <entry>1920x1080 interlaced video at 60 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_1080P24</entry> + <entry>14</entry> + <entry>1920x1080 progressive video at 24 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_1080P25</entry> + <entry>15</entry> + <entry>1920x1080 progressive video at 25 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_1080P30</entry> + <entry>16</entry> + <entry>1920x1080 progressive video at 30 fps as per SMPTE 296M.</entry> + </row> + <row> + <entry>V4L2_DV_1080P50</entry> + <entry>17</entry> + <entry>1920x1080 progressive video at 50 fps as per BT.1120.</entry> + </row> + <row> + <entry>V4L2_DV_1080P60</entry> + <entry>18</entry> + <entry>1920x1080 progressive video at 60 fps as per BT.1120.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-dv-enum-preset; <structfield>index</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml new file mode 100644 index 00000000..347d142e --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml @@ -0,0 +1,158 @@ +<refentry id="vidioc-enum-fmt"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUM_FMT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUM_FMT</refname> + <refpurpose>Enumerate image formats</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_fmtdesc +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUM_FMT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To enumerate image formats applications initialize the +<structfield>type</structfield> and <structfield>index</structfield> +field of &v4l2-fmtdesc; and call the +<constant>VIDIOC_ENUM_FMT</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL;. All formats are enumerable by beginning at index zero and +incrementing by one until <errorcode>EINVAL</errorcode> is +returned.</para> + + <table pgwide="1" frame="none" id="v4l2-fmtdesc"> + <title>struct <structname>v4l2_fmtdesc</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the format in the enumeration, set by +the application. This is in no way related to the <structfield> +pixelformat</structfield> field.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, set by the application. +Only these types are valid here: +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver +defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> +and higher.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>See <xref linkend="fmtdesc-flags" /></entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>description</structfield>[32]</entry> + <entry>Description of the format, a NUL-terminated ASCII +string. This information is intended for the user, for example: "YUV +4:2:2".</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry>The image format identifier. This is a +four character code as computed by the v4l2_fourcc() +macro:</entry> + </row> + <row> + <entry spanname="hspan"><para><programlisting id="v4l2-fourcc"> +#define v4l2_fourcc(a,b,c,d) (((__u32)(a)<<0)|((__u32)(b)<<8)|((__u32)(c)<<16)|((__u32)(d)<<24)) +</programlisting></para><para>Several image formats are already +defined by this specification in <xref linkend="pixfmt" />. Note these +codes are not the same as those used in the Windows world.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="fmtdesc-flags"> + <title>Image Format Description Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FMT_FLAG_COMPRESSED</constant></entry> + <entry>0x0001</entry> + <entry>This is a compressed format.</entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_EMULATED</constant></entry> + <entry>0x0002</entry> + <entry>This format is not native to the device but emulated +through software (usually libv4l2), where possible try to use a native format +instead for better performance.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-fmtdesc; <structfield>type</structfield> +is not supported or the <structfield>index</structfield> is out of +bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml b/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml new file mode 100644 index 00000000..5fd72c4c --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml @@ -0,0 +1,259 @@ +<refentry id="vidioc-enum-frameintervals"> + + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUM_FRAMEINTERVALS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUM_FRAMEINTERVALS</refname> + <refpurpose>Enumerate frame intervals</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_frmivalenum *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUM_FRAMEINTERVALS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a &v4l2-frmivalenum; structure that +contains a pixel format and size and receives a frame interval.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl allows applications to enumerate all frame +intervals that the device supports for the given pixel format and +frame size.</para> + <para>The supported pixel formats and frame sizes can be obtained +by using the &VIDIOC-ENUM-FMT; and &VIDIOC-ENUM-FRAMESIZES; +functions.</para> + <para>The return value and the content of the +<structfield>v4l2_frmivalenum.type</structfield> field depend on the +type of frame intervals the device supports. Here are the semantics of +the function for the different cases:</para> + <itemizedlist> + <listitem> + <para><emphasis role="bold">Discrete:</emphasis> The function +returns success if the given index value (zero-based) is valid. The +application should increase the index by one for each call until +<constant>EINVAL</constant> is returned. The `v4l2_frmivalenum.type` +field is set to `V4L2_FRMIVAL_TYPE_DISCRETE` by the driver. Of the +union only the `discrete` member is valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Step-wise:</emphasis> The function +returns success if the given index value is zero and +<constant>EINVAL</constant> for any other index value. The +<structfield>v4l2_frmivalenum.type</structfield> field is set to +<constant>V4L2_FRMIVAL_TYPE_STEPWISE</constant> by the driver. Of the +union only the <structfield>stepwise</structfield> member is +valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Continuous:</emphasis> This is a +special case of the step-wise type above. The function returns success +if the given index value is zero and <constant>EINVAL</constant> for +any other index value. The +<structfield>v4l2_frmivalenum.type</structfield> field is set to +<constant>V4L2_FRMIVAL_TYPE_CONTINUOUS</constant> by the driver. Of +the union only the <structfield>stepwise</structfield> member is valid +and the <structfield>step</structfield> value is set to 1.</para> + </listitem> + </itemizedlist> + + <para>When the application calls the function with index zero, it +must check the <structfield>type</structfield> field to determine the +type of frame interval enumeration the device supports. Only for the +<constant>V4L2_FRMIVAL_TYPE_DISCRETE</constant> type does it make +sense to increase the index value to receive more frame +intervals.</para> + <para>Note that the order in which the frame intervals are +returned has no special meaning. In particular does it not say +anything about potential default frame intervals.</para> + <para>Applications can assume that the enumeration data does not +change without any interaction from the application itself. This means +that the enumeration data is consistent if the application does not +perform any other ioctl calls while it runs the frame interval +enumeration.</para> + </refsect1> + + <refsect1> + <title>Notes</title> + + <itemizedlist> + <listitem> + <para><emphasis role="bold">Frame intervals and frame +rates:</emphasis> The V4L2 API uses frame intervals instead of frame +rates. Given the frame interval the frame rate can be computed as +follows:<screen>frame_rate = 1 / frame_interval</screen></para> + </listitem> + </itemizedlist> + + </refsect1> + + <refsect1> + <title>Structs</title> + + <para>In the structs below, <emphasis>IN</emphasis> denotes a +value that has to be filled in by the application, +<emphasis>OUT</emphasis> denotes values that the driver fills in. The +application should zero out all members except for the +<emphasis>IN</emphasis> fields.</para> + + <table pgwide="1" frame="none" id="v4l2-frmival-stepwise"> + <title>struct <structname>v4l2_frmival_stepwise</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>min</structfield></entry> + <entry>Minimum frame interval [s].</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>max</structfield></entry> + <entry>Maximum frame interval [s].</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>step</structfield></entry> + <entry>Frame interval step size [s].</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-frmivalenum"> + <title>struct <structname>v4l2_frmivalenum</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry></entry> + <entry>IN: Index of the given frame interval in the +enumeration.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixel_format</structfield></entry> + <entry></entry> + <entry>IN: Pixel format for which the frame intervals are +enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry></entry> + <entry>IN: Frame width for which the frame intervals are +enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry></entry> + <entry>IN: Frame height for which the frame intervals are +enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>OUT: Frame interval type the device supports.</entry> + </row> + <row> + <entry>union</entry> + <entry></entry> + <entry></entry> + <entry>OUT: Frame interval with the given index.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-fract;</entry> + <entry><structfield>discrete</structfield></entry> + <entry>Frame interval [s].</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-frmival-stepwise;</entry> + <entry><structfield>stepwise</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[2]</structfield></entry> + <entry></entry> + <entry>Reserved space for future use.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + <title>Enums</title> + + <table pgwide="1" frame="none" id="v4l2-frmivaltypes"> + <title>enum <structname>v4l2_frmivaltypes</structname></title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FRMIVAL_TYPE_DISCRETE</constant></entry> + <entry>1</entry> + <entry>Discrete frame interval.</entry> + </row> + <row> + <entry><constant>V4L2_FRMIVAL_TYPE_CONTINUOUS</constant></entry> + <entry>2</entry> + <entry>Continuous frame interval.</entry> + </row> + <row> + <entry><constant>V4L2_FRMIVAL_TYPE_STEPWISE</constant></entry> + <entry>3</entry> + <entry>Step-wise defined frame interval.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + </refsect1> + +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml b/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml new file mode 100644 index 00000000..f77a13f4 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml @@ -0,0 +1,271 @@ +<refentry id="vidioc-enum-framesizes"> + + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUM_FRAMESIZES</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUM_FRAMESIZES</refname> + <refpurpose>Enumerate frame sizes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_frmsizeenum *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUM_FRAMESIZES</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a &v4l2-frmsizeenum; that contains an index +and pixel format and receives a frame width and height.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>This ioctl allows applications to enumerate all frame sizes +(&ie; width and height in pixels) that the device supports for the +given pixel format.</para> + <para>The supported pixel formats can be obtained by using the +&VIDIOC-ENUM-FMT; function.</para> + <para>The return value and the content of the +<structfield>v4l2_frmsizeenum.type</structfield> field depend on the +type of frame sizes the device supports. Here are the semantics of the +function for the different cases:</para> + + <itemizedlist> + <listitem> + <para><emphasis role="bold">Discrete:</emphasis> The function +returns success if the given index value (zero-based) is valid. The +application should increase the index by one for each call until +<constant>EINVAL</constant> is returned. The +<structfield>v4l2_frmsizeenum.type</structfield> field is set to +<constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant> by the driver. Of the +union only the <structfield>discrete</structfield> member is +valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Step-wise:</emphasis> The function +returns success if the given index value is zero and +<constant>EINVAL</constant> for any other index value. The +<structfield>v4l2_frmsizeenum.type</structfield> field is set to +<constant>V4L2_FRMSIZE_TYPE_STEPWISE</constant> by the driver. Of the +union only the <structfield>stepwise</structfield> member is +valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Continuous:</emphasis> This is a +special case of the step-wise type above. The function returns success +if the given index value is zero and <constant>EINVAL</constant> for +any other index value. The +<structfield>v4l2_frmsizeenum.type</structfield> field is set to +<constant>V4L2_FRMSIZE_TYPE_CONTINUOUS</constant> by the driver. Of +the union only the <structfield>stepwise</structfield> member is valid +and the <structfield>step_width</structfield> and +<structfield>step_height</structfield> values are set to 1.</para> + </listitem> + </itemizedlist> + + <para>When the application calls the function with index zero, it +must check the <structfield>type</structfield> field to determine the +type of frame size enumeration the device supports. Only for the +<constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant> type does it make +sense to increase the index value to receive more frame sizes.</para> + <para>Note that the order in which the frame sizes are returned +has no special meaning. In particular does it not say anything about +potential default format sizes.</para> + <para>Applications can assume that the enumeration data does not +change without any interaction from the application itself. This means +that the enumeration data is consistent if the application does not +perform any other ioctl calls while it runs the frame size +enumeration.</para> + </refsect1> + + <refsect1> + <title>Structs</title> + + <para>In the structs below, <emphasis>IN</emphasis> denotes a +value that has to be filled in by the application, +<emphasis>OUT</emphasis> denotes values that the driver fills in. The +application should zero out all members except for the +<emphasis>IN</emphasis> fields.</para> + + <table pgwide="1" frame="none" id="v4l2-frmsize-discrete"> + <title>struct <structname>v4l2_frmsize_discrete</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the frame [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the frame [pixel].</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-frmsize-stepwise"> + <title>struct <structname>v4l2_frmsize_stepwise</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>min_width</structfield></entry> + <entry>Minimum frame width [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_width</structfield></entry> + <entry>Maximum frame width [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>step_width</structfield></entry> + <entry>Frame width step size [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>min_height</structfield></entry> + <entry>Minimum frame height [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_height</structfield></entry> + <entry>Maximum frame height [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>step_height</structfield></entry> + <entry>Frame height step size [pixel].</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-frmsizeenum"> + <title>struct <structname>v4l2_frmsizeenum</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry></entry> + <entry>IN: Index of the given frame size in the enumeration.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixel_format</structfield></entry> + <entry></entry> + <entry>IN: Pixel format for which the frame sizes are enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>OUT: Frame size type the device supports.</entry> + </row> + <row> + <entry>union</entry> + <entry></entry> + <entry></entry> + <entry>OUT: Frame size with the given index.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-frmsize-discrete;</entry> + <entry><structfield>discrete</structfield></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-frmsize-stepwise;</entry> + <entry><structfield>stepwise</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[2]</structfield></entry> + <entry></entry> + <entry>Reserved space for future use.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + <title>Enums</title> + + <table pgwide="1" frame="none" id="v4l2-frmsizetypes"> + <title>enum <structname>v4l2_frmsizetypes</structname></title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant></entry> + <entry>1</entry> + <entry>Discrete frame size.</entry> + </row> + <row> + <entry><constant>V4L2_FRMSIZE_TYPE_CONTINUOUS</constant></entry> + <entry>2</entry> + <entry>Continuous frame size.</entry> + </row> + <row> + <entry><constant>V4L2_FRMSIZE_TYPE_STEPWISE</constant></entry> + <entry>3</entry> + <entry>Step-wise defined frame size.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml b/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml new file mode 100644 index 00000000..ea816ab2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml @@ -0,0 +1,76 @@ +<refentry id="vidioc-enumaudio"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMAUDIO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMAUDIO</refname> + <refpurpose>Enumerate audio inputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audio *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMAUDIO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of an audio input applications +initialize the <structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-audio; +and call the <constant>VIDIOC_ENUMAUDIO</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all audio +inputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>See <xref linkend="vidioc-g-audio" /> for a description of +&v4l2-audio;.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the audio input is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml b/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml new file mode 100644 index 00000000..2e87cedb --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml @@ -0,0 +1,79 @@ +<refentry id="vidioc-enumaudioout"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMAUDOUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMAUDOUT</refname> + <refpurpose>Enumerate audio outputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audioout *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMAUDOUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of an audio output applications +initialize the <structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-audioout; and +call the <constant>VIDIOC_G_AUDOUT</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all audio +outputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>Note connectors on a TV card to loop back the received audio +signal to a sound card are not audio outputs in this sense.</para> + + <para>See <xref linkend="vidioc-g-audioout" /> for a description of +&v4l2-audioout;.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the audio output is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enuminput.xml b/Documentation/DocBook/media/v4l/vidioc-enuminput.xml new file mode 100644 index 00000000..9b8efcd6 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enuminput.xml @@ -0,0 +1,313 @@ +<refentry id="vidioc-enuminput"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMINPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMINPUT</refname> + <refpurpose>Enumerate video inputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_input +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMINPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a video input applications +initialize the <structfield>index</structfield> field of &v4l2-input; +and call the <constant>VIDIOC_ENUMINPUT</constant> ioctl with a +pointer to this structure. Drivers fill the rest of the structure or +return an &EINVAL; when the index is out of bounds. To enumerate all +inputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <table frame="none" pgwide="1" id="v4l2-input"> + <title>struct <structname>v4l2_input</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the input, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the video input, a NUL-terminated ASCII +string, for example: "Vin (Composite 2)". This information is intended +for the user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the input, see <xref + linkend="input-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>audioset</structfield></entry> + <entry><para>Drivers can enumerate up to 32 video and +audio inputs. This field shows which audio inputs were selectable as +audio source if this was the currently selected video input. It is a +bit mask. The LSB corresponds to audio input 0, the MSB to input 31. +Any number of bits can be set, or none.</para><para>When the driver +does not enumerate audio inputs no bits must be set. Applications +shall not interpret this as lack of audio support. Some drivers +automatically select audio sources and do not enumerate them since +there is no choice anyway.</para><para>For details on audio inputs and +how to select the current input see <xref + linkend="audio" />.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>tuner</structfield></entry> + <entry>Capture devices can have zero or more tuners (RF +demodulators). When the <structfield>type</structfield> is set to +<constant>V4L2_INPUT_TYPE_TUNER</constant> this is an RF connector and +this field identifies the tuner. It corresponds to +&v4l2-tuner; field <structfield>index</structfield>. For details on +tuners see <xref linkend="tuner" />.</entry> + </row> + <row> + <entry>&v4l2-std-id;</entry> + <entry><structfield>std</structfield></entry> + <entry>Every video input supports one or more different +video standards. This field is a set of all supported standards. For +details on video standards and how to switch see <xref +linkend="standard" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>status</structfield></entry> + <entry>This field provides status information about the +input. See <xref linkend="input-status" /> for flags. +With the exception of the sensor orientation bits <structfield>status</structfield> is only valid when this is the +current input.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capabilities</structfield></entry> + <entry>This field provides capabilities for the +input. See <xref linkend="input-capabilities" /> for flags.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[3]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="input-type"> + <title>Input Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_INPUT_TYPE_TUNER</constant></entry> + <entry>1</entry> + <entry>This input uses a tuner (RF demodulator).</entry> + </row> + <row> + <entry><constant>V4L2_INPUT_TYPE_CAMERA</constant></entry> + <entry>2</entry> + <entry>Analog baseband input, for example CVBS / +Composite Video, S-Video, RGB.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Status flags based on proposal by Mark McClelland, +video4linux-list@redhat.com on 18 Oct 2002, subject "Re: [V4L] Re: +v4l2 api". "Why are some of them inverted? So that the driver doesn't +have to lie about the status in cases where it can't tell one way or +the other. Plus, a status of zero would generally mean that everything +is OK." --> + + <table frame="none" pgwide="1" id="input-status"> + <title>Input Status Flags</title> + <tgroup cols="3"> + <colspec colname="c1" /> + <colspec colname="c2" align="center" /> + <colspec colname="c3" /> + <spanspec namest="c1" nameend="c3" spanname="hspan" + align="left" /> + <tbody valign="top"> + <row> + <entry spanname="hspan">General</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_POWER</constant></entry> + <entry>0x00000001</entry> + <entry>Attached device is off.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_SIGNAL</constant></entry> + <entry>0x00000002</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_COLOR</constant></entry> + <entry>0x00000004</entry> + <entry>The hardware supports color decoding, but does not +detect color modulation in the signal.</entry> + </row> + <row> + <entry spanname="hspan">Sensor Orientation</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_HFLIP</constant></entry> + <entry>0x00000010</entry> + <entry>The input is connected to a device that produces a signal +that is flipped horizontally and does not correct this before passing the +signal to userspace.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_VFLIP</constant></entry> + <entry>0x00000020</entry> + <entry>The input is connected to a device that produces a signal +that is flipped vertically and does not correct this before passing the +signal to userspace. Note that a 180 degree rotation is the same as HFLIP | VFLIP</entry> + </row> + <row> + <entry spanname="hspan">Analog Video</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_H_LOCK</constant></entry> + <entry>0x00000100</entry> + <entry>No horizontal sync lock.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_COLOR_KILL</constant></entry> + <entry>0x00000200</entry> + <entry>A color killer circuit automatically disables color +decoding when it detects no color modulation. When this flag is set +the color killer is enabled <emphasis>and</emphasis> has shut off +color decoding.</entry> + </row> + <row> + <entry spanname="hspan">Digital Video</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_SYNC</constant></entry> + <entry>0x00010000</entry> + <entry>No synchronization lock.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_EQU</constant></entry> + <entry>0x00020000</entry> + <entry>No equalizer lock.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_CARRIER</constant></entry> + <entry>0x00040000</entry> + <entry>Carrier recovery failed.</entry> + </row> + <row> + <entry spanname="hspan">VCR and Set-Top Box</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_MACROVISION</constant></entry> + <entry>0x01000000</entry> + <entry>Macrovision is an analog copy prevention system +mangling the video signal to confuse video recorders. When this +flag is set Macrovision has been detected.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_ACCESS</constant></entry> + <entry>0x02000000</entry> + <entry>Conditional access denied.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_VTR</constant></entry> + <entry>0x04000000</entry> + <entry>VTR time constant. [?]</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Capability flags based on video timings RFC by Muralidharan +Karicheri, titled RFC (v1.2): V4L - Support for video timings at the +input/output interface to linux-media@vger.kernel.org on 19 Oct 2009. + --> + <table frame="none" pgwide="1" id="input-capabilities"> + <title>Input capabilities</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_IN_CAP_PRESETS</constant></entry> + <entry>0x00000001</entry> + <entry>This input supports setting DV presets by using VIDIOC_S_DV_PRESET.</entry> + </row> + <row> + <entry><constant>V4L2_IN_CAP_CUSTOM_TIMINGS</constant></entry> + <entry>0x00000002</entry> + <entry>This input supports setting custom video timings by using VIDIOC_S_DV_TIMINGS.</entry> + </row> + <row> + <entry><constant>V4L2_IN_CAP_STD</constant></entry> + <entry>0x00000004</entry> + <entry>This input supports setting the TV standard by using VIDIOC_S_STD.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-input; <structfield>index</structfield> is +out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enumoutput.xml b/Documentation/DocBook/media/v4l/vidioc-enumoutput.xml new file mode 100644 index 00000000..a64d5ef1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumoutput.xml @@ -0,0 +1,198 @@ +<refentry id="vidioc-enumoutput"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMOUTPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMOUTPUT</refname> + <refpurpose>Enumerate video outputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_output *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMOUTPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a video outputs applications +initialize the <structfield>index</structfield> field of &v4l2-output; +and call the <constant>VIDIOC_ENUMOUTPUT</constant> ioctl with a +pointer to this structure. Drivers fill the rest of the structure or +return an &EINVAL; when the index is out of bounds. To enumerate all +outputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <table frame="none" pgwide="1" id="v4l2-output"> + <title>struct <structname>v4l2_output</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the output, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the video output, a NUL-terminated ASCII +string, for example: "Vout". This information is intended for the +user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the output, see <xref + linkend="output-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>audioset</structfield></entry> + <entry><para>Drivers can enumerate up to 32 video and +audio outputs. This field shows which audio outputs were +selectable as the current output if this was the currently selected +video output. It is a bit mask. The LSB corresponds to audio output 0, +the MSB to output 31. Any number of bits can be set, or +none.</para><para>When the driver does not enumerate audio outputs no +bits must be set. Applications shall not interpret this as lack of +audio support. Drivers may automatically select audio outputs without +enumerating them.</para><para>For details on audio outputs and how to +select the current output see <xref linkend="audio" />.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>modulator</structfield></entry> + <entry>Output devices can have zero or more RF modulators. +When the <structfield>type</structfield> is +<constant>V4L2_OUTPUT_TYPE_MODULATOR</constant> this is an RF +connector and this field identifies the modulator. It corresponds to +&v4l2-modulator; field <structfield>index</structfield>. For details +on modulators see <xref linkend="tuner" />.</entry> + </row> + <row> + <entry>&v4l2-std-id;</entry> + <entry><structfield>std</structfield></entry> + <entry>Every video output supports one or more different +video standards. This field is a set of all supported standards. For +details on video standards and how to switch see <xref + linkend="standard" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capabilities</structfield></entry> + <entry>This field provides capabilities for the +output. See <xref linkend="output-capabilities" /> for flags.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[3]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="output-type"> + <title>Output Type</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_OUTPUT_TYPE_MODULATOR</constant></entry> + <entry>1</entry> + <entry>This output is an analog TV modulator.</entry> + </row> + <row> + <entry><constant>V4L2_OUTPUT_TYPE_ANALOG</constant></entry> + <entry>2</entry> + <entry>Analog baseband output, for example Composite / +CVBS, S-Video, RGB.</entry> + </row> + <row> + <entry><constant>V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY</constant></entry> + <entry>3</entry> + <entry>[?]</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Capabilities flags based on video timings RFC by Muralidharan +Karicheri, titled RFC (v1.2): V4L - Support for video timings at the +input/output interface to linux-media@vger.kernel.org on 19 Oct 2009. + --> + <table frame="none" pgwide="1" id="output-capabilities"> + <title>Output capabilities</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_OUT_CAP_PRESETS</constant></entry> + <entry>0x00000001</entry> + <entry>This output supports setting DV presets by using VIDIOC_S_DV_PRESET.</entry> + </row> + <row> + <entry><constant>V4L2_OUT_CAP_CUSTOM_TIMINGS</constant></entry> + <entry>0x00000002</entry> + <entry>This output supports setting custom video timings by using VIDIOC_S_DV_TIMINGS.</entry> + </row> + <row> + <entry><constant>V4L2_OUT_CAP_STD</constant></entry> + <entry>0x00000004</entry> + <entry>This output supports setting the TV standard by using VIDIOC_S_STD.</entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-output; <structfield>index</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-enumstd.xml b/Documentation/DocBook/media/v4l/vidioc-enumstd.xml new file mode 100644 index 00000000..3a5fc540 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumstd.xml @@ -0,0 +1,383 @@ +<refentry id="vidioc-enumstd"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMSTD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMSTD</refname> + <refpurpose>Enumerate supported video standards</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_standard *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMSTD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a video standard, +especially a custom (driver defined) one, applications initialize the +<structfield>index</structfield> field of &v4l2-standard; and call the +<constant>VIDIOC_ENUMSTD</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all standards +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>. Drivers may enumerate a +different set of standards after switching the video input or +output.<footnote> + <para>The supported standards may overlap and we need an +unambiguous set to find the current standard returned by +<constant>VIDIOC_G_STD</constant>.</para> + </footnote></para> + + <table pgwide="1" frame="none" id="v4l2-standard"> + <title>struct <structname>v4l2_standard</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the video standard, set by the +application.</entry> + </row> + <row> + <entry>&v4l2-std-id;</entry> + <entry><structfield>id</structfield></entry> + <entry>The bits in this field identify the standard as +one of the common standards listed in <xref linkend="v4l2-std-id" />, +or if bits 32 to 63 are set as custom standards. Multiple bits can be +set if the hardware does not distinguish between these standards, +however separate indices do not indicate the opposite. The +<structfield>id</structfield> must be unique. No other enumerated +<structname>v4l2_standard</structname> structure, for this input or +output anyway, can contain the same set of bits.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[24]</entry> + <entry>Name of the standard, a NUL-terminated ASCII +string, for example: "PAL-B/G", "NTSC Japan". This information is +intended for the user.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>frameperiod</structfield></entry> + <entry>The frame period (not field period) is numerator +/ denominator. For example M/NTSC has a frame period of 1001 / +30000 seconds.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>framelines</structfield></entry> + <entry>Total lines per frame including blanking, +e. g. 625 for B/PAL.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-fract"> + <title>struct <structname>v4l2_fract</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>numerator</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>denominator</structfield></entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-std-id"> + <title>typedef <structname>v4l2_std_id</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u64</entry> + <entry><structfield>v4l2_std_id</structfield></entry> + <entry>This type is a set, each bit representing another +video standard as listed below and in <xref +linkend="video-standards" />. The 32 most significant bits are reserved +for custom (driver defined) video standards.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para><programlisting> +#define V4L2_STD_PAL_B ((v4l2_std_id)0x00000001) +#define V4L2_STD_PAL_B1 ((v4l2_std_id)0x00000002) +#define V4L2_STD_PAL_G ((v4l2_std_id)0x00000004) +#define V4L2_STD_PAL_H ((v4l2_std_id)0x00000008) +#define V4L2_STD_PAL_I ((v4l2_std_id)0x00000010) +#define V4L2_STD_PAL_D ((v4l2_std_id)0x00000020) +#define V4L2_STD_PAL_D1 ((v4l2_std_id)0x00000040) +#define V4L2_STD_PAL_K ((v4l2_std_id)0x00000080) + +#define V4L2_STD_PAL_M ((v4l2_std_id)0x00000100) +#define V4L2_STD_PAL_N ((v4l2_std_id)0x00000200) +#define V4L2_STD_PAL_Nc ((v4l2_std_id)0x00000400) +#define V4L2_STD_PAL_60 ((v4l2_std_id)0x00000800) +</programlisting></para><para><constant>V4L2_STD_PAL_60</constant> is +a hybrid standard with 525 lines, 60 Hz refresh rate, and PAL color +modulation with a 4.43 MHz color subcarrier. Some PAL video recorders +can play back NTSC tapes in this mode for display on a 50/60 Hz agnostic +PAL TV.</para><para><programlisting> +#define V4L2_STD_NTSC_M ((v4l2_std_id)0x00001000) +#define V4L2_STD_NTSC_M_JP ((v4l2_std_id)0x00002000) +#define V4L2_STD_NTSC_443 ((v4l2_std_id)0x00004000) +</programlisting></para><para><constant>V4L2_STD_NTSC_443</constant> +is a hybrid standard with 525 lines, 60 Hz refresh rate, and NTSC +color modulation with a 4.43 MHz color +subcarrier.</para><para><programlisting> +#define V4L2_STD_NTSC_M_KR ((v4l2_std_id)0x00008000) + +#define V4L2_STD_SECAM_B ((v4l2_std_id)0x00010000) +#define V4L2_STD_SECAM_D ((v4l2_std_id)0x00020000) +#define V4L2_STD_SECAM_G ((v4l2_std_id)0x00040000) +#define V4L2_STD_SECAM_H ((v4l2_std_id)0x00080000) +#define V4L2_STD_SECAM_K ((v4l2_std_id)0x00100000) +#define V4L2_STD_SECAM_K1 ((v4l2_std_id)0x00200000) +#define V4L2_STD_SECAM_L ((v4l2_std_id)0x00400000) +#define V4L2_STD_SECAM_LC ((v4l2_std_id)0x00800000) + +/* ATSC/HDTV */ +#define V4L2_STD_ATSC_8_VSB ((v4l2_std_id)0x01000000) +#define V4L2_STD_ATSC_16_VSB ((v4l2_std_id)0x02000000) +</programlisting></para><para><!-- ATSC proposal by Mark McClelland, +video4linux-list@redhat.com on 17 Oct 2002 +--><constant>V4L2_STD_ATSC_8_VSB</constant> and +<constant>V4L2_STD_ATSC_16_VSB</constant> are U.S. terrestrial digital +TV standards. Presently the V4L2 API does not support digital TV. See +also the Linux DVB API at <ulink +url="http://linuxtv.org">http://linuxtv.org</ulink>.</para> +<para><programlisting> +#define V4L2_STD_PAL_BG (V4L2_STD_PAL_B |\ + V4L2_STD_PAL_B1 |\ + V4L2_STD_PAL_G) +#define V4L2_STD_B (V4L2_STD_PAL_B |\ + V4L2_STD_PAL_B1 |\ + V4L2_STD_SECAM_B) +#define V4L2_STD_GH (V4L2_STD_PAL_G |\ + V4L2_STD_PAL_H |\ + V4L2_STD_SECAM_G |\ + V4L2_STD_SECAM_H) +#define V4L2_STD_PAL_DK (V4L2_STD_PAL_D |\ + V4L2_STD_PAL_D1 |\ + V4L2_STD_PAL_K) +#define V4L2_STD_PAL (V4L2_STD_PAL_BG |\ + V4L2_STD_PAL_DK |\ + V4L2_STD_PAL_H |\ + V4L2_STD_PAL_I) +#define V4L2_STD_NTSC (V4L2_STD_NTSC_M |\ + V4L2_STD_NTSC_M_JP |\ + V4L2_STD_NTSC_M_KR) +#define V4L2_STD_MN (V4L2_STD_PAL_M |\ + V4L2_STD_PAL_N |\ + V4L2_STD_PAL_Nc |\ + V4L2_STD_NTSC) +#define V4L2_STD_SECAM_DK (V4L2_STD_SECAM_D |\ + V4L2_STD_SECAM_K |\ + V4L2_STD_SECAM_K1) +#define V4L2_STD_DK (V4L2_STD_PAL_DK |\ + V4L2_STD_SECAM_DK) + +#define V4L2_STD_SECAM (V4L2_STD_SECAM_B |\ + V4L2_STD_SECAM_G |\ + V4L2_STD_SECAM_H |\ + V4L2_STD_SECAM_DK |\ + V4L2_STD_SECAM_L |\ + V4L2_STD_SECAM_LC) + +#define V4L2_STD_525_60 (V4L2_STD_PAL_M |\ + V4L2_STD_PAL_60 |\ + V4L2_STD_NTSC |\ + V4L2_STD_NTSC_443) +#define V4L2_STD_625_50 (V4L2_STD_PAL |\ + V4L2_STD_PAL_N |\ + V4L2_STD_PAL_Nc |\ + V4L2_STD_SECAM) + +#define V4L2_STD_UNKNOWN 0 +#define V4L2_STD_ALL (V4L2_STD_525_60 |\ + V4L2_STD_625_50) +</programlisting></para> + + <table pgwide="1" id="video-standards" orient="land"> + <title>Video Standards (based on [<xref linkend="itu470" />])</title> + <tgroup cols="12" colsep="1" rowsep="1" align="center"> + <colspec colname="c1" align="left" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <colspec colname="c5" /> + <colspec colnum="7" colname="c7" /> + <colspec colnum="9" colname="c9" /> + <colspec colnum="12" colname="c12" /> + <spanspec namest="c2" nameend="c3" spanname="m" align="center" /> + <spanspec namest="c4" nameend="c12" spanname="x" align="center" /> + <spanspec namest="c5" nameend="c7" spanname="b" align="center" /> + <spanspec namest="c9" nameend="c12" spanname="s" align="center" /> + <thead> + <row> + <entry>Characteristics</entry> + <entry><para>M/NTSC<footnote><para>Japan uses a standard +similar to M/NTSC +(V4L2_STD_NTSC_M_JP).</para></footnote></para></entry> + <entry>M/PAL</entry> + <entry><para>N/PAL<footnote><para> The values in +brackets apply to the combination N/PAL a.k.a. +N<subscript>C</subscript> used in Argentina +(V4L2_STD_PAL_Nc).</para></footnote></para></entry> + <entry align="center">B, B1, G/PAL</entry> + <entry align="center">D, D1, K/PAL</entry> + <entry align="center">H/PAL</entry> + <entry align="center">I/PAL</entry> + <entry align="center">B, G/SECAM</entry> + <entry align="center">D, K/SECAM</entry> + <entry align="center">K1/SECAM</entry> + <entry align="center">L/SECAM</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry>Frame lines</entry> + <entry spanname="m">525</entry> + <entry spanname="x">625</entry> + </row> + <row> + <entry>Frame period (s)</entry> + <entry spanname="m">1001/30000</entry> + <entry spanname="x">1/25</entry> + </row> + <row> + <entry>Chrominance sub-carrier frequency (Hz)</entry> + <entry>3579545 ± 10</entry> + <entry>3579611.49 ± 10</entry> + <entry>4433618.75 ± 5 (3582056.25 +± 5)</entry> + <entry spanname="b">4433618.75 ± 5</entry> + <entry>4433618.75 ± 1</entry> + <entry spanname="s">f<subscript>OR</subscript> = +4406250 ± 2000, f<subscript>OB</subscript> = 4250000 +± 2000</entry> + </row> + <row> + <entry>Nominal radio-frequency channel bandwidth +(MHz)</entry> + <entry>6</entry> + <entry>6</entry> + <entry>6</entry> + <entry>B: 7; B1, G: 8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + </row> + <row> + <entry>Sound carrier relative to vision carrier +(MHz)</entry> + <entry>+ 4.5</entry> + <entry>+ 4.5</entry> + <entry>+ 4.5</entry> + <entry><para>+ 5.5 ± 0.001 +<footnote><para>In the Federal Republic of Germany, Austria, Italy, +the Netherlands, Slovakia and Switzerland a system of two sound +carriers is used, the frequency of the second carrier being +242.1875 kHz above the frequency of the first sound carrier. For +stereophonic sound transmissions a similar system is used in +Australia.</para></footnote> <footnote><para>New Zealand uses a sound +carrier displaced 5.4996 ± 0.0005 MHz from the vision +carrier.</para></footnote> <footnote><para>In Denmark, Finland, New +Zealand, Sweden and Spain a system of two sound carriers is used. In +Iceland, Norway and Poland the same system is being introduced. The +second carrier is 5.85 MHz above the vision carrier and is DQPSK +modulated with 728 kbit/s sound and data multiplex. (NICAM +system)</para></footnote> <footnote><para>In the United Kingdom, a +system of two sound carriers is used. The second sound carrier is +6.552 MHz above the vision carrier and is DQPSK modulated with a +728 kbit/s sound and data multiplex able to carry two sound +channels. (NICAM system)</para></footnote></para></entry> + <entry>+ 6.5 ± 0.001</entry> + <entry>+ 5.5</entry> + <entry>+ 5.9996 ± 0.0005</entry> + <entry>+ 5.5 ± 0.001</entry> + <entry>+ 6.5 ± 0.001</entry> + <entry>+ 6.5</entry> + <entry><para>+ 6.5 <footnote><para>In France, a +digital carrier 5.85 MHz away from the vision carrier may be used in +addition to the main sound carrier. It is modulated in differentially +encoded QPSK with a 728 kbit/s sound and data multiplexer capable of +carrying two sound channels. (NICAM +system)</para></footnote></para></entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-standard; <structfield>index</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-audio.xml b/Documentation/DocBook/media/v4l/vidioc-g-audio.xml new file mode 100644 index 00000000..d7bb9b37 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-audio.xml @@ -0,0 +1,172 @@ +<refentry id="vidioc-g-audio"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_AUDIO, VIDIOC_S_AUDIO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_AUDIO</refname> + <refname>VIDIOC_S_AUDIO</refname> + <refpurpose>Query or select the current audio input and its +attributes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audio *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_audio *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_AUDIO, VIDIOC_S_AUDIO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current audio input applications zero out the +<structfield>reserved</structfield> array of a &v4l2-audio; +and call the <constant>VIDIOC_G_AUDIO</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video input.</para> + + <para>Audio inputs have one writable property, the audio mode. To +select the current audio input <emphasis>and</emphasis> change the +audio mode, applications initialize the +<structfield>index</structfield> and <structfield>mode</structfield> +fields, and the +<structfield>reserved</structfield> array of a +<structname>v4l2_audio</structname> structure and call the +<constant>VIDIOC_S_AUDIO</constant> ioctl. Drivers may switch to a +different audio mode if the request cannot be satisfied. However, this +is a write-only ioctl, it does not return the actual new audio +mode.</para> + + <table pgwide="1" frame="none" id="v4l2-audio"> + <title>struct <structname>v4l2_audio</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the audio input, set by the +driver or application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the audio input, a NUL-terminated ASCII +string, for example: "Line In". This information is intended for the +user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>Audio capability flags, see <xref + linkend="audio-capability" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>mode</structfield></entry> + <entry>Audio mode flags set by drivers and applications (on + <constant>VIDIOC_S_AUDIO</constant> ioctl), see <xref linkend="audio-mode" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="audio-capability"> + <title>Audio Capability Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_AUDCAP_STEREO</constant></entry> + <entry>0x00001</entry> + <entry>This is a stereo input. The flag is intended to +automatically disable stereo recording etc. when the signal is always +monaural. The API provides no means to detect if stereo is +<emphasis>received</emphasis>, unless the audio input belongs to a +tuner.</entry> + </row> + <row> + <entry><constant>V4L2_AUDCAP_AVL</constant></entry> + <entry>0x00002</entry> + <entry>Automatic Volume Level mode is supported.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="audio-mode"> + <title>Audio Mode Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_AUDMODE_AVL</constant></entry> + <entry>0x00001</entry> + <entry>AVL mode is on.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>No audio inputs combine with the current video input, +or the number of the selected audio input is out of bounds or it does +not combine.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml b/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml new file mode 100644 index 00000000..200a2704 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml @@ -0,0 +1,138 @@ +<refentry id="vidioc-g-audioout"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_AUDOUT</refname> + <refname>VIDIOC_S_AUDOUT</refname> + <refpurpose>Query or select the current audio output</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audioout *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_audioout *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current audio output applications zero out the +<structfield>reserved</structfield> array of a &v4l2-audioout; and +call the <constant>VIDIOC_G_AUDOUT</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video output.</para> + + <para>Audio outputs have no writable properties. Nevertheless, to +select the current audio output applications can initialize the +<structfield>index</structfield> field and +<structfield>reserved</structfield> array (which in the future may +contain writable properties) of a +<structname>v4l2_audioout</structname> structure and call the +<constant>VIDIOC_S_AUDOUT</constant> ioctl. Drivers switch to the +requested output or return the &EINVAL; when the index is out of +bounds. This is a write-only ioctl, it does not return the current +audio output attributes as <constant>VIDIOC_G_AUDOUT</constant> +does.</para> + + <para>Note connectors on a TV card to loop back the received audio +signal to a sound card are not audio outputs in this sense.</para> + + <table pgwide="1" frame="none" id="v4l2-audioout"> + <title>struct <structname>v4l2_audioout</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the audio output, set by the +driver or application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the audio output, a NUL-terminated ASCII +string, for example: "Line Out". This information is intended for the +user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>Audio capability flags, none defined yet. Drivers +must set this field to zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>mode</structfield></entry> + <entry>Audio mode, none defined yet. Drivers and +applications (on <constant>VIDIOC_S_AUDOUT</constant>) must set this +field to zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>No audio outputs combine with the current video +output, or the number of the selected audio output is out of bounds or +it does not combine.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-crop.xml b/Documentation/DocBook/media/v4l/vidioc-g-crop.xml new file mode 100644 index 00000000..01a50640 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-crop.xml @@ -0,0 +1,126 @@ +<refentry id="vidioc-g-crop"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_CROP, VIDIOC_S_CROP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_CROP</refname> + <refname>VIDIOC_S_CROP</refname> + <refpurpose>Get or set the current cropping rectangle</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_crop *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_crop *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_CROP, VIDIOC_S_CROP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the cropping rectangle size and position +applications set the <structfield>type</structfield> field of a +<structname>v4l2_crop</structname> structure to the respective buffer +(stream) type and call the <constant>VIDIOC_G_CROP</constant> ioctl +with a pointer to this structure. The driver fills the rest of the +structure or returns the &EINVAL; if cropping is not supported.</para> + + <para>To change the cropping rectangle applications initialize the +<structfield>type</structfield> and &v4l2-rect; substructure named +<structfield>c</structfield> of a v4l2_crop structure and call the +<constant>VIDIOC_S_CROP</constant> ioctl with a pointer to this +structure.</para> + + <para>The driver first adjusts the requested dimensions against +hardware limits, &ie; the bounds given by the capture/output window, +and it rounds to the closest possible values of horizontal and +vertical offset, width and height. In particular the driver must round +the vertical offset of the cropping rectangle to frame lines modulo +two, such that the field order cannot be confused.</para> + + <para>Second the driver adjusts the image size (the opposite +rectangle of the scaling process, source or target depending on the +data direction) to the closest size possible while maintaining the +current horizontal and vertical scaling factor.</para> + + <para>Finally the driver programs the hardware with the actual +cropping and image parameters. <constant>VIDIOC_S_CROP</constant> is a +write-only ioctl, it does not return the actual parameters. To query +them applications must call <constant>VIDIOC_G_CROP</constant> and +&VIDIOC-G-FMT;. When the parameters are unsuitable the application may +modify the cropping or image parameters and repeat the cycle until +satisfactory parameters have been negotiated.</para> + + <para>When cropping is not supported then no parameters are +changed and <constant>VIDIOC_S_CROP</constant> returns the +&EINVAL;.</para> + + <table pgwide="1" frame="none" id="v4l2-crop"> + <title>struct <structname>v4l2_crop</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, set by the application. +Only these types are valid here: <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver +defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> +and higher.</entry> + </row> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>c</structfield></entry> + <entry>Cropping rectangle. The same co-ordinate system as +for &v4l2-cropcap; <structfield>bounds</structfield> is used.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml b/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml new file mode 100644 index 00000000..12b1d050 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml @@ -0,0 +1,129 @@ +<refentry id="vidioc-g-ctrl"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_CTRL, VIDIOC_S_CTRL</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_CTRL</refname> + <refname>VIDIOC_S_CTRL</refname> + <refpurpose>Get or set the value of a control</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_control +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_CTRL, VIDIOC_S_CTRL</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To get the current value of a control applications +initialize the <structfield>id</structfield> field of a struct +<structname>v4l2_control</structname> and call the +<constant>VIDIOC_G_CTRL</constant> ioctl with a pointer to this +structure. To change the value of a control applications initialize +the <structfield>id</structfield> and <structfield>value</structfield> +fields of a struct <structname>v4l2_control</structname> and call the +<constant>VIDIOC_S_CTRL</constant> ioctl.</para> + + <para>When the <structfield>id</structfield> is invalid drivers +return an &EINVAL;. When the <structfield>value</structfield> is out +of bounds drivers can choose to take the closest valid value or return +an &ERANGE;, whatever seems more appropriate. However, +<constant>VIDIOC_S_CTRL</constant> is a write-only ioctl, it does not +return the actual new value.</para> + + <para>These ioctls work only with user controls. For other +control classes the &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; or +&VIDIOC-TRY-EXT-CTRLS; must be used.</para> + + <table pgwide="1" frame="none" id="v4l2-control"> + <title>struct <structname>v4l2_control</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>Identifies the control, set by the +application.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>value</structfield></entry> + <entry>New value or current value.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-control; <structfield>id</structfield> is +invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ERANGE</errorcode></term> + <listitem> + <para>The &v4l2-control; <structfield>value</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The control is temporarily not changeable, possibly +because another applications took over control of the device function +this control belongs to.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>Attempt to set a read-only control or to get a + write-only control.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml b/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml new file mode 100644 index 00000000..7940c114 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml @@ -0,0 +1,104 @@ +<refentry id="vidioc-g-dv-preset"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_DV_PRESET</refname> + <refname>VIDIOC_S_DV_PRESET</refname> + <refpurpose>Query or select the DV preset of the current input or output</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dv_preset *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + <para>To query and select the current DV preset, applications +use the <constant>VIDIOC_G_DV_PRESET</constant> and <constant>VIDIOC_S_DV_PRESET</constant> +ioctls which take a pointer to a &v4l2-dv-preset; type as argument. +Applications must zero the reserved array in &v4l2-dv-preset;. +<constant>VIDIOC_G_DV_PRESET</constant> returns a dv preset in the field +<structfield>preset</structfield> of &v4l2-dv-preset;.</para> + + <para><constant>VIDIOC_S_DV_PRESET</constant> accepts a pointer to a &v4l2-dv-preset; +that has the preset value to be set. Applications must zero the reserved array in &v4l2-dv-preset;. +If the preset is not supported, it returns an &EINVAL; </para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>This ioctl is not supported, or the +<constant>VIDIOC_S_DV_PRESET</constant>,<constant>VIDIOC_S_DV_PRESET</constant> parameter was unsuitable.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The device is busy and therefore can not change the preset.</para> + </listitem> + </varlistentry> + </variablelist> + + <table pgwide="1" frame="none" id="v4l2-dv-preset"> + <title>struct <structname>v4l2_dv_preset</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>preset</structfield></entry> + <entry>Preset value to represent the digital video timings</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[4]</structfield></entry> + <entry>Reserved fields for future use</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml b/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml new file mode 100644 index 00000000..4a8648ae --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml @@ -0,0 +1,218 @@ +<refentry id="vidioc-g-dv-timings"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_DV_TIMINGS</refname> + <refname>VIDIOC_S_DV_TIMINGS</refname> + <refpurpose>Get or set custom DV timings for input or output</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dv_timings *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + <para>To set custom DV timings for the input or output, applications use the +<constant>VIDIOC_S_DV_TIMINGS</constant> ioctl and to get the current custom timings, +applications use the <constant>VIDIOC_G_DV_TIMINGS</constant> ioctl. The detailed timing +information is filled in using the structure &v4l2-dv-timings;. These ioctls take +a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported +or the timing values are not correct, the driver returns &EINVAL;.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>This ioctl is not supported, or the +<constant>VIDIOC_S_DV_TIMINGS</constant> parameter was unsuitable.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The device is busy and therefore can not change the timings.</para> + </listitem> + </varlistentry> + </variablelist> + + <table pgwide="1" frame="none" id="v4l2-bt-timings"> + <title>struct <structname>v4l2_bt_timings</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the active video in pixels</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the active video in lines</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>interlaced</structfield></entry> + <entry>Progressive (0) or interlaced (1)</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>polarities</structfield></entry> + <entry>This is a bit mask that defines polarities of sync signals. +bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If the bit is set +(1) it is positive polarity and if is cleared (0), it is negative polarity.</entry> + </row> + <row> + <entry>__u64</entry> + <entry><structfield>pixelclock</structfield></entry> + <entry>Pixel clock in Hz. Ex. 74.25MHz->74250000</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>hfrontporch</structfield></entry> + <entry>Horizontal front porch in pixels</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>hsync</structfield></entry> + <entry>Horizontal sync length in pixels</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>hbackporch</structfield></entry> + <entry>Horizontal back porch in pixels</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>vfrontporch</structfield></entry> + <entry>Vertical front porch in lines</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>vsync</structfield></entry> + <entry>Vertical sync length in lines</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>vbackporch</structfield></entry> + <entry>Vertical back porch in lines</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>il_vfrontporch</structfield></entry> + <entry>Vertical front porch in lines for bottom field of interlaced field formats</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>il_vsync</structfield></entry> + <entry>Vertical sync length in lines for bottom field of interlaced field formats</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>il_vbackporch</structfield></entry> + <entry>Vertical back porch in lines for bottom field of interlaced field formats</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-dv-timings"> + <title>struct <structname>v4l2_dv_timings</structname></title> + <tgroup cols="4"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>Type of DV timings as listed in <xref linkend="dv-timing-types"/>.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield></structfield></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-bt-timings;</entry> + <entry><structfield>bt</structfield></entry> + <entry>Timings defined by BT.656/1120 specifications</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[32]</entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="dv-timing-types"> + <title>DV Timing types</title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>Timing type</entry> + <entry>value</entry> + <entry>Description</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry>V4L2_DV_BT_656_1120</entry> + <entry>0</entry> + <entry>BT.656/1120 timings</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml b/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml new file mode 100644 index 00000000..2aef02c9 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml @@ -0,0 +1,196 @@ +<refentry id="vidioc-g-enc-index"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_ENC_INDEX</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_ENC_INDEX</refname> + <refpurpose>Get meta data about a compressed video stream</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_enc_idx *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_ENC_INDEX</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>The <constant>VIDIOC_G_ENC_INDEX</constant> ioctl provides +meta data about a compressed video stream the same or another +application currently reads from the driver, which is useful for +random access into the stream without decoding it.</para> + + <para>To read the data applications must call +<constant>VIDIOC_G_ENC_INDEX</constant> with a pointer to a +&v4l2-enc-idx;. On success the driver fills the +<structfield>entry</structfield> array, stores the number of elements +written in the <structfield>entries</structfield> field, and +initializes the <structfield>entries_cap</structfield> field.</para> + + <para>Each element of the <structfield>entry</structfield> array +contains meta data about one picture. A +<constant>VIDIOC_G_ENC_INDEX</constant> call reads up to +<constant>V4L2_ENC_IDX_ENTRIES</constant> entries from a driver +buffer, which can hold up to <structfield>entries_cap</structfield> +entries. This number can be lower or higher than +<constant>V4L2_ENC_IDX_ENTRIES</constant>, but not zero. When the +application fails to read the meta data in time the oldest entries +will be lost. When the buffer is empty or no capturing/encoding is in +progress, <structfield>entries</structfield> will be zero.</para> + + <para>Currently this ioctl is only defined for MPEG-2 program +streams and video elementary streams.</para> + + <table pgwide="1" frame="none" id="v4l2-enc-idx"> + <title>struct <structname>v4l2_enc_idx</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>entries</structfield></entry> + <entry>The number of entries the driver stored in the +<structfield>entry</structfield> array.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>entries_cap</structfield></entry> + <entry>The number of entries the driver can +buffer. Must be greater than zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry spanname="hspan">Reserved for future extensions. +Drivers must set the array to zero.</entry> + </row> + <row> + <entry>&v4l2-enc-idx-entry;</entry> + <entry><structfield>entry</structfield>[<constant>V4L2_ENC_IDX_ENTRIES</constant>]</entry> + <entry>Meta data about a compressed video stream. Each +element of the array corresponds to one picture, sorted in ascending +order by their <structfield>offset</structfield>.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-enc-idx-entry"> + <title>struct <structname>v4l2_enc_idx_entry</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u64</entry> + <entry><structfield>offset</structfield></entry> + <entry>The offset in bytes from the beginning of the +compressed video stream to the beginning of this picture, that is a +<wordasword>PES packet header</wordasword> as defined in <xref + linkend="mpeg2part1" /> or a <wordasword>picture +header</wordasword> as defined in <xref linkend="mpeg2part2" />. When +the encoder is stopped, the driver resets the offset to zero.</entry> + </row> + <row> + <entry>__u64</entry> + <entry><structfield>pts</structfield></entry> + <entry>The 33 bit <wordasword>Presentation Time +Stamp</wordasword> of this picture as defined in <xref + linkend="mpeg2part1" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>length</structfield></entry> + <entry>The length of this picture in bytes.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Flags containing the coding type of this picture, see <xref + linkend="enc-idx-flags" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. +Drivers must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="enc-idx-flags"> + <title>Index Entry Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_I</constant></entry> + <entry>0x00</entry> + <entry>This is an Intra-coded picture.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_P</constant></entry> + <entry>0x01</entry> + <entry>This is a Predictive-coded picture.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_B</constant></entry> + <entry>0x02</entry> + <entry>This is a Bidirectionally predictive-coded +picture.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_MASK</constant></entry> + <entry>0x0F</entry> + <entry><wordasword>AND</wordasword> the flags field with +this mask to obtain the picture coding type.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml new file mode 100644 index 00000000..b17a7aac --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml @@ -0,0 +1,322 @@ +<refentry id="vidioc-g-ext-ctrls"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_EXT_CTRLS, VIDIOC_S_EXT_CTRLS, +VIDIOC_TRY_EXT_CTRLS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_EXT_CTRLS</refname> + <refname>VIDIOC_S_EXT_CTRLS</refname> + <refname>VIDIOC_TRY_EXT_CTRLS</refname> + <refpurpose>Get or set the value of several controls, try control +values</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_ext_controls +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_EXT_CTRLS, VIDIOC_S_EXT_CTRLS, +VIDIOC_TRY_EXT_CTRLS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>These ioctls allow the caller to get or set multiple +controls atomically. Control IDs are grouped into control classes (see +<xref linkend="ctrl-class" />) and all controls in the control array +must belong to the same control class.</para> + + <para>Applications must always fill in the +<structfield>count</structfield>, +<structfield>ctrl_class</structfield>, +<structfield>controls</structfield> and +<structfield>reserved</structfield> fields of &v4l2-ext-controls;, and +initialize the &v4l2-ext-control; array pointed to by the +<structfield>controls</structfield> fields.</para> + + <para>To get the current value of a set of controls applications +initialize the <structfield>id</structfield>, +<structfield>size</structfield> and <structfield>reserved2</structfield> fields +of each &v4l2-ext-control; and call the +<constant>VIDIOC_G_EXT_CTRLS</constant> ioctl. String controls controls +must also set the <structfield>string</structfield> field.</para> + + <para>If the <structfield>size</structfield> is too small to +receive the control result (only relevant for pointer-type controls +like strings), then the driver will set <structfield>size</structfield> +to a valid value and return an &ENOSPC;. You should re-allocate the +string memory to this new size and try again. It is possible that the +same issue occurs again if the string has grown in the meantime. It is +recommended to call &VIDIOC-QUERYCTRL; first and use +<structfield>maximum</structfield>+1 as the new <structfield>size</structfield> +value. It is guaranteed that that is sufficient memory. +</para> + + <para>To change the value of a set of controls applications +initialize the <structfield>id</structfield>, <structfield>size</structfield>, +<structfield>reserved2</structfield> and +<structfield>value/string</structfield> fields of each &v4l2-ext-control; and +call the <constant>VIDIOC_S_EXT_CTRLS</constant> ioctl. The controls +will only be set if <emphasis>all</emphasis> control values are +valid.</para> + + <para>To check if a set of controls have correct values applications +initialize the <structfield>id</structfield>, <structfield>size</structfield>, +<structfield>reserved2</structfield> and +<structfield>value/string</structfield> fields of each &v4l2-ext-control; and +call the <constant>VIDIOC_TRY_EXT_CTRLS</constant> ioctl. It is up to +the driver whether wrong values are automatically adjusted to a valid +value or if an error is returned.</para> + + <para>When the <structfield>id</structfield> or +<structfield>ctrl_class</structfield> is invalid drivers return an +&EINVAL;. When the value is out of bounds drivers can choose to take +the closest valid value or return an &ERANGE;, whatever seems more +appropriate. In the first case the new value is set in +&v4l2-ext-control;.</para> + + <para>The driver will only set/get these controls if all control +values are correct. This prevents the situation where only some of the +controls were set/get. Only low-level errors (⪚ a failed i2c +command) can still cause this situation.</para> + + <table pgwide="1" frame="none" id="v4l2-ext-control"> + <title>struct <structname>v4l2_ext_control</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry></entry> + <entry>Identifies the control, set by the +application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>size</structfield></entry> + <entry></entry> + <entry>The total size in bytes of the payload of this +control. This is normally 0, but for pointer controls this should be +set to the size of the memory containing the payload, or that will +receive the payload. If <constant>VIDIOC_G_EXT_CTRLS</constant> finds +that this value is less than is required to store +the payload result, then it is set to a value large enough to store the +payload result and ENOSPC is returned. Note that for string controls +this <structfield>size</structfield> field should not be confused with the length of the string. +This field refers to the size of the memory that contains the string. +The actual <emphasis>length</emphasis> of the string may well be much smaller. +</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved2</structfield>[1]</entry> + <entry></entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>__s32</entry> + <entry><structfield>value</structfield></entry> + <entry>New value or current value.</entry> + </row> + <row> + <entry></entry> + <entry>__s64</entry> + <entry><structfield>value64</structfield></entry> + <entry>New value or current value.</entry> + </row> + <row> + <entry></entry> + <entry>char *</entry> + <entry><structfield>string</structfield></entry> + <entry>A pointer to a string.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-ext-controls"> + <title>struct <structname>v4l2_ext_controls</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>ctrl_class</structfield></entry> + <entry>The control class to which all controls belong, see +<xref linkend="ctrl-class" />. Drivers that use a kernel framework for handling +controls will also accept a value of 0 here, meaning that the controls can +belong to any control class. Whether drivers support this can be tested by setting +<structfield>ctrl_class</structfield> to 0 and calling <constant>VIDIOC_TRY_EXT_CTRLS</constant> +with a <structfield>count</structfield> of 0. If that succeeds, then the driver +supports this feature.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>count</structfield></entry> + <entry>The number of controls in the controls array. May +also be zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>error_idx</structfield></entry> + <entry>Set by the driver in case of an error. If it is equal +to <structfield>count</structfield>, then no actual changes were made to +controls. In other words, the error was not associated with setting a particular +control. If it is another value, then only the controls up to <structfield>error_idx-1</structfield> +were modified and control <structfield>error_idx</structfield> is the one that +caused the error. The <structfield>error_idx</structfield> value is undefined +if the ioctl returned 0 (success).</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + <row> + <entry>&v4l2-ext-control; *</entry> + <entry><structfield>controls</structfield></entry> + <entry>Pointer to an array of +<structfield>count</structfield> v4l2_ext_control structures. Ignored +if <structfield>count</structfield> equals zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="ctrl-class"> + <title>Control classes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CTRL_CLASS_USER</constant></entry> + <entry>0x980000</entry> + <entry>The class containing user controls. These controls +are described in <xref linkend="control" />. All controls that can be set +using the &VIDIOC-S-CTRL; and &VIDIOC-G-CTRL; ioctl belong to this +class.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_CLASS_MPEG</constant></entry> + <entry>0x990000</entry> + <entry>The class containing MPEG compression controls. +These controls are described in <xref + linkend="mpeg-controls" />.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_CLASS_CAMERA</constant></entry> + <entry>0x9a0000</entry> + <entry>The class containing camera controls. +These controls are described in <xref + linkend="camera-controls" />.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_CLASS_FM_TX</constant></entry> + <entry>0x9b0000</entry> + <entry>The class containing FM Transmitter (FM TX) controls. +These controls are described in <xref + linkend="fm-tx-controls" />.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_CLASS_FLASH</constant></entry> + <entry>0x9c0000</entry> + <entry>The class containing flash device controls. +These controls are described in <xref + linkend="flash-controls" />.</entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-ext-control; <structfield>id</structfield> +is invalid or the &v4l2-ext-controls; +<structfield>ctrl_class</structfield> is invalid. This error code is +also returned by the <constant>VIDIOC_S_EXT_CTRLS</constant> and +<constant>VIDIOC_TRY_EXT_CTRLS</constant> ioctls if two or more +control values are in conflict.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ERANGE</errorcode></term> + <listitem> + <para>The &v4l2-ext-control; <structfield>value</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The control is temporarily not changeable, possibly +because another applications took over control of the device function +this control belongs to.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOSPC</errorcode></term> + <listitem> + <para>The space reserved for the control's payload is insufficient. +The field <structfield>size</structfield> is set to a value that is enough +to store the payload and this error code is returned.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>Attempt to try or set a read-only control or to get a + write-only control.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml b/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml new file mode 100644 index 00000000..7c63815e --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml @@ -0,0 +1,463 @@ +<refentry id="vidioc-g-fbuf"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_FBUF, VIDIOC_S_FBUF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_FBUF</refname> + <refname>VIDIOC_S_FBUF</refname> + <refpurpose>Get or set frame buffer overlay parameters</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_framebuffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_framebuffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_FBUF, VIDIOC_S_FBUF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Applications can use the <constant>VIDIOC_G_FBUF</constant> and +<constant>VIDIOC_S_FBUF</constant> ioctl to get and set the +framebuffer parameters for a <link linkend="overlay">Video +Overlay</link> or <link linkend="osd">Video Output Overlay</link> +(OSD). The type of overlay is implied by the device type (capture or +output device) and can be determined with the &VIDIOC-QUERYCAP; ioctl. +One <filename>/dev/videoN</filename> device must not support both +kinds of overlay.</para> + + <para>The V4L2 API distinguishes destructive and non-destructive +overlays. A destructive overlay copies captured video images into the +video memory of a graphics card. A non-destructive overlay blends +video images into a VGA signal or graphics into a video signal. +<wordasword>Video Output Overlays</wordasword> are always +non-destructive.</para> + + <para>To get the current parameters applications call the +<constant>VIDIOC_G_FBUF</constant> ioctl with a pointer to a +<structname>v4l2_framebuffer</structname> structure. The driver fills +all fields of the structure or returns an &EINVAL; when overlays are +not supported.</para> + + <para>To set the parameters for a <wordasword>Video Output +Overlay</wordasword>, applications must initialize the +<structfield>flags</structfield> field of a struct +<structname>v4l2_framebuffer</structname>. Since the framebuffer is +implemented on the TV card all other parameters are determined by the +driver. When an application calls <constant>VIDIOC_S_FBUF</constant> +with a pointer to this structure, the driver prepares for the overlay +and returns the framebuffer parameters as +<constant>VIDIOC_G_FBUF</constant> does, or it returns an error +code.</para> + + <para>To set the parameters for a <wordasword>non-destructive +Video Overlay</wordasword>, applications must initialize the +<structfield>flags</structfield> field, the +<structfield>fmt</structfield> substructure, and call +<constant>VIDIOC_S_FBUF</constant>. Again the driver prepares for the +overlay and returns the framebuffer parameters as +<constant>VIDIOC_G_FBUF</constant> does, or it returns an error +code.</para> + + <para>For a <wordasword>destructive Video Overlay</wordasword> +applications must additionally provide a +<structfield>base</structfield> address. Setting up a DMA to a +random memory location can jeopardize the system security, its +stability or even damage the hardware, therefore only the superuser +can set the parameters for a destructive video overlay.</para> + + <!-- NB v4l2_pix_format is also specified in pixfmt.sgml.--> + + <table pgwide="1" frame="none" id="v4l2-framebuffer"> + <title>struct <structname>v4l2_framebuffer</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry></entry> + <entry>Overlay capability flags set by the driver, see +<xref linkend="framebuffer-cap" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry>Overlay control flags set by application and +driver, see <xref linkend="framebuffer-flags" /></entry> + </row> + <row> + <entry>void *</entry> + <entry><structfield>base</structfield></entry> + <entry></entry> + <entry>Physical base address of the framebuffer, +that is the address of the pixel in the top left corner of the +framebuffer.<footnote><para>A physical base address may not suit all +platforms. GK notes in theory we should pass something like PCI device ++ memory region + offset instead. If you encounter problems please +discuss on the linux-media mailing list: &v4l-ml;.</para></footnote></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>This field is irrelevant to +<wordasword>non-destructive Video Overlays</wordasword>. For +<wordasword>destructive Video Overlays</wordasword> applications must +provide a base address. The driver may accept only base addresses +which are a multiple of two, four or eight bytes. For +<wordasword>Video Output Overlays</wordasword> the driver must return +a valid base address, so applications can find the corresponding Linux +framebuffer device (see <xref linkend="osd" />).</entry> + </row> + <row> + <entry>&v4l2-pix-format;</entry> + <entry><structfield>fmt</structfield></entry> + <entry></entry> + <entry>Layout of the frame buffer. The +<structname>v4l2_pix_format</structname> structure is defined in <xref +linkend="pixfmt" />, for clarification the fields and acceptable values + are listed below:</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the frame buffer in pixels.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the frame buffer in pixels.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry>The pixel format of the +framebuffer.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>For <wordasword>non-destructive Video +Overlays</wordasword> this field only defines a format for the +&v4l2-window; <structfield>chromakey</structfield> field.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>For <wordasword>destructive Video +Overlays</wordasword> applications must initialize this field. For +<wordasword>Video Output Overlays</wordasword> the driver must return +a valid format.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>Usually this is an RGB format (for example +<link linkend="V4L2-PIX-FMT-RGB565"><constant>V4L2_PIX_FMT_RGB565</constant></link>) +but YUV formats (only packed YUV formats when chroma keying is used, +not including <constant>V4L2_PIX_FMT_YUYV</constant> and +<constant>V4L2_PIX_FMT_UYVY</constant>) and the +<constant>V4L2_PIX_FMT_PAL8</constant> format are also permitted. The +behavior of the driver when an application requests a compressed +format is undefined. See <xref linkend="pixfmt" /> for information on +pixel formats.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry>Drivers and applications shall ignore this field. +If applicable, the field order is selected with the &VIDIOC-S-FMT; +ioctl, using the <structfield>field</structfield> field of +&v4l2-window;.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>bytesperline</structfield></entry> + <entry>Distance in bytes between the leftmost pixels in +two adjacent lines.</entry> + </row> + <row> + <entry spanname="hspan"><para>This field is irrelevant to +<wordasword>non-destructive Video +Overlays</wordasword>.</para><para>For <wordasword>destructive Video +Overlays</wordasword> both applications and drivers can set this field +to request padding bytes at the end of each line. Drivers however may +ignore the requested value, returning <structfield>width</structfield> +times bytes-per-pixel or a larger value required by the hardware. That +implies applications can just set this field to zero to get a +reasonable default.</para><para>For <wordasword>Video Output +Overlays</wordasword> the driver must return a valid +value.</para><para>Video hardware may access padding bytes, therefore +they must reside in accessible memory. Consider for example the case +where padding bytes after the last line of an image cross a system +page boundary. Capture devices may write padding bytes, the value is +undefined. Output devices ignore the contents of padding +bytes.</para><para>When the image format is planar the +<structfield>bytesperline</structfield> value applies to the largest +plane and is divided by the same factor as the +<structfield>width</structfield> field for any smaller planes. For +example the Cb and Cr planes of a YUV 4:2:0 image have half as many +padding bytes following each line as the Y plane. To avoid ambiguities +drivers must return a <structfield>bytesperline</structfield> value +rounded up to a multiple of the scale factor.</para></entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>sizeimage</structfield></entry> + <entry><para>This field is irrelevant to +<wordasword>non-destructive Video Overlays</wordasword>. For +<wordasword>destructive Video Overlays</wordasword> applications must +initialize this field. For <wordasword>Video Output +Overlays</wordasword> the driver must return a valid +format.</para><para>Together with <structfield>base</structfield> it +defines the framebuffer memory accessible by the +driver.</para></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-colorspace;</entry> + <entry><structfield>colorspace</structfield></entry> + <entry>This information supplements the +<structfield>pixelformat</structfield> and must be set by the driver, +see <xref linkend="colorspaces" />.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>priv</structfield></entry> + <entry>Reserved for additional information about custom +(driver defined) formats. When not used drivers and applications must +set this field to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="framebuffer-cap"> + <title>Frame Buffer Capability Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FBUF_CAP_EXTERNOVERLAY</constant></entry> + <entry>0x0001</entry> + <entry>The device is capable of non-destructive overlays. +When the driver clears this flag, only destructive overlays are +supported. There are no drivers yet which support both destructive and +non-destructive overlays. Video Output Overlays are in practice always +non-destructive.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_CHROMAKEY</constant></entry> + <entry>0x0002</entry> + <entry>The device supports clipping by chroma-keying the +images. That is, image pixels replace pixels in the VGA or video +signal only where the latter assume a certain color. Chroma-keying +makes no sense for destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant></entry> + <entry>0x0004</entry> + <entry>The device supports clipping using a list of clip +rectangles.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant></entry> + <entry>0x0008</entry> + <entry>The device supports clipping using a bit mask.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_LOCAL_ALPHA</constant></entry> + <entry>0x0010</entry> + <entry>The device supports clipping/blending using the +alpha channel of the framebuffer or VGA signal. Alpha blending makes +no sense for destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_GLOBAL_ALPHA</constant></entry> + <entry>0x0020</entry> + <entry>The device supports alpha blending using a global +alpha value. Alpha blending makes no sense for destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_LOCAL_INV_ALPHA</constant></entry> + <entry>0x0040</entry> + <entry>The device supports clipping/blending using the +inverted alpha channel of the framebuffer or VGA signal. Alpha +blending makes no sense for destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_SRC_CHROMAKEY</constant></entry> + <entry>0x0080</entry> + <entry>The device supports Source Chroma-keying. Video pixels +with the chroma-key colors are replaced by framebuffer pixels, which is exactly opposite of +<constant>V4L2_FBUF_CAP_CHROMAKEY</constant></entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="framebuffer-flags"> + <title>Frame Buffer Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FBUF_FLAG_PRIMARY</constant></entry> + <entry>0x0001</entry> + <entry>The framebuffer is the primary graphics surface. +In other words, the overlay is destructive. This flag is typically set by any +driver that doesn't have the <constant>V4L2_FBUF_CAP_EXTERNOVERLAY</constant> +capability and it is cleared otherwise.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_OVERLAY</constant></entry> + <entry>0x0002</entry> + <entry>If this flag is set for a video capture device, then the +driver will set the initial overlay size to cover the full framebuffer size, +otherwise the existing overlay size (as set by &VIDIOC-S-FMT;) will be used. + +Only one video capture driver (bttv) supports this flag. The use of this flag +for capture devices is deprecated. There is no way to detect which drivers +support this flag, so the only reliable method of setting the overlay size is +through &VIDIOC-S-FMT;. + +If this flag is set for a video output device, then the video output overlay +window is relative to the top-left corner of the framebuffer and restricted +to the size of the framebuffer. If it is cleared, then the video output +overlay window is relative to the video output display. + </entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_CHROMAKEY</constant></entry> + <entry>0x0004</entry> + <entry>Use chroma-keying. The chroma-key color is +determined by the <structfield>chromakey</structfield> field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see <xref + linkend="overlay" /> +and + <xref linkend="osd" />.</entry> + </row> + <row> + <entry spanname="hspan">There are no flags to enable +clipping using a list of clip rectangles or a bitmap. These methods +are negotiated with the &VIDIOC-S-FMT; ioctl, see <xref + linkend="overlay" /> and <xref linkend="osd" />.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_LOCAL_ALPHA</constant></entry> + <entry>0x0008</entry> + <entry>Use the alpha channel of the framebuffer to clip or +blend framebuffer pixels with video images. The blend +function is: output = framebuffer pixel * alpha + video pixel * (1 - +alpha). The actual alpha depth depends on the framebuffer pixel +format.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_GLOBAL_ALPHA</constant></entry> + <entry>0x0010</entry> + <entry>Use a global alpha value to blend the framebuffer +with video images. The blend function is: output = (framebuffer pixel +* alpha + video pixel * (255 - alpha)) / 255. The alpha value is +determined by the <structfield>global_alpha</structfield> field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see <xref + linkend="overlay" /> +and <xref linkend="osd" />.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_LOCAL_INV_ALPHA</constant></entry> + <entry>0x0020</entry> + <entry>Like +<constant>V4L2_FBUF_FLAG_LOCAL_ALPHA</constant>, use the alpha channel +of the framebuffer to clip or blend framebuffer pixels with video +images, but with an inverted alpha value. The blend function is: +output = framebuffer pixel * (1 - alpha) + video pixel * alpha. The +actual alpha depth depends on the framebuffer pixel format.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_SRC_CHROMAKEY</constant></entry> + <entry>0x0040</entry> + <entry>Use source chroma-keying. The source chroma-key color is +determined by the <structfield>chromakey</structfield> field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see <xref +linkend="overlay" /> and <xref linkend="osd" />. +Both chroma-keying are mutual exclusive to each other, so same +<structfield>chromakey</structfield> field of &v4l2-window; is being used.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EPERM</errorcode></term> + <listitem> + <para><constant>VIDIOC_S_FBUF</constant> can only be called +by a privileged user to negotiate the parameters for a destructive +overlay.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <constant>VIDIOC_S_FBUF</constant> parameters are unsuitable.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml new file mode 100644 index 00000000..17fbda15 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml @@ -0,0 +1,196 @@ +<refentry id="vidioc-g-fmt"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_FMT, VIDIOC_S_FMT, +VIDIOC_TRY_FMT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_FMT</refname> + <refname>VIDIOC_S_FMT</refname> + <refname>VIDIOC_TRY_FMT</refname> + <refpurpose>Get or set the data format, try a format</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_format +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_FMT, VIDIOC_S_FMT, VIDIOC_TRY_FMT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>These ioctls are used to negotiate the format of data +(typically image format) exchanged between driver and +application.</para> + + <para>To query the current parameters applications set the +<structfield>type</structfield> field of a struct +<structname>v4l2_format</structname> to the respective buffer (stream) +type. For example video capture devices use +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> or +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>. When the application +calls the <constant>VIDIOC_G_FMT</constant> ioctl with a pointer to +this structure the driver fills the respective member of the +<structfield>fmt</structfield> union. In case of video capture devices +that is either the &v4l2-pix-format; <structfield>pix</structfield> or +the &v4l2-pix-format-mplane; <structfield>pix_mp</structfield> member. +When the requested buffer type is not supported drivers return an +&EINVAL;.</para> + + <para>To change the current format parameters applications +initialize the <structfield>type</structfield> field and all +fields of the respective <structfield>fmt</structfield> +union member. For details see the documentation of the various devices +types in <xref linkend="devices" />. Good practice is to query the +current parameters first, and to +modify only those parameters not suitable for the application. When +the application calls the <constant>VIDIOC_S_FMT</constant> ioctl +with a pointer to a <structname>v4l2_format</structname> structure +the driver checks +and adjusts the parameters against hardware abilities. Drivers +should not return an error code unless the input is ambiguous, this is +a mechanism to fathom device capabilities and to approach parameters +acceptable for both the application and driver. On success the driver +may program the hardware, allocate resources and generally prepare for +data exchange. +Finally the <constant>VIDIOC_S_FMT</constant> ioctl returns the +current format parameters as <constant>VIDIOC_G_FMT</constant> does. +Very simple, inflexible devices may even ignore all input and always +return the default parameters. However all V4L2 devices exchanging +data with the application must implement the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl. When the requested buffer +type is not supported drivers return an &EINVAL; on a +<constant>VIDIOC_S_FMT</constant> attempt. When I/O is already in +progress or the resource is not available for other reasons drivers +return the &EBUSY;.</para> + + <para>The <constant>VIDIOC_TRY_FMT</constant> ioctl is equivalent +to <constant>VIDIOC_S_FMT</constant> with one exception: it does not +change driver state. It can also be called at any time, never +returning <errorcode>EBUSY</errorcode>. This function is provided to +negotiate parameters, to learn about hardware limitations, without +disabling I/O or possibly time consuming hardware preparations. +Although strongly recommended drivers are not required to implement +this ioctl.</para> + + <table pgwide="1" frame="none" id="v4l2-format"> + <title>struct <structname>v4l2_format</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>Type of the data stream, see <xref + linkend="v4l2-buf-type" />.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>fmt</structfield></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-pix-format;</entry> + <entry><structfield>pix</structfield></entry> + <entry>Definition of an image format, see <xref + linkend="pixfmt" />, used by video capture and output +devices.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-pix-format-mplane;</entry> + <entry><structfield>pix_mp</structfield></entry> + <entry>Definition of an image format, see <xref + linkend="pixfmt" />, used by video capture and output +devices that support the <link linkend="planar-apis">multi-planar +version of the API</link>.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-window;</entry> + <entry><structfield>win</structfield></entry> + <entry>Definition of an overlaid image, see <xref + linkend="overlay" />, used by video overlay devices.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-vbi-format;</entry> + <entry><structfield>vbi</structfield></entry> + <entry>Raw VBI capture or output parameters. This is +discussed in more detail in <xref linkend="raw-vbi" />. Used by raw VBI +capture and output devices.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-sliced-vbi-format;</entry> + <entry><structfield>sliced</structfield></entry> + <entry>Sliced VBI capture or output parameters. See +<xref linkend="sliced" /> for details. Used by sliced VBI +capture and output devices.</entry> + </row> + <row> + <entry></entry> + <entry>__u8</entry> + <entry><structfield>raw_data</structfield>[200]</entry> + <entry>Place holder for future extensions and custom +(driver defined) formats with <structfield>type</structfield> +<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-format; <structfield>type</structfield> +field is invalid, the requested buffer type not supported, or the +format is not supported with this buffer type.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml b/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml new file mode 100644 index 00000000..66e9a525 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml @@ -0,0 +1,140 @@ +<refentry id="vidioc-g-frequency"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_FREQUENCY</refname> + <refname>VIDIOC_S_FREQUENCY</refname> + <refpurpose>Get or set tuner or modulator radio +frequency</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_frequency +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_frequency +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To get the current tuner or modulator radio frequency +applications set the <structfield>tuner</structfield> field of a +&v4l2-frequency; to the respective tuner or modulator number (only +input devices have tuners, only output devices have modulators), zero +out the <structfield>reserved</structfield> array and +call the <constant>VIDIOC_G_FREQUENCY</constant> ioctl with a pointer +to this structure. The driver stores the current frequency in the +<structfield>frequency</structfield> field.</para> + + <para>To change the current tuner or modulator radio frequency +applications initialize the <structfield>tuner</structfield>, +<structfield>type</structfield> and +<structfield>frequency</structfield> fields, and the +<structfield>reserved</structfield> array of a &v4l2-frequency; and +call the <constant>VIDIOC_S_FREQUENCY</constant> ioctl with a pointer +to this structure. When the requested frequency is not possible the +driver assumes the closest possible value. However +<constant>VIDIOC_S_FREQUENCY</constant> is a write-only ioctl, it does +not return the actual new frequency.</para> + + <table pgwide="1" frame="none" id="v4l2-frequency"> + <title>struct <structname>v4l2_frequency</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>tuner</structfield></entry> + <entry>The tuner or modulator index number. This is the +same value as in the &v4l2-input; <structfield>tuner</structfield> +field and the &v4l2-tuner; <structfield>index</structfield> field, or +the &v4l2-output; <structfield>modulator</structfield> field and the +&v4l2-modulator; <structfield>index</structfield> field.</entry> + </row> + <row> + <entry>&v4l2-tuner-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>The tuner type. This is the same value as in the +&v4l2-tuner; <structfield>type</structfield> field. The type must be set +to <constant>V4L2_TUNER_RADIO</constant> for <filename>/dev/radioX</filename> +device nodes, and to <constant>V4L2_TUNER_ANALOG_TV</constant> +for all others. The field is not applicable to modulators, &ie; ignored +by drivers.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>frequency</structfield></entry> + <entry>Tuning frequency in units of 62.5 kHz, or if the +&v4l2-tuner; or &v4l2-modulator; <structfield>capabilities</structfield> flag +<constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[8]</entry> + <entry>Reserved for future extensions. Drivers and + applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>tuner</structfield> index is out of +bounds or the value in the <structfield>type</structfield> field is +wrong.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-input.xml b/Documentation/DocBook/media/v4l/vidioc-g-input.xml new file mode 100644 index 00000000..1d430650 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-input.xml @@ -0,0 +1,83 @@ +<refentry id="vidioc-g-input"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_INPUT</refname> + <refname>VIDIOC_S_INPUT</refname> + <refpurpose>Query or select the current video input</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_INPUT, VIDIOC_S_INPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current video input applications call the +<constant>VIDIOC_G_INPUT</constant> ioctl with a pointer to an integer +where the driver stores the number of the input, as in the +&v4l2-input; <structfield>index</structfield> field. This ioctl will +fail only when there are no video inputs, returning +<errorcode>EINVAL</errorcode>.</para> + + <para>To select a video input applications store the number of the +desired input in an integer and call the +<constant>VIDIOC_S_INPUT</constant> ioctl with a pointer to this +integer. Side effects are possible. For example inputs may support +different video standards, so the driver may implicitly switch the +current standard. Because of these possible side effects applications +must select an input before querying or negotiating any other parameters.</para> + + <para>Information about video inputs is available using the +&VIDIOC-ENUMINPUT; ioctl.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the video input is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml new file mode 100644 index 00000000..48748499 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml @@ -0,0 +1,175 @@ +<refentry id="vidioc-g-jpegcomp"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_JPEGCOMP</refname> + <refname>VIDIOC_S_JPEGCOMP</refname> + <refpurpose></refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_jpegcompression *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const v4l2_jpegcompression *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>These ioctls are <emphasis role="bold">deprecated</emphasis>. + New drivers and applications should use <link linkend="jpeg-controls"> + JPEG class controls</link> for image quality and JPEG markers control. + </para> + + <para>[to do]</para> + + <para>Ronald Bultje elaborates:</para> + + <!-- See video4linux-list@redhat.com on 16 Oct 2002, subject +"Re: [V4L] Re: v4l2 api / Zoran v4l2_jpegcompression" --> + + <para>APP is some application-specific information. The +application can set it itself, and it'll be stored in the JPEG-encoded +fields (eg; interlacing information for in an AVI or so). COM is the +same, but it's comments, like 'encoded by me' or so.</para> + + <para>jpeg_markers describes whether the huffman tables, +quantization tables and the restart interval information (all +JPEG-specific stuff) should be stored in the JPEG-encoded fields. +These define how the JPEG field is encoded. If you omit them, +applications assume you've used standard encoding. You usually do want +to add them.</para> + + <!-- NB VIDIOC_S_JPEGCOMP is w/o. --> + + <table pgwide="1" frame="none" id="v4l2-jpegcompression"> + <title>struct <structname>v4l2_jpegcompression</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>int</entry> + <entry><structfield>quality</structfield></entry> + <entry>Deprecated. If <link linkend="jpeg-quality-control"><constant> + V4L2_CID_JPEG_IMAGE_QUALITY</constant></link> control is exposed by + a driver applications should use it instead and ignore this field. + </entry> + </row> + <row> + <entry>int</entry> + <entry><structfield>APPn</structfield></entry> + <entry></entry> + </row> + <row> + <entry>int</entry> + <entry><structfield>APP_len</structfield></entry> + <entry></entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>APP_data</structfield>[60]</entry> + <entry></entry> + </row> + <row> + <entry>int</entry> + <entry><structfield>COM_len</structfield></entry> + <entry></entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>COM_data</structfield>[60]</entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>jpeg_markers</structfield></entry> + <entry>See <xref linkend="jpeg-markers"/>. Deprecated. + If <link linkend="jpeg-active-marker-control"><constant> + V4L2_CID_JPEG_ACTIVE_MARKER</constant></link> control + is exposed by a driver applications should use it instead + and ignore this field.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="jpeg-markers"> + <title>JPEG Markers Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_JPEG_MARKER_DHT</constant></entry> + <entry>(1<<3)</entry> + <entry>Define Huffman Tables</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_DQT</constant></entry> + <entry>(1<<4)</entry> + <entry>Define Quantization Tables</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_DRI</constant></entry> + <entry>(1<<5)</entry> + <entry>Define Restart Interval</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_COM</constant></entry> + <entry>(1<<6)</entry> + <entry>Comment segment</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_APP</constant></entry> + <entry>(1<<7)</entry> + <entry>App segment, driver will always use APP0</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml new file mode 100644 index 00000000..7f4ac7e4 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml @@ -0,0 +1,238 @@ +<refentry id="vidioc-g-modulator"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_MODULATOR</refname> + <refname>VIDIOC_S_MODULATOR</refname> + <refpurpose>Get or set modulator attributes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_modulator +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_modulator +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a modulator applications initialize +the <structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-modulator; and +call the <constant>VIDIOC_G_MODULATOR</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all modulators +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>Modulators have two writable properties, an audio +modulation set and the radio frequency. To change the modulated audio +subprograms, applications initialize the <structfield>index +</structfield> and <structfield>txsubchans</structfield> fields and the +<structfield>reserved</structfield> array and call the +<constant>VIDIOC_S_MODULATOR</constant> ioctl. Drivers may choose a +different audio modulation if the request cannot be satisfied. However +this is a write-only ioctl, it does not return the actual audio +modulation selected.</para> + + <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available.</para> + + <table pgwide="1" frame="none" id="v4l2-modulator"> + <title>struct <structname>v4l2_modulator</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the modulator, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the modulator, a NUL-terminated ASCII +string. This information is intended for the user.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>Modulator capability flags. No flags are defined +for this field, the tuner flags in &v4l2-tuner; +are used accordingly. The audio flags indicate the ability +to encode audio subprograms. They will <emphasis>not</emphasis> +change for example with the current video standard.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangelow</structfield></entry> + <entry>The lowest tunable frequency in units of 62.5 +KHz, or if the <structfield>capability</structfield> flag +<constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangehigh</structfield></entry> + <entry>The highest tunable frequency in units of 62.5 +KHz, or if the <structfield>capability</structfield> flag +<constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>txsubchans</structfield></entry> + <entry>With this field applications can determine how +audio sub-carriers shall be modulated. It contains a set of flags as +defined in <xref linkend="modulator-txsubchans" />. Note the tuner +<structfield>rxsubchans</structfield> flags are reused, but the +semantics are different. Video output devices are assumed to have an +analog or PCM audio input with 1-3 channels. The +<structfield>txsubchans</structfield> flags select one or more +channels for modulation, together with some audio subprogram +indicator, for example a stereo pilot tone.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="modulator-txsubchans"> + <title>Modulator Audio Transmission Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>0x0001</entry> + <entry>Modulate channel 1 as mono audio, when the input +has more channels, a down-mix of channel 1 and 2. This flag does not +combine with <constant>V4L2_TUNER_SUB_STEREO</constant> or +<constant>V4L2_TUNER_SUB_LANG1</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_STEREO</constant></entry> + <entry>0x0002</entry> + <entry>Modulate channel 1 and 2 as left and right +channel of a stereo audio signal. When the input has only one channel +or two channels and <constant>V4L2_TUNER_SUB_SAP</constant> is also +set, channel 1 is encoded as left and right channel. This flag does +not combine with <constant>V4L2_TUNER_SUB_MONO</constant> or +<constant>V4L2_TUNER_SUB_LANG1</constant>. When the driver does not +support stereo audio it shall fall back to mono.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG1</constant></entry> + <entry>0x0008</entry> + <entry>Modulate channel 1 and 2 as primary and secondary +language of a bilingual audio signal. When the input has only one +channel it is used for both languages. It is not possible to encode +the primary or secondary language only. This flag does not combine +with <constant>V4L2_TUNER_SUB_MONO</constant>, +<constant>V4L2_TUNER_SUB_STEREO</constant> or +<constant>V4L2_TUNER_SUB_SAP</constant>. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit bilingual audio the +<constant>VIDIOC_S_MODULATOR</constant> ioctl shall return an &EINVAL; +and the driver shall fall back to mono or stereo mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG2</constant></entry> + <entry>0x0004</entry> + <entry>Same effect as +<constant>V4L2_TUNER_SUB_SAP</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_SAP</constant></entry> + <entry>0x0004</entry> + <entry>When combined with <constant>V4L2_TUNER_SUB_MONO +</constant> the first channel is encoded as mono audio, the last +channel as Second Audio Program. When the input has only one channel +it is used for both audio tracks. When the input has three channels +the mono track is a down-mix of channel 1 and 2. When combined with +<constant>V4L2_TUNER_SUB_STEREO</constant> channel 1 and 2 are +encoded as left and right stereo audio, channel 3 as Second Audio +Program. When the input has only two channels, the first is encoded as +left and right channel and the second as SAP. When the input has only +one channel it is used for all audio tracks. It is not possible to +encode a Second Audio Program only. This flag must combine with +<constant>V4L2_TUNER_SUB_MONO</constant> or +<constant>V4L2_TUNER_SUB_STEREO</constant>. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit SAP the <constant>VIDIOC_S_MODULATOR</constant> ioctl +shall return an &EINVAL; and driver shall fall back to mono or stereo +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_RDS</constant></entry> + <entry>0x0010</entry> + <entry>Enable the RDS encoder for a radio FM transmitter.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-modulator; +<structfield>index</structfield> is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-output.xml b/Documentation/DocBook/media/v4l/vidioc-g-output.xml new file mode 100644 index 00000000..4533068e --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-output.xml @@ -0,0 +1,85 @@ +<refentry id="vidioc-g-output"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_OUTPUT</refname> + <refname>VIDIOC_S_OUTPUT</refname> + <refpurpose>Query or select the current video output</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current video output applications call the +<constant>VIDIOC_G_OUTPUT</constant> ioctl with a pointer to an integer +where the driver stores the number of the output, as in the +&v4l2-output; <structfield>index</structfield> field. This ioctl +will fail only when there are no video outputs, returning the +&EINVAL;.</para> + + <para>To select a video output applications store the number of the +desired output in an integer and call the +<constant>VIDIOC_S_OUTPUT</constant> ioctl with a pointer to this integer. +Side effects are possible. For example outputs may support different +video standards, so the driver may implicitly switch the current +standard. +standard. Because of these possible side effects applications +must select an output before querying or negotiating any other parameters.</para> + + <para>Information about video outputs is available using the +&VIDIOC-ENUMOUTPUT; ioctl.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the video output is out of bounds, or +there are no video outputs at all.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-parm.xml b/Documentation/DocBook/media/v4l/vidioc-g-parm.xml new file mode 100644 index 00000000..19b1d85d --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-parm.xml @@ -0,0 +1,315 @@ +<refentry id="vidioc-g-parm"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_PARM, VIDIOC_S_PARM</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_PARM</refname> + <refname>VIDIOC_S_PARM</refname> + <refpurpose>Get or set streaming parameters</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_streamparm *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_PARM, VIDIOC_S_PARM</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The current video standard determines a nominal number of +frames per second. If less than this number of frames is to be +captured or output, applications can request frame skipping or +duplicating on the driver side. This is especially useful when using +the <function>read()</function> or <function>write()</function>, which +are not augmented by timestamps or sequence counters, and to avoid +unnecessary data copying.</para> + + <para>Further these ioctls can be used to determine the number of +buffers used internally by a driver in read/write mode. For +implications see the section discussing the &func-read; +function.</para> + + <para>To get and set the streaming parameters applications call +the <constant>VIDIOC_G_PARM</constant> and +<constant>VIDIOC_S_PARM</constant> ioctl, respectively. They take a +pointer to a struct <structname>v4l2_streamparm</structname> which +contains a union holding separate parameters for input and output +devices.</para> + + <table pgwide="1" frame="none" id="v4l2-streamparm"> + <title>struct <structname>v4l2_streamparm</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>The buffer (stream) type, same as &v4l2-format; +<structfield>type</structfield>, set by the application.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>parm</structfield></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-captureparm;</entry> + <entry><structfield>capture</structfield></entry> + <entry>Parameters for capture devices, used when +<structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-outputparm;</entry> + <entry><structfield>output</structfield></entry> + <entry>Parameters for output devices, used when +<structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>.</entry> + </row> + <row> + <entry></entry> + <entry>__u8</entry> + <entry><structfield>raw_data</structfield>[200]</entry> + <entry>A place holder for future extensions and custom +(driver defined) buffer types <constant>V4L2_BUF_TYPE_PRIVATE</constant> and +higher.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-captureparm"> + <title>struct <structname>v4l2_captureparm</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>See <xref linkend="parm-caps" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capturemode</structfield></entry> + <entry>Set by drivers and applications, see <xref linkend="parm-flags" />.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>timeperframe</structfield></entry> + <entry><para>This is is the desired period between +successive frames captured by the driver, in seconds. The +field is intended to skip frames on the driver side, saving I/O +bandwidth.</para><para>Applications store here the desired frame +period, drivers return the actual frame period, which must be greater +or equal to the nominal frame period determined by the current video +standard (&v4l2-standard; <structfield>frameperiod</structfield> +field). Changing the video standard (also implicitly by switching the +video input) may reset this parameter to the nominal frame period. To +reset manually applications can just set this field to +zero.</para><para>Drivers support this function only when they set the +<constant>V4L2_CAP_TIMEPERFRAME</constant> flag in the +<structfield>capability</structfield> field.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>extendedmode</structfield></entry> + <entry>Custom (driver specific) streaming parameters. When +unused, applications and drivers must set this field to zero. +Applications using this field should check the driver name and +version, see <xref linkend="querycap" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>readbuffers</structfield></entry> + <entry>Applications set this field to the desired number +of buffers used internally by the driver in &func-read; mode. Drivers +return the actual number of buffers. When an application requests zero +buffers, drivers should just return the current setting rather than +the minimum or an error code. For details see <xref + linkend="rw" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-outputparm"> + <title>struct <structname>v4l2_outputparm</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>See <xref linkend="parm-caps" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>outputmode</structfield></entry> + <entry>Set by drivers and applications, see <xref + linkend="parm-flags" />.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>timeperframe</structfield></entry> + <entry>This is is the desired period between +successive frames output by the driver, in seconds.</entry> + </row> + <row> + <entry spanname="hspan"><para>The field is intended to +repeat frames on the driver side in &func-write; mode (in streaming +mode timestamps can be used to throttle the output), saving I/O +bandwidth.</para><para>Applications store here the desired frame +period, drivers return the actual frame period, which must be greater +or equal to the nominal frame period determined by the current video +standard (&v4l2-standard; <structfield>frameperiod</structfield> +field). Changing the video standard (also implicitly by switching the +video output) may reset this parameter to the nominal frame period. To +reset manually applications can just set this field to +zero.</para><para>Drivers support this function only when they set the +<constant>V4L2_CAP_TIMEPERFRAME</constant> flag in the +<structfield>capability</structfield> field.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>extendedmode</structfield></entry> + <entry>Custom (driver specific) streaming parameters. When +unused, applications and drivers must set this field to zero. +Applications using this field should check the driver name and +version, see <xref linkend="querycap" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>writebuffers</structfield></entry> + <entry>Applications set this field to the desired number +of buffers used internally by the driver in +<function>write()</function> mode. Drivers return the actual number of +buffers. When an application requests zero buffers, drivers should +just return the current setting rather than the minimum or an error +code. For details see <xref linkend="rw" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="parm-caps"> + <title>Streaming Parameters Capabilites</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CAP_TIMEPERFRAME</constant></entry> + <entry>0x1000</entry> + <entry>The frame skipping/repeating controlled by the +<structfield>timeperframe</structfield> field is supported.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="parm-flags"> + <title>Capture Parameters Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_MODE_HIGHQUALITY</constant></entry> + <entry>0x0001</entry> + <entry><para>High quality imaging mode. High quality mode +is intended for still imaging applications. The idea is to get the +best possible image quality that the hardware can deliver. It is not +defined how the driver writer may achieve that; it will depend on the +hardware and the ingenuity of the driver writer. High quality mode is +a different mode from the the regular motion video capture modes. In +high quality mode:<itemizedlist> + <listitem> + <para>The driver may be able to capture higher +resolutions than for motion capture.</para> + </listitem> + <listitem> + <para>The driver may support fewer pixel formats +than motion capture (eg; true color).</para> + </listitem> + <listitem> + <para>The driver may capture and arithmetically +combine multiple successive fields or frames to remove color edge +artifacts and reduce the noise in the video data. +</para> + </listitem> + <listitem> + <para>The driver may capture images in slices like +a scanner in order to handle larger format images than would otherwise +be possible. </para> + </listitem> + <listitem> + <para>An image capture operation may be +significantly slower than motion capture. </para> + </listitem> + <listitem> + <para>Moving objects in the image might have +excessive motion blur. </para> + </listitem> + <listitem> + <para>Capture might only work through the +<function>read()</function> call.</para> + </listitem> + </itemizedlist></para></entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-priority.xml b/Documentation/DocBook/media/v4l/vidioc-g-priority.xml new file mode 100644 index 00000000..6a81b4fe --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-priority.xml @@ -0,0 +1,135 @@ +<refentry id="vidioc-g-priority"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_PRIORITY, VIDIOC_S_PRIORITY</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_PRIORITY</refname> + <refname>VIDIOC_S_PRIORITY</refname> + <refpurpose>Query or request the access priority associated with a +file descriptor</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>enum v4l2_priority *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const enum v4l2_priority *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_PRIORITY, VIDIOC_S_PRIORITY</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to an enum v4l2_priority type.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current access priority +applications call the <constant>VIDIOC_G_PRIORITY</constant> ioctl +with a pointer to an enum v4l2_priority variable where the driver stores +the current priority.</para> + + <para>To request an access priority applications store the +desired priority in an enum v4l2_priority variable and call +<constant>VIDIOC_S_PRIORITY</constant> ioctl with a pointer to this +variable.</para> + + <table frame="none" pgwide="1" id="v4l2-priority"> + <title>enum v4l2_priority</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_PRIORITY_UNSET</constant></entry> + <entry>0</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_BACKGROUND</constant></entry> + <entry>1</entry> + <entry>Lowest priority, usually applications running in +background, for example monitoring VBI transmissions. A proxy +application running in user space will be necessary if multiple +applications want to read from a device at this priority.</entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_INTERACTIVE</constant></entry> + <entry>2</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_DEFAULT</constant></entry> + <entry>2</entry> + <entry>Medium priority, usually applications started and +interactively controlled by the user. For example TV viewers, Teletext +browsers, or just "panel" applications to change the channel or video +controls. This is the default priority unless an application requests +another.</entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_RECORD</constant></entry> + <entry>3</entry> + <entry>Highest priority. Only one file descriptor can have +this priority, it blocks any other fd from changing device properties. +Usually applications which must not be interrupted, like video +recording.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The requested priority value is invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>Another application already requested higher +priority.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-selection.xml b/Documentation/DocBook/media/v4l/vidioc-g-selection.xml new file mode 100644 index 00000000..bb04eff7 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-selection.xml @@ -0,0 +1,308 @@ +<refentry id="vidioc-g-selection"> + + <refmeta> + <refentrytitle>ioctl VIDIOC_G_SELECTION, VIDIOC_S_SELECTION</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_SELECTION</refname> + <refname>VIDIOC_S_SELECTION</refname> + <refpurpose>Get or set one of the selection rectangles</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_selection *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_SELECTION, VIDIOC_S_SELECTION</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental"> experimental </link> + interface and may change in the future.</para> + </note> + + <para>The ioctls are used to query and configure selection rectangles.</para> + +<para> To query the cropping (composing) rectangle set &v4l2-selection; +<structfield> type </structfield> field to the respective buffer type. +Do not use multiplanar buffers. Use <constant> V4L2_BUF_TYPE_VIDEO_CAPTURE +</constant> instead of <constant> V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE +</constant>. Use <constant> V4L2_BUF_TYPE_VIDEO_OUTPUT </constant> instead of +<constant> V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE </constant>. The next step is +setting the value of &v4l2-selection; <structfield>target</structfield> field +to <constant> V4L2_SEL_TGT_CROP_ACTIVE </constant> (<constant> +V4L2_SEL_TGT_COMPOSE_ACTIVE </constant>). Please refer to table <xref +linkend="v4l2-sel-target" /> or <xref linkend="selection-api" /> for additional +targets. The <structfield>flags</structfield> and <structfield>reserved +</structfield> fields of &v4l2-selection; are ignored and they must be filled +with zeros. The driver fills the rest of the structure or +returns &EINVAL; if incorrect buffer type or target was used. If cropping +(composing) is not supported then the active rectangle is not mutable and it is +always equal to the bounds rectangle. Finally, the &v4l2-rect; +<structfield>r</structfield> rectangle is filled with the current cropping +(composing) coordinates. The coordinates are expressed in driver-dependent +units. The only exception are rectangles for images in raw formats, whose +coordinates are always expressed in pixels. </para> + +<para> To change the cropping (composing) rectangle set the &v4l2-selection; +<structfield>type</structfield> field to the respective buffer type. Do not +use multiplanar buffers. Use <constant> V4L2_BUF_TYPE_VIDEO_CAPTURE +</constant> instead of <constant> V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE +</constant>. Use <constant> V4L2_BUF_TYPE_VIDEO_OUTPUT </constant> instead of +<constant> V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE </constant>. The next step is +setting the value of &v4l2-selection; <structfield>target</structfield> to +<constant>V4L2_SEL_TGT_CROP_ACTIVE</constant> (<constant> +V4L2_SEL_TGT_COMPOSE_ACTIVE </constant>). Please refer to table <xref +linkend="v4l2-sel-target" /> or <xref linkend="selection-api" /> for additional +targets. The &v4l2-rect; <structfield>r</structfield> rectangle need to be +set to the desired active area. Field &v4l2-selection; <structfield> reserved +</structfield> is ignored and must be filled with zeros. The driver may adjust +coordinates of the requested rectangle. An application may +introduce constraints to control rounding behaviour. The &v4l2-selection; +<structfield>flags</structfield> field must be set to one of the following: + +<itemizedlist> + <listitem> +<para><constant>0</constant> - The driver can adjust the rectangle size freely +and shall choose a crop/compose rectangle as close as possible to the requested +one.</para> + </listitem> + <listitem> +<para><constant>V4L2_SEL_FLAG_GE</constant> - The driver is not allowed to +shrink the rectangle. The original rectangle must lay inside the adjusted +one.</para> + </listitem> + <listitem> +<para><constant>V4L2_SEL_FLAG_LE</constant> - The driver is not allowed to +enlarge the rectangle. The adjusted rectangle must lay inside the original +one.</para> + </listitem> + <listitem> +<para><constant>V4L2_SEL_FLAG_GE | V4L2_SEL_FLAG_LE</constant> - The driver +must choose the size exactly the same as in the requested rectangle.</para> + </listitem> +</itemizedlist> + +Please refer to <xref linkend="sel-const-adjust" />. + +</para> + +<para> The driver may have to adjusts the requested dimensions against hardware +limits and other parts as the pipeline, i.e. the bounds given by the +capture/output window or TV display. The closest possible values of horizontal +and vertical offset and sizes are chosen according to following priority: + +<orderedlist> + <listitem> + <para>Satisfy constraints from &v4l2-selection; <structfield>flags</structfield>.</para> + </listitem> + <listitem> + <para>Adjust width, height, left, and top to hardware limits and alignments.</para> + </listitem> + <listitem> + <para>Keep center of adjusted rectangle as close as possible to the original one.</para> + </listitem> + <listitem> + <para>Keep width and height as close as possible to original ones.</para> + </listitem> + <listitem> + <para>Keep horizontal and vertical offset as close as possible to original ones.</para> + </listitem> +</orderedlist> + +On success the &v4l2-rect; <structfield>r</structfield> field contains +the adjusted rectangle. When the parameters are unsuitable the application may +modify the cropping (composing) or image parameters and repeat the cycle until +satisfactory parameters have been negotiated. If constraints flags have to be +violated at then ERANGE is returned. The error indicates that <emphasis> there +exist no rectangle </emphasis> that satisfies the constraints.</para> + + </refsect1> + + <refsect1> + <table frame="none" pgwide="1" id="v4l2-sel-target"> + <title>Selection targets.</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_SEL_TGT_CROP_ACTIVE</constant></entry> + <entry>0x0000</entry> + <entry>The area that is currently cropped by hardware.</entry> + </row> + <row> + <entry><constant>V4L2_SEL_TGT_CROP_DEFAULT</constant></entry> + <entry>0x0001</entry> + <entry>Suggested cropping rectangle that covers the "whole picture".</entry> + </row> + <row> + <entry><constant>V4L2_SEL_TGT_CROP_BOUNDS</constant></entry> + <entry>0x0002</entry> + <entry>Limits for the cropping rectangle.</entry> + </row> + <row> + <entry><constant>V4L2_SEL_TGT_COMPOSE_ACTIVE</constant></entry> + <entry>0x0100</entry> + <entry>The area to which data is composed by hardware.</entry> + </row> + <row> + <entry><constant>V4L2_SEL_TGT_COMPOSE_DEFAULT</constant></entry> + <entry>0x0101</entry> + <entry>Suggested composing rectangle that covers the "whole picture".</entry> + </row> + <row> + <entry><constant>V4L2_SEL_TGT_COMPOSE_BOUNDS</constant></entry> + <entry>0x0102</entry> + <entry>Limits for the composing rectangle.</entry> + </row> + <row> + <entry><constant>V4L2_SEL_TGT_COMPOSE_PADDED</constant></entry> + <entry>0x0103</entry> + <entry>The active area and all padding pixels that are inserted or modified by hardware.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + <table frame="none" pgwide="1" id="v4l2-sel-flags"> + <title>Selection constraint flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_SEL_FLAG_GE</constant></entry> + <entry>0x00000001</entry> + <entry>Indicates that the adjusted rectangle must contain the original + &v4l2-selection; <structfield>r</structfield> rectangle.</entry> + </row> + <row> + <entry><constant>V4L2_SEL_FLAG_LE</constant></entry> + <entry>0x00000002</entry> + <entry>Indicates that the adjusted rectangle must be inside the original + &v4l2-rect; <structfield>r</structfield> rectangle.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <section> + <figure id="sel-const-adjust"> + <title>Size adjustments with constraint flags.</title> + <mediaobject> + <imageobject> + <imagedata fileref="constraints.png" format="PNG" /> + </imageobject> + <textobject> + <phrase>Behaviour of rectangle adjustment for different constraint + flags.</phrase> + </textobject> + </mediaobject> + </figure> + </section> + + <refsect1> + <table pgwide="1" frame="none" id="v4l2-selection"> + <title>struct <structname>v4l2_selection</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the buffer (from &v4l2-buf-type;).</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>target</structfield></entry> + <entry>Used to select between <link linkend="v4l2-sel-target"> cropping + and composing rectangles</link>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Flags controlling the selection rectangle adjustments, refer to + <link linkend="v4l2-sel-flags">selection flags</link>.</entry> + </row> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>r</structfield></entry> + <entry>The selection rectangle.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[9]</structfield></entry> + <entry>Reserved fields for future use.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>Given buffer type <structfield>type</structfield> or +the selection target <structfield>target</structfield> is not supported, +or the <structfield>flags</structfield> argument is not valid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ERANGE</errorcode></term> + <listitem> + <para>It is not possible to adjust &v4l2-rect; <structfield> +r</structfield> rectangle to satisfy all contraints given in the +<structfield>flags</structfield> argument.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>It is not possible to apply change of the selection rectangle +at the moment. Usually because streaming is in progress.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml b/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml new file mode 100644 index 00000000..71741daa --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml @@ -0,0 +1,255 @@ +<refentry id="vidioc-g-sliced-vbi-cap"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_SLICED_VBI_CAP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_SLICED_VBI_CAP</refname> + <refpurpose>Query sliced VBI capabilities</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_sliced_vbi_cap *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_SLICED_VBI_CAP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To find out which data services are supported by a sliced +VBI capture or output device, applications initialize the +<structfield>type</structfield> field of a &v4l2-sliced-vbi-cap;, +clear the <structfield>reserved</structfield> array and +call the <constant>VIDIOC_G_SLICED_VBI_CAP</constant> ioctl. The +driver fills in the remaining fields or returns an &EINVAL; if the +sliced VBI API is unsupported or <structfield>type</structfield> +is invalid.</para> + + <para>Note the <structfield>type</structfield> field was added, +and the ioctl changed from read-only to write-read, in Linux 2.6.19.</para> + + <table pgwide="1" frame="none" id="v4l2-sliced-vbi-cap"> + <title>struct <structname>v4l2_sliced_vbi_cap</structname></title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="3*" /> + <colspec colname="c2" colwidth="3*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec spanname="hspan" namest="c3" nameend="c5" /> + <tbody valign="top"> + <row> + <entry>__u16</entry> + <entry><structfield>service_set</structfield></entry> + <entry spanname="hspan">A set of all data services +supported by the driver. Equal to the union of all elements of the +<structfield>service_lines </structfield> array.</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>service_lines</structfield>[2][24]</entry> + <entry spanname="hspan">Each element of this array +contains a set of data services the hardware can look for or insert +into a particular scan line. Data services are defined in <xref + linkend="vbi-services" />. Array indices map to ITU-R +line numbers (see also <xref + linkend="vbi-525" /> and <xref +linkend="vbi-625" />) as follows:</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Element</entry> + <entry>525 line systems</entry> + <entry>625 line systems</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][1]</entry> + <entry align="center">1</entry> + <entry align="center">1</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][23]</entry> + <entry align="center">23</entry> + <entry align="center">23</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][1]</entry> + <entry align="center">264</entry> + <entry align="center">314</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][23]</entry> + <entry align="center">286</entry> + <entry align="center">336</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan">The number of VBI lines the +hardware can capture or output per frame, or the number of services it +can identify on a given line may be limited. For example on PAL line +16 the hardware may be able to look for a VPS or Teletext signal, but +not both at the same time. Applications can learn about these limits +using the &VIDIOC-S-FMT; ioctl as described in <xref + linkend="sliced" />.</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan">Drivers must set +<structfield>service_lines</structfield>[0][0] and +<structfield>service_lines</structfield>[1][0] to zero.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, see <xref + linkend="v4l2-buf-type" />. Should be +<constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> or +<constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[3]</entry> + <entry spanname="hspan">This array is reserved for future +extensions. Applications and drivers must set it to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- See also dev-sliced-vbi.sgml --> + <table pgwide="1" frame="none" id="vbi-services"> + <title>Sliced VBI services</title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="2*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec spanname='rlp' namest='c3' nameend='c5' /> + <thead> + <row> + <entry>Symbol</entry> + <entry>Value</entry> + <entry>Reference</entry> + <entry>Lines, usually</entry> + <entry>Payload</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_SLICED_TELETEXT_B</constant> (Teletext +System B)</entry> + <entry>0x0001</entry> + <entry><xref linkend="ets300706" />, <xref linkend="itu653" /></entry> + <entry>PAL/SECAM line 7-22, 320-335 (second field 7-22)</entry> + <entry>Last 42 of the 45 byte Teletext packet, that is +without clock run-in and framing code, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VPS</constant></entry> + <entry>0x0400</entry> + <entry><xref linkend="ets300231" /></entry> + <entry>PAL line 16</entry> + <entry>Byte number 3 to 15 according to Figure 9 of +ETS 300 231, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_CAPTION_525</constant></entry> + <entry>0x1000</entry> + <entry><xref linkend="eia608" /></entry> + <entry>NTSC line 21, 284 (second field 21)</entry> + <entry>Two bytes in transmission order, including parity +bit, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_WSS_625</constant></entry> + <entry>0x4000</entry> + <entry><xref linkend="en300294" />, <xref linkend="itu1119" /></entry> + <entry>PAL/SECAM line 23</entry> + <entry><screen> +Byte 0 1 + msb lsb msb lsb +Bit 7 6 5 4 3 2 1 0 x x 13 12 11 10 9 +</screen></entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_525</constant></entry> + <entry>0x1000</entry> + <entry spanname="rlp">Set of services applicable to 525 +line systems.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_625</constant></entry> + <entry>0x4401</entry> + <entry spanname="rlp">Set of services applicable to 625 +line systems.</entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The value in the <structfield>type</structfield> field is +wrong.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-std.xml b/Documentation/DocBook/media/v4l/vidioc-g-std.xml new file mode 100644 index 00000000..99ff1a01 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-std.xml @@ -0,0 +1,90 @@ +<refentry id="vidioc-g-std"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_STD, VIDIOC_S_STD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_STD</refname> + <refname>VIDIOC_S_STD</refname> + <refpurpose>Query or select the video standard of the current input</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_std_id +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const v4l2_std_id +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_STD, VIDIOC_S_STD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query and select the current video standard applications +use the <constant>VIDIOC_G_STD</constant> and <constant>VIDIOC_S_STD</constant> ioctls which take a pointer to a +&v4l2-std-id; type as argument. <constant>VIDIOC_G_STD</constant> can +return a single flag or a set of flags as in &v4l2-standard; field +<structfield>id</structfield>. The flags must be unambiguous such +that they appear in only one enumerated <structname>v4l2_standard</structname> structure.</para> + + <para><constant>VIDIOC_S_STD</constant> accepts one or more +flags, being a write-only ioctl it does not return the actual new standard as +<constant>VIDIOC_G_STD</constant> does. When no flags are given or +the current input does not support the requested standard the driver +returns an &EINVAL;. When the standard set is ambiguous drivers may +return <errorcode>EINVAL</errorcode> or choose any of the requested +standards.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <constant>VIDIOC_S_STD</constant> parameter was unsuitable.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml b/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml new file mode 100644 index 00000000..91ec2fb6 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml @@ -0,0 +1,537 @@ +<refentry id="vidioc-g-tuner"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_TUNER, VIDIOC_S_TUNER</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_TUNER</refname> + <refname>VIDIOC_S_TUNER</refname> + <refpurpose>Get or set tuner attributes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_tuner +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_tuner +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_TUNER, VIDIOC_S_TUNER</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a tuner applications initialize the +<structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-tuner; and call the +<constant>VIDIOC_G_TUNER</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all tuners +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>Tuners have two writable properties, the audio mode and +the radio frequency. To change the audio mode, applications initialize +the <structfield>index</structfield>, +<structfield>audmode</structfield> and +<structfield>reserved</structfield> fields and call the +<constant>VIDIOC_S_TUNER</constant> ioctl. This will +<emphasis>not</emphasis> change the current tuner, which is determined +by the current video input. Drivers may choose a different audio mode +if the requested mode is invalid or unsupported. Since this is a +<!-- FIXME -->write-only ioctl, it does not return the actually +selected audio mode.</para> + + <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available.</para> + + <table pgwide="1" frame="none" id="v4l2-tuner"> + <title>struct <structname>v4l2_tuner</structname></title> + <tgroup cols="3"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="1*" /> + <spanspec spanname="hspan" namest="c3" nameend="c4" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry spanname="hspan">Identifies the tuner, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry spanname="hspan"><para>Name of the tuner, a +NUL-terminated ASCII string. This information is intended for the +user.<!-- FIXME Video inputs already have a name, the purpose of this +field is not quite clear.--></para></entry> + </row> + <row> + <entry>&v4l2-tuner-type;</entry> + <entry><structfield>type</structfield></entry> + <entry spanname="hspan">Type of the tuner, see <xref + linkend="v4l2-tuner-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry spanname="hspan"><para>Tuner capability flags, see +<xref linkend="tuner-capability" />. Audio flags indicate the ability +to decode audio subprograms. They will <emphasis>not</emphasis> +change, for example with the current video standard.</para><para>When +the structure refers to a radio tuner only the +<constant>V4L2_TUNER_CAP_LOW</constant>, +<constant>V4L2_TUNER_CAP_STEREO</constant> and +<constant>V4L2_TUNER_CAP_RDS</constant> flags can be set.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangelow</structfield></entry> + <entry spanname="hspan">The lowest tunable frequency in +units of 62.5 kHz, or if the <structfield>capability</structfield> +flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangehigh</structfield></entry> + <entry spanname="hspan">The highest tunable frequency in +units of 62.5 kHz, or if the <structfield>capability</structfield> +flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rxsubchans</structfield></entry> + <entry spanname="hspan"><para>Some tuners or audio +decoders can determine the received audio subprograms by analyzing +audio carriers, pilot tones or other indicators. To pass this +information drivers set flags defined in <xref + linkend="tuner-rxsubchans" /> in this field. For +example:</para></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>receiving mono audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>STEREO | SAP</constant></entry> + <entry>receiving stereo audio and a secondary audio +program</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>MONO | STEREO</constant></entry> + <entry>receiving mono or stereo audio, the hardware cannot +distinguish</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>LANG1 | LANG2</constant></entry> + <entry>receiving bilingual audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>MONO | STEREO | LANG1 | LANG2</constant></entry> + <entry>receiving mono, stereo or bilingual +audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan"><para>When the +<constant>V4L2_TUNER_CAP_STEREO</constant>, +<constant>_LANG1</constant>, <constant>_LANG2</constant> or +<constant>_SAP</constant> flag is cleared in the +<structfield>capability</structfield> field, the corresponding +<constant>V4L2_TUNER_SUB_</constant> flag must not be set +here.</para><para>This field is valid only if this is the tuner of the +current video input, or when the structure refers to a radio +tuner.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>audmode</structfield></entry> + <entry spanname="hspan"><para>The selected audio mode, see +<xref linkend="tuner-audmode" /> for valid values. The audio mode does +not affect audio subprogram detection, and like a <link +linkend="control">control</link> it does not automatically change +unless the requested mode is invalid or unsupported. See <xref + linkend="tuner-matrix" /> for possible results when +the selected and received audio programs do not +match.</para><para>Currently this is the only field of struct +<structname>v4l2_tuner</structname> applications can +change.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>signal</structfield></entry> + <entry spanname="hspan">The signal strength if known, ranging +from 0 to 65535. Higher values indicate a better signal.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>afc</structfield></entry> + <entry spanname="hspan">Automatic frequency control: When the +<structfield>afc</structfield> value is negative, the frequency is too +low, when positive too high.<!-- FIXME need example what to do when it never +settles at zero, &ie; range is what? --></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry spanname="hspan">Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-tuner-type"> + <title>enum v4l2_tuner_type</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_RADIO</constant></entry> + <entry>1</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_ANALOG_TV</constant></entry> + <entry>2</entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-capability"> + <title>Tuner and Modulator Capability Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_CAP_LOW</constant></entry> + <entry>0x0001</entry> + <entry>When set, tuning frequencies are expressed in units of +62.5 Hz, otherwise in units of 62.5 kHz.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_NORM</constant></entry> + <entry>0x0002</entry> + <entry>This is a multi-standard tuner; the video standard +can or must be switched. (B/G PAL tuners for example are typically not + considered multi-standard because the video standard is automatically + determined from the frequency band.) The set of supported video + standards is available from the &v4l2-input; pointing to this tuner, + see the description of ioctl &VIDIOC-ENUMINPUT; for details. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_STEREO</constant></entry> + <entry>0x0010</entry> + <entry>Stereo audio reception is supported.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_LANG1</constant></entry> + <entry>0x0040</entry> + <entry>Reception of the primary language of a bilingual +audio program is supported. Bilingual audio is a feature of +two-channel systems, transmitting the primary language monaural on the +main audio carrier and a secondary language monaural on a second +carrier. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_LANG2</constant></entry> + <entry>0x0020</entry> + <entry>Reception of the secondary language of a bilingual +audio program is supported. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_SAP</constant></entry> + <entry>0x0020</entry> + <entry><para>Reception of a secondary audio program is +supported. This is a feature of the BTSC system which accompanies the +NTSC video standard. Two audio carriers are available for mono or +stereo transmissions of a primary language, and an independent third +carrier for a monaural secondary language. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</para><para>Note the +<constant>V4L2_TUNER_CAP_LANG2</constant> and +<constant>V4L2_TUNER_CAP_SAP</constant> flags are synonyms. +<constant>V4L2_TUNER_CAP_SAP</constant> applies when the tuner +supports the <constant>V4L2_STD_NTSC_M</constant> video +standard.</para><!-- FIXME what if PAL+NTSC and Bi but not SAP? --></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_RDS</constant></entry> + <entry>0x0080</entry> + <entry>RDS capture is supported. This capability is only valid for +radio tuners.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_RDS_BLOCK_IO</constant></entry> + <entry>0x0100</entry> + <entry>The RDS data is passed as unparsed RDS blocks.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_RDS_CONTROLS</constant></entry> + <entry>0x0200</entry> + <entry>The RDS data is parsed by the hardware and set via controls.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-rxsubchans"> + <title>Tuner Audio Reception Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>0x0001</entry> + <entry>The tuner receives a mono audio signal.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_STEREO</constant></entry> + <entry>0x0002</entry> + <entry>The tuner receives a stereo audio signal.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG1</constant></entry> + <entry>0x0008</entry> + <entry>The tuner receives the primary language of a +bilingual audio signal. Drivers must clear this flag when the current +video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG2</constant></entry> + <entry>0x0004</entry> + <entry>The tuner receives the secondary language of a +bilingual audio signal (or a second audio program).</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_SAP</constant></entry> + <entry>0x0004</entry> + <entry>The tuner receives a Second Audio Program. Note the +<constant>V4L2_TUNER_SUB_LANG2</constant> and +<constant>V4L2_TUNER_SUB_SAP</constant> flags are synonyms. The +<constant>V4L2_TUNER_SUB_SAP</constant> flag applies when the +current video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_RDS</constant></entry> + <entry>0x0010</entry> + <entry>The tuner receives an RDS channel.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-audmode"> + <title>Tuner Audio Modes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_MODE_MONO</constant></entry> + <entry>0</entry> + <entry>Play mono audio. When the tuner receives a stereo +signal this a down-mix of the left and right channel. When the tuner +receives a bilingual or SAP signal this mode selects the primary +language.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_STEREO</constant></entry> + <entry>1</entry> + <entry><para>Play stereo audio. When the tuner receives +bilingual audio it may play different languages on the left and right +channel or the primary language is played on both channels.</para><para>Playing +different languages in this mode is +deprecated. New drivers should do this only in +<constant>MODE_LANG1_LANG2</constant>.</para><para>When the tuner +receives no stereo signal or does not support stereo reception the +driver shall fall back to <constant>MODE_MONO</constant>.</para></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG1</constant></entry> + <entry>3</entry> + <entry>Play the primary language, mono or stereo. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG2</constant></entry> + <entry>2</entry> + <entry>Play the secondary language, mono. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_SAP</constant></entry> + <entry>2</entry> + <entry>Play the Second Audio Program. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this mode. +Note the <constant>V4L2_TUNER_MODE_LANG2</constant> and +<constant>V4L2_TUNER_MODE_SAP</constant> are synonyms.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG1_LANG2</constant></entry> + <entry>4</entry> + <entry>Play the primary language on the left channel, the +secondary language on the right channel. When the tuner receives no +bilingual audio or SAP, it shall fall back to +<constant>MODE_LANG1</constant> or <constant>MODE_MONO</constant>. +Only <constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="all" id="tuner-matrix"> + <title>Tuner Audio Matrix</title> + <tgroup cols="6" align="center"> + <colspec align="left" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colwidth="1*" /> + <colspec colwidth="1*" /> + <colspec colnum="6" colname="c6" colwidth="1*" /> + <spanspec namest="c2" nameend="c6" spanname="hspan" align="center" /> + <thead> + <row> + <entry></entry> + <entry spanname="hspan">Selected +<constant>V4L2_TUNER_MODE_</constant></entry> + </row> + <row> + <entry>Received <constant>V4L2_TUNER_SUB_</constant></entry> + <entry><constant>MONO</constant></entry> + <entry><constant>STEREO</constant></entry> + <entry><constant>LANG1</constant></entry> + <entry><constant>LANG2 = SAP</constant></entry> + <entry><constant>LANG1_LANG2</constant><footnote><para>This +mode has been added in Linux 2.6.17 and may not be supported by older +drivers.</para></footnote></entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>MONO</constant></entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + <entry>Mono</entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + </row> + <row> + <entry><constant>MONO | SAP</constant></entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + <entry>Mono</entry> + <entry>SAP</entry> + <entry>Mono/SAP (preferred) or Mono/Mono</entry> + </row> + <row> + <entry><constant>STEREO</constant></entry> + <entry>L+R</entry> + <entry>L/R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>L/R (preferred) or L+R/L+R</entry> + </row> + <row> + <entry><constant>STEREO | SAP</constant></entry> + <entry>L+R</entry> + <entry>L/R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>SAP</entry> + <entry>L+R/SAP (preferred) or L/R or L+R/L+R</entry> + </row> + <row> + <entry><constant>LANG1 | LANG2</constant></entry> + <entry>Language 1</entry> + <entry>Lang1/Lang2 (deprecated<footnote><para>Playback of +both languages in <constant>MODE_STEREO</constant> is deprecated. In +the future drivers should produce only the primary language in this +mode. Applications should request +<constant>MODE_LANG1_LANG2</constant> to record both languages or a +stereo signal.</para></footnote>) or +Lang1/Lang1</entry> + <entry>Language 1</entry> + <entry>Language 2</entry> + <entry>Lang1/Lang2 (preferred) or Lang1/Lang1</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-tuner; <structfield>index</structfield> is +out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-log-status.xml b/Documentation/DocBook/media/v4l/vidioc-log-status.xml new file mode 100644 index 00000000..5ded7d35 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-log-status.xml @@ -0,0 +1,41 @@ +<refentry id="vidioc-log-status"> + <refmeta> + <refentrytitle>ioctl VIDIOC_LOG_STATUS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_LOG_STATUS</refname> + <refpurpose>Log driver status information</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>As the video/audio devices become more complicated it +becomes harder to debug problems. When this ioctl is called the driver +will output the current device status to the kernel log. This is +particular useful when dealing with problems like no sound, no video +and incorrectly tuned channels. Also many modern devices autodetect +video and audio standards and this ioctl will report what the device +thinks what the standard is. Mismatches may give an indication where +the problem is.</para> + + <para>This ioctl is optional and not all drivers support it. It +was introduced in Linux 2.6.15.</para> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-overlay.xml b/Documentation/DocBook/media/v4l/vidioc-overlay.xml new file mode 100644 index 00000000..250a7de1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-overlay.xml @@ -0,0 +1,74 @@ +<refentry id="vidioc-overlay"> + <refmeta> + <refentrytitle>ioctl VIDIOC_OVERLAY</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_OVERLAY</refname> + <refpurpose>Start or stop video overlay</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_OVERLAY</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl is part of the <link linkend="overlay">video + overlay</link> I/O method. Applications call + <constant>VIDIOC_OVERLAY</constant> to start or stop the + overlay. It takes a pointer to an integer which must be set to + zero by the application to stop overlay, to one to start.</para> + + <para>Drivers do not support &VIDIOC-STREAMON; or +&VIDIOC-STREAMOFF; with <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The overlay parameters have not been set up. See <xref +linkend="overlay" /> for the necessary steps.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml b/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml new file mode 100644 index 00000000..7bde6987 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml @@ -0,0 +1,88 @@ +<refentry id="vidioc-prepare-buf"> + <refmeta> + <refentrytitle>ioctl VIDIOC_PREPARE_BUF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_PREPARE_BUF</refname> + <refpurpose>Prepare a buffer for I/O</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_buffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_PREPARE_BUF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Applications can optionally call the +<constant>VIDIOC_PREPARE_BUF</constant> ioctl to pass ownership of the buffer +to the driver before actually enqueuing it, using the +<constant>VIDIOC_QBUF</constant> ioctl, and to prepare it for future I/O. +Such preparations may include cache invalidation or cleaning. Performing them +in advance saves time during the actual I/O. In case such cache operations are +not required, the application can use one of +<constant>V4L2_BUF_FLAG_NO_CACHE_INVALIDATE</constant> and +<constant>V4L2_BUF_FLAG_NO_CACHE_CLEAN</constant> flags to skip the respective +step.</para> + + <para>The <structname>v4l2_buffer</structname> structure is +specified in <xref linkend="buffer" />.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>File I/O is in progress.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer <structfield>type</structfield> is not +supported, or the <structfield>index</structfield> is out of bounds, +or no buffers have been allocated yet, or the +<structfield>userptr</structfield> or +<structfield>length</structfield> are invalid.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml new file mode 100644 index 00000000..9caa49af --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml @@ -0,0 +1,177 @@ +<refentry id="vidioc-qbuf"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QBUF, VIDIOC_DQBUF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QBUF</refname> + <refname>VIDIOC_DQBUF</refname> + <refpurpose>Exchange a buffer with the driver</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_buffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QBUF, VIDIOC_DQBUF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Applications call the <constant>VIDIOC_QBUF</constant> ioctl +to enqueue an empty (capturing) or filled (output) buffer in the +driver's incoming queue. The semantics depend on the selected I/O +method.</para> + + <para>To enqueue a buffer applications set the <structfield>type</structfield> +field of a &v4l2-buffer; to the same buffer type as was previously used +with &v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers; +<structfield>type</structfield>. Applications must also set the +<structfield>index</structfield> field. Valid index numbers range from +zero to the number of buffers allocated with &VIDIOC-REQBUFS; +(&v4l2-requestbuffers; <structfield>count</structfield>) minus one. The +contents of the struct <structname>v4l2_buffer</structname> returned +by a &VIDIOC-QUERYBUF; ioctl will do as well. When the buffer is +intended for output (<structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>, or +<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>) applications must also +initialize the <structfield>bytesused</structfield>, +<structfield>field</structfield> and +<structfield>timestamp</structfield> fields, see <xref +linkend="buffer" /> for details. +Applications must also set <structfield>flags</structfield> to 0. If a driver +supports capturing from specific video inputs and you want to specify a video +input, then <structfield>flags</structfield> should be set to +<constant>V4L2_BUF_FLAG_INPUT</constant> and the field +<structfield>input</structfield> must be initialized to the desired input. +The <structfield>reserved</structfield> field must be set to 0. When using +the <link linkend="planar-apis">multi-planar API</link>, the +<structfield>m.planes</structfield> field must contain a userspace pointer +to a filled-in array of &v4l2-plane; and the <structfield>length</structfield> +field must be set to the number of elements in that array. +</para> + + <para>To enqueue a <link linkend="mmap">memory mapped</link> +buffer applications set the <structfield>memory</structfield> +field to <constant>V4L2_MEMORY_MMAP</constant>. When +<constant>VIDIOC_QBUF</constant> is called with a pointer to this +structure the driver sets the +<constant>V4L2_BUF_FLAG_MAPPED</constant> and +<constant>V4L2_BUF_FLAG_QUEUED</constant> flags and clears the +<constant>V4L2_BUF_FLAG_DONE</constant> flag in the +<structfield>flags</structfield> field, or it returns an +&EINVAL;.</para> + + <para>To enqueue a <link linkend="userp">user pointer</link> +buffer applications set the <structfield>memory</structfield> +field to <constant>V4L2_MEMORY_USERPTR</constant>, the +<structfield>m.userptr</structfield> field to the address of the +buffer and <structfield>length</structfield> to its size. When the multi-planar +API is used, <structfield>m.userptr</structfield> and +<structfield>length</structfield> members of the passed array of &v4l2-plane; +have to be used instead. When <constant>VIDIOC_QBUF</constant> is called with +a pointer to this structure the driver sets the +<constant>V4L2_BUF_FLAG_QUEUED</constant> flag and clears the +<constant>V4L2_BUF_FLAG_MAPPED</constant> and +<constant>V4L2_BUF_FLAG_DONE</constant> flags in the +<structfield>flags</structfield> field, or it returns an error code. +This ioctl locks the memory pages of the buffer in physical memory, +they cannot be swapped out to disk. Buffers remain locked until +dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is +called, or until the device is closed.</para> + + <para>Applications call the <constant>VIDIOC_DQBUF</constant> +ioctl to dequeue a filled (capturing) or displayed (output) buffer +from the driver's outgoing queue. They just set the +<structfield>type</structfield>, <structfield>memory</structfield> +and <structfield>reserved</structfield> +fields of a &v4l2-buffer; as above, when <constant>VIDIOC_DQBUF</constant> +is called with a pointer to this structure the driver fills the +remaining fields or returns an error code. The driver may also set +<constant>V4L2_BUF_FLAG_ERROR</constant> in the <structfield>flags</structfield> +field. It indicates a non-critical (recoverable) streaming error. In such case +the application may continue as normal, but should be aware that data in the +dequeued buffer might be corrupted. When using the multi-planar API, the +planes array does not have to be passed; the <structfield>m.planes</structfield> +member must be set to NULL in that case.</para> + + <para>By default <constant>VIDIOC_DQBUF</constant> blocks when no +buffer is in the outgoing queue. When the +<constant>O_NONBLOCK</constant> flag was given to the &func-open; +function, <constant>VIDIOC_DQBUF</constant> returns immediately +with an &EAGAIN; when no buffer is available.</para> + + <para>The <structname>v4l2_buffer</structname> structure is +specified in <xref linkend="buffer" />.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>Non-blocking I/O has been selected using +<constant>O_NONBLOCK</constant> and no buffer was in the outgoing +queue.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer <structfield>type</structfield> is not +supported, or the <structfield>index</structfield> is out of bounds, +or no buffers have been allocated yet, or the +<structfield>userptr</structfield> or +<structfield>length</structfield> are invalid.</para> + </listitem> + <term><errorcode>EIO</errorcode></term> + <listitem> + <para><constant>VIDIOC_DQBUF</constant> failed due to an +internal error. Can also indicate temporary problems like signal +loss. Note the driver might dequeue an (empty) buffer despite +returning an error, or even stop capturing. Reusing such buffer may be unsafe +though and its details (e.g. <structfield>index</structfield>) may not be +returned either. It is recommended that drivers indicate recoverable errors +by setting the <constant>V4L2_BUF_FLAG_ERROR</constant> and returning 0 instead. +In that case the application should be able to safely reuse the buffer and +continue streaming. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml b/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml new file mode 100644 index 00000000..23b17f60 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml @@ -0,0 +1,65 @@ +<refentry id="vidioc-query-dv-preset"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERY_DV_PRESET</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERY_DV_PRESET</refname> + <refpurpose>Sense the DV preset received by the current +input</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dv_preset *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERY_DV_PRESET</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The hardware may be able to detect the current DV preset +automatically, similar to sensing the video standard. To do so, applications +call <constant> VIDIOC_QUERY_DV_PRESET</constant> with a pointer to a +&v4l2-dv-preset; type. Once the hardware detects a preset, that preset is +returned in the preset field of &v4l2-dv-preset;. If the preset could not be +detected because there was no signal, or the signal was unreliable, or the +signal did not map to a supported preset, then the value V4L2_DV_INVALID is +returned.</para> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml new file mode 100644 index 00000000..6e414d7b --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml @@ -0,0 +1,102 @@ +<refentry id="vidioc-querybuf"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYBUF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYBUF</refname> + <refpurpose>Query the status of a buffer</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_buffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYBUF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl is part of the <link linkend="mmap">memory +mapping</link> I/O method. It can be used to query the status of a +buffer at any time after buffers have been allocated with the +&VIDIOC-REQBUFS; ioctl.</para> + + <para>Applications set the <structfield>type</structfield> field + of a &v4l2-buffer; to the same buffer type as was previously used with +&v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers; +<structfield>type</structfield>, and the <structfield>index</structfield> + field. Valid index numbers range from zero +to the number of buffers allocated with &VIDIOC-REQBUFS; + (&v4l2-requestbuffers; <structfield>count</structfield>) minus one. +The <structfield>reserved</structfield> field should to set to 0. +When using the <link linkend="planar-apis">multi-planar API</link>, the +<structfield>m.planes</structfield> field must contain a userspace pointer to an +array of &v4l2-plane; and the <structfield>length</structfield> field has +to be set to the number of elements in that array. +After calling <constant>VIDIOC_QUERYBUF</constant> with a pointer to + this structure drivers return an error code or fill the rest of +the structure.</para> + + <para>In the <structfield>flags</structfield> field the +<constant>V4L2_BUF_FLAG_MAPPED</constant>, +<constant>V4L2_BUF_FLAG_QUEUED</constant> and +<constant>V4L2_BUF_FLAG_DONE</constant> flags will be valid. The +<structfield>memory</structfield> field will be set to the current +I/O method. For the single-planar API, the <structfield>m.offset</structfield> +contains the offset of the buffer from the start of the device memory, +the <structfield>length</structfield> field its size. For the multi-planar API, +fields <structfield>m.mem_offset</structfield> and +<structfield>length</structfield> in the <structfield>m.planes</structfield> +array elements will be used instead. The driver may or may not set the remaining +fields and flags, they are meaningless in this context.</para> + + <para>The <structname>v4l2_buffer</structname> structure is + specified in <xref linkend="buffer" />.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer <structfield>type</structfield> is not +supported, or the <structfield>index</structfield> is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml new file mode 100644 index 00000000..4643505c --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -0,0 +1,317 @@ +<refentry id="vidioc-querycap"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYCAP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYCAP</refname> + <refpurpose>Query device capabilities</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_capability *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYCAP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>All V4L2 devices support the +<constant>VIDIOC_QUERYCAP</constant> ioctl. It is used to identify +kernel devices compatible with this specification and to obtain +information about driver and hardware capabilities. The ioctl takes a +pointer to a &v4l2-capability; which is filled by the driver. When the +driver is not compatible with this specification the ioctl returns an +&EINVAL;.</para> + + <table pgwide="1" frame="none" id="v4l2-capability"> + <title>struct <structname>v4l2_capability</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>driver</structfield>[16]</entry> + <entry><para>Name of the driver, a unique NUL-terminated +ASCII string. For example: "bttv". Driver specific applications can +use this information to verify the driver identity. It is also useful +to work around known bugs, or to identify drivers in error reports.</para> +<para>Storing strings in fixed sized arrays is bad +practice but unavoidable here. Drivers and applications should take +precautions to never read or write beyond the end of the array and to +make sure the strings are properly NUL-terminated.</para></entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>card</structfield>[32]</entry> + <entry>Name of the device, a NUL-terminated ASCII string. +For example: "Yoyodyne TV/FM". One driver may support different brands +or models of video hardware. This information is intended for users, +for example in a menu of available devices. Since multiple TV cards of +the same brand may be installed which are supported by the same +driver, this name should be combined with the character device file +name (⪚ <filename>/dev/video2</filename>) or the +<structfield>bus_info</structfield> string to avoid +ambiguities.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>bus_info</structfield>[32]</entry> + <entry>Location of the device in the system, a +NUL-terminated ASCII string. For example: "PCI Slot 4". This +information is intended for users, to distinguish multiple +identical devices. If no such information is available the field may +simply count the devices controlled by the driver, or contain the +empty string (<structfield>bus_info</structfield>[0] = 0).<!-- XXX pci_dev->slot_name example --></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>version</structfield></entry> + <entry><para>Version number of the driver.</para> +<para>Starting on kernel 3.1, the version reported is provided per +V4L2 subsystem, following the same Kernel numberation scheme. However, it +should not always return the same version as the kernel, if, for example, +an stable or distribution-modified kernel uses the V4L2 stack from a +newer kernel.</para> +<para>The version number is formatted using the +<constant>KERNEL_VERSION()</constant> macro:</para></entry> + </row> + <row> + <entry spanname="hspan"><para> +<programlisting> +#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c)) + +__u32 version = KERNEL_VERSION(0, 8, 1); + +printf ("Version: %u.%u.%u\n", + (version >> 16) & 0xFF, + (version >> 8) & 0xFF, + version & 0xFF); +</programlisting></para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capabilities</structfield></entry> + <entry>Available capabilities of the physical device as a whole, see <xref + linkend="device-capabilities" />. The same physical device can export + multiple devices in /dev (e.g. /dev/videoX, /dev/vbiY and /dev/radioZ). + The <structfield>capabilities</structfield> field should contain a union + of all capabilities available around the several V4L2 devices exported + to userspace. + For all those devices the <structfield>capabilities</structfield> field + returns the same set of capabilities. This allows applications to open + just one of the devices (typically the video device) and discover whether + video, vbi and/or radio are also supported. + </entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>device_caps</structfield></entry> + <entry>Device capabilities of the opened device, see <xref + linkend="device-capabilities" />. Should contain the available capabilities + of that specific device node. So, for example, <structfield>device_caps</structfield> + of a radio device will only contain radio related capabilities and + no video or vbi capabilities. This field is only set if the <structfield>capabilities</structfield> + field contains the <constant>V4L2_CAP_DEVICE_CAPS</constant> capability. + Only the <structfield>capabilities</structfield> field can have the + <constant>V4L2_CAP_DEVICE_CAPS</constant> capability, <structfield>device_caps</structfield> + will never set <constant>V4L2_CAP_DEVICE_CAPS</constant>. + </entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[3]</entry> + <entry>Reserved for future extensions. Drivers must set +this array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="device-capabilities"> + <title>Device Capabilities Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CAP_VIDEO_CAPTURE</constant></entry> + <entry>0x00000001</entry> + <entry>The device supports the single-planar API through the <link +linkend="capture">Video Capture</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_CAPTURE_MPLANE</constant></entry> + <entry>0x00001000</entry> + <entry>The device supports the + <link linkend="planar-apis">multi-planar API</link> through the + <link linkend="capture">Video Capture</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_OUTPUT</constant></entry> + <entry>0x00000002</entry> + <entry>The device supports the single-planar API through the <link +linkend="output">Video Output</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_OUTPUT_MPLANE</constant></entry> + <entry>0x00002000</entry> + <entry>The device supports the + <link linkend="planar-apis">multi-planar API</link> through the + <link linkend="output">Video Output</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_OVERLAY</constant></entry> + <entry>0x00000004</entry> + <entry>The device supports the <link +linkend="overlay">Video Overlay</link> interface. A video overlay device +typically stores captured images directly in the video memory of a +graphics card, with hardware clipping and scaling.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VBI_CAPTURE</constant></entry> + <entry>0x00000010</entry> + <entry>The device supports the <link linkend="raw-vbi">Raw +VBI Capture</link> interface, providing Teletext and Closed Caption +data.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VBI_OUTPUT</constant></entry> + <entry>0x00000020</entry> + <entry>The device supports the <link linkend="raw-vbi">Raw VBI Output</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_SLICED_VBI_CAPTURE</constant></entry> + <entry>0x00000040</entry> + <entry>The device supports the <link linkend="sliced">Sliced VBI Capture</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_SLICED_VBI_OUTPUT</constant></entry> + <entry>0x00000080</entry> + <entry>The device supports the <link linkend="sliced">Sliced VBI Output</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_RDS_CAPTURE</constant></entry> + <entry>0x00000100</entry> + <entry>The device supports the <link linkend="rds">RDS</link> capture interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_OUTPUT_OVERLAY</constant></entry> + <entry>0x00000200</entry> + <entry>The device supports the <link linkend="osd">Video +Output Overlay</link> (OSD) interface. Unlike the <wordasword>Video +Overlay</wordasword> interface, this is a secondary function of video +output devices and overlays an image onto an outgoing video signal. +When the driver sets this flag, it must clear the +<constant>V4L2_CAP_VIDEO_OVERLAY</constant> flag and vice +versa.<footnote><para>The &v4l2-framebuffer; lacks an +&v4l2-buf-type; field, therefore the type of overlay is implied by the +driver capabilities.</para></footnote></entry> + </row> + <row> + <entry><constant>V4L2_CAP_HW_FREQ_SEEK</constant></entry> + <entry>0x00000400</entry> + <entry>The device supports the &VIDIOC-S-HW-FREQ-SEEK; ioctl for +hardware frequency seeking.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_RDS_OUTPUT</constant></entry> + <entry>0x00000800</entry> + <entry>The device supports the <link linkend="rds">RDS</link> output interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_TUNER</constant></entry> + <entry>0x00010000</entry> + <entry>The device has some sort of tuner to +receive RF-modulated video signals. For more information about +tuner programming see +<xref linkend="tuner" />.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_AUDIO</constant></entry> + <entry>0x00020000</entry> + <entry>The device has audio inputs or outputs. It may or +may not support audio recording or playback, in PCM or compressed +formats. PCM audio support must be implemented as ALSA or OSS +interface. For more information on audio inputs and outputs see <xref + linkend="audio" />.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_RADIO</constant></entry> + <entry>0x00040000</entry> + <entry>This is a radio receiver.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_MODULATOR</constant></entry> + <entry>0x00080000</entry> + <entry>The device has some sort of modulator to +emit RF-modulated video/audio signals. For more information about +modulator programming see +<xref linkend="tuner" />.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_READWRITE</constant></entry> + <entry>0x01000000</entry> + <entry>The device supports the <link +linkend="rw">read()</link> and/or <link linkend="rw">write()</link> +I/O methods.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_ASYNCIO</constant></entry> + <entry>0x02000000</entry> + <entry>The device supports the <link +linkend="async">asynchronous</link> I/O methods.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_STREAMING</constant></entry> + <entry>0x04000000</entry> + <entry>The device supports the <link +linkend="mmap">streaming</link> I/O method.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_DEVICE_CAPS</constant></entry> + <entry>0x80000000</entry> + <entry>The driver fills the <structfield>device_caps</structfield> + field. This capability can only appear in the <structfield>capabilities</structfield> + field and never in the <structfield>device_caps</structfield> field.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml new file mode 100644 index 00000000..36660d31 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml @@ -0,0 +1,445 @@ +<refentry id="vidioc-queryctrl"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYCTRL, VIDIOC_QUERYMENU</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYCTRL</refname> + <refname>VIDIOC_QUERYMENU</refname> + <refpurpose>Enumerate controls and menu control items</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_queryctrl *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_querymenu *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYCTRL, VIDIOC_QUERYMENU</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a control applications set the +<structfield>id</structfield> field of a &v4l2-queryctrl; and call the +<constant>VIDIOC_QUERYCTRL</constant> ioctl with a pointer to this +structure. The driver fills the rest of the structure or returns an +&EINVAL; when the <structfield>id</structfield> is invalid.</para> + + <para>It is possible to enumerate controls by calling +<constant>VIDIOC_QUERYCTRL</constant> with successive +<structfield>id</structfield> values starting from +<constant>V4L2_CID_BASE</constant> up to and exclusive +<constant>V4L2_CID_BASE_LASTP1</constant>. Drivers may return +<errorcode>EINVAL</errorcode> if a control in this range is not +supported. Further applications can enumerate private controls, which +are not defined in this specification, by starting at +<constant>V4L2_CID_PRIVATE_BASE</constant> and incrementing +<structfield>id</structfield> until the driver returns +<errorcode>EINVAL</errorcode>.</para> + + <para>In both cases, when the driver sets the +<constant>V4L2_CTRL_FLAG_DISABLED</constant> flag in the +<structfield>flags</structfield> field this control is permanently +disabled and should be ignored by the application.<footnote> + <para><constant>V4L2_CTRL_FLAG_DISABLED</constant> was +intended for two purposes: Drivers can skip predefined controls not +supported by the hardware (although returning EINVAL would do as +well), or disable predefined and private controls after hardware +detection without the trouble of reordering control arrays and indices +(EINVAL cannot be used to skip private controls because it would +prematurely end the enumeration).</para></footnote></para> + + <para>When the application ORs <structfield>id</structfield> with +<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> the driver returns the +next supported control, or <errorcode>EINVAL</errorcode> if there is +none. Drivers which do not support this flag yet always return +<errorcode>EINVAL</errorcode>.</para> + + <para>Additional information is required for menu controls: the +names of the menu items. To query them applications set the +<structfield>id</structfield> and <structfield>index</structfield> +fields of &v4l2-querymenu; and call the +<constant>VIDIOC_QUERYMENU</constant> ioctl with a pointer to this +structure. The driver fills the rest of the structure or returns an +&EINVAL; when the <structfield>id</structfield> or +<structfield>index</structfield> is invalid. Menu items are enumerated +by calling <constant>VIDIOC_QUERYMENU</constant> with successive +<structfield>index</structfield> values from &v4l2-queryctrl; +<structfield>minimum</structfield> to +<structfield>maximum</structfield>, inclusive. Note that it is possible +for <constant>VIDIOC_QUERYMENU</constant> to return an &EINVAL; for some +indices between <structfield>minimum</structfield> and <structfield>maximum</structfield>. +In that case that particular menu item is not supported by this driver. Also note that +the <structfield>minimum</structfield> value is not necessarily 0.</para> + + <para>See also the examples in <xref linkend="control" />.</para> + + <table pgwide="1" frame="none" id="v4l2-queryctrl"> + <title>struct <structname>v4l2_queryctrl</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>Identifies the control, set by the application. See +<xref linkend="control-id" /> for predefined IDs. When the ID is ORed +with V4L2_CTRL_FLAG_NEXT_CTRL the driver clears the flag and returns +the first control with a higher ID. Drivers which do not support this +flag yet always return an &EINVAL;.</entry> + </row> + <row> + <entry>&v4l2-ctrl-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of control, see <xref + linkend="v4l2-ctrl-type" />.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the control, a NUL-terminated ASCII +string. This information is intended for the user.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>minimum</structfield></entry> + <entry>Minimum value, inclusive. This field gives a lower +bound for <constant>V4L2_CTRL_TYPE_INTEGER</constant> controls and the +lowest valid index for <constant>V4L2_CTRL_TYPE_MENU</constant> controls. +For <constant>V4L2_CTRL_TYPE_STRING</constant> controls the minimum value +gives the minimum length of the string. This length <emphasis>does not include the terminating +zero</emphasis>. It may not be valid for any other type of control, including +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> controls. Note that this is a +signed value.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>maximum</structfield></entry> + <entry>Maximum value, inclusive. This field gives an upper +bound for <constant>V4L2_CTRL_TYPE_INTEGER</constant> controls and the +highest valid index for <constant>V4L2_CTRL_TYPE_MENU</constant> +controls. For <constant>V4L2_CTRL_TYPE_BITMASK</constant> controls it is the +set of usable bits. +For <constant>V4L2_CTRL_TYPE_STRING</constant> controls the maximum value +gives the maximum length of the string. This length <emphasis>does not include the terminating +zero</emphasis>. It may not be valid for any other type of control, including +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> controls. Note that this is a +signed value.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>step</structfield></entry> + <entry><para>This field gives a step size for +<constant>V4L2_CTRL_TYPE_INTEGER</constant> controls. For +<constant>V4L2_CTRL_TYPE_STRING</constant> controls this field refers to +the string length that has to be a multiple of this step size. +It may not be valid for any other type of control, including +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> +controls.</para><para>Generally drivers should not scale hardware +control values. It may be necessary for example when the +<structfield>name</structfield> or <structfield>id</structfield> imply +a particular unit and the hardware actually accepts only multiples of +said unit. If so, drivers must take care values are properly rounded +when scaling, such that errors will not accumulate on repeated +read-write cycles.</para><para>This field gives the smallest change of +an integer control actually affecting hardware. Often the information +is needed when the user can change controls by keyboard or GUI +buttons, rather than a slider. When for example a hardware register +accepts values 0-511 and the driver reports 0-65535, step should be +128.</para><para>Note that although signed, the step value is supposed to +be always positive.</para></entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>default_value</structfield></entry> + <entry>The default value of a +<constant>V4L2_CTRL_TYPE_INTEGER</constant>, +<constant>_BOOLEAN</constant> or <constant>_MENU</constant> control. +Not valid for other types of controls. Drivers reset controls only +when the driver is loaded, not later, in particular not when the +func-open; is called.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Control flags, see <xref + linkend="control-flags" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-querymenu"> + <title>struct <structname>v4l2_querymenu</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>Identifies the control, set by the application +from the respective &v4l2-queryctrl; +<structfield>id</structfield>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Index of the menu item, starting at zero, set by + the application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the menu item, a NUL-terminated ASCII +string. This information is intended for the user.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield></entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-ctrl-type"> + <title>enum v4l2_ctrl_type</title> + <tgroup cols="5" align="left"> + <colspec colwidth="30*" /> + <colspec colwidth="5*" align="center" /> + <colspec colwidth="5*" align="center" /> + <colspec colwidth="5*" align="center" /> + <colspec colwidth="55*" /> + <thead> + <row> + <entry>Type</entry> + <entry><structfield>minimum</structfield></entry> + <entry><structfield>step</structfield></entry> + <entry><structfield>maximum</structfield></entry> + <entry>Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_CTRL_TYPE_INTEGER</constant></entry> + <entry>any</entry> + <entry>any</entry> + <entry>any</entry> + <entry>An integer-valued control ranging from minimum to +maximum inclusive. The step value indicates the increment between +values which are actually different on the hardware.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_BOOLEAN</constant></entry> + <entry>0</entry> + <entry>1</entry> + <entry>1</entry> + <entry>A boolean-valued control. Zero corresponds to +"disabled", and one means "enabled".</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_MENU</constant></entry> + <entry>≥ 0</entry> + <entry>1</entry> + <entry>N-1</entry> + <entry>The control has a menu of N choices. The names of +the menu items can be enumerated with the +<constant>VIDIOC_QUERYMENU</constant> ioctl.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_BITMASK</constant></entry> + <entry>0</entry> + <entry>n/a</entry> + <entry>any</entry> + <entry>A bitmask field. The maximum value is the set of bits that can +be used, all other bits are to be 0. The maximum value is interpreted as a __u32, +allowing the use of bit 31 in the bitmask.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_BUTTON</constant></entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>A control which performs an action when set. +Drivers must ignore the value passed with +<constant>VIDIOC_S_CTRL</constant> and return an &EINVAL; on a +<constant>VIDIOC_G_CTRL</constant> attempt.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_INTEGER64</constant></entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>A 64-bit integer valued control. Minimum, maximum +and step size cannot be queried.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_STRING</constant></entry> + <entry>≥ 0</entry> + <entry>≥ 1</entry> + <entry>≥ 0</entry> + <entry>The minimum and maximum string lengths. The step size +means that the string must be (minimum + N * step) characters long for +N ≥ 0. These lengths do not include the terminating zero, so in order to +pass a string of length 8 to &VIDIOC-S-EXT-CTRLS; you need to set the +<structfield>size</structfield> field of &v4l2-ext-control; to 9. For &VIDIOC-G-EXT-CTRLS; you can +set the <structfield>size</structfield> field to <structfield>maximum</structfield> + 1. +Which character encoding is used will depend on the string control itself and +should be part of the control documentation.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant></entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>This is not a control. When +<constant>VIDIOC_QUERYCTRL</constant> is called with a control ID +equal to a control class code (see <xref linkend="ctrl-class" />) + 1, the +ioctl returns the name of the control class and this control type. +Older drivers which do not support this feature return an +&EINVAL;.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="control-flags"> + <title>Control Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CTRL_FLAG_DISABLED</constant></entry> + <entry>0x0001</entry> + <entry>This control is permanently disabled and should be +ignored by the application. Any attempt to change the control will +result in an &EINVAL;.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_GRABBED</constant></entry> + <entry>0x0002</entry> + <entry>This control is temporarily unchangeable, for +example because another application took over control of the +respective resource. Such controls may be displayed specially in a +user interface. Attempts to change the control may result in an +&EBUSY;.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_READ_ONLY</constant></entry> + <entry>0x0004</entry> + <entry>This control is permanently readable only. Any +attempt to change the control will result in an &EINVAL;.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_UPDATE</constant></entry> + <entry>0x0008</entry> + <entry>A hint that changing this control may affect the +value of other controls within the same control class. Applications +should update their user interface accordingly.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_INACTIVE</constant></entry> + <entry>0x0010</entry> + <entry>This control is not applicable to the current +configuration and should be displayed accordingly in a user interface. +For example the flag may be set on a MPEG audio level 2 bitrate +control when MPEG audio encoding level 1 was selected with another +control.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_SLIDER</constant></entry> + <entry>0x0020</entry> + <entry>A hint that this control is best represented as a +slider-like element in a user interface.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_WRITE_ONLY</constant></entry> + <entry>0x0040</entry> + <entry>This control is permanently writable only. Any +attempt to read the control will result in an &EACCES; error code. This +flag is typically present for relative controls or action controls where +writing a value will cause the device to carry out a given action +(⪚ motor control) but no meaningful value can be returned.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_VOLATILE</constant></entry> + <entry>0x0080</entry> + <entry>This control is volatile, which means that the value of the control +changes continuously. A typical example would be the current gain value if the device +is in auto-gain mode. In such a case the hardware calculates the gain value based on +the lighting conditions which can change over time. Note that setting a new value for +a volatile control will have no effect. The new value will just be ignored.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-queryctrl; <structfield>id</structfield> +is invalid. The &v4l2-querymenu; <structfield>id</structfield> is +invalid or <structfield>index</structfield> is out of range (less than +<structfield>minimum</structfield> or greater than <structfield>maximum</structfield>) +or this particular menu item is not supported by the driver.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>An attempt was made to read a write-only control.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-querystd.xml b/Documentation/DocBook/media/v4l/vidioc-querystd.xml new file mode 100644 index 00000000..4b79c7c0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-querystd.xml @@ -0,0 +1,66 @@ +<refentry id="vidioc-querystd"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYSTD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYSTD</refname> + <refpurpose>Sense the video standard received by the current +input</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_std_id *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYSTD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The hardware may be able to detect the current video +standard automatically. To do so, applications call <constant> +VIDIOC_QUERYSTD</constant> with a pointer to a &v4l2-std-id; type. The +driver stores here a set of candidates, this can be a single flag or a +set of supported standards if for example the hardware can only +distinguish between 50 and 60 Hz systems. When detection is not +possible or fails, the set must contain all standards supported by the +current video input or output.</para> + + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml new file mode 100644 index 00000000..7be4b1d2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml @@ -0,0 +1,134 @@ +<refentry id="vidioc-reqbufs"> + <refmeta> + <refentrytitle>ioctl VIDIOC_REQBUFS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_REQBUFS</refname> + <refpurpose>Initiate Memory Mapping or User Pointer I/O</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_requestbuffers *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_REQBUFS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl is used to initiate <link linkend="mmap">memory +mapped</link> or <link linkend="userp">user pointer</link> +I/O. Memory mapped buffers are located in device memory and must be +allocated with this ioctl before they can be mapped into the +application's address space. User buffers are allocated by +applications themselves, and this ioctl is merely used to switch the +driver into user pointer I/O mode and to setup some internal structures.</para> + + <para>To allocate device buffers applications initialize all +fields of the <structname>v4l2_requestbuffers</structname> structure. +They set the <structfield>type</structfield> field to the respective +stream or buffer type, the <structfield>count</structfield> field to +the desired number of buffers, <structfield>memory</structfield> +must be set to the requested I/O method and the <structfield>reserved</structfield> array +must be zeroed. When the ioctl +is called with a pointer to this structure the driver will attempt to allocate +the requested number of buffers and it stores the actual number +allocated in the <structfield>count</structfield> field. It can be +smaller than the number requested, even zero, when the driver runs out +of free memory. A larger number is also possible when the driver requires +more buffers to function correctly. For example video output requires at least two buffers, +one displayed and one filled by the application.</para> + <para>When the I/O method is not supported the ioctl +returns an &EINVAL;.</para> + + <para>Applications can call <constant>VIDIOC_REQBUFS</constant> +again to change the number of buffers, however this cannot succeed +when any buffers are still mapped. A <structfield>count</structfield> +value of zero frees all buffers, after aborting or finishing any DMA +in progress, an implicit &VIDIOC-STREAMOFF;. <!-- mhs: I see no +reason why munmap()ping one or even all buffers must imply +streamoff.--></para> + + <table pgwide="1" frame="none" id="v4l2-requestbuffers"> + <title>struct <structname>v4l2_requestbuffers</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>count</structfield></entry> + <entry>The number of buffers requested or granted.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the stream or buffers, this is the same +as the &v4l2-format; <structfield>type</structfield> field. See <xref + linkend="v4l2-buf-type" /> for valid values.</entry> + </row> + <row> + <entry>&v4l2-memory;</entry> + <entry><structfield>memory</structfield></entry> + <entry>Applications set this field to +<constant>V4L2_MEMORY_MMAP</constant> or +<constant>V4L2_MEMORY_USERPTR</constant>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>A place holder for future extensions and custom +(driver defined) buffer types <constant>V4L2_BUF_TYPE_PRIVATE</constant> and +higher. This array should be zeroed by applications.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer type (<structfield>type</structfield> field) or the +requested I/O method (<structfield>memory</structfield>) is not +supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml new file mode 100644 index 00000000..18b1a826 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml @@ -0,0 +1,127 @@ +<refentry id="vidioc-s-hw-freq-seek"> + <refmeta> + <refentrytitle>ioctl VIDIOC_S_HW_FREQ_SEEK</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_S_HW_FREQ_SEEK</refname> + <refpurpose>Perform a hardware frequency seek</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_hw_freq_seek +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_S_HW_FREQ_SEEK</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Start a hardware frequency seek from the current frequency. +To do this applications initialize the <structfield>tuner</structfield>, +<structfield>type</structfield>, <structfield>seek_upward</structfield>, +<structfield>spacing</structfield> and +<structfield>wrap_around</structfield> fields, and zero out the +<structfield>reserved</structfield> array of a &v4l2-hw-freq-seek; and +call the <constant>VIDIOC_S_HW_FREQ_SEEK</constant> ioctl with a pointer +to this structure.</para> + + <para>This ioctl is supported if the <constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability is set.</para> + + <table pgwide="1" frame="none" id="v4l2-hw-freq-seek"> + <title>struct <structname>v4l2_hw_freq_seek</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>tuner</structfield></entry> + <entry>The tuner index number. This is the +same value as in the &v4l2-input; <structfield>tuner</structfield> +field and the &v4l2-tuner; <structfield>index</structfield> field.</entry> + </row> + <row> + <entry>&v4l2-tuner-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>The tuner type. This is the same value as in the +&v4l2-tuner; <structfield>type</structfield> field.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>seek_upward</structfield></entry> + <entry>If non-zero, seek upward from the current frequency, else seek downward.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>wrap_around</structfield></entry> + <entry>If non-zero, wrap around when at the end of the frequency range, else stop seeking.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>spacing</structfield></entry> + <entry>If non-zero, defines the hardware seek resolution in Hz. The driver selects the nearest value that is supported by the device. If spacing is zero a reasonable default value is used.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[7]</entry> + <entry>Reserved for future extensions. Applications + must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>tuner</structfield> index is out of +bounds, the wrap_around value is not supported or the value in the <structfield>type</structfield> field is +wrong.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>The ioctl timed-out. Try again.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-streamon.xml b/Documentation/DocBook/media/v4l/vidioc-streamon.xml new file mode 100644 index 00000000..81cca456 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-streamon.xml @@ -0,0 +1,107 @@ +<refentry id="vidioc-streamon"> + <refmeta> + <refentrytitle>ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_STREAMON</refname> + <refname>VIDIOC_STREAMOFF</refname> + <refpurpose>Start or stop streaming I/O</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_STREAMON, VIDIOC_STREAMOFF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The <constant>VIDIOC_STREAMON</constant> and +<constant>VIDIOC_STREAMOFF</constant> ioctl start and stop the capture +or output process during streaming (<link linkend="mmap">memory +mapping</link> or <link linkend="userp">user pointer</link>) I/O.</para> + + <para>Specifically the capture hardware is disabled and no input +buffers are filled (if there are any empty buffers in the incoming +queue) until <constant>VIDIOC_STREAMON</constant> has been called. +Accordingly the output hardware is disabled, no video signal is +produced until <constant>VIDIOC_STREAMON</constant> has been called. +The ioctl will succeed only when at least one output buffer is in the +incoming queue.</para> + + <para>The <constant>VIDIOC_STREAMOFF</constant> ioctl, apart of +aborting or finishing any DMA in progress, unlocks any user pointer +buffers locked in physical memory, and it removes all buffers from the +incoming and outgoing queues. That means all images captured but not +dequeued yet will be lost, likewise all images enqueued for output but +not transmitted yet. I/O returns to the same state as after calling +&VIDIOC-REQBUFS; and can be restarted accordingly.</para> + + <para>Both ioctls take a pointer to an integer, the desired buffer or +stream type. This is the same as &v4l2-requestbuffers; +<structfield>type</structfield>.</para> + + <para>Note applications can be preempted for unknown periods right +before or after the <constant>VIDIOC_STREAMON</constant> or +<constant>VIDIOC_STREAMOFF</constant> calls, there is no notion of +starting or stopping "now". Buffer timestamps can be used to +synchronize with other events.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer<structfield>type</structfield> is not supported, + or no buffers have been allocated (memory mapping) or enqueued + (output) yet.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EPIPE</errorcode></term> + <listitem> + <para>The driver implements <link + linkend="pad-level-formats">pad-level format configuration</link> and + the pipeline configuration is invalid. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-interval.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-interval.xml new file mode 100644 index 00000000..2f8f4f0a --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-interval.xml @@ -0,0 +1,152 @@ +<refentry id="vidioc-subdev-enum-frame-interval"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</refname> + <refpurpose>Enumerate frame intervals</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_subdev_frame_interval_enum * + <parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental">experimental</link> + interface and may change in the future.</para> + </note> + + <para>This ioctl lets applications enumerate available frame intervals on a + given sub-device pad. Frame intervals only makes sense for sub-devices that + can control the frame period on their own. This includes, for instance, + image sensors and TV tuners.</para> + + <para>For the common use case of image sensors, the frame intervals + available on the sub-device output pad depend on the frame format and size + on the same pad. Applications must thus specify the desired format and size + when enumerating frame intervals.</para> + + <para>To enumerate frame intervals applications initialize the + <structfield>index</structfield>, <structfield>pad</structfield>, + <structfield>code</structfield>, <structfield>width</structfield> and + <structfield>height</structfield> fields of + &v4l2-subdev-frame-interval-enum; and call the + <constant>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</constant> ioctl with a pointer + to this structure. Drivers fill the rest of the structure or return + an &EINVAL; if one of the input fields is invalid. All frame intervals are + enumerable by beginning at index zero and incrementing by one until + <errorcode>EINVAL</errorcode> is returned.</para> + + <para>Available frame intervals may depend on the current 'try' formats + at other pads of the sub-device, as well as on the current active links. See + &VIDIOC-SUBDEV-G-FMT; for more information about the try formats.</para> + + <para>Sub-devices that support the frame interval enumeration ioctl should + implemented it on a single pad only. Its behaviour when supported on + multiple pads of the same sub-device is not defined.</para> + + <table pgwide="1" frame="none" id="v4l2-subdev-frame-interval-enum"> + <title>struct <structname>v4l2_subdev_frame_interval_enum</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the format in the enumeration, set by the + application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pad</structfield></entry> + <entry>Pad number as reported by the media controller API.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>code</structfield></entry> + <entry>The media bus format code, as defined in + <xref linkend="v4l2-mbus-format" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Frame width, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Frame height, in pixels.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>interval</structfield></entry> + <entry>Period, in seconds, between consecutive video frames.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[9]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-subdev-frame-interval-enum; + <structfield>pad</structfield> references a non-existing pad, one of + the <structfield>code</structfield>, <structfield>width</structfield> + or <structfield>height</structfield> fields are invalid for the given + pad or the <structfield>index</structfield> field is out of bounds. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-size.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-size.xml new file mode 100644 index 00000000..79ce42b7 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-size.xml @@ -0,0 +1,154 @@ +<refentry id="vidioc-subdev-enum-frame-size"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refname> + <refpurpose>Enumerate media bus frame sizes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_subdev_frame_size_enum * + <parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental">experimental</link> + interface and may change in the future.</para> + </note> + + <para>This ioctl allows applications to enumerate all frame sizes + supported by a sub-device on the given pad for the given media bus format. + Supported formats can be retrieved with the &VIDIOC-SUBDEV-ENUM-MBUS-CODE; + ioctl.</para> + + <para>To enumerate frame sizes applications initialize the + <structfield>pad</structfield>, <structfield>code</structfield> and + <structfield>index</structfield> fields of the + &v4l2-subdev-mbus-code-enum; and call the + <constant>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</constant> ioctl with a pointer to + the structure. Drivers fill the minimum and maximum frame sizes or return + an &EINVAL; if one of the input parameters is invalid.</para> + + <para>Sub-devices that only support discrete frame sizes (such as most + sensors) will return one or more frame sizes with identical minimum and + maximum values.</para> + + <para>Not all possible sizes in given [minimum, maximum] ranges need to be + supported. For instance, a scaler that uses a fixed-point scaling ratio + might not be able to produce every frame size between the minimum and + maximum values. Applications must use the &VIDIOC-SUBDEV-S-FMT; ioctl to + try the sub-device for an exact supported frame size.</para> + + <para>Available frame sizes may depend on the current 'try' formats at other + pads of the sub-device, as well as on the current active links and the + current values of V4L2 controls. See &VIDIOC-SUBDEV-G-FMT; for more + information about try formats.</para> + + <table pgwide="1" frame="none" id="v4l2-subdev-frame-size-enum"> + <title>struct <structname>v4l2_subdev_frame_size_enum</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the format in the enumeration, set by the + application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pad</structfield></entry> + <entry>Pad number as reported by the media controller API.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>code</structfield></entry> + <entry>The media bus format code, as defined in + <xref linkend="v4l2-mbus-format" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>min_width</structfield></entry> + <entry>Minimum frame width, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_width</structfield></entry> + <entry>Maximum frame width, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>min_height</structfield></entry> + <entry>Minimum frame height, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_height</structfield></entry> + <entry>Maximum frame height, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[9]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-subdev-frame-size-enum; <structfield>pad</structfield> + references a non-existing pad, the <structfield>code</structfield> is + invalid for the given pad or the <structfield>index</structfield> + field is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-enum-mbus-code.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-mbus-code.xml new file mode 100644 index 00000000..a6b34324 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-mbus-code.xml @@ -0,0 +1,119 @@ +<refentry id="vidioc-subdev-enum-mbus-code"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_MBUS_CODE</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBDEV_ENUM_MBUS_CODE</refname> + <refpurpose>Enumerate media bus formats</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_subdev_mbus_code_enum * + <parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_SUBDEV_ENUM_MBUS_CODE</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental">experimental</link> + interface and may change in the future.</para> + </note> + + <para>To enumerate media bus formats available at a given sub-device pad + applications initialize the <structfield>pad</structfield> and + <structfield>index</structfield> fields of &v4l2-subdev-mbus-code-enum; and + call the <constant>VIDIOC_SUBDEV_ENUM_MBUS_CODE</constant> ioctl with a + pointer to this structure. Drivers fill the rest of the structure or return + an &EINVAL; if either the <structfield>pad</structfield> or + <structfield>index</structfield> are invalid. All media bus formats are + enumerable by beginning at index zero and incrementing by one until + <errorcode>EINVAL</errorcode> is returned.</para> + + <para>Available media bus formats may depend on the current 'try' formats + at other pads of the sub-device, as well as on the current active links. See + &VIDIOC-SUBDEV-G-FMT; for more information about the try formats.</para> + + <table pgwide="1" frame="none" id="v4l2-subdev-mbus-code-enum"> + <title>struct <structname>v4l2_subdev_mbus_code_enum</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>pad</structfield></entry> + <entry>Pad number as reported by the media controller API.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the format in the enumeration, set by the + application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>code</structfield></entry> + <entry>The media bus format code, as defined in + <xref linkend="v4l2-mbus-format" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[9]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-subdev-mbus-code-enum; <structfield>pad</structfield> + references a non-existing pad, or the <structfield>index</structfield> + field is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-crop.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-crop.xml new file mode 100644 index 00000000..06197323 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-crop.xml @@ -0,0 +1,155 @@ +<refentry id="vidioc-subdev-g-crop"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBDEV_G_CROP</refname> + <refname>VIDIOC_SUBDEV_S_CROP</refname> + <refpurpose>Get or set the crop rectangle on a subdev pad</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_subdev_crop *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_subdev_crop *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental">experimental</link> + interface and may change in the future.</para> + </note> + + <para>To retrieve the current crop rectangle applications set the + <structfield>pad</structfield> field of a &v4l2-subdev-crop; to the + desired pad number as reported by the media API and the + <structfield>which</structfield> field to + <constant>V4L2_SUBDEV_FORMAT_ACTIVE</constant>. They then call the + <constant>VIDIOC_SUBDEV_G_CROP</constant> ioctl with a pointer to this + structure. The driver fills the members of the <structfield>rect</structfield> + field or returns &EINVAL; if the input arguments are invalid, or if cropping + is not supported on the given pad.</para> + + <para>To change the current crop rectangle applications set both the + <structfield>pad</structfield> and <structfield>which</structfield> fields + and all members of the <structfield>rect</structfield> field. They then call + the <constant>VIDIOC_SUBDEV_S_CROP</constant> ioctl with a pointer to this + structure. The driver verifies the requested crop rectangle, adjusts it + based on the hardware capabilities and configures the device. Upon return + the &v4l2-subdev-crop; contains the current format as would be returned + by a <constant>VIDIOC_SUBDEV_G_CROP</constant> call.</para> + + <para>Applications can query the device capabilities by setting the + <structfield>which</structfield> to + <constant>V4L2_SUBDEV_FORMAT_TRY</constant>. When set, 'try' crop + rectangles are not applied to the device by the driver, but are mangled + exactly as active crop rectangles and stored in the sub-device file handle. + Two applications querying the same sub-device would thus not interact with + each other.</para> + + <para>Drivers must not return an error solely because the requested crop + rectangle doesn't match the device capabilities. They must instead modify + the rectangle to match what the hardware can provide. The modified format + should be as close as possible to the original request.</para> + + <table pgwide="1" frame="none" id="v4l2-subdev-crop"> + <title>struct <structname>v4l2_subdev_crop</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>pad</structfield></entry> + <entry>Pad number as reported by the media framework.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>which</structfield></entry> + <entry>Crop rectangle to get or set, from + &v4l2-subdev-format-whence;.</entry> + </row> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>rect</structfield></entry> + <entry>Crop rectangle boundaries, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[8]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The crop rectangle can't be changed because the pad is currently + busy. This can be caused, for instance, by an active video stream on + the pad. The ioctl must not be retried without performing another + action to fix the problem first. Only returned by + <constant>VIDIOC_SUBDEV_S_CROP</constant></para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-subdev-crop; <structfield>pad</structfield> + references a non-existing pad, the <structfield>which</structfield> + field references a non-existing format, or cropping is not supported + on the given subdev pad.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml new file mode 100644 index 00000000..a67cde6f --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml @@ -0,0 +1,183 @@ +<refentry id="vidioc-subdev-g-fmt"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBDEV_G_FMT</refname> + <refname>VIDIOC_SUBDEV_S_FMT</refname> + <refpurpose>Get or set the data format on a subdev pad</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_subdev_format *<parameter>argp</parameter> + </paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental">experimental</link> + interface and may change in the future.</para> + </note> + + <para>These ioctls are used to negotiate the frame format at specific + subdev pads in the image pipeline.</para> + + <para>To retrieve the current format applications set the + <structfield>pad</structfield> field of a &v4l2-subdev-format; to the + desired pad number as reported by the media API and the + <structfield>which</structfield> field to + <constant>V4L2_SUBDEV_FORMAT_ACTIVE</constant>. When they call the + <constant>VIDIOC_SUBDEV_G_FMT</constant> ioctl with a pointer to this + structure the driver fills the members of the <structfield>format</structfield> + field.</para> + + <para>To change the current format applications set both the + <structfield>pad</structfield> and <structfield>which</structfield> fields + and all members of the <structfield>format</structfield> field. When they + call the <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl with a pointer to this + structure the driver verifies the requested format, adjusts it based on the + hardware capabilities and configures the device. Upon return the + &v4l2-subdev-format; contains the current format as would be returned by a + <constant>VIDIOC_SUBDEV_G_FMT</constant> call.</para> + + <para>Applications can query the device capabilities by setting the + <structfield>which</structfield> to + <constant>V4L2_SUBDEV_FORMAT_TRY</constant>. When set, 'try' formats are not + applied to the device by the driver, but are changed exactly as active + formats and stored in the sub-device file handle. Two applications querying + the same sub-device would thus not interact with each other.</para> + + <para>For instance, to try a format at the output pad of a sub-device, + applications would first set the try format at the sub-device input with the + <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl. They would then either + retrieve the default format at the output pad with the + <constant>VIDIOC_SUBDEV_G_FMT</constant> ioctl, or set the desired output + pad format with the <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl and check + the returned value.</para> + + <para>Try formats do not depend on active formats, but can depend on the + current links configuration or sub-device controls value. For instance, a + low-pass noise filter might crop pixels at the frame boundaries, modifying + its output frame size.</para> + + <para>Drivers must not return an error solely because the requested format + doesn't match the device capabilities. They must instead modify the format + to match what the hardware can provide. The modified format should be as + close as possible to the original request.</para> + + <table pgwide="1" frame="none" id="v4l2-subdev-format"> + <title>struct <structname>v4l2_subdev_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>pad</structfield></entry> + <entry>Pad number as reported by the media controller API.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>which</structfield></entry> + <entry>Format to modified, from &v4l2-subdev-format-whence;.</entry> + </row> + <row> + <entry>&v4l2-mbus-framefmt;</entry> + <entry><structfield>format</structfield></entry> + <entry>Definition of an image format, see <xref + linkend="v4l2-mbus-framefmt" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[8]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-subdev-format-whence"> + <title>enum <structname>v4l2_subdev_format_whence</structname></title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry>V4L2_SUBDEV_FORMAT_TRY</entry> + <entry>0</entry> + <entry>Try formats, used for querying device capabilities.</entry> + </row> + <row> + <entry>V4L2_SUBDEV_FORMAT_ACTIVE</entry> + <entry>1</entry> + <entry>Active formats, applied to the hardware.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The format can't be changed because the pad is currently busy. + This can be caused, for instance, by an active video stream on the + pad. The ioctl must not be retried without performing another action + to fix the problem first. Only returned by + <constant>VIDIOC_SUBDEV_S_FMT</constant></para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-subdev-format; <structfield>pad</structfield> + references a non-existing pad, or the <structfield>which</structfield> + field references a non-existing format.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-frame-interval.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-frame-interval.xml new file mode 100644 index 00000000..0bc3ea22 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-frame-interval.xml @@ -0,0 +1,141 @@ +<refentry id="vidioc-subdev-g-frame-interval"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBDEV_G_FRAME_INTERVAL</refname> + <refname>VIDIOC_SUBDEV_S_FRAME_INTERVAL</refname> + <refpurpose>Get or set the frame interval on a subdev pad</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_subdev_frame_interval *<parameter>argp</parameter> + </paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental">experimental</link> + interface and may change in the future.</para> + </note> + + <para>These ioctls are used to get and set the frame interval at specific + subdev pads in the image pipeline. The frame interval only makes sense for + sub-devices that can control the frame period on their own. This includes, + for instance, image sensors and TV tuners. Sub-devices that don't support + frame intervals must not implement these ioctls.</para> + + <para>To retrieve the current frame interval applications set the + <structfield>pad</structfield> field of a &v4l2-subdev-frame-interval; to + the desired pad number as reported by the media controller API. When they + call the <constant>VIDIOC_SUBDEV_G_FRAME_INTERVAL</constant> ioctl with a + pointer to this structure the driver fills the members of the + <structfield>interval</structfield> field.</para> + + <para>To change the current frame interval applications set both the + <structfield>pad</structfield> field and all members of the + <structfield>interval</structfield> field. When they call the + <constant>VIDIOC_SUBDEV_S_FRAME_INTERVAL</constant> ioctl with a pointer to + this structure the driver verifies the requested interval, adjusts it based + on the hardware capabilities and configures the device. Upon return the + &v4l2-subdev-frame-interval; contains the current frame interval as would be + returned by a <constant>VIDIOC_SUBDEV_G_FRAME_INTERVAL</constant> call. + </para> + + <para>Drivers must not return an error solely because the requested interval + doesn't match the device capabilities. They must instead modify the interval + to match what the hardware can provide. The modified interval should be as + close as possible to the original request.</para> + + <para>Sub-devices that support the frame interval ioctls should implement + them on a single pad only. Their behaviour when supported on multiple pads + of the same sub-device is not defined.</para> + + <table pgwide="1" frame="none" id="v4l2-subdev-frame-interval"> + <title>struct <structname>v4l2_subdev_frame_interval</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>pad</structfield></entry> + <entry>Pad number as reported by the media controller API.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>interval</structfield></entry> + <entry>Period, in seconds, between consecutive video frames.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[9]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The frame interval can't be changed because the pad is currently + busy. This can be caused, for instance, by an active video stream on + the pad. The ioctl must not be retried without performing another + action to fix the problem first. Only returned by + <constant>VIDIOC_SUBDEV_S_FRAME_INTERVAL</constant></para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-subdev-frame-interval; <structfield>pad</structfield> + references a non-existing pad, or the pad doesn't support frame + intervals.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml new file mode 100644 index 00000000..5c70b616 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml @@ -0,0 +1,206 @@ +<refentry id="vidioc-subscribe-event"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT</refname> + <refpurpose>Subscribe or unsubscribe event</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_event_subscription +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Subscribe or unsubscribe V4L2 event. Subscribed events are + dequeued by using the &VIDIOC-DQEVENT; ioctl.</para> + + <table frame="none" pgwide="1" id="v4l2-event-subscription"> + <title>struct <structname>v4l2_event_subscription</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the event.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>ID of the event source. If there is no ID associated with + the event source, then set this to 0. Whether or not an event + needs an ID depends on the event type.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Event flags, see <xref linkend="event-flags" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[5]</entry> + <entry>Reserved for future extensions. Drivers and applications + must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="event-type"> + <title>Event Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_EVENT_ALL</constant></entry> + <entry>0</entry> + <entry>All events. V4L2_EVENT_ALL is valid only for + VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once. + </entry> + </row> + <row> + <entry><constant>V4L2_EVENT_VSYNC</constant></entry> + <entry>1</entry> + <entry>This event is triggered on the vertical sync. + This event has a &v4l2-event-vsync; associated with it. + </entry> + </row> + <row> + <entry><constant>V4L2_EVENT_EOS</constant></entry> + <entry>2</entry> + <entry>This event is triggered when the end of a stream is reached. + This is typically used with MPEG decoders to report to the application + when the last of the MPEG stream has been decoded. + </entry> + </row> + <row> + <entry><constant>V4L2_EVENT_CTRL</constant></entry> + <entry>3</entry> + <entry><para>This event requires that the <structfield>id</structfield> + matches the control ID from which you want to receive events. + This event is triggered if the control's value changes, if a + button control is pressed or if the control's flags change. + This event has a &v4l2-event-ctrl; associated with it. This struct + contains much of the same information as &v4l2-queryctrl; and + &v4l2-control;.</para> + + <para>If the event is generated due to a call to &VIDIOC-S-CTRL; or + &VIDIOC-S-EXT-CTRLS;, then the event will <emphasis>not</emphasis> be sent to + the file handle that called the ioctl function. This prevents + nasty feedback loops. If you <emphasis>do</emphasis> want to get the + event, then set the <constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant> + flag. + </para> + + <para>This event type will ensure that no information is lost when + more events are raised than there is room internally. In that + case the &v4l2-event-ctrl; of the second-oldest event is kept, + but the <structfield>changes</structfield> field of the + second-oldest event is ORed with the <structfield>changes</structfield> + field of the oldest event.</para> + </entry> + </row> + <row> + <entry><constant>V4L2_EVENT_FRAME_SYNC</constant></entry> + <entry>4</entry> + <entry> + <para>Triggered immediately when the reception of a + frame has begun. This event has a + &v4l2-event-frame-sync; associated with it.</para> + + <para>If the hardware needs to be stopped in the case of a + buffer underrun it might not be able to generate this event. + In such cases the <structfield>frame_sequence</structfield> + field in &v4l2-event-frame-sync; will not be incremented. This + causes two consecutive frame sequence numbers to have n times + frame interval in between them.</para> + </entry> + </row> + <row> + <entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry> + <entry>0x08000000</entry> + <entry>Base event number for driver-private events.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="event-flags"> + <title>Event Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_EVENT_SUB_FL_SEND_INITIAL</constant></entry> + <entry>0x0001</entry> + <entry>When this event is subscribed an initial event will be sent + containing the current status. This only makes sense for events + that are triggered by a status change such as <constant>V4L2_EVENT_CTRL</constant>. + Other events will ignore this flag.</entry> + </row> + <row> + <entry><constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant></entry> + <entry>0x0002</entry> + <entry><para>If set, then events directly caused by an ioctl will also be sent to + the filehandle that called that ioctl. For example, changing a control using + &VIDIOC-S-CTRL; will cause a V4L2_EVENT_CTRL to be sent back to that same + filehandle. Normally such events are suppressed to prevent feedback loops + where an application changes a control to a one value and then another, and + then receives an event telling it that that control has changed to the first + value.</para> + + <para>Since it can't tell whether that event was caused by another application + or by the &VIDIOC-S-CTRL; call it is hard to decide whether to set the + control to the value in the event, or ignore it.</para> + + <para>Think carefully when you set this flag so you won't get into situations + like that.</para> + </entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + <refsect1> + &return-value; + </refsect1> +</refentry> diff --git a/Documentation/DocBook/media/vbi_525.gif.b64 b/Documentation/DocBook/media/vbi_525.gif.b64 new file mode 100644 index 00000000..d5dcf06f --- /dev/null +++ b/Documentation/DocBook/media/vbi_525.gif.b64 @@ -0,0 +1,84 @@ +R0lGODlhKgPIAIAAAAAAAP///yH5BAEAAAEALAAAAAAqA8gAAAL+jI+py+0Po5y02ouz3rz7D4bi 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<returnvalue>-1</returnvalue> and the <varname>errno</varname> variable is set appropriately. The generic error codes are described at the <link linkend='gen-errors'>Generic Error Codes</link> chapter.</para>"> +<!ENTITY return-value-dvb "<para>RETURN VALUE</para><para>On success <returnvalue>0</returnvalue> is returned, on error <returnvalue>-1</returnvalue> and the <varname>errno</varname> variable is set appropriately. The generic error codes are described at the <link linkend='gen-errors'>Generic Error Codes</link> chapter.</para>"> +<!ENTITY manvol "<manvolnum>2</manvolnum>"> + +<!-- Table templates: structs, structs w/union, defines. --> +<!ENTITY cs-str "<colspec colname='c1' colwidth='1*' /><colspec colname='c2' colwidth='1*' /><colspec colname='c3' colwidth='2*' /><spanspec spanname='hspan' namest='c1' nameend='c3' />"> +<!ENTITY cs-ustr "<colspec colname='c1' colwidth='1*' /><colspec colname='c2' colwidth='1*' /><colspec colname='c3' colwidth='1*' /><colspec colname='c4' colwidth='2*' /><spanspec spanname='hspan' namest='c1' nameend='c4' />"> +<!ENTITY cs-def "<colspec colname='c1' colwidth='3*' /><colspec colname='c2' colwidth='1*' /><colspec colname='c3' colwidth='4*' /><spanspec spanname='hspan' namest='c1' nameend='c3' />"> + +<!-- Video for Linux mailing list address. --> +<!ENTITY v4l-ml "<ulink url='http://www.linuxtv.org/lists.php'>http://www.linuxtv.org/lists.php</ulink>"> + +<!-- LinuxTV v4l-dvb repository. --> +<!ENTITY v4l-dvb "<ulink url='http://linuxtv.org/repo/'>http://linuxtv.org/repo/</ulink>"> +]> + +<book id="media_api"> +<bookinfo> +<title>LINUX MEDIA INFRASTRUCTURE API</title> + +<copyright> + <year>2009-2011</year> + <holder>LinuxTV Developers</holder> +</copyright> + +<legalnotice> + +<para>Permission is granted to copy, distribute and/or modify +this document under the terms of the GNU Free Documentation License, +Version 1.1 or any later version published by the Free Software +Foundation. A copy of the license is included in the chapter entitled +"GNU Free Documentation License"</para> +</legalnotice> + +</bookinfo> + +<toc></toc> <!-- autogenerated --> + +<preface> + <title>Introduction</title> + + <para>This document covers the Linux Kernel to Userspace API's used by + video and radio straming devices, including video cameras, + analog and digital TV receiver cards, AM/FM receiver cards, + streaming capture devices.</para> + <para>It is divided into three parts.</para> + <para>The first part covers radio, capture, + cameras and analog TV devices.</para> + <para>The second part covers the + API used for digital TV and Internet reception via one of the + several digital tv standards. While it is called as DVB API, + in fact it covers several different video standards including + DVB-T, DVB-S, DVB-C and ATSC. The API is currently being updated + to documment support also for DVB-S2, ISDB-T and ISDB-S.</para> + <para>The third part covers Remote Controller API</para> + <para>For additional information and for the latest development code, + see: <ulink url="http://linuxtv.org">http://linuxtv.org</ulink>.</para> + <para>For discussing improvements, reporting troubles, sending new drivers, etc, please mail to: <ulink url="http://vger.kernel.org/vger-lists.html#linux-media">Linux Media Mailing List (LMML).</ulink>.</para> + +</preface> + +<part id="v4l2spec"> +&sub-v4l2; +</part> +<part id="dvbapi"> +&sub-dvbapi; +</part> +<part id="v4ldvb_common"> +<partinfo> +<authorgroup> +<author> +<firstname>Mauro</firstname> +<surname>Chehab</surname> +<othername role="mi">Carvalho</othername> +<affiliation><address><email>mchehab@redhat.com</email></address></affiliation> +<contrib>Initial version.</contrib> +</author> +</authorgroup> +<copyright> + <year>2009-2011</year> + <holder>Mauro Carvalho Chehab</holder> +</copyright> + +<revhistory> +<!-- Put document revisions here, newest first. --> +<revision> +<revnumber>1.0.0</revnumber> +<date>2009-09-06</date> +<authorinitials>mcc</authorinitials> +<revremark>Initial revision</revremark> +</revision> +</revhistory> +</partinfo> + +<title>Remote Controller API</title> +<chapter id="remote_controllers"> +&sub-remote_controllers; +</chapter> +</part> +<part id="media_common"> +&sub-media-controller; +</part> + +<chapter id="gen_errors"> +&sub-gen-errors; +</chapter> + + +&sub-fdl-appendix; + +</book> diff --git a/Documentation/DocBook/mtdnand.tmpl b/Documentation/DocBook/mtdnand.tmpl new file mode 100644 index 00000000..0c674be0 --- /dev/null +++ b/Documentation/DocBook/mtdnand.tmpl @@ -0,0 +1,1300 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="MTD-NAND-Guide"> + <bookinfo> + <title>MTD NAND Driver Programming Interface</title> + + <authorgroup> + <author> + <firstname>Thomas</firstname> + <surname>Gleixner</surname> + <affiliation> + <address> + <email>tglx@linutronix.de</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2004</year> + <holder>Thomas Gleixner</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + The generic NAND driver supports almost all NAND and AG-AND based + chips and connects them to the Memory Technology Devices (MTD) + subsystem of the Linux Kernel. + </para> + <para> + This documentation is provided for developers who want to implement + board drivers or filesystem drivers suitable for NAND devices. + </para> + </chapter> + + <chapter id="bugs"> + <title>Known Bugs And Assumptions</title> + <para> + None. + </para> + </chapter> + + <chapter id="dochints"> + <title>Documentation hints</title> + <para> + The function and structure docs are autogenerated. Each function and + struct member has a short description which is marked with an [XXX] identifier. + The following chapters explain the meaning of those identifiers. + </para> + <sect1 id="Function_identifiers_XXX"> + <title>Function identifiers [XXX]</title> + <para> + The functions are marked with [XXX] identifiers in the short + comment. The identifiers explain the usage and scope of the + functions. Following identifiers are used: + </para> + <itemizedlist> + <listitem><para> + [MTD Interface]</para><para> + These functions provide the interface to the MTD kernel API. + They are not replacable and provide functionality + which is complete hardware independent. + </para></listitem> + <listitem><para> + [NAND Interface]</para><para> + These functions are exported and provide the interface to the NAND kernel API. + </para></listitem> + <listitem><para> + [GENERIC]</para><para> + Generic functions are not replacable and provide functionality + which is complete hardware independent. + </para></listitem> + <listitem><para> + [DEFAULT]</para><para> + Default functions provide hardware related functionality which is suitable + for most of the implementations. These functions can be replaced by the + board driver if neccecary. Those functions are called via pointers in the + NAND chip description structure. The board driver can set the functions which + should be replaced by board dependent functions before calling nand_scan(). + If the function pointer is NULL on entry to nand_scan() then the pointer + is set to the default function which is suitable for the detected chip type. + </para></listitem> + </itemizedlist> + </sect1> + <sect1 id="Struct_member_identifiers_XXX"> + <title>Struct member identifiers [XXX]</title> + <para> + The struct members are marked with [XXX] identifiers in the + comment. The identifiers explain the usage and scope of the + members. Following identifiers are used: + </para> + <itemizedlist> + <listitem><para> + [INTERN]</para><para> + These members are for NAND driver internal use only and must not be + modified. Most of these values are calculated from the chip geometry + information which is evaluated during nand_scan(). + </para></listitem> + <listitem><para> + [REPLACEABLE]</para><para> + Replaceable members hold hardware related functions which can be + provided by the board driver. The board driver can set the functions which + should be replaced by board dependent functions before calling nand_scan(). + If the function pointer is NULL on entry to nand_scan() then the pointer + is set to the default function which is suitable for the detected chip type. + </para></listitem> + <listitem><para> + [BOARDSPECIFIC]</para><para> + Board specific members hold hardware related information which must + be provided by the board driver. The board driver must set the function + pointers and datafields before calling nand_scan(). + </para></listitem> + <listitem><para> + [OPTIONAL]</para><para> + Optional members can hold information relevant for the board driver. The + generic NAND driver code does not use this information. + </para></listitem> + </itemizedlist> + </sect1> + </chapter> + + <chapter id="basicboarddriver"> + <title>Basic board driver</title> + <para> + For most boards it will be sufficient to provide just the + basic functions and fill out some really board dependent + members in the nand chip description structure. + </para> + <sect1 id="Basic_defines"> + <title>Basic defines</title> + <para> + At least you have to provide a mtd structure and + a storage for the ioremap'ed chip address. + You can allocate the mtd structure using kmalloc + or you can allocate it statically. + In case of static allocation you have to allocate + a nand_chip structure too. + </para> + <para> + Kmalloc based example + </para> + <programlisting> +static struct mtd_info *board_mtd; +static void __iomem *baseaddr; + </programlisting> + <para> + Static example + </para> + <programlisting> +static struct mtd_info board_mtd; +static struct nand_chip board_chip; +static void __iomem *baseaddr; + </programlisting> + </sect1> + <sect1 id="Partition_defines"> + <title>Partition defines</title> + <para> + If you want to divide your device into partitions, then + define a partitioning scheme suitable to your board. + </para> + <programlisting> +#define NUM_PARTITIONS 2 +static struct mtd_partition partition_info[] = { + { .name = "Flash partition 1", + .offset = 0, + .size = 8 * 1024 * 1024 }, + { .name = "Flash partition 2", + .offset = MTDPART_OFS_NEXT, + .size = MTDPART_SIZ_FULL }, +}; + </programlisting> + </sect1> + <sect1 id="Hardware_control_functions"> + <title>Hardware control function</title> + <para> + The hardware control function provides access to the + control pins of the NAND chip(s). + The access can be done by GPIO pins or by address lines. + If you use address lines, make sure that the timing + requirements are met. + </para> + <para> + <emphasis>GPIO based example</emphasis> + </para> + <programlisting> +static void board_hwcontrol(struct mtd_info *mtd, int cmd) +{ + switch(cmd){ + case NAND_CTL_SETCLE: /* Set CLE pin high */ break; + case NAND_CTL_CLRCLE: /* Set CLE pin low */ break; + case NAND_CTL_SETALE: /* Set ALE pin high */ break; + case NAND_CTL_CLRALE: /* Set ALE pin low */ break; + case NAND_CTL_SETNCE: /* Set nCE pin low */ break; + case NAND_CTL_CLRNCE: /* Set nCE pin high */ break; + } +} + </programlisting> + <para> + <emphasis>Address lines based example.</emphasis> It's assumed that the + nCE pin is driven by a chip select decoder. + </para> + <programlisting> +static void board_hwcontrol(struct mtd_info *mtd, int cmd) +{ + struct nand_chip *this = (struct nand_chip *) mtd->priv; + switch(cmd){ + case NAND_CTL_SETCLE: this->IO_ADDR_W |= CLE_ADRR_BIT; break; + case NAND_CTL_CLRCLE: this->IO_ADDR_W &= ~CLE_ADRR_BIT; break; + case NAND_CTL_SETALE: this->IO_ADDR_W |= ALE_ADRR_BIT; break; + case NAND_CTL_CLRALE: this->IO_ADDR_W &= ~ALE_ADRR_BIT; break; + } +} + </programlisting> + </sect1> + <sect1 id="Device_ready_function"> + <title>Device ready function</title> + <para> + If the hardware interface has the ready busy pin of the NAND chip connected to a + GPIO or other accessible I/O pin, this function is used to read back the state of the + pin. The function has no arguments and should return 0, if the device is busy (R/B pin + is low) and 1, if the device is ready (R/B pin is high). + If the hardware interface does not give access to the ready busy pin, then + the function must not be defined and the function pointer this->dev_ready is set to NULL. + </para> + </sect1> + <sect1 id="Init_function"> + <title>Init function</title> + <para> + The init function allocates memory and sets up all the board + specific parameters and function pointers. When everything + is set up nand_scan() is called. This function tries to + detect and identify then chip. If a chip is found all the + internal data fields are initialized accordingly. + The structure(s) have to be zeroed out first and then filled with the neccecary + information about the device. + </para> + <programlisting> +static int __init board_init (void) +{ + struct nand_chip *this; + int err = 0; + + /* Allocate memory for MTD device structure and private data */ + board_mtd = kzalloc(sizeof(struct mtd_info) + sizeof(struct nand_chip), GFP_KERNEL); + if (!board_mtd) { + printk ("Unable to allocate NAND MTD device structure.\n"); + err = -ENOMEM; + goto out; + } + + /* map physical address */ + baseaddr = ioremap(CHIP_PHYSICAL_ADDRESS, 1024); + if (!baseaddr) { + printk("Ioremap to access NAND chip failed\n"); + err = -EIO; + goto out_mtd; + } + + /* Get pointer to private data */ + this = (struct nand_chip *) (); + /* Link the private data with the MTD structure */ + board_mtd->priv = this; + + /* Set address of NAND IO lines */ + this->IO_ADDR_R = baseaddr; + this->IO_ADDR_W = baseaddr; + /* Reference hardware control function */ + this->hwcontrol = board_hwcontrol; + /* Set command delay time, see datasheet for correct value */ + this->chip_delay = CHIP_DEPENDEND_COMMAND_DELAY; + /* Assign the device ready function, if available */ + this->dev_ready = board_dev_ready; + this->eccmode = NAND_ECC_SOFT; + + /* Scan to find existence of the device */ + if (nand_scan (board_mtd, 1)) { + err = -ENXIO; + goto out_ior; + } + + add_mtd_partitions(board_mtd, partition_info, NUM_PARTITIONS); + goto out; + +out_ior: + iounmap(baseaddr); +out_mtd: + kfree (board_mtd); +out: + return err; +} +module_init(board_init); + </programlisting> + </sect1> + <sect1 id="Exit_function"> + <title>Exit function</title> + <para> + The exit function is only neccecary if the driver is + compiled as a module. It releases all resources which + are held by the chip driver and unregisters the partitions + in the MTD layer. + </para> + <programlisting> +#ifdef MODULE +static void __exit board_cleanup (void) +{ + /* Release resources, unregister device */ + nand_release (board_mtd); + + /* unmap physical address */ + iounmap(baseaddr); + + /* Free the MTD device structure */ + kfree (board_mtd); +} +module_exit(board_cleanup); +#endif + </programlisting> + </sect1> + </chapter> + + <chapter id="boarddriversadvanced"> + <title>Advanced board driver functions</title> + <para> + This chapter describes the advanced functionality of the NAND + driver. For a list of functions which can be overridden by the board + driver see the documentation of the nand_chip structure. + </para> + <sect1 id="Multiple_chip_control"> + <title>Multiple chip control</title> + <para> + The nand driver can control chip arrays. Therefore the + board driver must provide an own select_chip function. This + function must (de)select the requested chip. + The function pointer in the nand_chip structure must + be set before calling nand_scan(). The maxchip parameter + of nand_scan() defines the maximum number of chips to + scan for. Make sure that the select_chip function can + handle the requested number of chips. + </para> + <para> + The nand driver concatenates the chips to one virtual + chip and provides this virtual chip to the MTD layer. + </para> + <para> + <emphasis>Note: The driver can only handle linear chip arrays + of equally sized chips. There is no support for + parallel arrays which extend the buswidth.</emphasis> + </para> + <para> + <emphasis>GPIO based example</emphasis> + </para> + <programlisting> +static void board_select_chip (struct mtd_info *mtd, int chip) +{ + /* Deselect all chips, set all nCE pins high */ + GPIO(BOARD_NAND_NCE) |= 0xff; + if (chip >= 0) + GPIO(BOARD_NAND_NCE) &= ~ (1 << chip); +} + </programlisting> + <para> + <emphasis>Address lines based example.</emphasis> + Its assumed that the nCE pins are connected to an + address decoder. + </para> + <programlisting> +static void board_select_chip (struct mtd_info *mtd, int chip) +{ + struct nand_chip *this = (struct nand_chip *) mtd->priv; + + /* Deselect all chips */ + this->IO_ADDR_R &= ~BOARD_NAND_ADDR_MASK; + this->IO_ADDR_W &= ~BOARD_NAND_ADDR_MASK; + switch (chip) { + case 0: + this->IO_ADDR_R |= BOARD_NAND_ADDR_CHIP0; + this->IO_ADDR_W |= BOARD_NAND_ADDR_CHIP0; + break; + .... + case n: + this->IO_ADDR_R |= BOARD_NAND_ADDR_CHIPn; + this->IO_ADDR_W |= BOARD_NAND_ADDR_CHIPn; + break; + } +} + </programlisting> + </sect1> + <sect1 id="Hardware_ECC_support"> + <title>Hardware ECC support</title> + <sect2 id="Functions_and_constants"> + <title>Functions and constants</title> + <para> + The nand driver supports three different types of + hardware ECC. + <itemizedlist> + <listitem><para>NAND_ECC_HW3_256</para><para> + Hardware ECC generator providing 3 bytes ECC per + 256 byte. + </para> </listitem> + <listitem><para>NAND_ECC_HW3_512</para><para> + Hardware ECC generator providing 3 bytes ECC per + 512 byte. + </para> </listitem> + <listitem><para>NAND_ECC_HW6_512</para><para> + Hardware ECC generator providing 6 bytes ECC per + 512 byte. + </para> </listitem> + <listitem><para>NAND_ECC_HW8_512</para><para> + Hardware ECC generator providing 6 bytes ECC per + 512 byte. + </para> </listitem> + </itemizedlist> + If your hardware generator has a different functionality + add it at the appropriate place in nand_base.c + </para> + <para> + The board driver must provide following functions: + <itemizedlist> + <listitem><para>enable_hwecc</para><para> + This function is called before reading / writing to + the chip. Reset or initialize the hardware generator + in this function. The function is called with an + argument which let you distinguish between read + and write operations. + </para> </listitem> + <listitem><para>calculate_ecc</para><para> + This function is called after read / write from / to + the chip. Transfer the ECC from the hardware to + the buffer. If the option NAND_HWECC_SYNDROME is set + then the function is only called on write. See below. + </para> </listitem> + <listitem><para>correct_data</para><para> + In case of an ECC error this function is called for + error detection and correction. Return 1 respectively 2 + in case the error can be corrected. If the error is + not correctable return -1. If your hardware generator + matches the default algorithm of the nand_ecc software + generator then use the correction function provided + by nand_ecc instead of implementing duplicated code. + </para> </listitem> + </itemizedlist> + </para> + </sect2> + <sect2 id="Hardware_ECC_with_syndrome_calculation"> + <title>Hardware ECC with syndrome calculation</title> + <para> + Many hardware ECC implementations provide Reed-Solomon + codes and calculate an error syndrome on read. The syndrome + must be converted to a standard Reed-Solomon syndrome + before calling the error correction code in the generic + Reed-Solomon library. + </para> + <para> + The ECC bytes must be placed immediately after the data + bytes in order to make the syndrome generator work. This + is contrary to the usual layout used by software ECC. The + separation of data and out of band area is not longer + possible. The nand driver code handles this layout and + the remaining free bytes in the oob area are managed by + the autoplacement code. Provide a matching oob-layout + in this case. See rts_from4.c and diskonchip.c for + implementation reference. In those cases we must also + use bad block tables on FLASH, because the ECC layout is + interferring with the bad block marker positions. + See bad block table support for details. + </para> + </sect2> + </sect1> + <sect1 id="Bad_Block_table_support"> + <title>Bad block table support</title> + <para> + Most NAND chips mark the bad blocks at a defined + position in the spare area. Those blocks must + not be erased under any circumstances as the bad + block information would be lost. + It is possible to check the bad block mark each + time when the blocks are accessed by reading the + spare area of the first page in the block. This + is time consuming so a bad block table is used. + </para> + <para> + The nand driver supports various types of bad block + tables. + <itemizedlist> + <listitem><para>Per device</para><para> + The bad block table contains all bad block information + of the device which can consist of multiple chips. + </para> </listitem> + <listitem><para>Per chip</para><para> + A bad block table is used per chip and contains the + bad block information for this particular chip. + </para> </listitem> + <listitem><para>Fixed offset</para><para> + The bad block table is located at a fixed offset + in the chip (device). This applies to various + DiskOnChip devices. + </para> </listitem> + <listitem><para>Automatic placed</para><para> + The bad block table is automatically placed and + detected either at the end or at the beginning + of a chip (device) + </para> </listitem> + <listitem><para>Mirrored tables</para><para> + The bad block table is mirrored on the chip (device) to + allow updates of the bad block table without data loss. + </para> </listitem> + </itemizedlist> + </para> + <para> + nand_scan() calls the function nand_default_bbt(). + nand_default_bbt() selects appropriate default + bad block table desriptors depending on the chip information + which was retrieved by nand_scan(). + </para> + <para> + The standard policy is scanning the device for bad + blocks and build a ram based bad block table which + allows faster access than always checking the + bad block information on the flash chip itself. + </para> + <sect2 id="Flash_based_tables"> + <title>Flash based tables</title> + <para> + It may be desired or neccecary to keep a bad block table in FLASH. + For AG-AND chips this is mandatory, as they have no factory marked + bad blocks. They have factory marked good blocks. The marker pattern + is erased when the block is erased to be reused. So in case of + powerloss before writing the pattern back to the chip this block + would be lost and added to the bad blocks. Therefore we scan the + chip(s) when we detect them the first time for good blocks and + store this information in a bad block table before erasing any + of the blocks. + </para> + <para> + The blocks in which the tables are stored are procteted against + accidental access by marking them bad in the memory bad block + table. The bad block table management functions are allowed + to circumvernt this protection. + </para> + <para> + The simplest way to activate the FLASH based bad block table support + is to set the option NAND_BBT_USE_FLASH in the bbt_option field of + the nand chip structure before calling nand_scan(). For AG-AND + chips is this done by default. + This activates the default FLASH based bad block table functionality + of the NAND driver. The default bad block table options are + <itemizedlist> + <listitem><para>Store bad block table per chip</para></listitem> + <listitem><para>Use 2 bits per block</para></listitem> + <listitem><para>Automatic placement at the end of the chip</para></listitem> + <listitem><para>Use mirrored tables with version numbers</para></listitem> + <listitem><para>Reserve 4 blocks at the end of the chip</para></listitem> + </itemizedlist> + </para> + </sect2> + <sect2 id="User_defined_tables"> + <title>User defined tables</title> + <para> + User defined tables are created by filling out a + nand_bbt_descr structure and storing the pointer in the + nand_chip structure member bbt_td before calling nand_scan(). + If a mirror table is neccecary a second structure must be + created and a pointer to this structure must be stored + in bbt_md inside the nand_chip structure. If the bbt_md + member is set to NULL then only the main table is used + and no scan for the mirrored table is performed. + </para> + <para> + The most important field in the nand_bbt_descr structure + is the options field. The options define most of the + table properties. Use the predefined constants from + nand.h to define the options. + <itemizedlist> + <listitem><para>Number of bits per block</para> + <para>The supported number of bits is 1, 2, 4, 8.</para></listitem> + <listitem><para>Table per chip</para> + <para>Setting the constant NAND_BBT_PERCHIP selects that + a bad block table is managed for each chip in a chip array. + If this option is not set then a per device bad block table + is used.</para></listitem> + <listitem><para>Table location is absolute</para> + <para>Use the option constant NAND_BBT_ABSPAGE and + define the absolute page number where the bad block + table starts in the field pages. If you have selected bad block + tables per chip and you have a multi chip array then the start page + must be given for each chip in the chip array. Note: there is no scan + for a table ident pattern performed, so the fields + pattern, veroffs, offs, len can be left uninitialized</para></listitem> + <listitem><para>Table location is automatically detected</para> + <para>The table can either be located in the first or the last good + blocks of the chip (device). Set NAND_BBT_LASTBLOCK to place + the bad block table at the end of the chip (device). The + bad block tables are marked and identified by a pattern which + is stored in the spare area of the first page in the block which + holds the bad block table. Store a pointer to the pattern + in the pattern field. Further the length of the pattern has to be + stored in len and the offset in the spare area must be given + in the offs member of the nand_bbt_descr structure. For mirrored + bad block tables different patterns are mandatory.</para></listitem> + <listitem><para>Table creation</para> + <para>Set the option NAND_BBT_CREATE to enable the table creation + if no table can be found during the scan. Usually this is done only + once if a new chip is found. </para></listitem> + <listitem><para>Table write support</para> + <para>Set the option NAND_BBT_WRITE to enable the table write support. + This allows the update of the bad block table(s) in case a block has + to be marked bad due to wear. The MTD interface function block_markbad + is calling the update function of the bad block table. If the write + support is enabled then the table is updated on FLASH.</para> + <para> + Note: Write support should only be enabled for mirrored tables with + version control. + </para></listitem> + <listitem><para>Table version control</para> + <para>Set the option NAND_BBT_VERSION to enable the table version control. + It's highly recommended to enable this for mirrored tables with write + support. It makes sure that the risk of losing the bad block + table information is reduced to the loss of the information about the + one worn out block which should be marked bad. The version is stored in + 4 consecutive bytes in the spare area of the device. The position of + the version number is defined by the member veroffs in the bad block table + descriptor.</para></listitem> + <listitem><para>Save block contents on write</para> + <para> + In case that the block which holds the bad block table does contain + other useful information, set the option NAND_BBT_SAVECONTENT. When + the bad block table is written then the whole block is read the bad + block table is updated and the block is erased and everything is + written back. If this option is not set only the bad block table + is written and everything else in the block is ignored and erased. + </para></listitem> + <listitem><para>Number of reserved blocks</para> + <para> + For automatic placement some blocks must be reserved for + bad block table storage. The number of reserved blocks is defined + in the maxblocks member of the babd block table description structure. + Reserving 4 blocks for mirrored tables should be a reasonable number. + This also limits the number of blocks which are scanned for the bad + block table ident pattern. + </para></listitem> + </itemizedlist> + </para> + </sect2> + </sect1> + <sect1 id="Spare_area_placement"> + <title>Spare area (auto)placement</title> + <para> + The nand driver implements different possibilities for + placement of filesystem data in the spare area, + <itemizedlist> + <listitem><para>Placement defined by fs driver</para></listitem> + <listitem><para>Automatic placement</para></listitem> + </itemizedlist> + The default placement function is automatic placement. The + nand driver has built in default placement schemes for the + various chiptypes. If due to hardware ECC functionality the + default placement does not fit then the board driver can + provide a own placement scheme. + </para> + <para> + File system drivers can provide a own placement scheme which + is used instead of the default placement scheme. + </para> + <para> + Placement schemes are defined by a nand_oobinfo structure + <programlisting> +struct nand_oobinfo { + int useecc; + int eccbytes; + int eccpos[24]; + int oobfree[8][2]; +}; + </programlisting> + <itemizedlist> + <listitem><para>useecc</para><para> + The useecc member controls the ecc and placement function. The header + file include/mtd/mtd-abi.h contains constants to select ecc and + placement. MTD_NANDECC_OFF switches off the ecc complete. This is + not recommended and available for testing and diagnosis only. + MTD_NANDECC_PLACE selects caller defined placement, MTD_NANDECC_AUTOPLACE + selects automatic placement. + </para></listitem> + <listitem><para>eccbytes</para><para> + The eccbytes member defines the number of ecc bytes per page. + </para></listitem> + <listitem><para>eccpos</para><para> + The eccpos array holds the byte offsets in the spare area where + the ecc codes are placed. + </para></listitem> + <listitem><para>oobfree</para><para> + The oobfree array defines the areas in the spare area which can be + used for automatic placement. The information is given in the format + {offset, size}. offset defines the start of the usable area, size the + length in bytes. More than one area can be defined. The list is terminated + by an {0, 0} entry. + </para></listitem> + </itemizedlist> + </para> + <sect2 id="Placement_defined_by_fs_driver"> + <title>Placement defined by fs driver</title> + <para> + The calling function provides a pointer to a nand_oobinfo + structure which defines the ecc placement. For writes the + caller must provide a spare area buffer along with the + data buffer. The spare area buffer size is (number of pages) * + (size of spare area). For reads the buffer size is + (number of pages) * ((size of spare area) + (number of ecc + steps per page) * sizeof (int)). The driver stores the + result of the ecc check for each tuple in the spare buffer. + The storage sequence is + </para> + <para> + <spare data page 0><ecc result 0>...<ecc result n> + </para> + <para> + ... + </para> + <para> + <spare data page n><ecc result 0>...<ecc result n> + </para> + <para> + This is a legacy mode used by YAFFS1. + </para> + <para> + If the spare area buffer is NULL then only the ECC placement is + done according to the given scheme in the nand_oobinfo structure. + </para> + </sect2> + <sect2 id="Automatic_placement"> + <title>Automatic placement</title> + <para> + Automatic placement uses the built in defaults to place the + ecc bytes in the spare area. If filesystem data have to be stored / + read into the spare area then the calling function must provide a + buffer. The buffer size per page is determined by the oobfree array in + the nand_oobinfo structure. + </para> + <para> + If the spare area buffer is NULL then only the ECC placement is + done according to the default builtin scheme. + </para> + </sect2> + </sect1> + <sect1 id="Spare_area_autoplacement_default"> + <title>Spare area autoplacement default schemes</title> + <sect2 id="pagesize_256"> + <title>256 byte pagesize</title> +<informaltable><tgroup cols="3"><tbody> +<row> +<entry>Offset</entry> +<entry>Content</entry> +<entry>Comment</entry> +</row> +<row> +<entry>0x00</entry> +<entry>ECC byte 0</entry> +<entry>Error correction code byte 0</entry> +</row> +<row> +<entry>0x01</entry> +<entry>ECC byte 1</entry> +<entry>Error correction code byte 1</entry> +</row> +<row> +<entry>0x02</entry> +<entry>ECC byte 2</entry> +<entry>Error correction code byte 2</entry> +</row> +<row> +<entry>0x03</entry> +<entry>Autoplace 0</entry> +<entry></entry> +</row> +<row> +<entry>0x04</entry> +<entry>Autoplace 1</entry> +<entry></entry> +</row> +<row> +<entry>0x05</entry> +<entry>Bad block marker</entry> +<entry>If any bit in this byte is zero, then this block is bad. +This applies only to the first page in a block. In the remaining +pages this byte is reserved</entry> +</row> +<row> +<entry>0x06</entry> +<entry>Autoplace 2</entry> +<entry></entry> +</row> +<row> +<entry>0x07</entry> +<entry>Autoplace 3</entry> +<entry></entry> +</row> +</tbody></tgroup></informaltable> + </sect2> + <sect2 id="pagesize_512"> + <title>512 byte pagesize</title> +<informaltable><tgroup cols="3"><tbody> +<row> +<entry>Offset</entry> +<entry>Content</entry> +<entry>Comment</entry> +</row> +<row> +<entry>0x00</entry> +<entry>ECC byte 0</entry> +<entry>Error correction code byte 0 of the lower 256 Byte data in +this page</entry> +</row> +<row> +<entry>0x01</entry> +<entry>ECC byte 1</entry> +<entry>Error correction code byte 1 of the lower 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x02</entry> +<entry>ECC byte 2</entry> +<entry>Error correction code byte 2 of the lower 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x03</entry> +<entry>ECC byte 3</entry> +<entry>Error correction code byte 0 of the upper 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x04</entry> +<entry>reserved</entry> +<entry>reserved</entry> +</row> +<row> +<entry>0x05</entry> +<entry>Bad block marker</entry> +<entry>If any bit in this byte is zero, then this block is bad. +This applies only to the first page in a block. In the remaining +pages this byte is reserved</entry> +</row> +<row> +<entry>0x06</entry> +<entry>ECC byte 4</entry> +<entry>Error correction code byte 1 of the upper 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x07</entry> +<entry>ECC byte 5</entry> +<entry>Error correction code byte 2 of the upper 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x08 - 0x0F</entry> +<entry>Autoplace 0 - 7</entry> +<entry></entry> +</row> +</tbody></tgroup></informaltable> + </sect2> + <sect2 id="pagesize_2048"> + <title>2048 byte pagesize</title> +<informaltable><tgroup cols="3"><tbody> +<row> +<entry>Offset</entry> +<entry>Content</entry> +<entry>Comment</entry> +</row> +<row> +<entry>0x00</entry> +<entry>Bad block marker</entry> +<entry>If any bit in this byte is zero, then this block is bad. +This applies only to the first page in a block. In the remaining +pages this byte is reserved</entry> +</row> +<row> +<entry>0x01</entry> +<entry>Reserved</entry> +<entry>Reserved</entry> +</row> +<row> +<entry>0x02-0x27</entry> +<entry>Autoplace 0 - 37</entry> +<entry></entry> +</row> +<row> +<entry>0x28</entry> +<entry>ECC byte 0</entry> +<entry>Error correction code byte 0 of the first 256 Byte data in +this page</entry> +</row> +<row> +<entry>0x29</entry> +<entry>ECC byte 1</entry> +<entry>Error correction code byte 1 of the first 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x2A</entry> +<entry>ECC byte 2</entry> +<entry>Error correction code byte 2 of the first 256 Bytes data in +this page</entry> +</row> +<row> +<entry>0x2B</entry> +<entry>ECC byte 3</entry> +<entry>Error correction code byte 0 of the second 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x2C</entry> +<entry>ECC byte 4</entry> +<entry>Error correction code byte 1 of the second 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x2D</entry> +<entry>ECC byte 5</entry> +<entry>Error correction code byte 2 of the second 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x2E</entry> +<entry>ECC byte 6</entry> +<entry>Error correction code byte 0 of the third 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x2F</entry> +<entry>ECC byte 7</entry> +<entry>Error correction code byte 1 of the third 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x30</entry> +<entry>ECC byte 8</entry> +<entry>Error correction code byte 2 of the third 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x31</entry> +<entry>ECC byte 9</entry> +<entry>Error correction code byte 0 of the fourth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x32</entry> +<entry>ECC byte 10</entry> +<entry>Error correction code byte 1 of the fourth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x33</entry> +<entry>ECC byte 11</entry> +<entry>Error correction code byte 2 of the fourth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x34</entry> +<entry>ECC byte 12</entry> +<entry>Error correction code byte 0 of the fifth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x35</entry> +<entry>ECC byte 13</entry> +<entry>Error correction code byte 1 of the fifth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x36</entry> +<entry>ECC byte 14</entry> +<entry>Error correction code byte 2 of the fifth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x37</entry> +<entry>ECC byte 15</entry> +<entry>Error correction code byte 0 of the sixt 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x38</entry> +<entry>ECC byte 16</entry> +<entry>Error correction code byte 1 of the sixt 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x39</entry> +<entry>ECC byte 17</entry> +<entry>Error correction code byte 2 of the sixt 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x3A</entry> +<entry>ECC byte 18</entry> +<entry>Error correction code byte 0 of the seventh 256 Bytes of +data in this page</entry> +</row> +<row> +<entry>0x3B</entry> +<entry>ECC byte 19</entry> +<entry>Error correction code byte 1 of the seventh 256 Bytes of +data in this page</entry> +</row> +<row> +<entry>0x3C</entry> +<entry>ECC byte 20</entry> +<entry>Error correction code byte 2 of the seventh 256 Bytes of +data in this page</entry> +</row> +<row> +<entry>0x3D</entry> +<entry>ECC byte 21</entry> +<entry>Error correction code byte 0 of the eighth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x3E</entry> +<entry>ECC byte 22</entry> +<entry>Error correction code byte 1 of the eighth 256 Bytes of data +in this page</entry> +</row> +<row> +<entry>0x3F</entry> +<entry>ECC byte 23</entry> +<entry>Error correction code byte 2 of the eighth 256 Bytes of data +in this page</entry> +</row> +</tbody></tgroup></informaltable> + </sect2> + </sect1> + </chapter> + + <chapter id="filesystems"> + <title>Filesystem support</title> + <para> + The NAND driver provides all neccecary functions for a + filesystem via the MTD interface. + </para> + <para> + Filesystems must be aware of the NAND pecularities and + restrictions. One major restrictions of NAND Flash is, that you cannot + write as often as you want to a page. The consecutive writes to a page, + before erasing it again, are restricted to 1-3 writes, depending on the + manufacturers specifications. This applies similar to the spare area. + </para> + <para> + Therefore NAND aware filesystems must either write in page size chunks + or hold a writebuffer to collect smaller writes until they sum up to + pagesize. Available NAND aware filesystems: JFFS2, YAFFS. + </para> + <para> + The spare area usage to store filesystem data is controlled by + the spare area placement functionality which is described in one + of the earlier chapters. + </para> + </chapter> + <chapter id="tools"> + <title>Tools</title> + <para> + The MTD project provides a couple of helpful tools to handle NAND Flash. + <itemizedlist> + <listitem><para>flasherase, flasheraseall: Erase and format FLASH partitions</para></listitem> + <listitem><para>nandwrite: write filesystem images to NAND FLASH</para></listitem> + <listitem><para>nanddump: dump the contents of a NAND FLASH partitions</para></listitem> + </itemizedlist> + </para> + <para> + These tools are aware of the NAND restrictions. Please use those tools + instead of complaining about errors which are caused by non NAND aware + access methods. + </para> + </chapter> + + <chapter id="defines"> + <title>Constants</title> + <para> + This chapter describes the constants which might be relevant for a driver developer. + </para> + <sect1 id="Chip_option_constants"> + <title>Chip option constants</title> + <sect2 id="Constants_for_chip_id_table"> + <title>Constants for chip id table</title> + <para> + These constants are defined in nand.h. They are ored together to describe + the chip functionality. + <programlisting> +/* Chip can not auto increment pages */ +#define NAND_NO_AUTOINCR 0x00000001 +/* Buswitdh is 16 bit */ +#define NAND_BUSWIDTH_16 0x00000002 +/* Device supports partial programming without padding */ +#define NAND_NO_PADDING 0x00000004 +/* Chip has cache program function */ +#define NAND_CACHEPRG 0x00000008 +/* Chip has copy back function */ +#define NAND_COPYBACK 0x00000010 +/* AND Chip which has 4 banks and a confusing page / block + * assignment. See Renesas datasheet for further information */ +#define NAND_IS_AND 0x00000020 +/* Chip has a array of 4 pages which can be read without + * additional ready /busy waits */ +#define NAND_4PAGE_ARRAY 0x00000040 + </programlisting> + </para> + </sect2> + <sect2 id="Constants_for_runtime_options"> + <title>Constants for runtime options</title> + <para> + These constants are defined in nand.h. They are ored together to describe + the functionality. + <programlisting> +/* The hw ecc generator provides a syndrome instead a ecc value on read + * This can only work if we have the ecc bytes directly behind the + * data bytes. Applies for DOC and AG-AND Renesas HW Reed Solomon generators */ +#define NAND_HWECC_SYNDROME 0x00020000 + </programlisting> + </para> + </sect2> + </sect1> + + <sect1 id="EEC_selection_constants"> + <title>ECC selection constants</title> + <para> + Use these constants to select the ECC algorithm. + <programlisting> +/* No ECC. Usage is not recommended ! */ +#define NAND_ECC_NONE 0 +/* Software ECC 3 byte ECC per 256 Byte data */ +#define NAND_ECC_SOFT 1 +/* Hardware ECC 3 byte ECC per 256 Byte data */ +#define NAND_ECC_HW3_256 2 +/* Hardware ECC 3 byte ECC per 512 Byte data */ +#define NAND_ECC_HW3_512 3 +/* Hardware ECC 6 byte ECC per 512 Byte data */ +#define NAND_ECC_HW6_512 4 +/* Hardware ECC 6 byte ECC per 512 Byte data */ +#define NAND_ECC_HW8_512 6 + </programlisting> + </para> + </sect1> + + <sect1 id="Hardware_control_related_constants"> + <title>Hardware control related constants</title> + <para> + These constants describe the requested hardware access function when + the boardspecific hardware control function is called + <programlisting> +/* Select the chip by setting nCE to low */ +#define NAND_CTL_SETNCE 1 +/* Deselect the chip by setting nCE to high */ +#define NAND_CTL_CLRNCE 2 +/* Select the command latch by setting CLE to high */ +#define NAND_CTL_SETCLE 3 +/* Deselect the command latch by setting CLE to low */ +#define NAND_CTL_CLRCLE 4 +/* Select the address latch by setting ALE to high */ +#define NAND_CTL_SETALE 5 +/* Deselect the address latch by setting ALE to low */ +#define NAND_CTL_CLRALE 6 +/* Set write protection by setting WP to high. Not used! */ +#define NAND_CTL_SETWP 7 +/* Clear write protection by setting WP to low. Not used! */ +#define NAND_CTL_CLRWP 8 + </programlisting> + </para> + </sect1> + + <sect1 id="Bad_block_table_constants"> + <title>Bad block table related constants</title> + <para> + These constants describe the options used for bad block + table descriptors. + <programlisting> +/* Options for the bad block table descriptors */ + +/* The number of bits used per block in the bbt on the device */ +#define NAND_BBT_NRBITS_MSK 0x0000000F +#define NAND_BBT_1BIT 0x00000001 +#define NAND_BBT_2BIT 0x00000002 +#define NAND_BBT_4BIT 0x00000004 +#define NAND_BBT_8BIT 0x00000008 +/* The bad block table is in the last good block of the device */ +#define NAND_BBT_LASTBLOCK 0x00000010 +/* The bbt is at the given page, else we must scan for the bbt */ +#define NAND_BBT_ABSPAGE 0x00000020 +/* The bbt is at the given page, else we must scan for the bbt */ +#define NAND_BBT_SEARCH 0x00000040 +/* bbt is stored per chip on multichip devices */ +#define NAND_BBT_PERCHIP 0x00000080 +/* bbt has a version counter at offset veroffs */ +#define NAND_BBT_VERSION 0x00000100 +/* Create a bbt if none axists */ +#define NAND_BBT_CREATE 0x00000200 +/* Search good / bad pattern through all pages of a block */ +#define NAND_BBT_SCANALLPAGES 0x00000400 +/* Scan block empty during good / bad block scan */ +#define NAND_BBT_SCANEMPTY 0x00000800 +/* Write bbt if neccecary */ +#define NAND_BBT_WRITE 0x00001000 +/* Read and write back block contents when writing bbt */ +#define NAND_BBT_SAVECONTENT 0x00002000 + </programlisting> + </para> + </sect1> + + </chapter> + + <chapter id="structs"> + <title>Structures</title> + <para> + This chapter contains the autogenerated documentation of the structures which are + used in the NAND driver and might be relevant for a driver developer. Each + struct member has a short description which is marked with an [XXX] identifier. + See the chapter "Documentation hints" for an explanation. + </para> +!Iinclude/linux/mtd/nand.h + </chapter> + + <chapter id="pubfunctions"> + <title>Public Functions Provided</title> + <para> + This chapter contains the autogenerated documentation of the NAND kernel API functions + which are exported. Each function has a short description which is marked with an [XXX] identifier. + See the chapter "Documentation hints" for an explanation. + </para> +!Edrivers/mtd/nand/nand_base.c +!Edrivers/mtd/nand/nand_bbt.c +!Edrivers/mtd/nand/nand_ecc.c + </chapter> + + <chapter id="intfunctions"> + <title>Internal Functions Provided</title> + <para> + This chapter contains the autogenerated documentation of the NAND driver internal functions. + Each function has a short description which is marked with an [XXX] identifier. + See the chapter "Documentation hints" for an explanation. + The functions marked with [DEFAULT] might be relevant for a board driver developer. + </para> +!Idrivers/mtd/nand/nand_base.c +!Idrivers/mtd/nand/nand_bbt.c +<!-- No internal functions for kernel-doc: +X!Idrivers/mtd/nand/nand_ecc.c +--> + </chapter> + + <chapter id="credits"> + <title>Credits</title> + <para> + The following people have contributed to the NAND driver: + <orderedlist> + <listitem><para>Steven J. Hill<email>sjhill@realitydiluted.com</email></para></listitem> + <listitem><para>David Woodhouse<email>dwmw2@infradead.org</email></para></listitem> + <listitem><para>Thomas Gleixner<email>tglx@linutronix.de</email></para></listitem> + </orderedlist> + A lot of users have provided bugfixes, improvements and helping hands for testing. + Thanks a lot. + </para> + <para> + The following people have contributed to this document: + <orderedlist> + <listitem><para>Thomas Gleixner<email>tglx@linutronix.de</email></para></listitem> + </orderedlist> + </para> + </chapter> +</book> diff --git a/Documentation/DocBook/networking.tmpl b/Documentation/DocBook/networking.tmpl new file mode 100644 index 00000000..59ad69a9 --- /dev/null +++ b/Documentation/DocBook/networking.tmpl @@ -0,0 +1,111 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="LinuxNetworking"> + <bookinfo> + <title>Linux Networking and Network Devices APIs</title> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="netcore"> + <title>Linux Networking</title> + <sect1><title>Networking Base Types</title> +!Iinclude/linux/net.h + </sect1> + <sect1><title>Socket Buffer Functions</title> +!Iinclude/linux/skbuff.h +!Iinclude/net/sock.h +!Enet/socket.c +!Enet/core/skbuff.c +!Enet/core/sock.c +!Enet/core/datagram.c +!Enet/core/stream.c + </sect1> + <sect1><title>Socket Filter</title> +!Enet/core/filter.c + </sect1> + <sect1><title>Generic Network Statistics</title> +!Iinclude/linux/gen_stats.h +!Enet/core/gen_stats.c +!Enet/core/gen_estimator.c + </sect1> + <sect1><title>SUN RPC subsystem</title> +<!-- The !D functionality is not perfect, garbage has to be protected by comments +!Dnet/sunrpc/sunrpc_syms.c +--> +!Enet/sunrpc/xdr.c +!Enet/sunrpc/svc_xprt.c +!Enet/sunrpc/xprt.c +!Enet/sunrpc/sched.c +!Enet/sunrpc/socklib.c +!Enet/sunrpc/stats.c +!Enet/sunrpc/rpc_pipe.c +!Enet/sunrpc/rpcb_clnt.c +!Enet/sunrpc/clnt.c + </sect1> + <sect1><title>WiMAX</title> +!Enet/wimax/op-msg.c +!Enet/wimax/op-reset.c +!Enet/wimax/op-rfkill.c +!Enet/wimax/stack.c +!Iinclude/net/wimax.h +!Iinclude/linux/wimax.h + </sect1> + </chapter> + + <chapter id="netdev"> + <title>Network device support</title> + <sect1><title>Driver Support</title> +!Enet/core/dev.c +!Enet/ethernet/eth.c +!Enet/sched/sch_generic.c +!Iinclude/linux/etherdevice.h +!Iinclude/linux/netdevice.h + </sect1> + <sect1><title>PHY Support</title> +!Edrivers/net/phy/phy.c +!Idrivers/net/phy/phy.c +!Edrivers/net/phy/phy_device.c +!Idrivers/net/phy/phy_device.c +!Edrivers/net/phy/mdio_bus.c +!Idrivers/net/phy/mdio_bus.c + </sect1> +<!-- FIXME: Removed for now since no structured comments in source + <sect1><title>Wireless</title> +X!Enet/core/wireless.c + </sect1> +--> + </chapter> + +</book> diff --git a/Documentation/DocBook/rapidio.tmpl b/Documentation/DocBook/rapidio.tmpl new file mode 100644 index 00000000..50479360 --- /dev/null +++ b/Documentation/DocBook/rapidio.tmpl @@ -0,0 +1,158 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" [ + <!ENTITY rapidio SYSTEM "rapidio.xml"> + ]> + +<book id="RapidIO-Guide"> + <bookinfo> + <title>RapidIO Subsystem Guide</title> + + <authorgroup> + <author> + <firstname>Matt</firstname> + <surname>Porter</surname> + <affiliation> + <address> + <email>mporter@kernel.crashing.org</email> + <email>mporter@mvista.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2005</year> + <holder>MontaVista Software, Inc.</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + RapidIO is a high speed switched fabric interconnect with + features aimed at the embedded market. RapidIO provides + support for memory-mapped I/O as well as message-based + transactions over the switched fabric network. RapidIO has + a standardized discovery mechanism not unlike the PCI bus + standard that allows simple detection of devices in a + network. + </para> + <para> + This documentation is provided for developers intending + to support RapidIO on new architectures, write new drivers, + or to understand the subsystem internals. + </para> + </chapter> + + <chapter id="bugs"> + <title>Known Bugs and Limitations</title> + + <sect1 id="known_bugs"> + <title>Bugs</title> + <para>None. ;)</para> + </sect1> + <sect1 id="Limitations"> + <title>Limitations</title> + <para> + <orderedlist> + <listitem><para>Access/management of RapidIO memory regions is not supported</para></listitem> + <listitem><para>Multiple host enumeration is not supported</para></listitem> + </orderedlist> + </para> + </sect1> + </chapter> + + <chapter id="drivers"> + <title>RapidIO driver interface</title> + <para> + Drivers are provided a set of calls in order + to interface with the subsystem to gather info + on devices, request/map memory region resources, + and manage mailboxes/doorbells. + </para> + <sect1 id="Functions"> + <title>Functions</title> +!Iinclude/linux/rio_drv.h +!Edrivers/rapidio/rio-driver.c +!Edrivers/rapidio/rio.c + </sect1> + </chapter> + + <chapter id="internals"> + <title>Internals</title> + + <para> + This chapter contains the autogenerated documentation of the RapidIO + subsystem. + </para> + + <sect1 id="Structures"><title>Structures</title> +!Iinclude/linux/rio.h + </sect1> + <sect1 id="Enumeration_and_Discovery"><title>Enumeration and Discovery</title> +!Idrivers/rapidio/rio-scan.c + </sect1> + <sect1 id="Driver_functionality"><title>Driver functionality</title> +!Idrivers/rapidio/rio.c +!Idrivers/rapidio/rio-access.c + </sect1> + <sect1 id="Device_model_support"><title>Device model support</title> +!Idrivers/rapidio/rio-driver.c + </sect1> + <sect1 id="Sysfs_support"><title>Sysfs support</title> +!Idrivers/rapidio/rio-sysfs.c + </sect1> + <sect1 id="PPC32_support"><title>PPC32 support</title> +!Iarch/powerpc/sysdev/fsl_rio.c + </sect1> + </chapter> + + <chapter id="credits"> + <title>Credits</title> + <para> + The following people have contributed to the RapidIO + subsystem directly or indirectly: + <orderedlist> + <listitem><para>Matt Porter<email>mporter@kernel.crashing.org</email></para></listitem> + <listitem><para>Randy Vinson<email>rvinson@mvista.com</email></para></listitem> + <listitem><para>Dan Malek<email>dan@embeddedalley.com</email></para></listitem> + </orderedlist> + </para> + <para> + The following people have contributed to this document: + <orderedlist> + <listitem><para>Matt Porter<email>mporter@kernel.crashing.org</email></para></listitem> + </orderedlist> + </para> + </chapter> +</book> diff --git a/Documentation/DocBook/regulator.tmpl b/Documentation/DocBook/regulator.tmpl new file mode 100644 index 00000000..346e552f --- /dev/null +++ b/Documentation/DocBook/regulator.tmpl @@ -0,0 +1,304 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="regulator-api"> + <bookinfo> + <title>Voltage and current regulator API</title> + + <authorgroup> + <author> + <firstname>Liam</firstname> + <surname>Girdwood</surname> + <affiliation> + <address> + <email>lrg@slimlogic.co.uk</email> + </address> + </affiliation> + </author> + <author> + <firstname>Mark</firstname> + <surname>Brown</surname> + <affiliation> + <orgname>Wolfson Microelectronics</orgname> + <address> + <email>broonie@opensource.wolfsonmicro.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2007-2008</year> + <holder>Wolfson Microelectronics</holder> + </copyright> + <copyright> + <year>2008</year> + <holder>Liam Girdwood</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + This framework is designed to provide a standard kernel + interface to control voltage and current regulators. + </para> + <para> + The intention is to allow systems to dynamically control + regulator power output in order to save power and prolong + battery life. This applies to both voltage regulators (where + voltage output is controllable) and current sinks (where current + limit is controllable). + </para> + <para> + Note that additional (and currently more complete) documentation + is available in the Linux kernel source under + <filename>Documentation/power/regulator</filename>. + </para> + + <sect1 id="glossary"> + <title>Glossary</title> + <para> + The regulator API uses a number of terms which may not be + familiar: + </para> + <glossary> + + <glossentry> + <glossterm>Regulator</glossterm> + <glossdef> + <para> + Electronic device that supplies power to other devices. Most + regulators can enable and disable their output and some can also + control their output voltage or current. + </para> + </glossdef> + </glossentry> + + <glossentry> + <glossterm>Consumer</glossterm> + <glossdef> + <para> + Electronic device which consumes power provided by a regulator. + These may either be static, requiring only a fixed supply, or + dynamic, requiring active management of the regulator at + runtime. + </para> + </glossdef> + </glossentry> + + <glossentry> + <glossterm>Power Domain</glossterm> + <glossdef> + <para> + The electronic circuit supplied by a given regulator, including + the regulator and all consumer devices. The configuration of + the regulator is shared between all the components in the + circuit. + </para> + </glossdef> + </glossentry> + + <glossentry> + <glossterm>Power Management Integrated Circuit</glossterm> + <acronym>PMIC</acronym> + <glossdef> + <para> + An IC which contains numerous regulators and often also other + subsystems. In an embedded system the primary PMIC is often + equivalent to a combination of the PSU and southbridge in a + desktop system. + </para> + </glossdef> + </glossentry> + </glossary> + </sect1> + </chapter> + + <chapter id="consumer"> + <title>Consumer driver interface</title> + <para> + This offers a similar API to the kernel clock framework. + Consumer drivers use <link + linkend='API-regulator-get'>get</link> and <link + linkend='API-regulator-put'>put</link> operations to acquire and + release regulators. Functions are + provided to <link linkend='API-regulator-enable'>enable</link> + and <link linkend='API-regulator-disable'>disable</link> the + reguator and to get and set the runtime parameters of the + regulator. + </para> + <para> + When requesting regulators consumers use symbolic names for their + supplies, such as "Vcc", which are mapped into actual regulator + devices by the machine interface. + </para> + <para> + A stub version of this API is provided when the regulator + framework is not in use in order to minimise the need to use + ifdefs. + </para> + + <sect1 id="consumer-enable"> + <title>Enabling and disabling</title> + <para> + The regulator API provides reference counted enabling and + disabling of regulators. Consumer devices use the <function><link + linkend='API-regulator-enable'>regulator_enable</link></function> + and <function><link + linkend='API-regulator-disable'>regulator_disable</link> + </function> functions to enable and disable regulators. Calls + to the two functions must be balanced. + </para> + <para> + Note that since multiple consumers may be using a regulator and + machine constraints may not allow the regulator to be disabled + there is no guarantee that calling + <function>regulator_disable</function> will actually cause the + supply provided by the regulator to be disabled. Consumer + drivers should assume that the regulator may be enabled at all + times. + </para> + </sect1> + + <sect1 id="consumer-config"> + <title>Configuration</title> + <para> + Some consumer devices may need to be able to dynamically + configure their supplies. For example, MMC drivers may need to + select the correct operating voltage for their cards. This may + be done while the regulator is enabled or disabled. + </para> + <para> + The <function><link + linkend='API-regulator-set-voltage'>regulator_set_voltage</link> + </function> and <function><link + linkend='API-regulator-set-current-limit' + >regulator_set_current_limit</link> + </function> functions provide the primary interface for this. + Both take ranges of voltages and currents, supporting drivers + that do not require a specific value (eg, CPU frequency scaling + normally permits the CPU to use a wider range of supply + voltages at lower frequencies but does not require that the + supply voltage be lowered). Where an exact value is required + both minimum and maximum values should be identical. + </para> + </sect1> + + <sect1 id="consumer-callback"> + <title>Callbacks</title> + <para> + Callbacks may also be <link + linkend='API-regulator-register-notifier'>registered</link> + for events such as regulation failures. + </para> + </sect1> + </chapter> + + <chapter id="driver"> + <title>Regulator driver interface</title> + <para> + Drivers for regulator chips <link + linkend='API-regulator-register'>register</link> the regulators + with the regulator core, providing operations structures to the + core. A <link + linkend='API-regulator-notifier-call-chain'>notifier</link> interface + allows error conditions to be reported to the core. + </para> + <para> + Registration should be triggered by explicit setup done by the + platform, supplying a <link + linkend='API-struct-regulator-init-data'>struct + regulator_init_data</link> for the regulator containing + <link linkend='machine-constraint'>constraint</link> and + <link linkend='machine-supply'>supply</link> information. + </para> + </chapter> + + <chapter id="machine"> + <title>Machine interface</title> + <para> + This interface provides a way to define how regulators are + connected to consumers on a given system and what the valid + operating parameters are for the system. + </para> + + <sect1 id="machine-supply"> + <title>Supplies</title> + <para> + Regulator supplies are specified using <link + linkend='API-struct-regulator-consumer-supply'>struct + regulator_consumer_supply</link>. This is done at + <link linkend='driver'>driver registration + time</link> as part of the machine constraints. + </para> + </sect1> + + <sect1 id="machine-constraint"> + <title>Constraints</title> + <para> + As well as defining the connections the machine interface + also provides constraints defining the operations that + clients are allowed to perform and the parameters that may be + set. This is required since generally regulator devices will + offer more flexibility than it is safe to use on a given + system, for example supporting higher supply voltages than the + consumers are rated for. + </para> + <para> + This is done at <link linkend='driver'>driver + registration time</link> by providing a <link + linkend='API-struct-regulation-constraints'>struct + regulation_constraints</link>. + </para> + <para> + The constraints may also specify an initial configuration for the + regulator in the constraints, which is particularly useful for + use with static consumers. + </para> + </sect1> + </chapter> + + <chapter id="api"> + <title>API reference</title> + <para> + Due to limitations of the kernel documentation framework and the + existing layout of the source code the entire regulator API is + documented here. + </para> +!Iinclude/linux/regulator/consumer.h +!Iinclude/linux/regulator/machine.h +!Iinclude/linux/regulator/driver.h +!Edrivers/regulator/core.c + </chapter> +</book> diff --git a/Documentation/DocBook/s390-drivers.tmpl b/Documentation/DocBook/s390-drivers.tmpl new file mode 100644 index 00000000..95bfc12e --- /dev/null +++ b/Documentation/DocBook/s390-drivers.tmpl @@ -0,0 +1,161 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="s390drivers"> + <bookinfo> + <title>Writing s390 channel device drivers</title> + + <authorgroup> + <author> + <firstname>Cornelia</firstname> + <surname>Huck</surname> + <affiliation> + <address> + <email>cornelia.huck@de.ibm.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2007</year> + <holder>IBM Corp.</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + This document describes the interfaces available for device drivers that + drive s390 based channel attached I/O devices. This includes interfaces for + interaction with the hardware and interfaces for interacting with the + common driver core. Those interfaces are provided by the s390 common I/O + layer. + </para> + <para> + The document assumes a familarity with the technical terms associated + with the s390 channel I/O architecture. For a description of this + architecture, please refer to the "z/Architecture: Principles of + Operation", IBM publication no. SA22-7832. + </para> + <para> + While most I/O devices on a s390 system are typically driven through the + channel I/O mechanism described here, there are various other methods + (like the diag interface). These are out of the scope of this document. + </para> + <para> + Some additional information can also be found in the kernel source + under Documentation/s390/driver-model.txt. + </para> + </chapter> + <chapter id="ccw"> + <title>The ccw bus</title> + <para> + The ccw bus typically contains the majority of devices available to + a s390 system. Named after the channel command word (ccw), the basic + command structure used to address its devices, the ccw bus contains + so-called channel attached devices. They are addressed via I/O + subchannels, visible on the css bus. A device driver for + channel-attached devices, however, will never interact with the + subchannel directly, but only via the I/O device on the ccw bus, + the ccw device. + </para> + <sect1 id="channelIO"> + <title>I/O functions for channel-attached devices</title> + <para> + Some hardware structures have been translated into C structures for use + by the common I/O layer and device drivers. For more information on + the hardware structures represented here, please consult the Principles + of Operation. + </para> +!Iarch/s390/include/asm/cio.h + </sect1> + <sect1 id="ccwdev"> + <title>ccw devices</title> + <para> + Devices that want to initiate channel I/O need to attach to the ccw bus. + Interaction with the driver core is done via the common I/O layer, which + provides the abstractions of ccw devices and ccw device drivers. + </para> + <para> + The functions that initiate or terminate channel I/O all act upon a + ccw device structure. Device drivers must not bypass those functions + or strange side effects may happen. + </para> +!Iarch/s390/include/asm/ccwdev.h +!Edrivers/s390/cio/device.c +!Edrivers/s390/cio/device_ops.c + </sect1> + <sect1 id="cmf"> + <title>The channel-measurement facility</title> + <para> + The channel-measurement facility provides a means to collect + measurement data which is made available by the channel subsystem + for each channel attached device. + </para> +!Iarch/s390/include/asm/cmb.h +!Edrivers/s390/cio/cmf.c + </sect1> + </chapter> + + <chapter id="ccwgroup"> + <title>The ccwgroup bus</title> + <para> + The ccwgroup bus only contains artificial devices, created by the user. + Many networking devices (e.g. qeth) are in fact composed of several + ccw devices (like read, write and data channel for qeth). The + ccwgroup bus provides a mechanism to create a meta-device which + contains those ccw devices as slave devices and can be associated + with the netdevice. + </para> + <sect1 id="ccwgroupdevices"> + <title>ccw group devices</title> +!Iarch/s390/include/asm/ccwgroup.h +!Edrivers/s390/cio/ccwgroup.c + </sect1> + </chapter> + + <chapter id="genericinterfaces"> + <title>Generic interfaces</title> + <para> + Some interfaces are available to other drivers that do not necessarily + have anything to do with the busses described above, but still are + indirectly using basic infrastructure in the common I/O layer. + One example is the support for adapter interrupts. + </para> +!Edrivers/s390/cio/airq.c + </chapter> + +</book> diff --git a/Documentation/DocBook/scsi.tmpl b/Documentation/DocBook/scsi.tmpl new file mode 100644 index 00000000..324b5349 --- /dev/null +++ b/Documentation/DocBook/scsi.tmpl @@ -0,0 +1,409 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="scsimid"> + <bookinfo> + <title>SCSI Interfaces Guide</title> + + <authorgroup> + <author> + <firstname>James</firstname> + <surname>Bottomley</surname> + <affiliation> + <address> + <email>James.Bottomley@hansenpartnership.com</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Rob</firstname> + <surname>Landley</surname> + <affiliation> + <address> + <email>rob@landley.net</email> + </address> + </affiliation> + </author> + + </authorgroup> + + <copyright> + <year>2007</year> + <holder>Linux Foundation</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + + <toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <sect1 id="protocol_vs_bus"> + <title>Protocol vs bus</title> + <para> + Once upon a time, the Small Computer Systems Interface defined both + a parallel I/O bus and a data protocol to connect a wide variety of + peripherals (disk drives, tape drives, modems, printers, scanners, + optical drives, test equipment, and medical devices) to a host + computer. + </para> + <para> + Although the old parallel (fast/wide/ultra) SCSI bus has largely + fallen out of use, the SCSI command set is more widely used than ever + to communicate with devices over a number of different busses. + </para> + <para> + The <ulink url='http://www.t10.org/scsi-3.htm'>SCSI protocol</ulink> + is a big-endian peer-to-peer packet based protocol. SCSI commands + are 6, 10, 12, or 16 bytes long, often followed by an associated data + payload. + </para> + <para> + SCSI commands can be transported over just about any kind of bus, and + are the default protocol for storage devices attached to USB, SATA, + SAS, Fibre Channel, FireWire, and ATAPI devices. SCSI packets are + also commonly exchanged over Infiniband, + <ulink url='http://i2o.shadowconnect.com/faq.php'>I20</ulink>, TCP/IP + (<ulink url='http://en.wikipedia.org/wiki/ISCSI'>iSCSI</ulink>), even + <ulink url='http://cyberelk.net/tim/parport/parscsi.html'>Parallel + ports</ulink>. + </para> + </sect1> + <sect1 id="subsystem_design"> + <title>Design of the Linux SCSI subsystem</title> + <para> + The SCSI subsystem uses a three layer design, with upper, mid, and low + layers. Every operation involving the SCSI subsystem (such as reading + a sector from a disk) uses one driver at each of the 3 levels: one + upper layer driver, one lower layer driver, and the SCSI midlayer. + </para> + <para> + The SCSI upper layer provides the interface between userspace and the + kernel, in the form of block and char device nodes for I/O and + ioctl(). The SCSI lower layer contains drivers for specific hardware + devices. + </para> + <para> + In between is the SCSI mid-layer, analogous to a network routing + layer such as the IPv4 stack. The SCSI mid-layer routes a packet + based data protocol between the upper layer's /dev nodes and the + corresponding devices in the lower layer. It manages command queues, + provides error handling and power management functions, and responds + to ioctl() requests. + </para> + </sect1> + </chapter> + + <chapter id="upper_layer"> + <title>SCSI upper layer</title> + <para> + The upper layer supports the user-kernel interface by providing + device nodes. + </para> + <sect1 id="sd"> + <title>sd (SCSI Disk)</title> + <para>sd (sd_mod.o)</para> +<!-- !Idrivers/scsi/sd.c --> + </sect1> + <sect1 id="sr"> + <title>sr (SCSI CD-ROM)</title> + <para>sr (sr_mod.o)</para> + </sect1> + <sect1 id="st"> + <title>st (SCSI Tape)</title> + <para>st (st.o)</para> + </sect1> + <sect1 id="sg"> + <title>sg (SCSI Generic)</title> + <para>sg (sg.o)</para> + </sect1> + <sect1 id="ch"> + <title>ch (SCSI Media Changer)</title> + <para>ch (ch.c)</para> + </sect1> + </chapter> + + <chapter id="mid_layer"> + <title>SCSI mid layer</title> + + <sect1 id="midlayer_implementation"> + <title>SCSI midlayer implementation</title> + <sect2 id="scsi_device.h"> + <title>include/scsi/scsi_device.h</title> + <para> + </para> +!Iinclude/scsi/scsi_device.h + </sect2> + + <sect2 id="scsi.c"> + <title>drivers/scsi/scsi.c</title> + <para>Main file for the SCSI midlayer.</para> +!Edrivers/scsi/scsi.c + </sect2> + <sect2 id="scsicam.c"> + <title>drivers/scsi/scsicam.c</title> + <para> + <ulink url='http://www.t10.org/ftp/t10/drafts/cam/cam-r12b.pdf'>SCSI + Common Access Method</ulink> support functions, for use with + HDIO_GETGEO, etc. + </para> +!Edrivers/scsi/scsicam.c + </sect2> + <sect2 id="scsi_error.c"> + <title>drivers/scsi/scsi_error.c</title> + <para>Common SCSI error/timeout handling routines.</para> +!Edrivers/scsi/scsi_error.c + </sect2> + <sect2 id="scsi_devinfo.c"> + <title>drivers/scsi/scsi_devinfo.c</title> + <para> + Manage scsi_dev_info_list, which tracks blacklisted and whitelisted + devices. + </para> +!Idrivers/scsi/scsi_devinfo.c + </sect2> + <sect2 id="scsi_ioctl.c"> + <title>drivers/scsi/scsi_ioctl.c</title> + <para> + Handle ioctl() calls for SCSI devices. + </para> +!Edrivers/scsi/scsi_ioctl.c + </sect2> + <sect2 id="scsi_lib.c"> + <title>drivers/scsi/scsi_lib.c</title> + <para> + SCSI queuing library. + </para> +!Edrivers/scsi/scsi_lib.c + </sect2> + <sect2 id="scsi_lib_dma.c"> + <title>drivers/scsi/scsi_lib_dma.c</title> + <para> + SCSI library functions depending on DMA + (map and unmap scatter-gather lists). + </para> +!Edrivers/scsi/scsi_lib_dma.c + </sect2> + <sect2 id="scsi_module.c"> + <title>drivers/scsi/scsi_module.c</title> + <para> + The file drivers/scsi/scsi_module.c contains legacy support for + old-style host templates. It should never be used by any new driver. + </para> + </sect2> + <sect2 id="scsi_proc.c"> + <title>drivers/scsi/scsi_proc.c</title> + <para> + The functions in this file provide an interface between + the PROC file system and the SCSI device drivers + It is mainly used for debugging, statistics and to pass + information directly to the lowlevel driver. + + I.E. plumbing to manage /proc/scsi/* + </para> +!Idrivers/scsi/scsi_proc.c + </sect2> + <sect2 id="scsi_netlink.c"> + <title>drivers/scsi/scsi_netlink.c</title> + <para> + Infrastructure to provide async events from transports to userspace + via netlink, using a single NETLINK_SCSITRANSPORT protocol for all + transports. + + See <ulink url='http://marc.info/?l=linux-scsi&m=115507374832500&w=2'>the + original patch submission</ulink> for more details. + </para> +!Idrivers/scsi/scsi_netlink.c + </sect2> + <sect2 id="scsi_scan.c"> + <title>drivers/scsi/scsi_scan.c</title> + <para> + Scan a host to determine which (if any) devices are attached. + + The general scanning/probing algorithm is as follows, exceptions are + made to it depending on device specific flags, compilation options, + and global variable (boot or module load time) settings. + + A specific LUN is scanned via an INQUIRY command; if the LUN has a + device attached, a scsi_device is allocated and setup for it. + + For every id of every channel on the given host, start by scanning + LUN 0. Skip hosts that don't respond at all to a scan of LUN 0. + Otherwise, if LUN 0 has a device attached, allocate and setup a + scsi_device for it. If target is SCSI-3 or up, issue a REPORT LUN, + and scan all of the LUNs returned by the REPORT LUN; else, + sequentially scan LUNs up until some maximum is reached, or a LUN is + seen that cannot have a device attached to it. + </para> +!Idrivers/scsi/scsi_scan.c + </sect2> + <sect2 id="scsi_sysctl.c"> + <title>drivers/scsi/scsi_sysctl.c</title> + <para> + Set up the sysctl entry: "/dev/scsi/logging_level" + (DEV_SCSI_LOGGING_LEVEL) which sets/returns scsi_logging_level. + </para> + </sect2> + <sect2 id="scsi_sysfs.c"> + <title>drivers/scsi/scsi_sysfs.c</title> + <para> + SCSI sysfs interface routines. + </para> +!Edrivers/scsi/scsi_sysfs.c + </sect2> + <sect2 id="hosts.c"> + <title>drivers/scsi/hosts.c</title> + <para> + mid to lowlevel SCSI driver interface + </para> +!Edrivers/scsi/hosts.c + </sect2> + <sect2 id="constants.c"> + <title>drivers/scsi/constants.c</title> + <para> + mid to lowlevel SCSI driver interface + </para> +!Edrivers/scsi/constants.c + </sect2> + </sect1> + + <sect1 id="Transport_classes"> + <title>Transport classes</title> + <para> + Transport classes are service libraries for drivers in the SCSI + lower layer, which expose transport attributes in sysfs. + </para> + <sect2 id="Fibre_Channel_transport"> + <title>Fibre Channel transport</title> + <para> + The file drivers/scsi/scsi_transport_fc.c defines transport attributes + for Fibre Channel. + </para> +!Edrivers/scsi/scsi_transport_fc.c + </sect2> + <sect2 id="iSCSI_transport"> + <title>iSCSI transport class</title> + <para> + The file drivers/scsi/scsi_transport_iscsi.c defines transport + attributes for the iSCSI class, which sends SCSI packets over TCP/IP + connections. + </para> +!Edrivers/scsi/scsi_transport_iscsi.c + </sect2> + <sect2 id="SAS_transport"> + <title>Serial Attached SCSI (SAS) transport class</title> + <para> + The file drivers/scsi/scsi_transport_sas.c defines transport + attributes for Serial Attached SCSI, a variant of SATA aimed at + large high-end systems. + </para> + <para> + The SAS transport class contains common code to deal with SAS HBAs, + an aproximated representation of SAS topologies in the driver model, + and various sysfs attributes to expose these topologies and management + interfaces to userspace. + </para> + <para> + In addition to the basic SCSI core objects this transport class + introduces two additional intermediate objects: The SAS PHY + as represented by struct sas_phy defines an "outgoing" PHY on + a SAS HBA or Expander, and the SAS remote PHY represented by + struct sas_rphy defines an "incoming" PHY on a SAS Expander or + end device. Note that this is purely a software concept, the + underlying hardware for a PHY and a remote PHY is the exactly + the same. + </para> + <para> + There is no concept of a SAS port in this code, users can see + what PHYs form a wide port based on the port_identifier attribute, + which is the same for all PHYs in a port. + </para> +!Edrivers/scsi/scsi_transport_sas.c + </sect2> + <sect2 id="SATA_transport"> + <title>SATA transport class</title> + <para> + The SATA transport is handled by libata, which has its own book of + documentation in this directory. + </para> + </sect2> + <sect2 id="SPI_transport"> + <title>Parallel SCSI (SPI) transport class</title> + <para> + The file drivers/scsi/scsi_transport_spi.c defines transport + attributes for traditional (fast/wide/ultra) SCSI busses. + </para> +!Edrivers/scsi/scsi_transport_spi.c + </sect2> + <sect2 id="SRP_transport"> + <title>SCSI RDMA (SRP) transport class</title> + <para> + The file drivers/scsi/scsi_transport_srp.c defines transport + attributes for SCSI over Remote Direct Memory Access. + </para> +!Edrivers/scsi/scsi_transport_srp.c + </sect2> + </sect1> + + </chapter> + + <chapter id="lower_layer"> + <title>SCSI lower layer</title> + <sect1 id="hba_drivers"> + <title>Host Bus Adapter transport types</title> + <para> + Many modern device controllers use the SCSI command set as a protocol to + communicate with their devices through many different types of physical + connections. + </para> + <para> + In SCSI language a bus capable of carrying SCSI commands is + called a "transport", and a controller connecting to such a bus is + called a "host bus adapter" (HBA). + </para> + <sect2 id="scsi_debug.c"> + <title>Debug transport</title> + <para> + The file drivers/scsi/scsi_debug.c simulates a host adapter with a + variable number of disks (or disk like devices) attached, sharing a + common amount of RAM. Does a lot of checking to make sure that we are + not getting blocks mixed up, and panics the kernel if anything out of + the ordinary is seen. + </para> + <para> + To be more realistic, the simulated devices have the transport + attributes of SAS disks. + </para> + <para> + For documentation see + <ulink url='http://sg.danny.cz/sg/sdebug26.html'>http://sg.danny.cz/sg/sdebug26.html</ulink> + </para> +<!-- !Edrivers/scsi/scsi_debug.c --> + </sect2> + <sect2 id="todo"> + <title>todo</title> + <para>Parallel (fast/wide/ultra) SCSI, USB, SATA, + SAS, Fibre Channel, FireWire, ATAPI devices, Infiniband, + I20, iSCSI, Parallel ports, netlink... + </para> + </sect2> + </sect1> + </chapter> +</book> diff --git a/Documentation/DocBook/sh.tmpl b/Documentation/DocBook/sh.tmpl new file mode 100644 index 00000000..4a38f604 --- /dev/null +++ b/Documentation/DocBook/sh.tmpl @@ -0,0 +1,105 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="sh-drivers"> + <bookinfo> + <title>SuperH Interfaces Guide</title> + + <authorgroup> + <author> + <firstname>Paul</firstname> + <surname>Mundt</surname> + <affiliation> + <address> + <email>lethal@linux-sh.org</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2008-2010</year> + <holder>Paul Mundt</holder> + </copyright> + <copyright> + <year>2008-2010</year> + <holder>Renesas Technology Corp.</holder> + </copyright> + <copyright> + <year>2010</year> + <holder>Renesas Electronics Corp.</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="mm"> + <title>Memory Management</title> + <sect1 id="sh4"> + <title>SH-4</title> + <sect2 id="sq"> + <title>Store Queue API</title> +!Earch/sh/kernel/cpu/sh4/sq.c + </sect2> + </sect1> + <sect1 id="sh5"> + <title>SH-5</title> + <sect2 id="tlb"> + <title>TLB Interfaces</title> +!Iarch/sh/mm/tlb-sh5.c +!Iarch/sh/include/asm/tlb_64.h + </sect2> + </sect1> + </chapter> + <chapter id="mach"> + <title>Machine Specific Interfaces</title> + <sect1 id="dreamcast"> + <title>mach-dreamcast</title> +!Iarch/sh/boards/mach-dreamcast/rtc.c + </sect1> + <sect1 id="x3proto"> + <title>mach-x3proto</title> +!Earch/sh/boards/mach-x3proto/ilsel.c + </sect1> + </chapter> + <chapter id="busses"> + <title>Busses</title> + <sect1 id="superhyway"> + <title>SuperHyway</title> +!Edrivers/sh/superhyway/superhyway.c + </sect1> + + <sect1 id="maple"> + <title>Maple</title> +!Edrivers/sh/maple/maple.c + </sect1> + </chapter> +</book> diff --git a/Documentation/DocBook/stylesheet.xsl b/Documentation/DocBook/stylesheet.xsl new file mode 100644 index 00000000..85b25275 --- /dev/null +++ b/Documentation/DocBook/stylesheet.xsl @@ -0,0 +1,10 @@ +<?xml version="1.0" encoding="UTF-8"?> +<stylesheet xmlns="http://www.w3.org/1999/XSL/Transform" version="1.0"> +<param name="chunk.quietly">1</param> +<param name="funcsynopsis.style">ansi</param> +<param name="funcsynopsis.tabular.threshold">80</param> +<param name="callout.graphics">0</param> +<!-- <param name="paper.type">A4</param> --> +<param name="generate.section.toc.level">2</param> +<param name="use.id.as.filename">1</param> +</stylesheet> diff --git a/Documentation/DocBook/tracepoint.tmpl b/Documentation/DocBook/tracepoint.tmpl new file mode 100644 index 00000000..b57a9ede --- /dev/null +++ b/Documentation/DocBook/tracepoint.tmpl @@ -0,0 +1,112 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="Tracepoints"> + <bookinfo> + <title>The Linux Kernel Tracepoint API</title> + + <authorgroup> + <author> + <firstname>Jason</firstname> + <surname>Baron</surname> + <affiliation> + <address> + <email>jbaron@redhat.com</email> + </address> + </affiliation> + </author> + <author> + <firstname>William</firstname> + <surname>Cohen</surname> + <affiliation> + <address> + <email>wcohen@redhat.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + + <toc></toc> + <chapter id="intro"> + <title>Introduction</title> + <para> + Tracepoints are static probe points that are located in strategic points + throughout the kernel. 'Probes' register/unregister with tracepoints + via a callback mechanism. The 'probes' are strictly typed functions that + are passed a unique set of parameters defined by each tracepoint. + </para> + + <para> + From this simple callback mechanism, 'probes' can be used to profile, debug, + and understand kernel behavior. There are a number of tools that provide a + framework for using 'probes'. These tools include Systemtap, ftrace, and + LTTng. + </para> + + <para> + Tracepoints are defined in a number of header files via various macros. Thus, + the purpose of this document is to provide a clear accounting of the available + tracepoints. The intention is to understand not only what tracepoints are + available but also to understand where future tracepoints might be added. + </para> + + <para> + The API presented has functions of the form: + <function>trace_tracepointname(function parameters)</function>. These are the + tracepoints callbacks that are found throughout the code. Registering and + unregistering probes with these callback sites is covered in the + <filename>Documentation/trace/*</filename> directory. + </para> + </chapter> + + <chapter id="irq"> + <title>IRQ</title> +!Iinclude/trace/events/irq.h + </chapter> + + <chapter id="signal"> + <title>SIGNAL</title> +!Iinclude/trace/events/signal.h + </chapter> + + <chapter id="block"> + <title>Block IO</title> +!Iinclude/trace/events/block.h + </chapter> + + <chapter id="workqueue"> + <title>Workqueue</title> +!Iinclude/trace/events/workqueue.h + </chapter> +</book> diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl new file mode 100644 index 00000000..ac3d0018 --- /dev/null +++ b/Documentation/DocBook/uio-howto.tmpl @@ -0,0 +1,994 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" +"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" []> + +<book id="index"> +<bookinfo> +<title>The Userspace I/O HOWTO</title> + +<author> + <firstname>Hans-Jürgen</firstname> + <surname>Koch</surname> + <authorblurb><para>Linux developer, Linutronix</para></authorblurb> + <affiliation> + <orgname> + <ulink url="http://www.linutronix.de">Linutronix</ulink> + </orgname> + + <address> + <email>hjk@hansjkoch.de</email> + </address> + </affiliation> +</author> + +<copyright> + <year>2006-2008</year> + <holder>Hans-Jürgen Koch.</holder> +</copyright> +<copyright> + <year>2009</year> + <holder>Red Hat Inc, Michael S. Tsirkin (mst@redhat.com)</holder> +</copyright> + +<legalnotice> +<para> +This documentation is Free Software licensed under the terms of the +GPL version 2. +</para> +</legalnotice> + +<pubdate>2006-12-11</pubdate> + +<abstract> + <para>This HOWTO describes concept and usage of Linux kernel's + Userspace I/O system.</para> +</abstract> + +<revhistory> + <revision> + <revnumber>0.9</revnumber> + <date>2009-07-16</date> + <authorinitials>mst</authorinitials> + <revremark>Added generic pci driver + </revremark> + </revision> + <revision> + <revnumber>0.8</revnumber> + <date>2008-12-24</date> + <authorinitials>hjk</authorinitials> + <revremark>Added name attributes in mem and portio sysfs directories. + </revremark> + </revision> + <revision> + <revnumber>0.7</revnumber> + <date>2008-12-23</date> + <authorinitials>hjk</authorinitials> + <revremark>Added generic platform drivers and offset attribute.</revremark> + </revision> + <revision> + <revnumber>0.6</revnumber> + <date>2008-12-05</date> + <authorinitials>hjk</authorinitials> + <revremark>Added description of portio sysfs attributes.</revremark> + </revision> + <revision> + <revnumber>0.5</revnumber> + <date>2008-05-22</date> + <authorinitials>hjk</authorinitials> + <revremark>Added description of write() function.</revremark> + </revision> + <revision> + <revnumber>0.4</revnumber> + <date>2007-11-26</date> + <authorinitials>hjk</authorinitials> + <revremark>Removed section about uio_dummy.</revremark> + </revision> + <revision> + <revnumber>0.3</revnumber> + <date>2007-04-29</date> + <authorinitials>hjk</authorinitials> + <revremark>Added section about userspace drivers.</revremark> + </revision> + <revision> + <revnumber>0.2</revnumber> + <date>2007-02-13</date> + <authorinitials>hjk</authorinitials> + <revremark>Update after multiple mappings were added.</revremark> + </revision> + <revision> + <revnumber>0.1</revnumber> + <date>2006-12-11</date> + <authorinitials>hjk</authorinitials> + <revremark>First draft.</revremark> + </revision> +</revhistory> +</bookinfo> + +<chapter id="aboutthisdoc"> +<?dbhtml filename="aboutthis.html"?> +<title>About this document</title> + +<sect1 id="translations"> +<?dbhtml filename="translations.html"?> +<title>Translations</title> + +<para>If you know of any translations for this document, or you are +interested in translating it, please email me +<email>hjk@hansjkoch.de</email>. +</para> +</sect1> + +<sect1 id="preface"> +<title>Preface</title> + <para> + For many types of devices, creating a Linux kernel driver is + overkill. All that is really needed is some way to handle an + interrupt and provide access to the memory space of the + device. The logic of controlling the device does not + necessarily have to be within the kernel, as the device does + not need to take advantage of any of other resources that the + kernel provides. One such common class of devices that are + like this are for industrial I/O cards. + </para> + <para> + To address this situation, the userspace I/O system (UIO) was + designed. For typical industrial I/O cards, only a very small + kernel module is needed. The main part of the driver will run in + user space. This simplifies development and reduces the risk of + serious bugs within a kernel module. + </para> + <para> + Please note that UIO is not an universal driver interface. Devices + that are already handled well by other kernel subsystems (like + networking or serial or USB) are no candidates for an UIO driver. + Hardware that is ideally suited for an UIO driver fulfills all of + the following: + </para> +<itemizedlist> +<listitem> + <para>The device has memory that can be mapped. The device can be + controlled completely by writing to this memory.</para> +</listitem> +<listitem> + <para>The device usually generates interrupts.</para> +</listitem> +<listitem> + <para>The device does not fit into one of the standard kernel + subsystems.</para> +</listitem> +</itemizedlist> +</sect1> + +<sect1 id="thanks"> +<title>Acknowledgments</title> + <para>I'd like to thank Thomas Gleixner and Benedikt Spranger of + Linutronix, who have not only written most of the UIO code, but also + helped greatly writing this HOWTO by giving me all kinds of background + information.</para> +</sect1> + +<sect1 id="feedback"> +<title>Feedback</title> + <para>Find something wrong with this document? (Or perhaps something + right?) I would love to hear from you. Please email me at + <email>hjk@hansjkoch.de</email>.</para> +</sect1> +</chapter> + +<chapter id="about"> +<?dbhtml filename="about.html"?> +<title>About UIO</title> + +<para>If you use UIO for your card's driver, here's what you get:</para> + +<itemizedlist> +<listitem> + <para>only one small kernel module to write and maintain.</para> +</listitem> +<listitem> + <para>develop the main part of your driver in user space, + with all the tools and libraries you're used to.</para> +</listitem> +<listitem> + <para>bugs in your driver won't crash the kernel.</para> +</listitem> +<listitem> + <para>updates of your driver can take place without recompiling + the kernel.</para> +</listitem> +</itemizedlist> + +<sect1 id="how_uio_works"> +<title>How UIO works</title> + <para> + Each UIO device is accessed through a device file and several + sysfs attribute files. The device file will be called + <filename>/dev/uio0</filename> for the first device, and + <filename>/dev/uio1</filename>, <filename>/dev/uio2</filename> + and so on for subsequent devices. + </para> + + <para><filename>/dev/uioX</filename> is used to access the + address space of the card. Just use + <function>mmap()</function> to access registers or RAM + locations of your card. + </para> + + <para> + Interrupts are handled by reading from + <filename>/dev/uioX</filename>. A blocking + <function>read()</function> from + <filename>/dev/uioX</filename> will return as soon as an + interrupt occurs. You can also use + <function>select()</function> on + <filename>/dev/uioX</filename> to wait for an interrupt. The + integer value read from <filename>/dev/uioX</filename> + represents the total interrupt count. You can use this number + to figure out if you missed some interrupts. + </para> + <para> + For some hardware that has more than one interrupt source internally, + but not separate IRQ mask and status registers, there might be + situations where userspace cannot determine what the interrupt source + was if the kernel handler disables them by writing to the chip's IRQ + register. In such a case, the kernel has to disable the IRQ completely + to leave the chip's register untouched. Now the userspace part can + determine the cause of the interrupt, but it cannot re-enable + interrupts. Another cornercase is chips where re-enabling interrupts + is a read-modify-write operation to a combined IRQ status/acknowledge + register. This would be racy if a new interrupt occurred + simultaneously. + </para> + <para> + To address these problems, UIO also implements a write() function. It + is normally not used and can be ignored for hardware that has only a + single interrupt source or has separate IRQ mask and status registers. + If you need it, however, a write to <filename>/dev/uioX</filename> + will call the <function>irqcontrol()</function> function implemented + by the driver. You have to write a 32-bit value that is usually either + 0 or 1 to disable or enable interrupts. If a driver does not implement + <function>irqcontrol()</function>, <function>write()</function> will + return with <varname>-ENOSYS</varname>. + </para> + + <para> + To handle interrupts properly, your custom kernel module can + provide its own interrupt handler. It will automatically be + called by the built-in handler. + </para> + + <para> + For cards that don't generate interrupts but need to be + polled, there is the possibility to set up a timer that + triggers the interrupt handler at configurable time intervals. + This interrupt simulation is done by calling + <function>uio_event_notify()</function> + from the timer's event handler. + </para> + + <para> + Each driver provides attributes that are used to read or write + variables. These attributes are accessible through sysfs + files. A custom kernel driver module can add its own + attributes to the device owned by the uio driver, but not added + to the UIO device itself at this time. This might change in the + future if it would be found to be useful. + </para> + + <para> + The following standard attributes are provided by the UIO + framework: + </para> +<itemizedlist> +<listitem> + <para> + <filename>name</filename>: The name of your device. It is + recommended to use the name of your kernel module for this. + </para> +</listitem> +<listitem> + <para> + <filename>version</filename>: A version string defined by your + driver. This allows the user space part of your driver to deal + with different versions of the kernel module. + </para> +</listitem> +<listitem> + <para> + <filename>event</filename>: The total number of interrupts + handled by the driver since the last time the device node was + read. + </para> +</listitem> +</itemizedlist> +<para> + These attributes appear under the + <filename>/sys/class/uio/uioX</filename> directory. Please + note that this directory might be a symlink, and not a real + directory. Any userspace code that accesses it must be able + to handle this. +</para> +<para> + Each UIO device can make one or more memory regions available for + memory mapping. This is necessary because some industrial I/O cards + require access to more than one PCI memory region in a driver. +</para> +<para> + Each mapping has its own directory in sysfs, the first mapping + appears as <filename>/sys/class/uio/uioX/maps/map0/</filename>. + Subsequent mappings create directories <filename>map1/</filename>, + <filename>map2/</filename>, and so on. These directories will only + appear if the size of the mapping is not 0. +</para> +<para> + Each <filename>mapX/</filename> directory contains four read-only files + that show attributes of the memory: +</para> +<itemizedlist> +<listitem> + <para> + <filename>name</filename>: A string identifier for this mapping. This + is optional, the string can be empty. Drivers can set this to make it + easier for userspace to find the correct mapping. + </para> +</listitem> +<listitem> + <para> + <filename>addr</filename>: The address of memory that can be mapped. + </para> +</listitem> +<listitem> + <para> + <filename>size</filename>: The size, in bytes, of the memory + pointed to by addr. + </para> +</listitem> +<listitem> + <para> + <filename>offset</filename>: The offset, in bytes, that has to be + added to the pointer returned by <function>mmap()</function> to get + to the actual device memory. This is important if the device's memory + is not page aligned. Remember that pointers returned by + <function>mmap()</function> are always page aligned, so it is good + style to always add this offset. + </para> +</listitem> +</itemizedlist> + +<para> + From userspace, the different mappings are distinguished by adjusting + the <varname>offset</varname> parameter of the + <function>mmap()</function> call. To map the memory of mapping N, you + have to use N times the page size as your offset: +</para> +<programlisting format="linespecific"> +offset = N * getpagesize(); +</programlisting> + +<para> + Sometimes there is hardware with memory-like regions that can not be + mapped with the technique described here, but there are still ways to + access them from userspace. The most common example are x86 ioports. + On x86 systems, userspace can access these ioports using + <function>ioperm()</function>, <function>iopl()</function>, + <function>inb()</function>, <function>outb()</function>, and similar + functions. +</para> +<para> + Since these ioport regions can not be mapped, they will not appear under + <filename>/sys/class/uio/uioX/maps/</filename> like the normal memory + described above. Without information about the port regions a hardware + has to offer, it becomes difficult for the userspace part of the + driver to find out which ports belong to which UIO device. +</para> +<para> + To address this situation, the new directory + <filename>/sys/class/uio/uioX/portio/</filename> was added. It only + exists if the driver wants to pass information about one or more port + regions to userspace. If that is the case, subdirectories named + <filename>port0</filename>, <filename>port1</filename>, and so on, + will appear underneath + <filename>/sys/class/uio/uioX/portio/</filename>. +</para> +<para> + Each <filename>portX/</filename> directory contains four read-only + files that show name, start, size, and type of the port region: +</para> +<itemizedlist> +<listitem> + <para> + <filename>name</filename>: A string identifier for this port region. + The string is optional and can be empty. Drivers can set it to make it + easier for userspace to find a certain port region. + </para> +</listitem> +<listitem> + <para> + <filename>start</filename>: The first port of this region. + </para> +</listitem> +<listitem> + <para> + <filename>size</filename>: The number of ports in this region. + </para> +</listitem> +<listitem> + <para> + <filename>porttype</filename>: A string describing the type of port. + </para> +</listitem> +</itemizedlist> + + +</sect1> +</chapter> + +<chapter id="custom_kernel_module" xreflabel="Writing your own kernel module"> +<?dbhtml filename="custom_kernel_module.html"?> +<title>Writing your own kernel module</title> + <para> + Please have a look at <filename>uio_cif.c</filename> as an + example. The following paragraphs explain the different + sections of this file. + </para> + +<sect1 id="uio_info"> +<title>struct uio_info</title> + <para> + This structure tells the framework the details of your driver, + Some of the members are required, others are optional. + </para> + +<itemizedlist> +<listitem><para> +<varname>const char *name</varname>: Required. The name of your driver as +it will appear in sysfs. I recommend using the name of your module for this. +</para></listitem> + +<listitem><para> +<varname>const char *version</varname>: Required. This string appears in +<filename>/sys/class/uio/uioX/version</filename>. +</para></listitem> + +<listitem><para> +<varname>struct uio_mem mem[ MAX_UIO_MAPS ]</varname>: Required if you +have memory that can be mapped with <function>mmap()</function>. For each +mapping you need to fill one of the <varname>uio_mem</varname> structures. +See the description below for details. +</para></listitem> + +<listitem><para> +<varname>struct uio_port port[ MAX_UIO_PORTS_REGIONS ]</varname>: Required +if you want to pass information about ioports to userspace. For each port +region you need to fill one of the <varname>uio_port</varname> structures. +See the description below for details. +</para></listitem> + +<listitem><para> +<varname>long irq</varname>: Required. If your hardware generates an +interrupt, it's your modules task to determine the irq number during +initialization. If you don't have a hardware generated interrupt but +want to trigger the interrupt handler in some other way, set +<varname>irq</varname> to <varname>UIO_IRQ_CUSTOM</varname>. +If you had no interrupt at all, you could set +<varname>irq</varname> to <varname>UIO_IRQ_NONE</varname>, though this +rarely makes sense. +</para></listitem> + +<listitem><para> +<varname>unsigned long irq_flags</varname>: Required if you've set +<varname>irq</varname> to a hardware interrupt number. The flags given +here will be used in the call to <function>request_irq()</function>. +</para></listitem> + +<listitem><para> +<varname>int (*mmap)(struct uio_info *info, struct vm_area_struct +*vma)</varname>: Optional. If you need a special +<function>mmap()</function> function, you can set it here. If this +pointer is not NULL, your <function>mmap()</function> will be called +instead of the built-in one. +</para></listitem> + +<listitem><para> +<varname>int (*open)(struct uio_info *info, struct inode *inode) +</varname>: Optional. You might want to have your own +<function>open()</function>, e.g. to enable interrupts only when your +device is actually used. +</para></listitem> + +<listitem><para> +<varname>int (*release)(struct uio_info *info, struct inode *inode) +</varname>: Optional. If you define your own +<function>open()</function>, you will probably also want a custom +<function>release()</function> function. +</para></listitem> + +<listitem><para> +<varname>int (*irqcontrol)(struct uio_info *info, s32 irq_on) +</varname>: Optional. If you need to be able to enable or disable +interrupts from userspace by writing to <filename>/dev/uioX</filename>, +you can implement this function. The parameter <varname>irq_on</varname> +will be 0 to disable interrupts and 1 to enable them. +</para></listitem> +</itemizedlist> + +<para> +Usually, your device will have one or more memory regions that can be mapped +to user space. For each region, you have to set up a +<varname>struct uio_mem</varname> in the <varname>mem[]</varname> array. +Here's a description of the fields of <varname>struct uio_mem</varname>: +</para> + +<itemizedlist> +<listitem><para> +<varname>const char *name</varname>: Optional. Set this to help identify +the memory region, it will show up in the corresponding sysfs node. +</para></listitem> + +<listitem><para> +<varname>int memtype</varname>: Required if the mapping is used. Set this to +<varname>UIO_MEM_PHYS</varname> if you you have physical memory on your +card to be mapped. Use <varname>UIO_MEM_LOGICAL</varname> for logical +memory (e.g. allocated with <function>kmalloc()</function>). There's also +<varname>UIO_MEM_VIRTUAL</varname> for virtual memory. +</para></listitem> + +<listitem><para> +<varname>phys_addr_t addr</varname>: Required if the mapping is used. +Fill in the address of your memory block. This address is the one that +appears in sysfs. +</para></listitem> + +<listitem><para> +<varname>unsigned long size</varname>: Fill in the size of the +memory block that <varname>addr</varname> points to. If <varname>size</varname> +is zero, the mapping is considered unused. Note that you +<emphasis>must</emphasis> initialize <varname>size</varname> with zero for +all unused mappings. +</para></listitem> + +<listitem><para> +<varname>void *internal_addr</varname>: If you have to access this memory +region from within your kernel module, you will want to map it internally by +using something like <function>ioremap()</function>. Addresses +returned by this function cannot be mapped to user space, so you must not +store it in <varname>addr</varname>. Use <varname>internal_addr</varname> +instead to remember such an address. +</para></listitem> +</itemizedlist> + +<para> +Please do not touch the <varname>map</varname> element of +<varname>struct uio_mem</varname>! It is used by the UIO framework +to set up sysfs files for this mapping. Simply leave it alone. +</para> + +<para> +Sometimes, your device can have one or more port regions which can not be +mapped to userspace. But if there are other possibilities for userspace to +access these ports, it makes sense to make information about the ports +available in sysfs. For each region, you have to set up a +<varname>struct uio_port</varname> in the <varname>port[]</varname> array. +Here's a description of the fields of <varname>struct uio_port</varname>: +</para> + +<itemizedlist> +<listitem><para> +<varname>char *porttype</varname>: Required. Set this to one of the predefined +constants. Use <varname>UIO_PORT_X86</varname> for the ioports found in x86 +architectures. +</para></listitem> + +<listitem><para> +<varname>unsigned long start</varname>: Required if the port region is used. +Fill in the number of the first port of this region. +</para></listitem> + +<listitem><para> +<varname>unsigned long size</varname>: Fill in the number of ports in this +region. If <varname>size</varname> is zero, the region is considered unused. +Note that you <emphasis>must</emphasis> initialize <varname>size</varname> +with zero for all unused regions. +</para></listitem> +</itemizedlist> + +<para> +Please do not touch the <varname>portio</varname> element of +<varname>struct uio_port</varname>! It is used internally by the UIO +framework to set up sysfs files for this region. Simply leave it alone. +</para> + +</sect1> + +<sect1 id="adding_irq_handler"> +<title>Adding an interrupt handler</title> + <para> + What you need to do in your interrupt handler depends on your + hardware and on how you want to handle it. You should try to + keep the amount of code in your kernel interrupt handler low. + If your hardware requires no action that you + <emphasis>have</emphasis> to perform after each interrupt, + then your handler can be empty.</para> <para>If, on the other + hand, your hardware <emphasis>needs</emphasis> some action to + be performed after each interrupt, then you + <emphasis>must</emphasis> do it in your kernel module. Note + that you cannot rely on the userspace part of your driver. Your + userspace program can terminate at any time, possibly leaving + your hardware in a state where proper interrupt handling is + still required. + </para> + + <para> + There might also be applications where you want to read data + from your hardware at each interrupt and buffer it in a piece + of kernel memory you've allocated for that purpose. With this + technique you could avoid loss of data if your userspace + program misses an interrupt. + </para> + + <para> + A note on shared interrupts: Your driver should support + interrupt sharing whenever this is possible. It is possible if + and only if your driver can detect whether your hardware has + triggered the interrupt or not. This is usually done by looking + at an interrupt status register. If your driver sees that the + IRQ bit is actually set, it will perform its actions, and the + handler returns IRQ_HANDLED. If the driver detects that it was + not your hardware that caused the interrupt, it will do nothing + and return IRQ_NONE, allowing the kernel to call the next + possible interrupt handler. + </para> + + <para> + If you decide not to support shared interrupts, your card + won't work in computers with no free interrupts. As this + frequently happens on the PC platform, you can save yourself a + lot of trouble by supporting interrupt sharing. + </para> +</sect1> + +<sect1 id="using_uio_pdrv"> +<title>Using uio_pdrv for platform devices</title> + <para> + In many cases, UIO drivers for platform devices can be handled in a + generic way. In the same place where you define your + <varname>struct platform_device</varname>, you simply also implement + your interrupt handler and fill your + <varname>struct uio_info</varname>. A pointer to this + <varname>struct uio_info</varname> is then used as + <varname>platform_data</varname> for your platform device. + </para> + <para> + You also need to set up an array of <varname>struct resource</varname> + containing addresses and sizes of your memory mappings. This + information is passed to the driver using the + <varname>.resource</varname> and <varname>.num_resources</varname> + elements of <varname>struct platform_device</varname>. + </para> + <para> + You now have to set the <varname>.name</varname> element of + <varname>struct platform_device</varname> to + <varname>"uio_pdrv"</varname> to use the generic UIO platform device + driver. This driver will fill the <varname>mem[]</varname> array + according to the resources given, and register the device. + </para> + <para> + The advantage of this approach is that you only have to edit a file + you need to edit anyway. You do not have to create an extra driver. + </para> +</sect1> + +<sect1 id="using_uio_pdrv_genirq"> +<title>Using uio_pdrv_genirq for platform devices</title> + <para> + Especially in embedded devices, you frequently find chips where the + irq pin is tied to its own dedicated interrupt line. In such cases, + where you can be really sure the interrupt is not shared, we can take + the concept of <varname>uio_pdrv</varname> one step further and use a + generic interrupt handler. That's what + <varname>uio_pdrv_genirq</varname> does. + </para> + <para> + The setup for this driver is the same as described above for + <varname>uio_pdrv</varname>, except that you do not implement an + interrupt handler. The <varname>.handler</varname> element of + <varname>struct uio_info</varname> must remain + <varname>NULL</varname>. The <varname>.irq_flags</varname> element + must not contain <varname>IRQF_SHARED</varname>. + </para> + <para> + You will set the <varname>.name</varname> element of + <varname>struct platform_device</varname> to + <varname>"uio_pdrv_genirq"</varname> to use this driver. + </para> + <para> + The generic interrupt handler of <varname>uio_pdrv_genirq</varname> + will simply disable the interrupt line using + <function>disable_irq_nosync()</function>. After doing its work, + userspace can reenable the interrupt by writing 0x00000001 to the UIO + device file. The driver already implements an + <function>irq_control()</function> to make this possible, you must not + implement your own. + </para> + <para> + Using <varname>uio_pdrv_genirq</varname> not only saves a few lines of + interrupt handler code. You also do not need to know anything about + the chip's internal registers to create the kernel part of the driver. + All you need to know is the irq number of the pin the chip is + connected to. + </para> +</sect1> + +</chapter> + +<chapter id="userspace_driver" xreflabel="Writing a driver in user space"> +<?dbhtml filename="userspace_driver.html"?> +<title>Writing a driver in userspace</title> + <para> + Once you have a working kernel module for your hardware, you can + write the userspace part of your driver. You don't need any special + libraries, your driver can be written in any reasonable language, + you can use floating point numbers and so on. In short, you can + use all the tools and libraries you'd normally use for writing a + userspace application. + </para> + +<sect1 id="getting_uio_information"> +<title>Getting information about your UIO device</title> + <para> + Information about all UIO devices is available in sysfs. The + first thing you should do in your driver is check + <varname>name</varname> and <varname>version</varname> to + make sure your talking to the right device and that its kernel + driver has the version you expect. + </para> + <para> + You should also make sure that the memory mapping you need + exists and has the size you expect. + </para> + <para> + There is a tool called <varname>lsuio</varname> that lists + UIO devices and their attributes. It is available here: + </para> + <para> + <ulink url="http://www.osadl.org/projects/downloads/UIO/user/"> + http://www.osadl.org/projects/downloads/UIO/user/</ulink> + </para> + <para> + With <varname>lsuio</varname> you can quickly check if your + kernel module is loaded and which attributes it exports. + Have a look at the manpage for details. + </para> + <para> + The source code of <varname>lsuio</varname> can serve as an + example for getting information about an UIO device. + The file <filename>uio_helper.c</filename> contains a lot of + functions you could use in your userspace driver code. + </para> +</sect1> + +<sect1 id="mmap_device_memory"> +<title>mmap() device memory</title> + <para> + After you made sure you've got the right device with the + memory mappings you need, all you have to do is to call + <function>mmap()</function> to map the device's memory + to userspace. + </para> + <para> + The parameter <varname>offset</varname> of the + <function>mmap()</function> call has a special meaning + for UIO devices: It is used to select which mapping of + your device you want to map. To map the memory of + mapping N, you have to use N times the page size as + your offset: + </para> +<programlisting format="linespecific"> + offset = N * getpagesize(); +</programlisting> + <para> + N starts from zero, so if you've got only one memory + range to map, set <varname>offset = 0</varname>. + A drawback of this technique is that memory is always + mapped beginning with its start address. + </para> +</sect1> + +<sect1 id="wait_for_interrupts"> +<title>Waiting for interrupts</title> + <para> + After you successfully mapped your devices memory, you + can access it like an ordinary array. Usually, you will + perform some initialization. After that, your hardware + starts working and will generate an interrupt as soon + as it's finished, has some data available, or needs your + attention because an error occurred. + </para> + <para> + <filename>/dev/uioX</filename> is a read-only file. A + <function>read()</function> will always block until an + interrupt occurs. There is only one legal value for the + <varname>count</varname> parameter of + <function>read()</function>, and that is the size of a + signed 32 bit integer (4). Any other value for + <varname>count</varname> causes <function>read()</function> + to fail. The signed 32 bit integer read is the interrupt + count of your device. If the value is one more than the value + you read the last time, everything is OK. If the difference + is greater than one, you missed interrupts. + </para> + <para> + You can also use <function>select()</function> on + <filename>/dev/uioX</filename>. + </para> +</sect1> + +</chapter> + +<chapter id="uio_pci_generic" xreflabel="Using Generic driver for PCI cards"> +<?dbhtml filename="uio_pci_generic.html"?> +<title>Generic PCI UIO driver</title> + <para> + The generic driver is a kernel module named uio_pci_generic. + It can work with any device compliant to PCI 2.3 (circa 2002) and + any compliant PCI Express device. Using this, you only need to + write the userspace driver, removing the need to write + a hardware-specific kernel module. + </para> + +<sect1 id="uio_pci_generic_binding"> +<title>Making the driver recognize the device</title> + <para> +Since the driver does not declare any device ids, it will not get loaded +automatically and will not automatically bind to any devices, you must load it +and allocate id to the driver yourself. For example: + <programlisting> + modprobe uio_pci_generic + echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id + </programlisting> + </para> + <para> +If there already is a hardware specific kernel driver for your device, the +generic driver still won't bind to it, in this case if you want to use the +generic driver (why would you?) you'll have to manually unbind the hardware +specific driver and bind the generic driver, like this: + <programlisting> + echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind + echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind + </programlisting> + </para> + <para> +You can verify that the device has been bound to the driver +by looking for it in sysfs, for example like the following: + <programlisting> + ls -l /sys/bus/pci/devices/0000:00:19.0/driver + </programlisting> +Which if successful should print + <programlisting> + .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic + </programlisting> +Note that the generic driver will not bind to old PCI 2.2 devices. +If binding the device failed, run the following command: + <programlisting> + dmesg + </programlisting> +and look in the output for failure reasons + </para> +</sect1> + +<sect1 id="uio_pci_generic_internals"> +<title>Things to know about uio_pci_generic</title> + <para> +Interrupts are handled using the Interrupt Disable bit in the PCI command +register and Interrupt Status bit in the PCI status register. All devices +compliant to PCI 2.3 (circa 2002) and all compliant PCI Express devices should +support these bits. uio_pci_generic detects this support, and won't bind to +devices which do not support the Interrupt Disable Bit in the command register. + </para> + <para> +On each interrupt, uio_pci_generic sets the Interrupt Disable bit. +This prevents the device from generating further interrupts +until the bit is cleared. The userspace driver should clear this +bit before blocking and waiting for more interrupts. + </para> +</sect1> +<sect1 id="uio_pci_generic_userspace"> +<title>Writing userspace driver using uio_pci_generic</title> + <para> +Userspace driver can use pci sysfs interface, or the +libpci libray that wraps it, to talk to the device and to +re-enable interrupts by writing to the command register. + </para> +</sect1> +<sect1 id="uio_pci_generic_example"> +<title>Example code using uio_pci_generic</title> + <para> +Here is some sample userspace driver code using uio_pci_generic: +<programlisting> +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> + +int main() +{ + int uiofd; + int configfd; + int err; + int i; + unsigned icount; + unsigned char command_high; + + uiofd = open("/dev/uio0", O_RDONLY); + if (uiofd < 0) { + perror("uio open:"); + return errno; + } + configfd = open("/sys/class/uio/uio0/device/config", O_RDWR); + if (uiofd < 0) { + perror("config open:"); + return errno; + } + + /* Read and cache command value */ + err = pread(configfd, &command_high, 1, 5); + if (err != 1) { + perror("command config read:"); + return errno; + } + command_high &= ~0x4; + + for(i = 0;; ++i) { + /* Print out a message, for debugging. */ + if (i == 0) + fprintf(stderr, "Started uio test driver.\n"); + else + fprintf(stderr, "Interrupts: %d\n", icount); + + /****************************************/ + /* Here we got an interrupt from the + device. Do something to it. */ + /****************************************/ + + /* Re-enable interrupts. */ + err = pwrite(configfd, &command_high, 1, 5); + if (err != 1) { + perror("config write:"); + break; + } + + /* Wait for next interrupt. */ + err = read(uiofd, &icount, 4); + if (err != 4) { + perror("uio read:"); + break; + } + + } + return errno; +} + +</programlisting> + </para> +</sect1> + +</chapter> + +<appendix id="app1"> +<title>Further information</title> +<itemizedlist> + <listitem><para> + <ulink url="http://www.osadl.org"> + OSADL homepage.</ulink> + </para></listitem> + <listitem><para> + <ulink url="http://www.linutronix.de"> + Linutronix homepage.</ulink> + </para></listitem> +</itemizedlist> +</appendix> + +</book> diff --git a/Documentation/DocBook/usb.tmpl b/Documentation/DocBook/usb.tmpl new file mode 100644 index 00000000..8d57c188 --- /dev/null +++ b/Documentation/DocBook/usb.tmpl @@ -0,0 +1,980 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="Linux-USB-API"> + <bookinfo> + <title>The Linux-USB Host Side API</title> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + +<chapter id="intro"> + <title>Introduction to USB on Linux</title> + + <para>A Universal Serial Bus (USB) is used to connect a host, + such as a PC or workstation, to a number of peripheral + devices. USB uses a tree structure, with the host as the + root (the system's master), hubs as interior nodes, and + peripherals as leaves (and slaves). + Modern PCs support several such trees of USB devices, usually + one USB 2.0 tree (480 Mbit/sec each) with + a few USB 1.1 trees (12 Mbit/sec each) that are used when you + connect a USB 1.1 device directly to the machine's "root hub". + </para> + + <para>That master/slave asymmetry was designed-in for a number of + reasons, one being ease of use. It is not physically possible to + assemble (legal) USB cables incorrectly: all upstream "to the host" + connectors are the rectangular type (matching the sockets on + root hubs), and all downstream connectors are the squarish type + (or they are built into the peripheral). + Also, the host software doesn't need to deal with distributed + auto-configuration since the pre-designated master node manages all that. + And finally, at the electrical level, bus protocol overhead is reduced by + eliminating arbitration and moving scheduling into the host software. + </para> + + <para>USB 1.0 was announced in January 1996 and was revised + as USB 1.1 (with improvements in hub specification and + support for interrupt-out transfers) in September 1998. + USB 2.0 was released in April 2000, adding high-speed + transfers and transaction-translating hubs (used for USB 1.1 + and 1.0 backward compatibility). + </para> + + <para>Kernel developers added USB support to Linux early in the 2.2 kernel + series, shortly before 2.3 development forked. Updates from 2.3 were + regularly folded back into 2.2 releases, which improved reliability and + brought <filename>/sbin/hotplug</filename> support as well more drivers. + Such improvements were continued in the 2.5 kernel series, where they added + USB 2.0 support, improved performance, and made the host controller drivers + (HCDs) more consistent. They also simplified the API (to make bugs less + likely) and added internal "kerneldoc" documentation. + </para> + + <para>Linux can run inside USB devices as well as on + the hosts that control the devices. + But USB device drivers running inside those peripherals + don't do the same things as the ones running inside hosts, + so they've been given a different name: + <emphasis>gadget drivers</emphasis>. + This document does not cover gadget drivers. + </para> + + </chapter> + +<chapter id="host"> + <title>USB Host-Side API Model</title> + + <para>Host-side drivers for USB devices talk to the "usbcore" APIs. + There are two. One is intended for + <emphasis>general-purpose</emphasis> drivers (exposed through + driver frameworks), and the other is for drivers that are + <emphasis>part of the core</emphasis>. + Such core drivers include the <emphasis>hub</emphasis> driver + (which manages trees of USB devices) and several different kinds + of <emphasis>host controller drivers</emphasis>, + which control individual busses. + </para> + + <para>The device model seen by USB drivers is relatively complex. + </para> + + <itemizedlist> + + <listitem><para>USB supports four kinds of data transfers + (control, bulk, interrupt, and isochronous). Two of them (control + and bulk) use bandwidth as it's available, + while the other two (interrupt and isochronous) + are scheduled to provide guaranteed bandwidth. + </para></listitem> + + <listitem><para>The device description model includes one or more + "configurations" per device, only one of which is active at a time. + Devices that are capable of high-speed operation must also support + full-speed configurations, along with a way to ask about the + "other speed" configurations which might be used. + </para></listitem> + + <listitem><para>Configurations have one or more "interfaces", each + of which may have "alternate settings". Interfaces may be + standardized by USB "Class" specifications, or may be specific to + a vendor or device.</para> + + <para>USB device drivers actually bind to interfaces, not devices. + Think of them as "interface drivers", though you + may not see many devices where the distinction is important. + <emphasis>Most USB devices are simple, with only one configuration, + one interface, and one alternate setting.</emphasis> + </para></listitem> + + <listitem><para>Interfaces have one or more "endpoints", each of + which supports one type and direction of data transfer such as + "bulk out" or "interrupt in". The entire configuration may have + up to sixteen endpoints in each direction, allocated as needed + among all the interfaces. + </para></listitem> + + <listitem><para>Data transfer on USB is packetized; each endpoint + has a maximum packet size. + Drivers must often be aware of conventions such as flagging the end + of bulk transfers using "short" (including zero length) packets. + </para></listitem> + + <listitem><para>The Linux USB API supports synchronous calls for + control and bulk messages. + It also supports asynchnous calls for all kinds of data transfer, + using request structures called "URBs" (USB Request Blocks). + </para></listitem> + + </itemizedlist> + + <para>Accordingly, the USB Core API exposed to device drivers + covers quite a lot of territory. You'll probably need to consult + the USB 2.0 specification, available online from www.usb.org at + no cost, as well as class or device specifications. + </para> + + <para>The only host-side drivers that actually touch hardware + (reading/writing registers, handling IRQs, and so on) are the HCDs. + In theory, all HCDs provide the same functionality through the same + API. In practice, that's becoming more true on the 2.5 kernels, + but there are still differences that crop up especially with + fault handling. Different controllers don't necessarily report + the same aspects of failures, and recovery from faults (including + software-induced ones like unlinking an URB) isn't yet fully + consistent. + Device driver authors should make a point of doing disconnect + testing (while the device is active) with each different host + controller driver, to make sure drivers don't have bugs of + their own as well as to make sure they aren't relying on some + HCD-specific behavior. + (You will need external USB 1.1 and/or + USB 2.0 hubs to perform all those tests.) + </para> + + </chapter> + +<chapter id="types"><title>USB-Standard Types</title> + + <para>In <filename><linux/usb/ch9.h></filename> you will find + the USB data types defined in chapter 9 of the USB specification. + These data types are used throughout USB, and in APIs including + this host side API, gadget APIs, and usbfs. + </para> + +!Iinclude/linux/usb/ch9.h + + </chapter> + +<chapter id="hostside"><title>Host-Side Data Types and Macros</title> + + <para>The host side API exposes several layers to drivers, some of + which are more necessary than others. + These support lifecycle models for host side drivers + and devices, and support passing buffers through usbcore to + some HCD that performs the I/O for the device driver. + </para> + + +!Iinclude/linux/usb.h + + </chapter> + + <chapter id="usbcore"><title>USB Core APIs</title> + + <para>There are two basic I/O models in the USB API. + The most elemental one is asynchronous: drivers submit requests + in the form of an URB, and the URB's completion callback + handle the next step. + All USB transfer types support that model, although there + are special cases for control URBs (which always have setup + and status stages, but may not have a data stage) and + isochronous URBs (which allow large packets and include + per-packet fault reports). + Built on top of that is synchronous API support, where a + driver calls a routine that allocates one or more URBs, + submits them, and waits until they complete. + There are synchronous wrappers for single-buffer control + and bulk transfers (which are awkward to use in some + driver disconnect scenarios), and for scatterlist based + streaming i/o (bulk or interrupt). + </para> + + <para>USB drivers need to provide buffers that can be + used for DMA, although they don't necessarily need to + provide the DMA mapping themselves. + There are APIs to use used when allocating DMA buffers, + which can prevent use of bounce buffers on some systems. + In some cases, drivers may be able to rely on 64bit DMA + to eliminate another kind of bounce buffer. + </para> + +!Edrivers/usb/core/urb.c +!Edrivers/usb/core/message.c +!Edrivers/usb/core/file.c +!Edrivers/usb/core/driver.c +!Edrivers/usb/core/usb.c +!Edrivers/usb/core/hub.c + </chapter> + + <chapter id="hcd"><title>Host Controller APIs</title> + + <para>These APIs are only for use by host controller drivers, + most of which implement standard register interfaces such as + EHCI, OHCI, or UHCI. + UHCI was one of the first interfaces, designed by Intel and + also used by VIA; it doesn't do much in hardware. + OHCI was designed later, to have the hardware do more work + (bigger transfers, tracking protocol state, and so on). + EHCI was designed with USB 2.0; its design has features that + resemble OHCI (hardware does much more work) as well as + UHCI (some parts of ISO support, TD list processing). + </para> + + <para>There are host controllers other than the "big three", + although most PCI based controllers (and a few non-PCI based + ones) use one of those interfaces. + Not all host controllers use DMA; some use PIO, and there + is also a simulator. + </para> + + <para>The same basic APIs are available to drivers for all + those controllers. + For historical reasons they are in two layers: + <structname>struct usb_bus</structname> is a rather thin + layer that became available in the 2.2 kernels, while + <structname>struct usb_hcd</structname> is a more featureful + layer (available in later 2.4 kernels and in 2.5) that + lets HCDs share common code, to shrink driver size + and significantly reduce hcd-specific behaviors. + </para> + +!Edrivers/usb/core/hcd.c +!Edrivers/usb/core/hcd-pci.c +!Idrivers/usb/core/buffer.c + </chapter> + + <chapter id="usbfs"> + <title>The USB Filesystem (usbfs)</title> + + <para>This chapter presents the Linux <emphasis>usbfs</emphasis>. + You may prefer to avoid writing new kernel code for your + USB driver; that's the problem that usbfs set out to solve. + User mode device drivers are usually packaged as applications + or libraries, and may use usbfs through some programming library + that wraps it. Such libraries include + <ulink url="http://libusb.sourceforge.net">libusb</ulink> + for C/C++, and + <ulink url="http://jUSB.sourceforge.net">jUSB</ulink> for Java. + </para> + + <note><title>Unfinished</title> + <para>This particular documentation is incomplete, + especially with respect to the asynchronous mode. + As of kernel 2.5.66 the code and this (new) documentation + need to be cross-reviewed. + </para> + </note> + + <para>Configure usbfs into Linux kernels by enabling the + <emphasis>USB filesystem</emphasis> option (CONFIG_USB_DEVICEFS), + and you get basic support for user mode USB device drivers. + Until relatively recently it was often (confusingly) called + <emphasis>usbdevfs</emphasis> although it wasn't solving what + <emphasis>devfs</emphasis> was. + Every USB device will appear in usbfs, regardless of whether or + not it has a kernel driver. + </para> + + <sect1 id="usbfs-files"> + <title>What files are in "usbfs"?</title> + + <para>Conventionally mounted at + <filename>/proc/bus/usb</filename>, usbfs + features include: + <itemizedlist> + <listitem><para><filename>/proc/bus/usb/devices</filename> + ... a text file + showing each of the USB devices on known to the kernel, + and their configuration descriptors. + You can also poll() this to learn about new devices. + </para></listitem> + <listitem><para><filename>/proc/bus/usb/BBB/DDD</filename> + ... magic files + exposing the each device's configuration descriptors, and + supporting a series of ioctls for making device requests, + including I/O to devices. (Purely for access by programs.) + </para></listitem> + </itemizedlist> + </para> + + <para> Each bus is given a number (BBB) based on when it was + enumerated; within each bus, each device is given a similar + number (DDD). + Those BBB/DDD paths are not "stable" identifiers; + expect them to change even if you always leave the devices + plugged in to the same hub port. + <emphasis>Don't even think of saving these in application + configuration files.</emphasis> + Stable identifiers are available, for user mode applications + that want to use them. HID and networking devices expose + these stable IDs, so that for example you can be sure that + you told the right UPS to power down its second server. + "usbfs" doesn't (yet) expose those IDs. + </para> + + </sect1> + + <sect1 id="usbfs-fstab"> + <title>Mounting and Access Control</title> + + <para>There are a number of mount options for usbfs, which will + be of most interest to you if you need to override the default + access control policy. + That policy is that only root may read or write device files + (<filename>/proc/bus/BBB/DDD</filename>) although anyone may read + the <filename>devices</filename> + or <filename>drivers</filename> files. + I/O requests to the device also need the CAP_SYS_RAWIO capability, + </para> + + <para>The significance of that is that by default, all user mode + device drivers need super-user privileges. + You can change modes or ownership in a driver setup + when the device hotplugs, or maye just start the + driver right then, as a privileged server (or some activity + within one). + That's the most secure approach for multi-user systems, + but for single user systems ("trusted" by that user) + it's more convenient just to grant everyone all access + (using the <emphasis>devmode=0666</emphasis> option) + so the driver can start whenever it's needed. + </para> + + <para>The mount options for usbfs, usable in /etc/fstab or + in command line invocations of <emphasis>mount</emphasis>, are: + + <variablelist> + <varlistentry> + <term><emphasis>busgid</emphasis>=NNNNN</term> + <listitem><para>Controls the GID used for the + /proc/bus/usb/BBB + directories. (Default: 0)</para></listitem></varlistentry> + <varlistentry><term><emphasis>busmode</emphasis>=MMM</term> + <listitem><para>Controls the file mode used for the + /proc/bus/usb/BBB + directories. (Default: 0555) + </para></listitem></varlistentry> + <varlistentry><term><emphasis>busuid</emphasis>=NNNNN</term> + <listitem><para>Controls the UID used for the + /proc/bus/usb/BBB + directories. (Default: 0)</para></listitem></varlistentry> + + <varlistentry><term><emphasis>devgid</emphasis>=NNNNN</term> + <listitem><para>Controls the GID used for the + /proc/bus/usb/BBB/DDD + files. (Default: 0)</para></listitem></varlistentry> + <varlistentry><term><emphasis>devmode</emphasis>=MMM</term> + <listitem><para>Controls the file mode used for the + /proc/bus/usb/BBB/DDD + files. (Default: 0644)</para></listitem></varlistentry> + <varlistentry><term><emphasis>devuid</emphasis>=NNNNN</term> + <listitem><para>Controls the UID used for the + /proc/bus/usb/BBB/DDD + files. (Default: 0)</para></listitem></varlistentry> + + <varlistentry><term><emphasis>listgid</emphasis>=NNNNN</term> + <listitem><para>Controls the GID used for the + /proc/bus/usb/devices and drivers files. + (Default: 0)</para></listitem></varlistentry> + <varlistentry><term><emphasis>listmode</emphasis>=MMM</term> + <listitem><para>Controls the file mode used for the + /proc/bus/usb/devices and drivers files. + (Default: 0444)</para></listitem></varlistentry> + <varlistentry><term><emphasis>listuid</emphasis>=NNNNN</term> + <listitem><para>Controls the UID used for the + /proc/bus/usb/devices and drivers files. + (Default: 0)</para></listitem></varlistentry> + </variablelist> + + </para> + + <para>Note that many Linux distributions hard-wire the mount options + for usbfs in their init scripts, such as + <filename>/etc/rc.d/rc.sysinit</filename>, + rather than making it easy to set this per-system + policy in <filename>/etc/fstab</filename>. + </para> + + </sect1> + + <sect1 id="usbfs-devices"> + <title>/proc/bus/usb/devices</title> + + <para>This file is handy for status viewing tools in user + mode, which can scan the text format and ignore most of it. + More detailed device status (including class and vendor + status) is available from device-specific files. + For information about the current format of this file, + see the + <filename>Documentation/usb/proc_usb_info.txt</filename> + file in your Linux kernel sources. + </para> + + <para>This file, in combination with the poll() system call, can + also be used to detect when devices are added or removed: +<programlisting>int fd; +struct pollfd pfd; + +fd = open("/proc/bus/usb/devices", O_RDONLY); +pfd = { fd, POLLIN, 0 }; +for (;;) { + /* The first time through, this call will return immediately. */ + poll(&pfd, 1, -1); + + /* To see what's changed, compare the file's previous and current + contents or scan the filesystem. (Scanning is more precise.) */ +}</programlisting> + Note that this behavior is intended to be used for informational + and debug purposes. It would be more appropriate to use programs + such as udev or HAL to initialize a device or start a user-mode + helper program, for instance. + </para> + </sect1> + + <sect1 id="usbfs-bbbddd"> + <title>/proc/bus/usb/BBB/DDD</title> + + <para>Use these files in one of these basic ways: + </para> + + <para><emphasis>They can be read,</emphasis> + producing first the device descriptor + (18 bytes) and then the descriptors for the current configuration. + See the USB 2.0 spec for details about those binary data formats. + You'll need to convert most multibyte values from little endian + format to your native host byte order, although a few of the + fields in the device descriptor (both of the BCD-encoded fields, + and the vendor and product IDs) will be byteswapped for you. + Note that configuration descriptors include descriptors for + interfaces, altsettings, endpoints, and maybe additional + class descriptors. + </para> + + <para><emphasis>Perform USB operations</emphasis> using + <emphasis>ioctl()</emphasis> requests to make endpoint I/O + requests (synchronously or asynchronously) or manage + the device. + These requests need the CAP_SYS_RAWIO capability, + as well as filesystem access permissions. + Only one ioctl request can be made on one of these + device files at a time. + This means that if you are synchronously reading an endpoint + from one thread, you won't be able to write to a different + endpoint from another thread until the read completes. + This works for <emphasis>half duplex</emphasis> protocols, + but otherwise you'd use asynchronous i/o requests. + </para> + + </sect1> + + + <sect1 id="usbfs-lifecycle"> + <title>Life Cycle of User Mode Drivers</title> + + <para>Such a driver first needs to find a device file + for a device it knows how to handle. + Maybe it was told about it because a + <filename>/sbin/hotplug</filename> event handling agent + chose that driver to handle the new device. + Or maybe it's an application that scans all the + /proc/bus/usb device files, and ignores most devices. + In either case, it should <function>read()</function> all + the descriptors from the device file, + and check them against what it knows how to handle. + It might just reject everything except a particular + vendor and product ID, or need a more complex policy. + </para> + + <para>Never assume there will only be one such device + on the system at a time! + If your code can't handle more than one device at + a time, at least detect when there's more than one, and + have your users choose which device to use. + </para> + + <para>Once your user mode driver knows what device to use, + it interacts with it in either of two styles. + The simple style is to make only control requests; some + devices don't need more complex interactions than those. + (An example might be software using vendor-specific control + requests for some initialization or configuration tasks, + with a kernel driver for the rest.) + </para> + + <para>More likely, you need a more complex style driver: + one using non-control endpoints, reading or writing data + and claiming exclusive use of an interface. + <emphasis>Bulk</emphasis> transfers are easiest to use, + but only their sibling <emphasis>interrupt</emphasis> transfers + work with low speed devices. + Both interrupt and <emphasis>isochronous</emphasis> transfers + offer service guarantees because their bandwidth is reserved. + Such "periodic" transfers are awkward to use through usbfs, + unless you're using the asynchronous calls. However, interrupt + transfers can also be used in a synchronous "one shot" style. + </para> + + <para>Your user-mode driver should never need to worry + about cleaning up request state when the device is + disconnected, although it should close its open file + descriptors as soon as it starts seeing the ENODEV + errors. + </para> + + </sect1> + + <sect1 id="usbfs-ioctl"><title>The ioctl() Requests</title> + + <para>To use these ioctls, you need to include the following + headers in your userspace program: +<programlisting>#include <linux/usb.h> +#include <linux/usbdevice_fs.h> +#include <asm/byteorder.h></programlisting> + The standard USB device model requests, from "Chapter 9" of + the USB 2.0 specification, are automatically included from + the <filename><linux/usb/ch9.h></filename> header. + </para> + + <para>Unless noted otherwise, the ioctl requests + described here will + update the modification time on the usbfs file to which + they are applied (unless they fail). + A return of zero indicates success; otherwise, a + standard USB error code is returned. (These are + documented in + <filename>Documentation/usb/error-codes.txt</filename> + in your kernel sources.) + </para> + + <para>Each of these files multiplexes access to several + I/O streams, one per endpoint. + Each device has one control endpoint (endpoint zero) + which supports a limited RPC style RPC access. + Devices are configured + by khubd (in the kernel) setting a device-wide + <emphasis>configuration</emphasis> that affects things + like power consumption and basic functionality. + The endpoints are part of USB <emphasis>interfaces</emphasis>, + which may have <emphasis>altsettings</emphasis> + affecting things like which endpoints are available. + Many devices only have a single configuration and interface, + so drivers for them will ignore configurations and altsettings. + </para> + + + <sect2 id="usbfs-mgmt"> + <title>Management/Status Requests</title> + + <para>A number of usbfs requests don't deal very directly + with device I/O. + They mostly relate to device management and status. + These are all synchronous requests. + </para> + + <variablelist> + + <varlistentry><term>USBDEVFS_CLAIMINTERFACE</term> + <listitem><para>This is used to force usbfs to + claim a specific interface, + which has not previously been claimed by usbfs or any other + kernel driver. + The ioctl parameter is an integer holding the number of + the interface (bInterfaceNumber from descriptor). + </para><para> + Note that if your driver doesn't claim an interface + before trying to use one of its endpoints, and no + other driver has bound to it, then the interface is + automatically claimed by usbfs. + </para><para> + This claim will be released by a RELEASEINTERFACE ioctl, + or by closing the file descriptor. + File modification time is not updated by this request. + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_CONNECTINFO</term> + <listitem><para>Says whether the device is lowspeed. + The ioctl parameter points to a structure like this: +<programlisting>struct usbdevfs_connectinfo { + unsigned int devnum; + unsigned char slow; +}; </programlisting> + File modification time is not updated by this request. + </para><para> + <emphasis>You can't tell whether a "not slow" + device is connected at high speed (480 MBit/sec) + or just full speed (12 MBit/sec).</emphasis> + You should know the devnum value already, + it's the DDD value of the device file name. + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_GETDRIVER</term> + <listitem><para>Returns the name of the kernel driver + bound to a given interface (a string). Parameter + is a pointer to this structure, which is modified: +<programlisting>struct usbdevfs_getdriver { + unsigned int interface; + char driver[USBDEVFS_MAXDRIVERNAME + 1]; +};</programlisting> + File modification time is not updated by this request. + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_IOCTL</term> + <listitem><para>Passes a request from userspace through + to a kernel driver that has an ioctl entry in the + <emphasis>struct usb_driver</emphasis> it registered. +<programlisting>struct usbdevfs_ioctl { + int ifno; + int ioctl_code; + void *data; +}; + +/* user mode call looks like this. + * 'request' becomes the driver->ioctl() 'code' parameter. + * the size of 'param' is encoded in 'request', and that data + * is copied to or from the driver->ioctl() 'buf' parameter. + */ +static int +usbdev_ioctl (int fd, int ifno, unsigned request, void *param) +{ + struct usbdevfs_ioctl wrapper; + + wrapper.ifno = ifno; + wrapper.ioctl_code = request; + wrapper.data = param; + + return ioctl (fd, USBDEVFS_IOCTL, &wrapper); +} </programlisting> + File modification time is not updated by this request. + </para><para> + This request lets kernel drivers talk to user mode code + through filesystem operations even when they don't create + a character or block special device. + It's also been used to do things like ask devices what + device special file should be used. + Two pre-defined ioctls are used + to disconnect and reconnect kernel drivers, so + that user mode code can completely manage binding + and configuration of devices. + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_RELEASEINTERFACE</term> + <listitem><para>This is used to release the claim usbfs + made on interface, either implicitly or because of a + USBDEVFS_CLAIMINTERFACE call, before the file + descriptor is closed. + The ioctl parameter is an integer holding the number of + the interface (bInterfaceNumber from descriptor); + File modification time is not updated by this request. + </para><warning><para> + <emphasis>No security check is made to ensure + that the task which made the claim is the one + which is releasing it. + This means that user mode driver may interfere + other ones. </emphasis> + </para></warning></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_RESETEP</term> + <listitem><para>Resets the data toggle value for an endpoint + (bulk or interrupt) to DATA0. + The ioctl parameter is an integer endpoint number + (1 to 15, as identified in the endpoint descriptor), + with USB_DIR_IN added if the device's endpoint sends + data to the host. + </para><warning><para> + <emphasis>Avoid using this request. + It should probably be removed.</emphasis> + Using it typically means the device and driver will lose + toggle synchronization. If you really lost synchronization, + you likely need to completely handshake with the device, + using a request like CLEAR_HALT + or SET_INTERFACE. + </para></warning></listitem></varlistentry> + + </variablelist> + + </sect2> + + <sect2 id="usbfs-sync"> + <title>Synchronous I/O Support</title> + + <para>Synchronous requests involve the kernel blocking + until the user mode request completes, either by + finishing successfully or by reporting an error. + In most cases this is the simplest way to use usbfs, + although as noted above it does prevent performing I/O + to more than one endpoint at a time. + </para> + + <variablelist> + + <varlistentry><term>USBDEVFS_BULK</term> + <listitem><para>Issues a bulk read or write request to the + device. + The ioctl parameter is a pointer to this structure: +<programlisting>struct usbdevfs_bulktransfer { + unsigned int ep; + unsigned int len; + unsigned int timeout; /* in milliseconds */ + void *data; +};</programlisting> + </para><para>The "ep" value identifies a + bulk endpoint number (1 to 15, as identified in an endpoint + descriptor), + masked with USB_DIR_IN when referring to an endpoint which + sends data to the host from the device. + The length of the data buffer is identified by "len"; + Recent kernels support requests up to about 128KBytes. + <emphasis>FIXME say how read length is returned, + and how short reads are handled.</emphasis>. + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_CLEAR_HALT</term> + <listitem><para>Clears endpoint halt (stall) and + resets the endpoint toggle. This is only + meaningful for bulk or interrupt endpoints. + The ioctl parameter is an integer endpoint number + (1 to 15, as identified in an endpoint descriptor), + masked with USB_DIR_IN when referring to an endpoint which + sends data to the host from the device. + </para><para> + Use this on bulk or interrupt endpoints which have + stalled, returning <emphasis>-EPIPE</emphasis> status + to a data transfer request. + Do not issue the control request directly, since + that could invalidate the host's record of the + data toggle. + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_CONTROL</term> + <listitem><para>Issues a control request to the device. + The ioctl parameter points to a structure like this: +<programlisting>struct usbdevfs_ctrltransfer { + __u8 bRequestType; + __u8 bRequest; + __u16 wValue; + __u16 wIndex; + __u16 wLength; + __u32 timeout; /* in milliseconds */ + void *data; +};</programlisting> + </para><para> + The first eight bytes of this structure are the contents + of the SETUP packet to be sent to the device; see the + USB 2.0 specification for details. + The bRequestType value is composed by combining a + USB_TYPE_* value, a USB_DIR_* value, and a + USB_RECIP_* value (from + <emphasis><linux/usb.h></emphasis>). + If wLength is nonzero, it describes the length of the data + buffer, which is either written to the device + (USB_DIR_OUT) or read from the device (USB_DIR_IN). + </para><para> + At this writing, you can't transfer more than 4 KBytes + of data to or from a device; usbfs has a limit, and + some host controller drivers have a limit. + (That's not usually a problem.) + <emphasis>Also</emphasis> there's no way to say it's + not OK to get a short read back from the device. + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_RESET</term> + <listitem><para>Does a USB level device reset. + The ioctl parameter is ignored. + After the reset, this rebinds all device interfaces. + File modification time is not updated by this request. + </para><warning><para> + <emphasis>Avoid using this call</emphasis> + until some usbcore bugs get fixed, + since it does not fully synchronize device, interface, + and driver (not just usbfs) state. + </para></warning></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_SETINTERFACE</term> + <listitem><para>Sets the alternate setting for an + interface. The ioctl parameter is a pointer to a + structure like this: +<programlisting>struct usbdevfs_setinterface { + unsigned int interface; + unsigned int altsetting; +}; </programlisting> + File modification time is not updated by this request. + </para><para> + Those struct members are from some interface descriptor + applying to the current configuration. + The interface number is the bInterfaceNumber value, and + the altsetting number is the bAlternateSetting value. + (This resets each endpoint in the interface.) + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_SETCONFIGURATION</term> + <listitem><para>Issues the + <function>usb_set_configuration</function> call + for the device. + The parameter is an integer holding the number of + a configuration (bConfigurationValue from descriptor). + File modification time is not updated by this request. + </para><warning><para> + <emphasis>Avoid using this call</emphasis> + until some usbcore bugs get fixed, + since it does not fully synchronize device, interface, + and driver (not just usbfs) state. + </para></warning></listitem></varlistentry> + + </variablelist> + </sect2> + + <sect2 id="usbfs-async"> + <title>Asynchronous I/O Support</title> + + <para>As mentioned above, there are situations where it may be + important to initiate concurrent operations from user mode code. + This is particularly important for periodic transfers + (interrupt and isochronous), but it can be used for other + kinds of USB requests too. + In such cases, the asynchronous requests described here + are essential. Rather than submitting one request and having + the kernel block until it completes, the blocking is separate. + </para> + + <para>These requests are packaged into a structure that + resembles the URB used by kernel device drivers. + (No POSIX Async I/O support here, sorry.) + It identifies the endpoint type (USBDEVFS_URB_TYPE_*), + endpoint (number, masked with USB_DIR_IN as appropriate), + buffer and length, and a user "context" value serving to + uniquely identify each request. + (It's usually a pointer to per-request data.) + Flags can modify requests (not as many as supported for + kernel drivers). + </para> + + <para>Each request can specify a realtime signal number + (between SIGRTMIN and SIGRTMAX, inclusive) to request a + signal be sent when the request completes. + </para> + + <para>When usbfs returns these urbs, the status value + is updated, and the buffer may have been modified. + Except for isochronous transfers, the actual_length is + updated to say how many bytes were transferred; if the + USBDEVFS_URB_DISABLE_SPD flag is set + ("short packets are not OK"), if fewer bytes were read + than were requested then you get an error report. + </para> + +<programlisting>struct usbdevfs_iso_packet_desc { + unsigned int length; + unsigned int actual_length; + unsigned int status; +}; + +struct usbdevfs_urb { + unsigned char type; + unsigned char endpoint; + int status; + unsigned int flags; + void *buffer; + int buffer_length; + int actual_length; + int start_frame; + int number_of_packets; + int error_count; + unsigned int signr; + void *usercontext; + struct usbdevfs_iso_packet_desc iso_frame_desc[]; +};</programlisting> + + <para> For these asynchronous requests, the file modification + time reflects when the request was initiated. + This contrasts with their use with the synchronous requests, + where it reflects when requests complete. + </para> + + <variablelist> + + <varlistentry><term>USBDEVFS_DISCARDURB</term> + <listitem><para> + <emphasis>TBS</emphasis> + File modification time is not updated by this request. + </para><para> + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_DISCSIGNAL</term> + <listitem><para> + <emphasis>TBS</emphasis> + File modification time is not updated by this request. + </para><para> + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_REAPURB</term> + <listitem><para> + <emphasis>TBS</emphasis> + File modification time is not updated by this request. + </para><para> + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_REAPURBNDELAY</term> + <listitem><para> + <emphasis>TBS</emphasis> + File modification time is not updated by this request. + </para><para> + </para></listitem></varlistentry> + + <varlistentry><term>USBDEVFS_SUBMITURB</term> + <listitem><para> + <emphasis>TBS</emphasis> + </para><para> + </para></listitem></varlistentry> + + </variablelist> + </sect2> + + </sect1> + + </chapter> + +</book> +<!-- vim:syntax=sgml:sw=4 +--> diff --git a/Documentation/DocBook/writing-an-alsa-driver.tmpl b/Documentation/DocBook/writing-an-alsa-driver.tmpl new file mode 100644 index 00000000..cab4ec58 --- /dev/null +++ b/Documentation/DocBook/writing-an-alsa-driver.tmpl @@ -0,0 +1,6229 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<!-- ****************************************************** --> +<!-- Header --> +<!-- ****************************************************** --> +<book id="Writing-an-ALSA-Driver"> + <bookinfo> + <title>Writing an ALSA Driver</title> + <author> + <firstname>Takashi</firstname> + <surname>Iwai</surname> + <affiliation> + <address> + <email>tiwai@suse.de</email> + </address> + </affiliation> + </author> + + <date>Oct 15, 2007</date> + <edition>0.3.7</edition> + + <abstract> + <para> + This document describes how to write an ALSA (Advanced Linux + Sound Architecture) driver. + </para> + </abstract> + + <legalnotice> + <para> + Copyright (c) 2002-2005 Takashi Iwai <email>tiwai@suse.de</email> + </para> + + <para> + This document is free; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + </para> + + <para> + This document is distributed in the hope that it will be useful, + but <emphasis>WITHOUT ANY WARRANTY</emphasis>; without even the + implied warranty of <emphasis>MERCHANTABILITY or FITNESS FOR A + PARTICULAR PURPOSE</emphasis>. See the GNU General Public License + for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + </legalnotice> + + </bookinfo> + +<!-- ****************************************************** --> +<!-- Preface --> +<!-- ****************************************************** --> + <preface id="preface"> + <title>Preface</title> + <para> + This document describes how to write an + <ulink url="http://www.alsa-project.org/"><citetitle> + ALSA (Advanced Linux Sound Architecture)</citetitle></ulink> + driver. The document focuses mainly on PCI soundcards. + In the case of other device types, the API might + be different, too. However, at least the ALSA kernel API is + consistent, and therefore it would be still a bit help for + writing them. + </para> + + <para> + This document targets people who already have enough + C language skills and have basic linux kernel programming + knowledge. This document doesn't explain the general + topic of linux kernel coding and doesn't cover low-level + driver implementation details. It only describes + the standard way to write a PCI sound driver on ALSA. + </para> + + <para> + If you are already familiar with the older ALSA ver.0.5.x API, you + can check the drivers such as <filename>sound/pci/es1938.c</filename> or + <filename>sound/pci/maestro3.c</filename> which have also almost the same + code-base in the ALSA 0.5.x tree, so you can compare the differences. + </para> + + <para> + This document is still a draft version. Any feedback and + corrections, please!! + </para> + </preface> + + +<!-- ****************************************************** --> +<!-- File Tree Structure --> +<!-- ****************************************************** --> + <chapter id="file-tree"> + <title>File Tree Structure</title> + + <section id="file-tree-general"> + <title>General</title> + <para> + The ALSA drivers are provided in two ways. + </para> + + <para> + One is the trees provided as a tarball or via cvs from the + ALSA's ftp site, and another is the 2.6 (or later) Linux kernel + tree. To synchronize both, the ALSA driver tree is split into + two different trees: alsa-kernel and alsa-driver. The former + contains purely the source code for the Linux 2.6 (or later) + tree. This tree is designed only for compilation on 2.6 or + later environment. The latter, alsa-driver, contains many subtle + files for compiling ALSA drivers outside of the Linux kernel tree, + wrapper functions for older 2.2 and 2.4 kernels, to adapt the latest kernel API, + and additional drivers which are still in development or in + tests. The drivers in alsa-driver tree will be moved to + alsa-kernel (and eventually to the 2.6 kernel tree) when they are + finished and confirmed to work fine. + </para> + + <para> + The file tree structure of ALSA driver is depicted below. Both + alsa-kernel and alsa-driver have almost the same file + structure, except for <quote>core</quote> directory. It's + named as <quote>acore</quote> in alsa-driver tree. + + <example> + <title>ALSA File Tree Structure</title> + <literallayout> + sound + /core + /oss + /seq + /oss + /instr + /ioctl32 + /include + /drivers + /mpu401 + /opl3 + /i2c + /l3 + /synth + /emux + /pci + /(cards) + /isa + /(cards) + /arm + /ppc + /sparc + /usb + /pcmcia /(cards) + /oss + </literallayout> + </example> + </para> + </section> + + <section id="file-tree-core-directory"> + <title>core directory</title> + <para> + This directory contains the middle layer which is the heart + of ALSA drivers. In this directory, the native ALSA modules are + stored. The sub-directories contain different modules and are + dependent upon the kernel config. + </para> + + <section id="file-tree-core-directory-oss"> + <title>core/oss</title> + + <para> + The codes for PCM and mixer OSS emulation modules are stored + in this directory. The rawmidi OSS emulation is included in + the ALSA rawmidi code since it's quite small. The sequencer + code is stored in <filename>core/seq/oss</filename> directory (see + <link linkend="file-tree-core-directory-seq-oss"><citetitle> + below</citetitle></link>). + </para> + </section> + + <section id="file-tree-core-directory-ioctl32"> + <title>core/ioctl32</title> + + <para> + This directory contains the 32bit-ioctl wrappers for 64bit + architectures such like x86-64, ppc64 and sparc64. For 32bit + and alpha architectures, these are not compiled. + </para> + </section> + + <section id="file-tree-core-directory-seq"> + <title>core/seq</title> + <para> + This directory and its sub-directories are for the ALSA + sequencer. This directory contains the sequencer core and + primary sequencer modules such like snd-seq-midi, + snd-seq-virmidi, etc. They are compiled only when + <constant>CONFIG_SND_SEQUENCER</constant> is set in the kernel + config. + </para> + </section> + + <section id="file-tree-core-directory-seq-oss"> + <title>core/seq/oss</title> + <para> + This contains the OSS sequencer emulation codes. + </para> + </section> + + <section id="file-tree-core-directory-deq-instr"> + <title>core/seq/instr</title> + <para> + This directory contains the modules for the sequencer + instrument layer. + </para> + </section> + </section> + + <section id="file-tree-include-directory"> + <title>include directory</title> + <para> + This is the place for the public header files of ALSA drivers, + which are to be exported to user-space, or included by + several files at different directories. Basically, the private + header files should not be placed in this directory, but you may + still find files there, due to historical reasons :) + </para> + </section> + + <section id="file-tree-drivers-directory"> + <title>drivers directory</title> + <para> + This directory contains code shared among different drivers + on different architectures. They are hence supposed not to be + architecture-specific. + For example, the dummy pcm driver and the serial MIDI + driver are found in this directory. In the sub-directories, + there is code for components which are independent from + bus and cpu architectures. + </para> + + <section id="file-tree-drivers-directory-mpu401"> + <title>drivers/mpu401</title> + <para> + The MPU401 and MPU401-UART modules are stored here. + </para> + </section> + + <section id="file-tree-drivers-directory-opl3"> + <title>drivers/opl3 and opl4</title> + <para> + The OPL3 and OPL4 FM-synth stuff is found here. + </para> + </section> + </section> + + <section id="file-tree-i2c-directory"> + <title>i2c directory</title> + <para> + This contains the ALSA i2c components. + </para> + + <para> + Although there is a standard i2c layer on Linux, ALSA has its + own i2c code for some cards, because the soundcard needs only a + simple operation and the standard i2c API is too complicated for + such a purpose. + </para> + + <section id="file-tree-i2c-directory-l3"> + <title>i2c/l3</title> + <para> + This is a sub-directory for ARM L3 i2c. + </para> + </section> + </section> + + <section id="file-tree-synth-directory"> + <title>synth directory</title> + <para> + This contains the synth middle-level modules. + </para> + + <para> + So far, there is only Emu8000/Emu10k1 synth driver under + the <filename>synth/emux</filename> sub-directory. + </para> + </section> + + <section id="file-tree-pci-directory"> + <title>pci directory</title> + <para> + This directory and its sub-directories hold the top-level card modules + for PCI soundcards and the code specific to the PCI BUS. + </para> + + <para> + The drivers compiled from a single file are stored directly + in the pci directory, while the drivers with several source files are + stored on their own sub-directory (e.g. emu10k1, ice1712). + </para> + </section> + + <section id="file-tree-isa-directory"> + <title>isa directory</title> + <para> + This directory and its sub-directories hold the top-level card modules + for ISA soundcards. + </para> + </section> + + <section id="file-tree-arm-ppc-sparc-directories"> + <title>arm, ppc, and sparc directories</title> + <para> + They are used for top-level card modules which are + specific to one of these architectures. + </para> + </section> + + <section id="file-tree-usb-directory"> + <title>usb directory</title> + <para> + This directory contains the USB-audio driver. In the latest version, the + USB MIDI driver is integrated in the usb-audio driver. + </para> + </section> + + <section id="file-tree-pcmcia-directory"> + <title>pcmcia directory</title> + <para> + The PCMCIA, especially PCCard drivers will go here. CardBus + drivers will be in the pci directory, because their API is identical + to that of standard PCI cards. + </para> + </section> + + <section id="file-tree-oss-directory"> + <title>oss directory</title> + <para> + The OSS/Lite source files are stored here in Linux 2.6 (or + later) tree. In the ALSA driver tarball, this directory is empty, + of course :) + </para> + </section> + </chapter> + + +<!-- ****************************************************** --> +<!-- Basic Flow for PCI Drivers --> +<!-- ****************************************************** --> + <chapter id="basic-flow"> + <title>Basic Flow for PCI Drivers</title> + + <section id="basic-flow-outline"> + <title>Outline</title> + <para> + The minimum flow for PCI soundcards is as follows: + + <itemizedlist> + <listitem><para>define the PCI ID table (see the section + <link linkend="pci-resource-entries"><citetitle>PCI Entries + </citetitle></link>).</para></listitem> + <listitem><para>create <function>probe()</function> callback.</para></listitem> + <listitem><para>create <function>remove()</function> callback.</para></listitem> + <listitem><para>create a <structname>pci_driver</structname> structure + containing the three pointers above.</para></listitem> + <listitem><para>create an <function>init()</function> function just calling + the <function>pci_register_driver()</function> to register the pci_driver table + defined above.</para></listitem> + <listitem><para>create an <function>exit()</function> function to call + the <function>pci_unregister_driver()</function> function.</para></listitem> + </itemizedlist> + </para> + </section> + + <section id="basic-flow-example"> + <title>Full Code Example</title> + <para> + The code example is shown below. Some parts are kept + unimplemented at this moment but will be filled in the + next sections. The numbers in the comment lines of the + <function>snd_mychip_probe()</function> function + refer to details explained in the following section. + + <example> + <title>Basic Flow for PCI Drivers - Example</title> + <programlisting> +<![CDATA[ + #include <linux/init.h> + #include <linux/pci.h> + #include <linux/slab.h> + #include <sound/core.h> + #include <sound/initval.h> + + /* module parameters (see "Module Parameters") */ + /* SNDRV_CARDS: maximum number of cards supported by this module */ + static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; + static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; + static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP; + + /* definition of the chip-specific record */ + struct mychip { + struct snd_card *card; + /* the rest of the implementation will be in section + * "PCI Resource Management" + */ + }; + + /* chip-specific destructor + * (see "PCI Resource Management") + */ + static int snd_mychip_free(struct mychip *chip) + { + .... /* will be implemented later... */ + } + + /* component-destructor + * (see "Management of Cards and Components") + */ + static int snd_mychip_dev_free(struct snd_device *device) + { + return snd_mychip_free(device->device_data); + } + + /* chip-specific constructor + * (see "Management of Cards and Components") + */ + static int __devinit snd_mychip_create(struct snd_card *card, + struct pci_dev *pci, + struct mychip **rchip) + { + struct mychip *chip; + int err; + static struct snd_device_ops ops = { + .dev_free = snd_mychip_dev_free, + }; + + *rchip = NULL; + + /* check PCI availability here + * (see "PCI Resource Management") + */ + .... + + /* allocate a chip-specific data with zero filled */ + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (chip == NULL) + return -ENOMEM; + + chip->card = card; + + /* rest of initialization here; will be implemented + * later, see "PCI Resource Management" + */ + .... + + err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops); + if (err < 0) { + snd_mychip_free(chip); + return err; + } + + snd_card_set_dev(card, &pci->dev); + + *rchip = chip; + return 0; + } + + /* constructor -- see "Constructor" sub-section */ + static int __devinit snd_mychip_probe(struct pci_dev *pci, + const struct pci_device_id *pci_id) + { + static int dev; + struct snd_card *card; + struct mychip *chip; + int err; + + /* (1) */ + if (dev >= SNDRV_CARDS) + return -ENODEV; + if (!enable[dev]) { + dev++; + return -ENOENT; + } + + /* (2) */ + err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card); + if (err < 0) + return err; + + /* (3) */ + err = snd_mychip_create(card, pci, &chip); + if (err < 0) { + snd_card_free(card); + return err; + } + + /* (4) */ + strcpy(card->driver, "My Chip"); + strcpy(card->shortname, "My Own Chip 123"); + sprintf(card->longname, "%s at 0x%lx irq %i", + card->shortname, chip->ioport, chip->irq); + + /* (5) */ + .... /* implemented later */ + + /* (6) */ + err = snd_card_register(card); + if (err < 0) { + snd_card_free(card); + return err; + } + + /* (7) */ + pci_set_drvdata(pci, card); + dev++; + return 0; + } + + /* destructor -- see the "Destructor" sub-section */ + static void __devexit snd_mychip_remove(struct pci_dev *pci) + { + snd_card_free(pci_get_drvdata(pci)); + pci_set_drvdata(pci, NULL); + } +]]> + </programlisting> + </example> + </para> + </section> + + <section id="basic-flow-constructor"> + <title>Constructor</title> + <para> + The real constructor of PCI drivers is the <function>probe</function> callback. + The <function>probe</function> callback and other component-constructors which are called + from the <function>probe</function> callback should be defined with + the <parameter>__devinit</parameter> prefix. You + cannot use the <parameter>__init</parameter> prefix for them, + because any PCI device could be a hotplug device. + </para> + + <para> + In the <function>probe</function> callback, the following scheme is often used. + </para> + + <section id="basic-flow-constructor-device-index"> + <title>1) Check and increment the device index.</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int dev; + .... + if (dev >= SNDRV_CARDS) + return -ENODEV; + if (!enable[dev]) { + dev++; + return -ENOENT; + } +]]> + </programlisting> + </informalexample> + + where enable[dev] is the module option. + </para> + + <para> + Each time the <function>probe</function> callback is called, check the + availability of the device. If not available, simply increment + the device index and returns. dev will be incremented also + later (<link + linkend="basic-flow-constructor-set-pci"><citetitle>step + 7</citetitle></link>). + </para> + </section> + + <section id="basic-flow-constructor-create-card"> + <title>2) Create a card instance</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + struct snd_card *card; + int err; + .... + err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The details will be explained in the section + <link linkend="card-management-card-instance"><citetitle> + Management of Cards and Components</citetitle></link>. + </para> + </section> + + <section id="basic-flow-constructor-create-main"> + <title>3) Create a main component</title> + <para> + In this part, the PCI resources are allocated. + + <informalexample> + <programlisting> +<![CDATA[ + struct mychip *chip; + .... + err = snd_mychip_create(card, pci, &chip); + if (err < 0) { + snd_card_free(card); + return err; + } +]]> + </programlisting> + </informalexample> + + The details will be explained in the section <link + linkend="pci-resource"><citetitle>PCI Resource + Management</citetitle></link>. + </para> + </section> + + <section id="basic-flow-constructor-main-component"> + <title>4) Set the driver ID and name strings.</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + strcpy(card->driver, "My Chip"); + strcpy(card->shortname, "My Own Chip 123"); + sprintf(card->longname, "%s at 0x%lx irq %i", + card->shortname, chip->ioport, chip->irq); +]]> + </programlisting> + </informalexample> + + The driver field holds the minimal ID string of the + chip. This is used by alsa-lib's configurator, so keep it + simple but unique. + Even the same driver can have different driver IDs to + distinguish the functionality of each chip type. + </para> + + <para> + The shortname field is a string shown as more verbose + name. The longname field contains the information + shown in <filename>/proc/asound/cards</filename>. + </para> + </section> + + <section id="basic-flow-constructor-create-other"> + <title>5) Create other components, such as mixer, MIDI, etc.</title> + <para> + Here you define the basic components such as + <link linkend="pcm-interface"><citetitle>PCM</citetitle></link>, + mixer (e.g. <link linkend="api-ac97"><citetitle>AC97</citetitle></link>), + MIDI (e.g. <link linkend="midi-interface"><citetitle>MPU-401</citetitle></link>), + and other interfaces. + Also, if you want a <link linkend="proc-interface"><citetitle>proc + file</citetitle></link>, define it here, too. + </para> + </section> + + <section id="basic-flow-constructor-register-card"> + <title>6) Register the card instance.</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + err = snd_card_register(card); + if (err < 0) { + snd_card_free(card); + return err; + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + Will be explained in the section <link + linkend="card-management-registration"><citetitle>Management + of Cards and Components</citetitle></link>, too. + </para> + </section> + + <section id="basic-flow-constructor-set-pci"> + <title>7) Set the PCI driver data and return zero.</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + pci_set_drvdata(pci, card); + dev++; + return 0; +]]> + </programlisting> + </informalexample> + + In the above, the card record is stored. This pointer is + used in the remove callback and power-management + callbacks, too. + </para> + </section> + </section> + + <section id="basic-flow-destructor"> + <title>Destructor</title> + <para> + The destructor, remove callback, simply releases the card + instance. Then the ALSA middle layer will release all the + attached components automatically. + </para> + + <para> + It would be typically like the following: + + <informalexample> + <programlisting> +<![CDATA[ + static void __devexit snd_mychip_remove(struct pci_dev *pci) + { + snd_card_free(pci_get_drvdata(pci)); + pci_set_drvdata(pci, NULL); + } +]]> + </programlisting> + </informalexample> + + The above code assumes that the card pointer is set to the PCI + driver data. + </para> + </section> + + <section id="basic-flow-header-files"> + <title>Header Files</title> + <para> + For the above example, at least the following include files + are necessary. + + <informalexample> + <programlisting> +<![CDATA[ + #include <linux/init.h> + #include <linux/pci.h> + #include <linux/slab.h> + #include <sound/core.h> + #include <sound/initval.h> +]]> + </programlisting> + </informalexample> + + where the last one is necessary only when module options are + defined in the source file. If the code is split into several + files, the files without module options don't need them. + </para> + + <para> + In addition to these headers, you'll need + <filename><linux/interrupt.h></filename> for interrupt + handling, and <filename><asm/io.h></filename> for I/O + access. If you use the <function>mdelay()</function> or + <function>udelay()</function> functions, you'll need to include + <filename><linux/delay.h></filename> too. + </para> + + <para> + The ALSA interfaces like the PCM and control APIs are defined in other + <filename><sound/xxx.h></filename> header files. + They have to be included after + <filename><sound/core.h></filename>. + </para> + + </section> + </chapter> + + +<!-- ****************************************************** --> +<!-- Management of Cards and Components --> +<!-- ****************************************************** --> + <chapter id="card-management"> + <title>Management of Cards and Components</title> + + <section id="card-management-card-instance"> + <title>Card Instance</title> + <para> + For each soundcard, a <quote>card</quote> record must be allocated. + </para> + + <para> + A card record is the headquarters of the soundcard. It manages + the whole list of devices (components) on the soundcard, such as + PCM, mixers, MIDI, synthesizer, and so on. Also, the card + record holds the ID and the name strings of the card, manages + the root of proc files, and controls the power-management states + and hotplug disconnections. The component list on the card + record is used to manage the correct release of resources at + destruction. + </para> + + <para> + As mentioned above, to create a card instance, call + <function>snd_card_create()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_card *card; + int err; + err = snd_card_create(index, id, module, extra_size, &card); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The function takes five arguments, the card-index number, the + id string, the module pointer (usually + <constant>THIS_MODULE</constant>), + the size of extra-data space, and the pointer to return the + card instance. The extra_size argument is used to + allocate card->private_data for the + chip-specific data. Note that these data + are allocated by <function>snd_card_create()</function>. + </para> + </section> + + <section id="card-management-component"> + <title>Components</title> + <para> + After the card is created, you can attach the components + (devices) to the card instance. In an ALSA driver, a component is + represented as a struct <structname>snd_device</structname> object. + A component can be a PCM instance, a control interface, a raw + MIDI interface, etc. Each such instance has one component + entry. + </para> + + <para> + A component can be created via + <function>snd_device_new()</function> function. + + <informalexample> + <programlisting> +<![CDATA[ + snd_device_new(card, SNDRV_DEV_XXX, chip, &ops); +]]> + </programlisting> + </informalexample> + </para> + + <para> + This takes the card pointer, the device-level + (<constant>SNDRV_DEV_XXX</constant>), the data pointer, and the + callback pointers (<parameter>&ops</parameter>). The + device-level defines the type of components and the order of + registration and de-registration. For most components, the + device-level is already defined. For a user-defined component, + you can use <constant>SNDRV_DEV_LOWLEVEL</constant>. + </para> + + <para> + This function itself doesn't allocate the data space. The data + must be allocated manually beforehand, and its pointer is passed + as the argument. This pointer is used as the + (<parameter>chip</parameter> identifier in the above example) + for the instance. + </para> + + <para> + Each pre-defined ALSA component such as ac97 and pcm calls + <function>snd_device_new()</function> inside its + constructor. The destructor for each component is defined in the + callback pointers. Hence, you don't need to take care of + calling a destructor for such a component. + </para> + + <para> + If you wish to create your own component, you need to + set the destructor function to the dev_free callback in + the <parameter>ops</parameter>, so that it can be released + automatically via <function>snd_card_free()</function>. + The next example will show an implementation of chip-specific + data. + </para> + </section> + + <section id="card-management-chip-specific"> + <title>Chip-Specific Data</title> + <para> + Chip-specific information, e.g. the I/O port address, its + resource pointer, or the irq number, is stored in the + chip-specific record. + + <informalexample> + <programlisting> +<![CDATA[ + struct mychip { + .... + }; +]]> + </programlisting> + </informalexample> + </para> + + <para> + In general, there are two ways of allocating the chip record. + </para> + + <section id="card-management-chip-specific-snd-card-new"> + <title>1. Allocating via <function>snd_card_create()</function>.</title> + <para> + As mentioned above, you can pass the extra-data-length + to the 4th argument of <function>snd_card_create()</function>, i.e. + + <informalexample> + <programlisting> +<![CDATA[ + err = snd_card_create(index[dev], id[dev], THIS_MODULE, + sizeof(struct mychip), &card); +]]> + </programlisting> + </informalexample> + + struct <structname>mychip</structname> is the type of the chip record. + </para> + + <para> + In return, the allocated record can be accessed as + + <informalexample> + <programlisting> +<![CDATA[ + struct mychip *chip = card->private_data; +]]> + </programlisting> + </informalexample> + + With this method, you don't have to allocate twice. + The record is released together with the card instance. + </para> + </section> + + <section id="card-management-chip-specific-allocate-extra"> + <title>2. Allocating an extra device.</title> + + <para> + After allocating a card instance via + <function>snd_card_create()</function> (with + <constant>0</constant> on the 4th arg), call + <function>kzalloc()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_card *card; + struct mychip *chip; + err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card); + ..... + chip = kzalloc(sizeof(*chip), GFP_KERNEL); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The chip record should have the field to hold the card + pointer at least, + + <informalexample> + <programlisting> +<![CDATA[ + struct mychip { + struct snd_card *card; + .... + }; +]]> + </programlisting> + </informalexample> + </para> + + <para> + Then, set the card pointer in the returned chip instance. + + <informalexample> + <programlisting> +<![CDATA[ + chip->card = card; +]]> + </programlisting> + </informalexample> + </para> + + <para> + Next, initialize the fields, and register this chip + record as a low-level device with a specified + <parameter>ops</parameter>, + + <informalexample> + <programlisting> +<![CDATA[ + static struct snd_device_ops ops = { + .dev_free = snd_mychip_dev_free, + }; + .... + snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops); +]]> + </programlisting> + </informalexample> + + <function>snd_mychip_dev_free()</function> is the + device-destructor function, which will call the real + destructor. + </para> + + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int snd_mychip_dev_free(struct snd_device *device) + { + return snd_mychip_free(device->device_data); + } +]]> + </programlisting> + </informalexample> + + where <function>snd_mychip_free()</function> is the real destructor. + </para> + </section> + </section> + + <section id="card-management-registration"> + <title>Registration and Release</title> + <para> + After all components are assigned, register the card instance + by calling <function>snd_card_register()</function>. Access + to the device files is enabled at this point. That is, before + <function>snd_card_register()</function> is called, the + components are safely inaccessible from external side. If this + call fails, exit the probe function after releasing the card via + <function>snd_card_free()</function>. + </para> + + <para> + For releasing the card instance, you can call simply + <function>snd_card_free()</function>. As mentioned earlier, all + components are released automatically by this call. + </para> + + <para> + As further notes, the destructors (both + <function>snd_mychip_dev_free</function> and + <function>snd_mychip_free</function>) cannot be defined with + the <parameter>__devexit</parameter> prefix, because they may be + called from the constructor, too, at the false path. + </para> + + <para> + For a device which allows hotplugging, you can use + <function>snd_card_free_when_closed</function>. This one will + postpone the destruction until all devices are closed. + </para> + + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- PCI Resource Management --> +<!-- ****************************************************** --> + <chapter id="pci-resource"> + <title>PCI Resource Management</title> + + <section id="pci-resource-example"> + <title>Full Code Example</title> + <para> + In this section, we'll complete the chip-specific constructor, + destructor and PCI entries. Example code is shown first, + below. + + <example> + <title>PCI Resource Management Example</title> + <programlisting> +<![CDATA[ + struct mychip { + struct snd_card *card; + struct pci_dev *pci; + + unsigned long port; + int irq; + }; + + static int snd_mychip_free(struct mychip *chip) + { + /* disable hardware here if any */ + .... /* (not implemented in this document) */ + + /* release the irq */ + if (chip->irq >= 0) + free_irq(chip->irq, chip); + /* release the I/O ports & memory */ + pci_release_regions(chip->pci); + /* disable the PCI entry */ + pci_disable_device(chip->pci); + /* release the data */ + kfree(chip); + return 0; + } + + /* chip-specific constructor */ + static int __devinit snd_mychip_create(struct snd_card *card, + struct pci_dev *pci, + struct mychip **rchip) + { + struct mychip *chip; + int err; + static struct snd_device_ops ops = { + .dev_free = snd_mychip_dev_free, + }; + + *rchip = NULL; + + /* initialize the PCI entry */ + err = pci_enable_device(pci); + if (err < 0) + return err; + /* check PCI availability (28bit DMA) */ + if (pci_set_dma_mask(pci, DMA_BIT_MASK(28)) < 0 || + pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(28)) < 0) { + printk(KERN_ERR "error to set 28bit mask DMA\n"); + pci_disable_device(pci); + return -ENXIO; + } + + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (chip == NULL) { + pci_disable_device(pci); + return -ENOMEM; + } + + /* initialize the stuff */ + chip->card = card; + chip->pci = pci; + chip->irq = -1; + + /* (1) PCI resource allocation */ + err = pci_request_regions(pci, "My Chip"); + if (err < 0) { + kfree(chip); + pci_disable_device(pci); + return err; + } + chip->port = pci_resource_start(pci, 0); + if (request_irq(pci->irq, snd_mychip_interrupt, + IRQF_SHARED, KBUILD_MODNAME, chip)) { + printk(KERN_ERR "cannot grab irq %d\n", pci->irq); + snd_mychip_free(chip); + return -EBUSY; + } + chip->irq = pci->irq; + + /* (2) initialization of the chip hardware */ + .... /* (not implemented in this document) */ + + err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops); + if (err < 0) { + snd_mychip_free(chip); + return err; + } + + snd_card_set_dev(card, &pci->dev); + + *rchip = chip; + return 0; + } + + /* PCI IDs */ + static struct pci_device_id snd_mychip_ids[] = { + { PCI_VENDOR_ID_FOO, PCI_DEVICE_ID_BAR, + PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, }, + .... + { 0, } + }; + MODULE_DEVICE_TABLE(pci, snd_mychip_ids); + + /* pci_driver definition */ + static struct pci_driver driver = { + .name = KBUILD_MODNAME, + .id_table = snd_mychip_ids, + .probe = snd_mychip_probe, + .remove = __devexit_p(snd_mychip_remove), + }; + + /* module initialization */ + static int __init alsa_card_mychip_init(void) + { + return pci_register_driver(&driver); + } + + /* module clean up */ + static void __exit alsa_card_mychip_exit(void) + { + pci_unregister_driver(&driver); + } + + module_init(alsa_card_mychip_init) + module_exit(alsa_card_mychip_exit) + + EXPORT_NO_SYMBOLS; /* for old kernels only */ +]]> + </programlisting> + </example> + </para> + </section> + + <section id="pci-resource-some-haftas"> + <title>Some Hafta's</title> + <para> + The allocation of PCI resources is done in the + <function>probe()</function> function, and usually an extra + <function>xxx_create()</function> function is written for this + purpose. + </para> + + <para> + In the case of PCI devices, you first have to call + the <function>pci_enable_device()</function> function before + allocating resources. Also, you need to set the proper PCI DMA + mask to limit the accessed I/O range. In some cases, you might + need to call <function>pci_set_master()</function> function, + too. + </para> + + <para> + Suppose the 28bit mask, and the code to be added would be like: + + <informalexample> + <programlisting> +<![CDATA[ + err = pci_enable_device(pci); + if (err < 0) + return err; + if (pci_set_dma_mask(pci, DMA_BIT_MASK(28)) < 0 || + pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(28)) < 0) { + printk(KERN_ERR "error to set 28bit mask DMA\n"); + pci_disable_device(pci); + return -ENXIO; + } + +]]> + </programlisting> + </informalexample> + </para> + </section> + + <section id="pci-resource-resource-allocation"> + <title>Resource Allocation</title> + <para> + The allocation of I/O ports and irqs is done via standard kernel + functions. Unlike ALSA ver.0.5.x., there are no helpers for + that. And these resources must be released in the destructor + function (see below). Also, on ALSA 0.9.x, you don't need to + allocate (pseudo-)DMA for PCI like in ALSA 0.5.x. + </para> + + <para> + Now assume that the PCI device has an I/O port with 8 bytes + and an interrupt. Then struct <structname>mychip</structname> will have the + following fields: + + <informalexample> + <programlisting> +<![CDATA[ + struct mychip { + struct snd_card *card; + + unsigned long port; + int irq; + }; +]]> + </programlisting> + </informalexample> + </para> + + <para> + For an I/O port (and also a memory region), you need to have + the resource pointer for the standard resource management. For + an irq, you have to keep only the irq number (integer). But you + need to initialize this number as -1 before actual allocation, + since irq 0 is valid. The port address and its resource pointer + can be initialized as null by + <function>kzalloc()</function> automatically, so you + don't have to take care of resetting them. + </para> + + <para> + The allocation of an I/O port is done like this: + + <informalexample> + <programlisting> +<![CDATA[ + err = pci_request_regions(pci, "My Chip"); + if (err < 0) { + kfree(chip); + pci_disable_device(pci); + return err; + } + chip->port = pci_resource_start(pci, 0); +]]> + </programlisting> + </informalexample> + </para> + + <para> + <!-- obsolete --> + It will reserve the I/O port region of 8 bytes of the given + PCI device. The returned value, chip->res_port, is allocated + via <function>kmalloc()</function> by + <function>request_region()</function>. The pointer must be + released via <function>kfree()</function>, but there is a + problem with this. This issue will be explained later. + </para> + + <para> + The allocation of an interrupt source is done like this: + + <informalexample> + <programlisting> +<![CDATA[ + if (request_irq(pci->irq, snd_mychip_interrupt, + IRQF_SHARED, KBUILD_MODNAME, chip)) { + printk(KERN_ERR "cannot grab irq %d\n", pci->irq); + snd_mychip_free(chip); + return -EBUSY; + } + chip->irq = pci->irq; +]]> + </programlisting> + </informalexample> + + where <function>snd_mychip_interrupt()</function> is the + interrupt handler defined <link + linkend="pcm-interface-interrupt-handler"><citetitle>later</citetitle></link>. + Note that chip->irq should be defined + only when <function>request_irq()</function> succeeded. + </para> + + <para> + On the PCI bus, interrupts can be shared. Thus, + <constant>IRQF_SHARED</constant> is used as the interrupt flag of + <function>request_irq()</function>. + </para> + + <para> + The last argument of <function>request_irq()</function> is the + data pointer passed to the interrupt handler. Usually, the + chip-specific record is used for that, but you can use what you + like, too. + </para> + + <para> + I won't give details about the interrupt handler at this + point, but at least its appearance can be explained now. The + interrupt handler looks usually like the following: + + <informalexample> + <programlisting> +<![CDATA[ + static irqreturn_t snd_mychip_interrupt(int irq, void *dev_id) + { + struct mychip *chip = dev_id; + .... + return IRQ_HANDLED; + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + Now let's write the corresponding destructor for the resources + above. The role of destructor is simple: disable the hardware + (if already activated) and release the resources. So far, we + have no hardware part, so the disabling code is not written here. + </para> + + <para> + To release the resources, the <quote>check-and-release</quote> + method is a safer way. For the interrupt, do like this: + + <informalexample> + <programlisting> +<![CDATA[ + if (chip->irq >= 0) + free_irq(chip->irq, chip); +]]> + </programlisting> + </informalexample> + + Since the irq number can start from 0, you should initialize + chip->irq with a negative value (e.g. -1), so that you can + check the validity of the irq number as above. + </para> + + <para> + When you requested I/O ports or memory regions via + <function>pci_request_region()</function> or + <function>pci_request_regions()</function> like in this example, + release the resource(s) using the corresponding function, + <function>pci_release_region()</function> or + <function>pci_release_regions()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + pci_release_regions(chip->pci); +]]> + </programlisting> + </informalexample> + </para> + + <para> + When you requested manually via <function>request_region()</function> + or <function>request_mem_region</function>, you can release it via + <function>release_resource()</function>. Suppose that you keep + the resource pointer returned from <function>request_region()</function> + in chip->res_port, the release procedure looks like: + + <informalexample> + <programlisting> +<![CDATA[ + release_and_free_resource(chip->res_port); +]]> + </programlisting> + </informalexample> + </para> + + <para> + Don't forget to call <function>pci_disable_device()</function> + before the end. + </para> + + <para> + And finally, release the chip-specific record. + + <informalexample> + <programlisting> +<![CDATA[ + kfree(chip); +]]> + </programlisting> + </informalexample> + </para> + + <para> + Again, remember that you cannot + use the <parameter>__devexit</parameter> prefix for this destructor. + </para> + + <para> + We didn't implement the hardware disabling part in the above. + If you need to do this, please note that the destructor may be + called even before the initialization of the chip is completed. + It would be better to have a flag to skip hardware disabling + if the hardware was not initialized yet. + </para> + + <para> + When the chip-data is assigned to the card using + <function>snd_device_new()</function> with + <constant>SNDRV_DEV_LOWLELVEL</constant> , its destructor is + called at the last. That is, it is assured that all other + components like PCMs and controls have already been released. + You don't have to stop PCMs, etc. explicitly, but just + call low-level hardware stopping. + </para> + + <para> + The management of a memory-mapped region is almost as same as + the management of an I/O port. You'll need three fields like + the following: + + <informalexample> + <programlisting> +<![CDATA[ + struct mychip { + .... + unsigned long iobase_phys; + void __iomem *iobase_virt; + }; +]]> + </programlisting> + </informalexample> + + and the allocation would be like below: + + <informalexample> + <programlisting> +<![CDATA[ + if ((err = pci_request_regions(pci, "My Chip")) < 0) { + kfree(chip); + return err; + } + chip->iobase_phys = pci_resource_start(pci, 0); + chip->iobase_virt = ioremap_nocache(chip->iobase_phys, + pci_resource_len(pci, 0)); +]]> + </programlisting> + </informalexample> + + and the corresponding destructor would be: + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_mychip_free(struct mychip *chip) + { + .... + if (chip->iobase_virt) + iounmap(chip->iobase_virt); + .... + pci_release_regions(chip->pci); + .... + } +]]> + </programlisting> + </informalexample> + </para> + + </section> + + <section id="pci-resource-device-struct"> + <title>Registration of Device Struct</title> + <para> + At some point, typically after calling <function>snd_device_new()</function>, + you need to register the struct <structname>device</structname> of the chip + you're handling for udev and co. ALSA provides a macro for compatibility with + older kernels. Simply call like the following: + <informalexample> + <programlisting> +<![CDATA[ + snd_card_set_dev(card, &pci->dev); +]]> + </programlisting> + </informalexample> + so that it stores the PCI's device pointer to the card. This will be + referred by ALSA core functions later when the devices are registered. + </para> + <para> + In the case of non-PCI, pass the proper device struct pointer of the BUS + instead. (In the case of legacy ISA without PnP, you don't have to do + anything.) + </para> + </section> + + <section id="pci-resource-entries"> + <title>PCI Entries</title> + <para> + So far, so good. Let's finish the missing PCI + stuff. At first, we need a + <structname>pci_device_id</structname> table for this + chipset. It's a table of PCI vendor/device ID number, and some + masks. + </para> + + <para> + For example, + + <informalexample> + <programlisting> +<![CDATA[ + static struct pci_device_id snd_mychip_ids[] = { + { PCI_VENDOR_ID_FOO, PCI_DEVICE_ID_BAR, + PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, }, + .... + { 0, } + }; + MODULE_DEVICE_TABLE(pci, snd_mychip_ids); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The first and second fields of + the <structname>pci_device_id</structname> structure are the vendor and + device IDs. If you have no reason to filter the matching + devices, you can leave the remaining fields as above. The last + field of the <structname>pci_device_id</structname> struct contains + private data for this entry. You can specify any value here, for + example, to define specific operations for supported device IDs. + Such an example is found in the intel8x0 driver. + </para> + + <para> + The last entry of this list is the terminator. You must + specify this all-zero entry. + </para> + + <para> + Then, prepare the <structname>pci_driver</structname> record: + + <informalexample> + <programlisting> +<![CDATA[ + static struct pci_driver driver = { + .name = KBUILD_MODNAME, + .id_table = snd_mychip_ids, + .probe = snd_mychip_probe, + .remove = __devexit_p(snd_mychip_remove), + }; +]]> + </programlisting> + </informalexample> + </para> + + <para> + The <structfield>probe</structfield> and + <structfield>remove</structfield> functions have already + been defined in the previous sections. + The <structfield>remove</structfield> function should + be defined with the + <function>__devexit_p()</function> macro, so that it's not + defined for built-in (and non-hot-pluggable) case. The + <structfield>name</structfield> + field is the name string of this device. Note that you must not + use a slash <quote>/</quote> in this string. + </para> + + <para> + And at last, the module entries: + + <informalexample> + <programlisting> +<![CDATA[ + static int __init alsa_card_mychip_init(void) + { + return pci_register_driver(&driver); + } + + static void __exit alsa_card_mychip_exit(void) + { + pci_unregister_driver(&driver); + } + + module_init(alsa_card_mychip_init) + module_exit(alsa_card_mychip_exit) +]]> + </programlisting> + </informalexample> + </para> + + <para> + Note that these module entries are tagged with + <parameter>__init</parameter> and + <parameter>__exit</parameter> prefixes, not + <parameter>__devinit</parameter> nor + <parameter>__devexit</parameter>. + </para> + + <para> + Oh, one thing was forgotten. If you have no exported symbols, + you need to declare it in 2.2 or 2.4 kernels (it's not necessary in 2.6 kernels). + + <informalexample> + <programlisting> +<![CDATA[ + EXPORT_NO_SYMBOLS; +]]> + </programlisting> + </informalexample> + + That's all! + </para> + </section> + </chapter> + + +<!-- ****************************************************** --> +<!-- PCM Interface --> +<!-- ****************************************************** --> + <chapter id="pcm-interface"> + <title>PCM Interface</title> + + <section id="pcm-interface-general"> + <title>General</title> + <para> + The PCM middle layer of ALSA is quite powerful and it is only + necessary for each driver to implement the low-level functions + to access its hardware. + </para> + + <para> + For accessing to the PCM layer, you need to include + <filename><sound/pcm.h></filename> first. In addition, + <filename><sound/pcm_params.h></filename> might be needed + if you access to some functions related with hw_param. + </para> + + <para> + Each card device can have up to four pcm instances. A pcm + instance corresponds to a pcm device file. The limitation of + number of instances comes only from the available bit size of + the Linux's device numbers. Once when 64bit device number is + used, we'll have more pcm instances available. + </para> + + <para> + A pcm instance consists of pcm playback and capture streams, + and each pcm stream consists of one or more pcm substreams. Some + soundcards support multiple playback functions. For example, + emu10k1 has a PCM playback of 32 stereo substreams. In this case, at + each open, a free substream is (usually) automatically chosen + and opened. Meanwhile, when only one substream exists and it was + already opened, the successful open will either block + or error with <constant>EAGAIN</constant> according to the + file open mode. But you don't have to care about such details in your + driver. The PCM middle layer will take care of such work. + </para> + </section> + + <section id="pcm-interface-example"> + <title>Full Code Example</title> + <para> + The example code below does not include any hardware access + routines but shows only the skeleton, how to build up the PCM + interfaces. + + <example> + <title>PCM Example Code</title> + <programlisting> +<![CDATA[ + #include <sound/pcm.h> + .... + + /* hardware definition */ + static struct snd_pcm_hardware snd_mychip_playback_hw = { + .info = (SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_BLOCK_TRANSFER | + SNDRV_PCM_INFO_MMAP_VALID), + .formats = SNDRV_PCM_FMTBIT_S16_LE, + .rates = SNDRV_PCM_RATE_8000_48000, + .rate_min = 8000, + .rate_max = 48000, + .channels_min = 2, + .channels_max = 2, + .buffer_bytes_max = 32768, + .period_bytes_min = 4096, + .period_bytes_max = 32768, + .periods_min = 1, + .periods_max = 1024, + }; + + /* hardware definition */ + static struct snd_pcm_hardware snd_mychip_capture_hw = { + .info = (SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_BLOCK_TRANSFER | + SNDRV_PCM_INFO_MMAP_VALID), + .formats = SNDRV_PCM_FMTBIT_S16_LE, + .rates = SNDRV_PCM_RATE_8000_48000, + .rate_min = 8000, + .rate_max = 48000, + .channels_min = 2, + .channels_max = 2, + .buffer_bytes_max = 32768, + .period_bytes_min = 4096, + .period_bytes_max = 32768, + .periods_min = 1, + .periods_max = 1024, + }; + + /* open callback */ + static int snd_mychip_playback_open(struct snd_pcm_substream *substream) + { + struct mychip *chip = snd_pcm_substream_chip(substream); + struct snd_pcm_runtime *runtime = substream->runtime; + + runtime->hw = snd_mychip_playback_hw; + /* more hardware-initialization will be done here */ + .... + return 0; + } + + /* close callback */ + static int snd_mychip_playback_close(struct snd_pcm_substream *substream) + { + struct mychip *chip = snd_pcm_substream_chip(substream); + /* the hardware-specific codes will be here */ + .... + return 0; + + } + + /* open callback */ + static int snd_mychip_capture_open(struct snd_pcm_substream *substream) + { + struct mychip *chip = snd_pcm_substream_chip(substream); + struct snd_pcm_runtime *runtime = substream->runtime; + + runtime->hw = snd_mychip_capture_hw; + /* more hardware-initialization will be done here */ + .... + return 0; + } + + /* close callback */ + static int snd_mychip_capture_close(struct snd_pcm_substream *substream) + { + struct mychip *chip = snd_pcm_substream_chip(substream); + /* the hardware-specific codes will be here */ + .... + return 0; + + } + + /* hw_params callback */ + static int snd_mychip_pcm_hw_params(struct snd_pcm_substream *substream, + struct snd_pcm_hw_params *hw_params) + { + return snd_pcm_lib_malloc_pages(substream, + params_buffer_bytes(hw_params)); + } + + /* hw_free callback */ + static int snd_mychip_pcm_hw_free(struct snd_pcm_substream *substream) + { + return snd_pcm_lib_free_pages(substream); + } + + /* prepare callback */ + static int snd_mychip_pcm_prepare(struct snd_pcm_substream *substream) + { + struct mychip *chip = snd_pcm_substream_chip(substream); + struct snd_pcm_runtime *runtime = substream->runtime; + + /* set up the hardware with the current configuration + * for example... + */ + mychip_set_sample_format(chip, runtime->format); + mychip_set_sample_rate(chip, runtime->rate); + mychip_set_channels(chip, runtime->channels); + mychip_set_dma_setup(chip, runtime->dma_addr, + chip->buffer_size, + chip->period_size); + return 0; + } + + /* trigger callback */ + static int snd_mychip_pcm_trigger(struct snd_pcm_substream *substream, + int cmd) + { + switch (cmd) { + case SNDRV_PCM_TRIGGER_START: + /* do something to start the PCM engine */ + .... + break; + case SNDRV_PCM_TRIGGER_STOP: + /* do something to stop the PCM engine */ + .... + break; + default: + return -EINVAL; + } + } + + /* pointer callback */ + static snd_pcm_uframes_t + snd_mychip_pcm_pointer(struct snd_pcm_substream *substream) + { + struct mychip *chip = snd_pcm_substream_chip(substream); + unsigned int current_ptr; + + /* get the current hardware pointer */ + current_ptr = mychip_get_hw_pointer(chip); + return current_ptr; + } + + /* operators */ + static struct snd_pcm_ops snd_mychip_playback_ops = { + .open = snd_mychip_playback_open, + .close = snd_mychip_playback_close, + .ioctl = snd_pcm_lib_ioctl, + .hw_params = snd_mychip_pcm_hw_params, + .hw_free = snd_mychip_pcm_hw_free, + .prepare = snd_mychip_pcm_prepare, + .trigger = snd_mychip_pcm_trigger, + .pointer = snd_mychip_pcm_pointer, + }; + + /* operators */ + static struct snd_pcm_ops snd_mychip_capture_ops = { + .open = snd_mychip_capture_open, + .close = snd_mychip_capture_close, + .ioctl = snd_pcm_lib_ioctl, + .hw_params = snd_mychip_pcm_hw_params, + .hw_free = snd_mychip_pcm_hw_free, + .prepare = snd_mychip_pcm_prepare, + .trigger = snd_mychip_pcm_trigger, + .pointer = snd_mychip_pcm_pointer, + }; + + /* + * definitions of capture are omitted here... + */ + + /* create a pcm device */ + static int __devinit snd_mychip_new_pcm(struct mychip *chip) + { + struct snd_pcm *pcm; + int err; + + err = snd_pcm_new(chip->card, "My Chip", 0, 1, 1, &pcm); + if (err < 0) + return err; + pcm->private_data = chip; + strcpy(pcm->name, "My Chip"); + chip->pcm = pcm; + /* set operators */ + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, + &snd_mychip_playback_ops); + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, + &snd_mychip_capture_ops); + /* pre-allocation of buffers */ + /* NOTE: this may fail */ + snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV, + snd_dma_pci_data(chip->pci), + 64*1024, 64*1024); + return 0; + } +]]> + </programlisting> + </example> + </para> + </section> + + <section id="pcm-interface-constructor"> + <title>Constructor</title> + <para> + A pcm instance is allocated by the <function>snd_pcm_new()</function> + function. It would be better to create a constructor for pcm, + namely, + + <informalexample> + <programlisting> +<![CDATA[ + static int __devinit snd_mychip_new_pcm(struct mychip *chip) + { + struct snd_pcm *pcm; + int err; + + err = snd_pcm_new(chip->card, "My Chip", 0, 1, 1, &pcm); + if (err < 0) + return err; + pcm->private_data = chip; + strcpy(pcm->name, "My Chip"); + chip->pcm = pcm; + .... + return 0; + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + The <function>snd_pcm_new()</function> function takes four + arguments. The first argument is the card pointer to which this + pcm is assigned, and the second is the ID string. + </para> + + <para> + The third argument (<parameter>index</parameter>, 0 in the + above) is the index of this new pcm. It begins from zero. If + you create more than one pcm instances, specify the + different numbers in this argument. For example, + <parameter>index</parameter> = 1 for the second PCM device. + </para> + + <para> + The fourth and fifth arguments are the number of substreams + for playback and capture, respectively. Here 1 is used for + both arguments. When no playback or capture substreams are available, + pass 0 to the corresponding argument. + </para> + + <para> + If a chip supports multiple playbacks or captures, you can + specify more numbers, but they must be handled properly in + open/close, etc. callbacks. When you need to know which + substream you are referring to, then it can be obtained from + struct <structname>snd_pcm_substream</structname> data passed to each callback + as follows: + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_pcm_substream *substream; + int index = substream->number; +]]> + </programlisting> + </informalexample> + </para> + + <para> + After the pcm is created, you need to set operators for each + pcm stream. + + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, + &snd_mychip_playback_ops); + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, + &snd_mychip_capture_ops); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The operators are defined typically like this: + + <informalexample> + <programlisting> +<![CDATA[ + static struct snd_pcm_ops snd_mychip_playback_ops = { + .open = snd_mychip_pcm_open, + .close = snd_mychip_pcm_close, + .ioctl = snd_pcm_lib_ioctl, + .hw_params = snd_mychip_pcm_hw_params, + .hw_free = snd_mychip_pcm_hw_free, + .prepare = snd_mychip_pcm_prepare, + .trigger = snd_mychip_pcm_trigger, + .pointer = snd_mychip_pcm_pointer, + }; +]]> + </programlisting> + </informalexample> + + All the callbacks are described in the + <link linkend="pcm-interface-operators"><citetitle> + Operators</citetitle></link> subsection. + </para> + + <para> + After setting the operators, you probably will want to + pre-allocate the buffer. For the pre-allocation, simply call + the following: + + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV, + snd_dma_pci_data(chip->pci), + 64*1024, 64*1024); +]]> + </programlisting> + </informalexample> + + It will allocate a buffer up to 64kB as default. + Buffer management details will be described in the later section <link + linkend="buffer-and-memory"><citetitle>Buffer and Memory + Management</citetitle></link>. + </para> + + <para> + Additionally, you can set some extra information for this pcm + in pcm->info_flags. + The available values are defined as + <constant>SNDRV_PCM_INFO_XXX</constant> in + <filename><sound/asound.h></filename>, which is used for + the hardware definition (described later). When your soundchip + supports only half-duplex, specify like this: + + <informalexample> + <programlisting> +<![CDATA[ + pcm->info_flags = SNDRV_PCM_INFO_HALF_DUPLEX; +]]> + </programlisting> + </informalexample> + </para> + </section> + + <section id="pcm-interface-destructor"> + <title>... And the Destructor?</title> + <para> + The destructor for a pcm instance is not always + necessary. Since the pcm device will be released by the middle + layer code automatically, you don't have to call the destructor + explicitly. + </para> + + <para> + The destructor would be necessary if you created + special records internally and needed to release them. In such a + case, set the destructor function to + pcm->private_free: + + <example> + <title>PCM Instance with a Destructor</title> + <programlisting> +<![CDATA[ + static void mychip_pcm_free(struct snd_pcm *pcm) + { + struct mychip *chip = snd_pcm_chip(pcm); + /* free your own data */ + kfree(chip->my_private_pcm_data); + /* do what you like else */ + .... + } + + static int __devinit snd_mychip_new_pcm(struct mychip *chip) + { + struct snd_pcm *pcm; + .... + /* allocate your own data */ + chip->my_private_pcm_data = kmalloc(...); + /* set the destructor */ + pcm->private_data = chip; + pcm->private_free = mychip_pcm_free; + .... + } +]]> + </programlisting> + </example> + </para> + </section> + + <section id="pcm-interface-runtime"> + <title>Runtime Pointer - The Chest of PCM Information</title> + <para> + When the PCM substream is opened, a PCM runtime instance is + allocated and assigned to the substream. This pointer is + accessible via <constant>substream->runtime</constant>. + This runtime pointer holds most information you need + to control the PCM: the copy of hw_params and sw_params configurations, the buffer + pointers, mmap records, spinlocks, etc. + </para> + + <para> + The definition of runtime instance is found in + <filename><sound/pcm.h></filename>. Here are + the contents of this file: + <informalexample> + <programlisting> +<![CDATA[ +struct _snd_pcm_runtime { + /* -- Status -- */ + struct snd_pcm_substream *trigger_master; + snd_timestamp_t trigger_tstamp; /* trigger timestamp */ + int overrange; + snd_pcm_uframes_t avail_max; + snd_pcm_uframes_t hw_ptr_base; /* Position at buffer restart */ + snd_pcm_uframes_t hw_ptr_interrupt; /* Position at interrupt time*/ + + /* -- HW params -- */ + snd_pcm_access_t access; /* access mode */ + snd_pcm_format_t format; /* SNDRV_PCM_FORMAT_* */ + snd_pcm_subformat_t subformat; /* subformat */ + unsigned int rate; /* rate in Hz */ + unsigned int channels; /* channels */ + snd_pcm_uframes_t period_size; /* period size */ + unsigned int periods; /* periods */ + snd_pcm_uframes_t buffer_size; /* buffer size */ + unsigned int tick_time; /* tick time */ + snd_pcm_uframes_t min_align; /* Min alignment for the format */ + size_t byte_align; + unsigned int frame_bits; + unsigned int sample_bits; + unsigned int info; + unsigned int rate_num; + unsigned int rate_den; + + /* -- SW params -- */ + struct timespec tstamp_mode; /* mmap timestamp is updated */ + unsigned int period_step; + unsigned int sleep_min; /* min ticks to sleep */ + snd_pcm_uframes_t start_threshold; + snd_pcm_uframes_t stop_threshold; + snd_pcm_uframes_t silence_threshold; /* Silence filling happens when + noise is nearest than this */ + snd_pcm_uframes_t silence_size; /* Silence filling size */ + snd_pcm_uframes_t boundary; /* pointers wrap point */ + + snd_pcm_uframes_t silenced_start; + snd_pcm_uframes_t silenced_size; + + snd_pcm_sync_id_t sync; /* hardware synchronization ID */ + + /* -- mmap -- */ + volatile struct snd_pcm_mmap_status *status; + volatile struct snd_pcm_mmap_control *control; + atomic_t mmap_count; + + /* -- locking / scheduling -- */ + spinlock_t lock; + wait_queue_head_t sleep; + struct timer_list tick_timer; + struct fasync_struct *fasync; + + /* -- private section -- */ + void *private_data; + void (*private_free)(struct snd_pcm_runtime *runtime); + + /* -- hardware description -- */ + struct snd_pcm_hardware hw; + struct snd_pcm_hw_constraints hw_constraints; + + /* -- interrupt callbacks -- */ + void (*transfer_ack_begin)(struct snd_pcm_substream *substream); + void (*transfer_ack_end)(struct snd_pcm_substream *substream); + + /* -- timer -- */ + unsigned int timer_resolution; /* timer resolution */ + + /* -- DMA -- */ + unsigned char *dma_area; /* DMA area */ + dma_addr_t dma_addr; /* physical bus address (not accessible from main CPU) */ + size_t dma_bytes; /* size of DMA area */ + + struct snd_dma_buffer *dma_buffer_p; /* allocated buffer */ + +#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE) + /* -- OSS things -- */ + struct snd_pcm_oss_runtime oss; +#endif +}; +]]> + </programlisting> + </informalexample> + </para> + + <para> + For the operators (callbacks) of each sound driver, most of + these records are supposed to be read-only. Only the PCM + middle-layer changes / updates them. The exceptions are + the hardware description (hw), interrupt callbacks + (transfer_ack_xxx), DMA buffer information, and the private + data. Besides, if you use the standard buffer allocation + method via <function>snd_pcm_lib_malloc_pages()</function>, + you don't need to set the DMA buffer information by yourself. + </para> + + <para> + In the sections below, important records are explained. + </para> + + <section id="pcm-interface-runtime-hw"> + <title>Hardware Description</title> + <para> + The hardware descriptor (struct <structname>snd_pcm_hardware</structname>) + contains the definitions of the fundamental hardware + configuration. Above all, you'll need to define this in + <link linkend="pcm-interface-operators-open-callback"><citetitle> + the open callback</citetitle></link>. + Note that the runtime instance holds the copy of the + descriptor, not the pointer to the existing descriptor. That + is, in the open callback, you can modify the copied descriptor + (<constant>runtime->hw</constant>) as you need. For example, if the maximum + number of channels is 1 only on some chip models, you can + still use the same hardware descriptor and change the + channels_max later: + <informalexample> + <programlisting> +<![CDATA[ + struct snd_pcm_runtime *runtime = substream->runtime; + ... + runtime->hw = snd_mychip_playback_hw; /* common definition */ + if (chip->model == VERY_OLD_ONE) + runtime->hw.channels_max = 1; +]]> + </programlisting> + </informalexample> + </para> + + <para> + Typically, you'll have a hardware descriptor as below: + <informalexample> + <programlisting> +<![CDATA[ + static struct snd_pcm_hardware snd_mychip_playback_hw = { + .info = (SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_BLOCK_TRANSFER | + SNDRV_PCM_INFO_MMAP_VALID), + .formats = SNDRV_PCM_FMTBIT_S16_LE, + .rates = SNDRV_PCM_RATE_8000_48000, + .rate_min = 8000, + .rate_max = 48000, + .channels_min = 2, + .channels_max = 2, + .buffer_bytes_max = 32768, + .period_bytes_min = 4096, + .period_bytes_max = 32768, + .periods_min = 1, + .periods_max = 1024, + }; +]]> + </programlisting> + </informalexample> + </para> + + <para> + <itemizedlist> + <listitem><para> + The <structfield>info</structfield> field contains the type and + capabilities of this pcm. The bit flags are defined in + <filename><sound/asound.h></filename> as + <constant>SNDRV_PCM_INFO_XXX</constant>. Here, at least, you + have to specify whether the mmap is supported and which + interleaved format is supported. + When the is supported, add the + <constant>SNDRV_PCM_INFO_MMAP</constant> flag here. When the + hardware supports the interleaved or the non-interleaved + formats, <constant>SNDRV_PCM_INFO_INTERLEAVED</constant> or + <constant>SNDRV_PCM_INFO_NONINTERLEAVED</constant> flag must + be set, respectively. If both are supported, you can set both, + too. + </para> + + <para> + In the above example, <constant>MMAP_VALID</constant> and + <constant>BLOCK_TRANSFER</constant> are specified for the OSS mmap + mode. Usually both are set. Of course, + <constant>MMAP_VALID</constant> is set only if the mmap is + really supported. + </para> + + <para> + The other possible flags are + <constant>SNDRV_PCM_INFO_PAUSE</constant> and + <constant>SNDRV_PCM_INFO_RESUME</constant>. The + <constant>PAUSE</constant> bit means that the pcm supports the + <quote>pause</quote> operation, while the + <constant>RESUME</constant> bit means that the pcm supports + the full <quote>suspend/resume</quote> operation. + If the <constant>PAUSE</constant> flag is set, + the <structfield>trigger</structfield> callback below + must handle the corresponding (pause push/release) commands. + The suspend/resume trigger commands can be defined even without + the <constant>RESUME</constant> flag. See <link + linkend="power-management"><citetitle> + Power Management</citetitle></link> section for details. + </para> + + <para> + When the PCM substreams can be synchronized (typically, + synchronized start/stop of a playback and a capture streams), + you can give <constant>SNDRV_PCM_INFO_SYNC_START</constant>, + too. In this case, you'll need to check the linked-list of + PCM substreams in the trigger callback. This will be + described in the later section. + </para> + </listitem> + + <listitem> + <para> + <structfield>formats</structfield> field contains the bit-flags + of supported formats (<constant>SNDRV_PCM_FMTBIT_XXX</constant>). + If the hardware supports more than one format, give all or'ed + bits. In the example above, the signed 16bit little-endian + format is specified. + </para> + </listitem> + + <listitem> + <para> + <structfield>rates</structfield> field contains the bit-flags of + supported rates (<constant>SNDRV_PCM_RATE_XXX</constant>). + When the chip supports continuous rates, pass + <constant>CONTINUOUS</constant> bit additionally. + The pre-defined rate bits are provided only for typical + rates. If your chip supports unconventional rates, you need to add + the <constant>KNOT</constant> bit and set up the hardware + constraint manually (explained later). + </para> + </listitem> + + <listitem> + <para> + <structfield>rate_min</structfield> and + <structfield>rate_max</structfield> define the minimum and + maximum sample rate. This should correspond somehow to + <structfield>rates</structfield> bits. + </para> + </listitem> + + <listitem> + <para> + <structfield>channel_min</structfield> and + <structfield>channel_max</structfield> + define, as you might already expected, the minimum and maximum + number of channels. + </para> + </listitem> + + <listitem> + <para> + <structfield>buffer_bytes_max</structfield> defines the + maximum buffer size in bytes. There is no + <structfield>buffer_bytes_min</structfield> field, since + it can be calculated from the minimum period size and the + minimum number of periods. + Meanwhile, <structfield>period_bytes_min</structfield> and + define the minimum and maximum size of the period in bytes. + <structfield>periods_max</structfield> and + <structfield>periods_min</structfield> define the maximum and + minimum number of periods in the buffer. + </para> + + <para> + The <quote>period</quote> is a term that corresponds to + a fragment in the OSS world. The period defines the size at + which a PCM interrupt is generated. This size strongly + depends on the hardware. + Generally, the smaller period size will give you more + interrupts, that is, more controls. + In the case of capture, this size defines the input latency. + On the other hand, the whole buffer size defines the + output latency for the playback direction. + </para> + </listitem> + + <listitem> + <para> + There is also a field <structfield>fifo_size</structfield>. + This specifies the size of the hardware FIFO, but currently it + is neither used in the driver nor in the alsa-lib. So, you + can ignore this field. + </para> + </listitem> + </itemizedlist> + </para> + </section> + + <section id="pcm-interface-runtime-config"> + <title>PCM Configurations</title> + <para> + Ok, let's go back again to the PCM runtime records. + The most frequently referred records in the runtime instance are + the PCM configurations. + The PCM configurations are stored in the runtime instance + after the application sends <type>hw_params</type> data via + alsa-lib. There are many fields copied from hw_params and + sw_params structs. For example, + <structfield>format</structfield> holds the format type + chosen by the application. This field contains the enum value + <constant>SNDRV_PCM_FORMAT_XXX</constant>. + </para> + + <para> + One thing to be noted is that the configured buffer and period + sizes are stored in <quote>frames</quote> in the runtime. + In the ALSA world, 1 frame = channels * samples-size. + For conversion between frames and bytes, you can use the + <function>frames_to_bytes()</function> and + <function>bytes_to_frames()</function> helper functions. + <informalexample> + <programlisting> +<![CDATA[ + period_bytes = frames_to_bytes(runtime, runtime->period_size); +]]> + </programlisting> + </informalexample> + </para> + + <para> + Also, many software parameters (sw_params) are + stored in frames, too. Please check the type of the field. + <type>snd_pcm_uframes_t</type> is for the frames as unsigned + integer while <type>snd_pcm_sframes_t</type> is for the frames + as signed integer. + </para> + </section> + + <section id="pcm-interface-runtime-dma"> + <title>DMA Buffer Information</title> + <para> + The DMA buffer is defined by the following four fields, + <structfield>dma_area</structfield>, + <structfield>dma_addr</structfield>, + <structfield>dma_bytes</structfield> and + <structfield>dma_private</structfield>. + The <structfield>dma_area</structfield> holds the buffer + pointer (the logical address). You can call + <function>memcpy</function> from/to + this pointer. Meanwhile, <structfield>dma_addr</structfield> + holds the physical address of the buffer. This field is + specified only when the buffer is a linear buffer. + <structfield>dma_bytes</structfield> holds the size of buffer + in bytes. <structfield>dma_private</structfield> is used for + the ALSA DMA allocator. + </para> + + <para> + If you use a standard ALSA function, + <function>snd_pcm_lib_malloc_pages()</function>, for + allocating the buffer, these fields are set by the ALSA middle + layer, and you should <emphasis>not</emphasis> change them by + yourself. You can read them but not write them. + On the other hand, if you want to allocate the buffer by + yourself, you'll need to manage it in hw_params callback. + At least, <structfield>dma_bytes</structfield> is mandatory. + <structfield>dma_area</structfield> is necessary when the + buffer is mmapped. If your driver doesn't support mmap, this + field is not necessary. <structfield>dma_addr</structfield> + is also optional. You can use + <structfield>dma_private</structfield> as you like, too. + </para> + </section> + + <section id="pcm-interface-runtime-status"> + <title>Running Status</title> + <para> + The running status can be referred via <constant>runtime->status</constant>. + This is the pointer to the struct <structname>snd_pcm_mmap_status</structname> + record. For example, you can get the current DMA hardware + pointer via <constant>runtime->status->hw_ptr</constant>. + </para> + + <para> + The DMA application pointer can be referred via + <constant>runtime->control</constant>, which points to the + struct <structname>snd_pcm_mmap_control</structname> record. + However, accessing directly to this value is not recommended. + </para> + </section> + + <section id="pcm-interface-runtime-private"> + <title>Private Data</title> + <para> + You can allocate a record for the substream and store it in + <constant>runtime->private_data</constant>. Usually, this + is done in + <link linkend="pcm-interface-operators-open-callback"><citetitle> + the open callback</citetitle></link>. + Don't mix this with <constant>pcm->private_data</constant>. + The <constant>pcm->private_data</constant> usually points to the + chip instance assigned statically at the creation of PCM, while the + <constant>runtime->private_data</constant> points to a dynamic + data structure created at the PCM open callback. + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_open(struct snd_pcm_substream *substream) + { + struct my_pcm_data *data; + .... + data = kmalloc(sizeof(*data), GFP_KERNEL); + substream->runtime->private_data = data; + .... + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + The allocated object must be released in + <link linkend="pcm-interface-operators-open-callback"><citetitle> + the close callback</citetitle></link>. + </para> + </section> + + <section id="pcm-interface-runtime-intr"> + <title>Interrupt Callbacks</title> + <para> + The field <structfield>transfer_ack_begin</structfield> and + <structfield>transfer_ack_end</structfield> are called at + the beginning and at the end of + <function>snd_pcm_period_elapsed()</function>, respectively. + </para> + </section> + + </section> + + <section id="pcm-interface-operators"> + <title>Operators</title> + <para> + OK, now let me give details about each pcm callback + (<parameter>ops</parameter>). In general, every callback must + return 0 if successful, or a negative error number + such as <constant>-EINVAL</constant>. To choose an appropriate + error number, it is advised to check what value other parts of + the kernel return when the same kind of request fails. + </para> + + <para> + The callback function takes at least the argument with + <structname>snd_pcm_substream</structname> pointer. To retrieve + the chip record from the given substream instance, you can use the + following macro. + + <informalexample> + <programlisting> +<![CDATA[ + int xxx() { + struct mychip *chip = snd_pcm_substream_chip(substream); + .... + } +]]> + </programlisting> + </informalexample> + + The macro reads <constant>substream->private_data</constant>, + which is a copy of <constant>pcm->private_data</constant>. + You can override the former if you need to assign different data + records per PCM substream. For example, the cmi8330 driver assigns + different private_data for playback and capture directions, + because it uses two different codecs (SB- and AD-compatible) for + different directions. + </para> + + <section id="pcm-interface-operators-open-callback"> + <title>open callback</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_open(struct snd_pcm_substream *substream); +]]> + </programlisting> + </informalexample> + + This is called when a pcm substream is opened. + </para> + + <para> + At least, here you have to initialize the runtime->hw + record. Typically, this is done by like this: + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_open(struct snd_pcm_substream *substream) + { + struct mychip *chip = snd_pcm_substream_chip(substream); + struct snd_pcm_runtime *runtime = substream->runtime; + + runtime->hw = snd_mychip_playback_hw; + return 0; + } +]]> + </programlisting> + </informalexample> + + where <parameter>snd_mychip_playback_hw</parameter> is the + pre-defined hardware description. + </para> + + <para> + You can allocate a private data in this callback, as described + in <link linkend="pcm-interface-runtime-private"><citetitle> + Private Data</citetitle></link> section. + </para> + + <para> + If the hardware configuration needs more constraints, set the + hardware constraints here, too. + See <link linkend="pcm-interface-constraints"><citetitle> + Constraints</citetitle></link> for more details. + </para> + </section> + + <section id="pcm-interface-operators-close-callback"> + <title>close callback</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_close(struct snd_pcm_substream *substream); +]]> + </programlisting> + </informalexample> + + Obviously, this is called when a pcm substream is closed. + </para> + + <para> + Any private instance for a pcm substream allocated in the + open callback will be released here. + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_close(struct snd_pcm_substream *substream) + { + .... + kfree(substream->runtime->private_data); + .... + } +]]> + </programlisting> + </informalexample> + </para> + </section> + + <section id="pcm-interface-operators-ioctl-callback"> + <title>ioctl callback</title> + <para> + This is used for any special call to pcm ioctls. But + usually you can pass a generic ioctl callback, + <function>snd_pcm_lib_ioctl</function>. + </para> + </section> + + <section id="pcm-interface-operators-hw-params-callback"> + <title>hw_params callback</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_hw_params(struct snd_pcm_substream *substream, + struct snd_pcm_hw_params *hw_params); +]]> + </programlisting> + </informalexample> + </para> + + <para> + This is called when the hardware parameter + (<structfield>hw_params</structfield>) is set + up by the application, + that is, once when the buffer size, the period size, the + format, etc. are defined for the pcm substream. + </para> + + <para> + Many hardware setups should be done in this callback, + including the allocation of buffers. + </para> + + <para> + Parameters to be initialized are retrieved by + <function>params_xxx()</function> macros. To allocate + buffer, you can call a helper function, + + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params)); +]]> + </programlisting> + </informalexample> + + <function>snd_pcm_lib_malloc_pages()</function> is available + only when the DMA buffers have been pre-allocated. + See the section <link + linkend="buffer-and-memory-buffer-types"><citetitle> + Buffer Types</citetitle></link> for more details. + </para> + + <para> + Note that this and <structfield>prepare</structfield> callbacks + may be called multiple times per initialization. + For example, the OSS emulation may + call these callbacks at each change via its ioctl. + </para> + + <para> + Thus, you need to be careful not to allocate the same buffers + many times, which will lead to memory leaks! Calling the + helper function above many times is OK. It will release the + previous buffer automatically when it was already allocated. + </para> + + <para> + Another note is that this callback is non-atomic + (schedulable). This is important, because the + <structfield>trigger</structfield> callback + is atomic (non-schedulable). That is, mutexes or any + schedule-related functions are not available in + <structfield>trigger</structfield> callback. + Please see the subsection + <link linkend="pcm-interface-atomicity"><citetitle> + Atomicity</citetitle></link> for details. + </para> + </section> + + <section id="pcm-interface-operators-hw-free-callback"> + <title>hw_free callback</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_hw_free(struct snd_pcm_substream *substream); +]]> + </programlisting> + </informalexample> + </para> + + <para> + This is called to release the resources allocated via + <structfield>hw_params</structfield>. For example, releasing the + buffer via + <function>snd_pcm_lib_malloc_pages()</function> is done by + calling the following: + + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_lib_free_pages(substream); +]]> + </programlisting> + </informalexample> + </para> + + <para> + This function is always called before the close callback is called. + Also, the callback may be called multiple times, too. + Keep track whether the resource was already released. + </para> + </section> + + <section id="pcm-interface-operators-prepare-callback"> + <title>prepare callback</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_prepare(struct snd_pcm_substream *substream); +]]> + </programlisting> + </informalexample> + </para> + + <para> + This callback is called when the pcm is + <quote>prepared</quote>. You can set the format type, sample + rate, etc. here. The difference from + <structfield>hw_params</structfield> is that the + <structfield>prepare</structfield> callback will be called each + time + <function>snd_pcm_prepare()</function> is called, i.e. when + recovering after underruns, etc. + </para> + + <para> + Note that this callback is now non-atomic. + You can use schedule-related functions safely in this callback. + </para> + + <para> + In this and the following callbacks, you can refer to the + values via the runtime record, + substream->runtime. + For example, to get the current + rate, format or channels, access to + runtime->rate, + runtime->format or + runtime->channels, respectively. + The physical address of the allocated buffer is set to + runtime->dma_area. The buffer and period sizes are + in runtime->buffer_size and runtime->period_size, + respectively. + </para> + + <para> + Be careful that this callback will be called many times at + each setup, too. + </para> + </section> + + <section id="pcm-interface-operators-trigger-callback"> + <title>trigger callback</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_trigger(struct snd_pcm_substream *substream, int cmd); +]]> + </programlisting> + </informalexample> + + This is called when the pcm is started, stopped or paused. + </para> + + <para> + Which action is specified in the second argument, + <constant>SNDRV_PCM_TRIGGER_XXX</constant> in + <filename><sound/pcm.h></filename>. At least, + the <constant>START</constant> and <constant>STOP</constant> + commands must be defined in this callback. + + <informalexample> + <programlisting> +<![CDATA[ + switch (cmd) { + case SNDRV_PCM_TRIGGER_START: + /* do something to start the PCM engine */ + break; + case SNDRV_PCM_TRIGGER_STOP: + /* do something to stop the PCM engine */ + break; + default: + return -EINVAL; + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + When the pcm supports the pause operation (given in the info + field of the hardware table), the <constant>PAUSE_PUSE</constant> + and <constant>PAUSE_RELEASE</constant> commands must be + handled here, too. The former is the command to pause the pcm, + and the latter to restart the pcm again. + </para> + + <para> + When the pcm supports the suspend/resume operation, + regardless of full or partial suspend/resume support, + the <constant>SUSPEND</constant> and <constant>RESUME</constant> + commands must be handled, too. + These commands are issued when the power-management status is + changed. Obviously, the <constant>SUSPEND</constant> and + <constant>RESUME</constant> commands + suspend and resume the pcm substream, and usually, they + are identical to the <constant>STOP</constant> and + <constant>START</constant> commands, respectively. + See the <link linkend="power-management"><citetitle> + Power Management</citetitle></link> section for details. + </para> + + <para> + As mentioned, this callback is atomic. You cannot call + functions which may sleep. + The trigger callback should be as minimal as possible, + just really triggering the DMA. The other stuff should be + initialized hw_params and prepare callbacks properly + beforehand. + </para> + </section> + + <section id="pcm-interface-operators-pointer-callback"> + <title>pointer callback</title> + <para> + <informalexample> + <programlisting> +<![CDATA[ + static snd_pcm_uframes_t snd_xxx_pointer(struct snd_pcm_substream *substream) +]]> + </programlisting> + </informalexample> + + This callback is called when the PCM middle layer inquires + the current hardware position on the buffer. The position must + be returned in frames, + ranging from 0 to buffer_size - 1. + </para> + + <para> + This is called usually from the buffer-update routine in the + pcm middle layer, which is invoked when + <function>snd_pcm_period_elapsed()</function> is called in the + interrupt routine. Then the pcm middle layer updates the + position and calculates the available space, and wakes up the + sleeping poll threads, etc. + </para> + + <para> + This callback is also atomic. + </para> + </section> + + <section id="pcm-interface-operators-copy-silence"> + <title>copy and silence callbacks</title> + <para> + These callbacks are not mandatory, and can be omitted in + most cases. These callbacks are used when the hardware buffer + cannot be in the normal memory space. Some chips have their + own buffer on the hardware which is not mappable. In such a + case, you have to transfer the data manually from the memory + buffer to the hardware buffer. Or, if the buffer is + non-contiguous on both physical and virtual memory spaces, + these callbacks must be defined, too. + </para> + + <para> + If these two callbacks are defined, copy and set-silence + operations are done by them. The detailed will be described in + the later section <link + linkend="buffer-and-memory"><citetitle>Buffer and Memory + Management</citetitle></link>. + </para> + </section> + + <section id="pcm-interface-operators-ack"> + <title>ack callback</title> + <para> + This callback is also not mandatory. This callback is called + when the appl_ptr is updated in read or write operations. + Some drivers like emu10k1-fx and cs46xx need to track the + current appl_ptr for the internal buffer, and this callback + is useful only for such a purpose. + </para> + <para> + This callback is atomic. + </para> + </section> + + <section id="pcm-interface-operators-page-callback"> + <title>page callback</title> + + <para> + This callback is optional too. This callback is used + mainly for non-contiguous buffers. The mmap calls this + callback to get the page address. Some examples will be + explained in the later section <link + linkend="buffer-and-memory"><citetitle>Buffer and Memory + Management</citetitle></link>, too. + </para> + </section> + </section> + + <section id="pcm-interface-interrupt-handler"> + <title>Interrupt Handler</title> + <para> + The rest of pcm stuff is the PCM interrupt handler. The + role of PCM interrupt handler in the sound driver is to update + the buffer position and to tell the PCM middle layer when the + buffer position goes across the prescribed period size. To + inform this, call the <function>snd_pcm_period_elapsed()</function> + function. + </para> + + <para> + There are several types of sound chips to generate the interrupts. + </para> + + <section id="pcm-interface-interrupt-handler-boundary"> + <title>Interrupts at the period (fragment) boundary</title> + <para> + This is the most frequently found type: the hardware + generates an interrupt at each period boundary. + In this case, you can call + <function>snd_pcm_period_elapsed()</function> at each + interrupt. + </para> + + <para> + <function>snd_pcm_period_elapsed()</function> takes the + substream pointer as its argument. Thus, you need to keep the + substream pointer accessible from the chip instance. For + example, define substream field in the chip record to hold the + current running substream pointer, and set the pointer value + at open callback (and reset at close callback). + </para> + + <para> + If you acquire a spinlock in the interrupt handler, and the + lock is used in other pcm callbacks, too, then you have to + release the lock before calling + <function>snd_pcm_period_elapsed()</function>, because + <function>snd_pcm_period_elapsed()</function> calls other pcm + callbacks inside. + </para> + + <para> + Typical code would be like: + + <example> + <title>Interrupt Handler Case #1</title> + <programlisting> +<![CDATA[ + static irqreturn_t snd_mychip_interrupt(int irq, void *dev_id) + { + struct mychip *chip = dev_id; + spin_lock(&chip->lock); + .... + if (pcm_irq_invoked(chip)) { + /* call updater, unlock before it */ + spin_unlock(&chip->lock); + snd_pcm_period_elapsed(chip->substream); + spin_lock(&chip->lock); + /* acknowledge the interrupt if necessary */ + } + .... + spin_unlock(&chip->lock); + return IRQ_HANDLED; + } +]]> + </programlisting> + </example> + </para> + </section> + + <section id="pcm-interface-interrupt-handler-timer"> + <title>High frequency timer interrupts</title> + <para> + This happense when the hardware doesn't generate interrupts + at the period boundary but issues timer interrupts at a fixed + timer rate (e.g. es1968 or ymfpci drivers). + In this case, you need to check the current hardware + position and accumulate the processed sample length at each + interrupt. When the accumulated size exceeds the period + size, call + <function>snd_pcm_period_elapsed()</function> and reset the + accumulator. + </para> + + <para> + Typical code would be like the following. + + <example> + <title>Interrupt Handler Case #2</title> + <programlisting> +<![CDATA[ + static irqreturn_t snd_mychip_interrupt(int irq, void *dev_id) + { + struct mychip *chip = dev_id; + spin_lock(&chip->lock); + .... + if (pcm_irq_invoked(chip)) { + unsigned int last_ptr, size; + /* get the current hardware pointer (in frames) */ + last_ptr = get_hw_ptr(chip); + /* calculate the processed frames since the + * last update + */ + if (last_ptr < chip->last_ptr) + size = runtime->buffer_size + last_ptr + - chip->last_ptr; + else + size = last_ptr - chip->last_ptr; + /* remember the last updated point */ + chip->last_ptr = last_ptr; + /* accumulate the size */ + chip->size += size; + /* over the period boundary? */ + if (chip->size >= runtime->period_size) { + /* reset the accumulator */ + chip->size %= runtime->period_size; + /* call updater */ + spin_unlock(&chip->lock); + snd_pcm_period_elapsed(substream); + spin_lock(&chip->lock); + } + /* acknowledge the interrupt if necessary */ + } + .... + spin_unlock(&chip->lock); + return IRQ_HANDLED; + } +]]> + </programlisting> + </example> + </para> + </section> + + <section id="pcm-interface-interrupt-handler-both"> + <title>On calling <function>snd_pcm_period_elapsed()</function></title> + <para> + In both cases, even if more than one period are elapsed, you + don't have to call + <function>snd_pcm_period_elapsed()</function> many times. Call + only once. And the pcm layer will check the current hardware + pointer and update to the latest status. + </para> + </section> + </section> + + <section id="pcm-interface-atomicity"> + <title>Atomicity</title> + <para> + One of the most important (and thus difficult to debug) problems + in kernel programming are race conditions. + In the Linux kernel, they are usually avoided via spin-locks, mutexes + or semaphores. In general, if a race condition can happen + in an interrupt handler, it has to be managed atomically, and you + have to use a spinlock to protect the critical session. If the + critical section is not in interrupt handler code and + if taking a relatively long time to execute is acceptable, you + should use mutexes or semaphores instead. + </para> + + <para> + As already seen, some pcm callbacks are atomic and some are + not. For example, the <parameter>hw_params</parameter> callback is + non-atomic, while <parameter>trigger</parameter> callback is + atomic. This means, the latter is called already in a spinlock + held by the PCM middle layer. Please take this atomicity into + account when you choose a locking scheme in the callbacks. + </para> + + <para> + In the atomic callbacks, you cannot use functions which may call + <function>schedule</function> or go to + <function>sleep</function>. Semaphores and mutexes can sleep, + and hence they cannot be used inside the atomic callbacks + (e.g. <parameter>trigger</parameter> callback). + To implement some delay in such a callback, please use + <function>udelay()</function> or <function>mdelay()</function>. + </para> + + <para> + All three atomic callbacks (trigger, pointer, and ack) are + called with local interrupts disabled. + </para> + + </section> + <section id="pcm-interface-constraints"> + <title>Constraints</title> + <para> + If your chip supports unconventional sample rates, or only the + limited samples, you need to set a constraint for the + condition. + </para> + + <para> + For example, in order to restrict the sample rates in the some + supported values, use + <function>snd_pcm_hw_constraint_list()</function>. + You need to call this function in the open callback. + + <example> + <title>Example of Hardware Constraints</title> + <programlisting> +<![CDATA[ + static unsigned int rates[] = + {4000, 10000, 22050, 44100}; + static struct snd_pcm_hw_constraint_list constraints_rates = { + .count = ARRAY_SIZE(rates), + .list = rates, + .mask = 0, + }; + + static int snd_mychip_pcm_open(struct snd_pcm_substream *substream) + { + int err; + .... + err = snd_pcm_hw_constraint_list(substream->runtime, 0, + SNDRV_PCM_HW_PARAM_RATE, + &constraints_rates); + if (err < 0) + return err; + .... + } +]]> + </programlisting> + </example> + </para> + + <para> + There are many different constraints. + Look at <filename>sound/pcm.h</filename> for a complete list. + You can even define your own constraint rules. + For example, let's suppose my_chip can manage a substream of 1 channel + if and only if the format is S16_LE, otherwise it supports any format + specified in the <structname>snd_pcm_hardware</structname> structure (or in any + other constraint_list). You can build a rule like this: + + <example> + <title>Example of Hardware Constraints for Channels</title> + <programlisting> +<![CDATA[ + static int hw_rule_format_by_channels(struct snd_pcm_hw_params *params, + struct snd_pcm_hw_rule *rule) + { + struct snd_interval *c = hw_param_interval(params, + SNDRV_PCM_HW_PARAM_CHANNELS); + struct snd_mask *f = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT); + struct snd_mask fmt; + + snd_mask_any(&fmt); /* Init the struct */ + if (c->min < 2) { + fmt.bits[0] &= SNDRV_PCM_FMTBIT_S16_LE; + return snd_mask_refine(f, &fmt); + } + return 0; + } +]]> + </programlisting> + </example> + </para> + + <para> + Then you need to call this function to add your rule: + + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_hw_rule_add(substream->runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS, + hw_rule_channels_by_format, 0, SNDRV_PCM_HW_PARAM_FORMAT, + -1); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The rule function is called when an application sets the number of + channels. But an application can set the format before the number of + channels. Thus you also need to define the inverse rule: + + <example> + <title>Example of Hardware Constraints for Channels</title> + <programlisting> +<![CDATA[ + static int hw_rule_channels_by_format(struct snd_pcm_hw_params *params, + struct snd_pcm_hw_rule *rule) + { + struct snd_interval *c = hw_param_interval(params, + SNDRV_PCM_HW_PARAM_CHANNELS); + struct snd_mask *f = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT); + struct snd_interval ch; + + snd_interval_any(&ch); + if (f->bits[0] == SNDRV_PCM_FMTBIT_S16_LE) { + ch.min = ch.max = 1; + ch.integer = 1; + return snd_interval_refine(c, &ch); + } + return 0; + } +]]> + </programlisting> + </example> + </para> + + <para> + ...and in the open callback: + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_hw_rule_add(substream->runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT, + hw_rule_format_by_channels, 0, SNDRV_PCM_HW_PARAM_CHANNELS, + -1); +]]> + </programlisting> + </informalexample> + </para> + + <para> + I won't give more details here, rather I + would like to say, <quote>Luke, use the source.</quote> + </para> + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- Control Interface --> +<!-- ****************************************************** --> + <chapter id="control-interface"> + <title>Control Interface</title> + + <section id="control-interface-general"> + <title>General</title> + <para> + The control interface is used widely for many switches, + sliders, etc. which are accessed from user-space. Its most + important use is the mixer interface. In other words, since ALSA + 0.9.x, all the mixer stuff is implemented on the control kernel API. + </para> + + <para> + ALSA has a well-defined AC97 control module. If your chip + supports only the AC97 and nothing else, you can skip this + section. + </para> + + <para> + The control API is defined in + <filename><sound/control.h></filename>. + Include this file if you want to add your own controls. + </para> + </section> + + <section id="control-interface-definition"> + <title>Definition of Controls</title> + <para> + To create a new control, you need to define the + following three + callbacks: <structfield>info</structfield>, + <structfield>get</structfield> and + <structfield>put</structfield>. Then, define a + struct <structname>snd_kcontrol_new</structname> record, such as: + + <example> + <title>Definition of a Control</title> + <programlisting> +<![CDATA[ + static struct snd_kcontrol_new my_control __devinitdata = { + .iface = SNDRV_CTL_ELEM_IFACE_MIXER, + .name = "PCM Playback Switch", + .index = 0, + .access = SNDRV_CTL_ELEM_ACCESS_READWRITE, + .private_value = 0xffff, + .info = my_control_info, + .get = my_control_get, + .put = my_control_put + }; +]]> + </programlisting> + </example> + </para> + + <para> + Most likely the control is created via + <function>snd_ctl_new1()</function>, and in such a case, you can + add the <parameter>__devinitdata</parameter> prefix to the + definition as above. + </para> + + <para> + The <structfield>iface</structfield> field specifies the control + type, <constant>SNDRV_CTL_ELEM_IFACE_XXX</constant>, which + is usually <constant>MIXER</constant>. + Use <constant>CARD</constant> for global controls that are not + logically part of the mixer. + If the control is closely associated with some specific device on + the sound card, use <constant>HWDEP</constant>, + <constant>PCM</constant>, <constant>RAWMIDI</constant>, + <constant>TIMER</constant>, or <constant>SEQUENCER</constant>, and + specify the device number with the + <structfield>device</structfield> and + <structfield>subdevice</structfield> fields. + </para> + + <para> + The <structfield>name</structfield> is the name identifier + string. Since ALSA 0.9.x, the control name is very important, + because its role is classified from its name. There are + pre-defined standard control names. The details are described in + the <link linkend="control-interface-control-names"><citetitle> + Control Names</citetitle></link> subsection. + </para> + + <para> + The <structfield>index</structfield> field holds the index number + of this control. If there are several different controls with + the same name, they can be distinguished by the index + number. This is the case when + several codecs exist on the card. If the index is zero, you can + omit the definition above. + </para> + + <para> + The <structfield>access</structfield> field contains the access + type of this control. Give the combination of bit masks, + <constant>SNDRV_CTL_ELEM_ACCESS_XXX</constant>, there. + The details will be explained in + the <link linkend="control-interface-access-flags"><citetitle> + Access Flags</citetitle></link> subsection. + </para> + + <para> + The <structfield>private_value</structfield> field contains + an arbitrary long integer value for this record. When using + the generic <structfield>info</structfield>, + <structfield>get</structfield> and + <structfield>put</structfield> callbacks, you can pass a value + through this field. If several small numbers are necessary, you can + combine them in bitwise. Or, it's possible to give a pointer + (casted to unsigned long) of some record to this field, too. + </para> + + <para> + The <structfield>tlv</structfield> field can be used to provide + metadata about the control; see the + <link linkend="control-interface-tlv"> + <citetitle>Metadata</citetitle></link> subsection. + </para> + + <para> + The other three are + <link linkend="control-interface-callbacks"><citetitle> + callback functions</citetitle></link>. + </para> + </section> + + <section id="control-interface-control-names"> + <title>Control Names</title> + <para> + There are some standards to define the control names. A + control is usually defined from the three parts as + <quote>SOURCE DIRECTION FUNCTION</quote>. + </para> + + <para> + The first, <constant>SOURCE</constant>, specifies the source + of the control, and is a string such as <quote>Master</quote>, + <quote>PCM</quote>, <quote>CD</quote> and + <quote>Line</quote>. There are many pre-defined sources. + </para> + + <para> + The second, <constant>DIRECTION</constant>, is one of the + following strings according to the direction of the control: + <quote>Playback</quote>, <quote>Capture</quote>, <quote>Bypass + Playback</quote> and <quote>Bypass Capture</quote>. Or, it can + be omitted, meaning both playback and capture directions. + </para> + + <para> + The third, <constant>FUNCTION</constant>, is one of the + following strings according to the function of the control: + <quote>Switch</quote>, <quote>Volume</quote> and + <quote>Route</quote>. + </para> + + <para> + The example of control names are, thus, <quote>Master Capture + Switch</quote> or <quote>PCM Playback Volume</quote>. + </para> + + <para> + There are some exceptions: + </para> + + <section id="control-interface-control-names-global"> + <title>Global capture and playback</title> + <para> + <quote>Capture Source</quote>, <quote>Capture Switch</quote> + and <quote>Capture Volume</quote> are used for the global + capture (input) source, switch and volume. Similarly, + <quote>Playback Switch</quote> and <quote>Playback + Volume</quote> are used for the global output gain switch and + volume. + </para> + </section> + + <section id="control-interface-control-names-tone"> + <title>Tone-controls</title> + <para> + tone-control switch and volumes are specified like + <quote>Tone Control - XXX</quote>, e.g. <quote>Tone Control - + Switch</quote>, <quote>Tone Control - Bass</quote>, + <quote>Tone Control - Center</quote>. + </para> + </section> + + <section id="control-interface-control-names-3d"> + <title>3D controls</title> + <para> + 3D-control switches and volumes are specified like <quote>3D + Control - XXX</quote>, e.g. <quote>3D Control - + Switch</quote>, <quote>3D Control - Center</quote>, <quote>3D + Control - Space</quote>. + </para> + </section> + + <section id="control-interface-control-names-mic"> + <title>Mic boost</title> + <para> + Mic-boost switch is set as <quote>Mic Boost</quote> or + <quote>Mic Boost (6dB)</quote>. + </para> + + <para> + More precise information can be found in + <filename>Documentation/sound/alsa/ControlNames.txt</filename>. + </para> + </section> + </section> + + <section id="control-interface-access-flags"> + <title>Access Flags</title> + + <para> + The access flag is the bitmask which specifies the access type + of the given control. The default access type is + <constant>SNDRV_CTL_ELEM_ACCESS_READWRITE</constant>, + which means both read and write are allowed to this control. + When the access flag is omitted (i.e. = 0), it is + considered as <constant>READWRITE</constant> access as default. + </para> + + <para> + When the control is read-only, pass + <constant>SNDRV_CTL_ELEM_ACCESS_READ</constant> instead. + In this case, you don't have to define + the <structfield>put</structfield> callback. + Similarly, when the control is write-only (although it's a rare + case), you can use the <constant>WRITE</constant> flag instead, and + you don't need the <structfield>get</structfield> callback. + </para> + + <para> + If the control value changes frequently (e.g. the VU meter), + <constant>VOLATILE</constant> flag should be given. This means + that the control may be changed without + <link linkend="control-interface-change-notification"><citetitle> + notification</citetitle></link>. Applications should poll such + a control constantly. + </para> + + <para> + When the control is inactive, set + the <constant>INACTIVE</constant> flag, too. + There are <constant>LOCK</constant> and + <constant>OWNER</constant> flags to change the write + permissions. + </para> + + </section> + + <section id="control-interface-callbacks"> + <title>Callbacks</title> + + <section id="control-interface-callbacks-info"> + <title>info callback</title> + <para> + The <structfield>info</structfield> callback is used to get + detailed information on this control. This must store the + values of the given struct <structname>snd_ctl_elem_info</structname> + object. For example, for a boolean control with a single + element: + + <example> + <title>Example of info callback</title> + <programlisting> +<![CDATA[ + static int snd_myctl_mono_info(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_info *uinfo) + { + uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN; + uinfo->count = 1; + uinfo->value.integer.min = 0; + uinfo->value.integer.max = 1; + return 0; + } +]]> + </programlisting> + </example> + </para> + + <para> + The <structfield>type</structfield> field specifies the type + of the control. There are <constant>BOOLEAN</constant>, + <constant>INTEGER</constant>, <constant>ENUMERATED</constant>, + <constant>BYTES</constant>, <constant>IEC958</constant> and + <constant>INTEGER64</constant>. The + <structfield>count</structfield> field specifies the + number of elements in this control. For example, a stereo + volume would have count = 2. The + <structfield>value</structfield> field is a union, and + the values stored are depending on the type. The boolean and + integer types are identical. + </para> + + <para> + The enumerated type is a bit different from others. You'll + need to set the string for the currently given item index. + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_myctl_enum_info(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_info *uinfo) + { + static char *texts[4] = { + "First", "Second", "Third", "Fourth" + }; + uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED; + uinfo->count = 1; + uinfo->value.enumerated.items = 4; + if (uinfo->value.enumerated.item > 3) + uinfo->value.enumerated.item = 3; + strcpy(uinfo->value.enumerated.name, + texts[uinfo->value.enumerated.item]); + return 0; + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + Some common info callbacks are available for your convenience: + <function>snd_ctl_boolean_mono_info()</function> and + <function>snd_ctl_boolean_stereo_info()</function>. + Obviously, the former is an info callback for a mono channel + boolean item, just like <function>snd_myctl_mono_info</function> + above, and the latter is for a stereo channel boolean item. + </para> + + </section> + + <section id="control-interface-callbacks-get"> + <title>get callback</title> + + <para> + This callback is used to read the current value of the + control and to return to user-space. + </para> + + <para> + For example, + + <example> + <title>Example of get callback</title> + <programlisting> +<![CDATA[ + static int snd_myctl_get(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_value *ucontrol) + { + struct mychip *chip = snd_kcontrol_chip(kcontrol); + ucontrol->value.integer.value[0] = get_some_value(chip); + return 0; + } +]]> + </programlisting> + </example> + </para> + + <para> + The <structfield>value</structfield> field depends on + the type of control as well as on the info callback. For example, + the sb driver uses this field to store the register offset, + the bit-shift and the bit-mask. The + <structfield>private_value</structfield> field is set as follows: + <informalexample> + <programlisting> +<![CDATA[ + .private_value = reg | (shift << 16) | (mask << 24) +]]> + </programlisting> + </informalexample> + and is retrieved in callbacks like + <informalexample> + <programlisting> +<![CDATA[ + static int snd_sbmixer_get_single(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_value *ucontrol) + { + int reg = kcontrol->private_value & 0xff; + int shift = (kcontrol->private_value >> 16) & 0xff; + int mask = (kcontrol->private_value >> 24) & 0xff; + .... + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + In the <structfield>get</structfield> callback, + you have to fill all the elements if the + control has more than one elements, + i.e. <structfield>count</structfield> > 1. + In the example above, we filled only one element + (<structfield>value.integer.value[0]</structfield>) since it's + assumed as <structfield>count</structfield> = 1. + </para> + </section> + + <section id="control-interface-callbacks-put"> + <title>put callback</title> + + <para> + This callback is used to write a value from user-space. + </para> + + <para> + For example, + + <example> + <title>Example of put callback</title> + <programlisting> +<![CDATA[ + static int snd_myctl_put(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_value *ucontrol) + { + struct mychip *chip = snd_kcontrol_chip(kcontrol); + int changed = 0; + if (chip->current_value != + ucontrol->value.integer.value[0]) { + change_current_value(chip, + ucontrol->value.integer.value[0]); + changed = 1; + } + return changed; + } +]]> + </programlisting> + </example> + + As seen above, you have to return 1 if the value is + changed. If the value is not changed, return 0 instead. + If any fatal error happens, return a negative error code as + usual. + </para> + + <para> + As in the <structfield>get</structfield> callback, + when the control has more than one elements, + all elements must be evaluated in this callback, too. + </para> + </section> + + <section id="control-interface-callbacks-all"> + <title>Callbacks are not atomic</title> + <para> + All these three callbacks are basically not atomic. + </para> + </section> + </section> + + <section id="control-interface-constructor"> + <title>Constructor</title> + <para> + When everything is ready, finally we can create a new + control. To create a control, there are two functions to be + called, <function>snd_ctl_new1()</function> and + <function>snd_ctl_add()</function>. + </para> + + <para> + In the simplest way, you can do like this: + + <informalexample> + <programlisting> +<![CDATA[ + err = snd_ctl_add(card, snd_ctl_new1(&my_control, chip)); + if (err < 0) + return err; +]]> + </programlisting> + </informalexample> + + where <parameter>my_control</parameter> is the + struct <structname>snd_kcontrol_new</structname> object defined above, and chip + is the object pointer to be passed to + kcontrol->private_data + which can be referred to in callbacks. + </para> + + <para> + <function>snd_ctl_new1()</function> allocates a new + <structname>snd_kcontrol</structname> instance (that's why the definition + of <parameter>my_control</parameter> can be with + the <parameter>__devinitdata</parameter> + prefix), and <function>snd_ctl_add</function> assigns the given + control component to the card. + </para> + </section> + + <section id="control-interface-change-notification"> + <title>Change Notification</title> + <para> + If you need to change and update a control in the interrupt + routine, you can call <function>snd_ctl_notify()</function>. For + example, + + <informalexample> + <programlisting> +<![CDATA[ + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, id_pointer); +]]> + </programlisting> + </informalexample> + + This function takes the card pointer, the event-mask, and the + control id pointer for the notification. The event-mask + specifies the types of notification, for example, in the above + example, the change of control values is notified. + The id pointer is the pointer of struct <structname>snd_ctl_elem_id</structname> + to be notified. + You can find some examples in <filename>es1938.c</filename> or + <filename>es1968.c</filename> for hardware volume interrupts. + </para> + </section> + + <section id="control-interface-tlv"> + <title>Metadata</title> + <para> + To provide information about the dB values of a mixer control, use + on of the <constant>DECLARE_TLV_xxx</constant> macros from + <filename><sound/tlv.h></filename> to define a variable + containing this information, set the<structfield>tlv.p + </structfield> field to point to this variable, and include the + <constant>SNDRV_CTL_ELEM_ACCESS_TLV_READ</constant> flag in the + <structfield>access</structfield> field; like this: + <informalexample> + <programlisting> +<![CDATA[ + static DECLARE_TLV_DB_SCALE(db_scale_my_control, -4050, 150, 0); + + static struct snd_kcontrol_new my_control __devinitdata = { + ... + .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | + SNDRV_CTL_ELEM_ACCESS_TLV_READ, + ... + .tlv.p = db_scale_my_control, + }; +]]> + </programlisting> + </informalexample> + </para> + + <para> + The <function>DECLARE_TLV_DB_SCALE</function> macro defines + information about a mixer control where each step in the control's + value changes the dB value by a constant dB amount. + The first parameter is the name of the variable to be defined. + The second parameter is the minimum value, in units of 0.01 dB. + The third parameter is the step size, in units of 0.01 dB. + Set the fourth parameter to 1 if the minimum value actually mutes + the control. + </para> + + <para> + The <function>DECLARE_TLV_DB_LINEAR</function> macro defines + information about a mixer control where the control's value affects + the output linearly. + The first parameter is the name of the variable to be defined. + The second parameter is the minimum value, in units of 0.01 dB. + The third parameter is the maximum value, in units of 0.01 dB. + If the minimum value mutes the control, set the second parameter to + <constant>TLV_DB_GAIN_MUTE</constant>. + </para> + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- API for AC97 Codec --> +<!-- ****************************************************** --> + <chapter id="api-ac97"> + <title>API for AC97 Codec</title> + + <section> + <title>General</title> + <para> + The ALSA AC97 codec layer is a well-defined one, and you don't + have to write much code to control it. Only low-level control + routines are necessary. The AC97 codec API is defined in + <filename><sound/ac97_codec.h></filename>. + </para> + </section> + + <section id="api-ac97-example"> + <title>Full Code Example</title> + <para> + <example> + <title>Example of AC97 Interface</title> + <programlisting> +<![CDATA[ + struct mychip { + .... + struct snd_ac97 *ac97; + .... + }; + + static unsigned short snd_mychip_ac97_read(struct snd_ac97 *ac97, + unsigned short reg) + { + struct mychip *chip = ac97->private_data; + .... + /* read a register value here from the codec */ + return the_register_value; + } + + static void snd_mychip_ac97_write(struct snd_ac97 *ac97, + unsigned short reg, unsigned short val) + { + struct mychip *chip = ac97->private_data; + .... + /* write the given register value to the codec */ + } + + static int snd_mychip_ac97(struct mychip *chip) + { + struct snd_ac97_bus *bus; + struct snd_ac97_template ac97; + int err; + static struct snd_ac97_bus_ops ops = { + .write = snd_mychip_ac97_write, + .read = snd_mychip_ac97_read, + }; + + err = snd_ac97_bus(chip->card, 0, &ops, NULL, &bus); + if (err < 0) + return err; + memset(&ac97, 0, sizeof(ac97)); + ac97.private_data = chip; + return snd_ac97_mixer(bus, &ac97, &chip->ac97); + } + +]]> + </programlisting> + </example> + </para> + </section> + + <section id="api-ac97-constructor"> + <title>Constructor</title> + <para> + To create an ac97 instance, first call <function>snd_ac97_bus</function> + with an <type>ac97_bus_ops_t</type> record with callback functions. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_ac97_bus *bus; + static struct snd_ac97_bus_ops ops = { + .write = snd_mychip_ac97_write, + .read = snd_mychip_ac97_read, + }; + + snd_ac97_bus(card, 0, &ops, NULL, &pbus); +]]> + </programlisting> + </informalexample> + + The bus record is shared among all belonging ac97 instances. + </para> + + <para> + And then call <function>snd_ac97_mixer()</function> with an + struct <structname>snd_ac97_template</structname> + record together with the bus pointer created above. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_ac97_template ac97; + int err; + + memset(&ac97, 0, sizeof(ac97)); + ac97.private_data = chip; + snd_ac97_mixer(bus, &ac97, &chip->ac97); +]]> + </programlisting> + </informalexample> + + where chip->ac97 is a pointer to a newly created + <type>ac97_t</type> instance. + In this case, the chip pointer is set as the private data, so that + the read/write callback functions can refer to this chip instance. + This instance is not necessarily stored in the chip + record. If you need to change the register values from the + driver, or need the suspend/resume of ac97 codecs, keep this + pointer to pass to the corresponding functions. + </para> + </section> + + <section id="api-ac97-callbacks"> + <title>Callbacks</title> + <para> + The standard callbacks are <structfield>read</structfield> and + <structfield>write</structfield>. Obviously they + correspond to the functions for read and write accesses to the + hardware low-level codes. + </para> + + <para> + The <structfield>read</structfield> callback returns the + register value specified in the argument. + + <informalexample> + <programlisting> +<![CDATA[ + static unsigned short snd_mychip_ac97_read(struct snd_ac97 *ac97, + unsigned short reg) + { + struct mychip *chip = ac97->private_data; + .... + return the_register_value; + } +]]> + </programlisting> + </informalexample> + + Here, the chip can be cast from ac97->private_data. + </para> + + <para> + Meanwhile, the <structfield>write</structfield> callback is + used to set the register value. + + <informalexample> + <programlisting> +<![CDATA[ + static void snd_mychip_ac97_write(struct snd_ac97 *ac97, + unsigned short reg, unsigned short val) +]]> + </programlisting> + </informalexample> + </para> + + <para> + These callbacks are non-atomic like the control API callbacks. + </para> + + <para> + There are also other callbacks: + <structfield>reset</structfield>, + <structfield>wait</structfield> and + <structfield>init</structfield>. + </para> + + <para> + The <structfield>reset</structfield> callback is used to reset + the codec. If the chip requires a special kind of reset, you can + define this callback. + </para> + + <para> + The <structfield>wait</structfield> callback is used to + add some waiting time in the standard initialization of the codec. If the + chip requires the extra waiting time, define this callback. + </para> + + <para> + The <structfield>init</structfield> callback is used for + additional initialization of the codec. + </para> + </section> + + <section id="api-ac97-updating-registers"> + <title>Updating Registers in The Driver</title> + <para> + If you need to access to the codec from the driver, you can + call the following functions: + <function>snd_ac97_write()</function>, + <function>snd_ac97_read()</function>, + <function>snd_ac97_update()</function> and + <function>snd_ac97_update_bits()</function>. + </para> + + <para> + Both <function>snd_ac97_write()</function> and + <function>snd_ac97_update()</function> functions are used to + set a value to the given register + (<constant>AC97_XXX</constant>). The difference between them is + that <function>snd_ac97_update()</function> doesn't write a + value if the given value has been already set, while + <function>snd_ac97_write()</function> always rewrites the + value. + + <informalexample> + <programlisting> +<![CDATA[ + snd_ac97_write(ac97, AC97_MASTER, 0x8080); + snd_ac97_update(ac97, AC97_MASTER, 0x8080); +]]> + </programlisting> + </informalexample> + </para> + + <para> + <function>snd_ac97_read()</function> is used to read the value + of the given register. For example, + + <informalexample> + <programlisting> +<![CDATA[ + value = snd_ac97_read(ac97, AC97_MASTER); +]]> + </programlisting> + </informalexample> + </para> + + <para> + <function>snd_ac97_update_bits()</function> is used to update + some bits in the given register. + + <informalexample> + <programlisting> +<![CDATA[ + snd_ac97_update_bits(ac97, reg, mask, value); +]]> + </programlisting> + </informalexample> + </para> + + <para> + Also, there is a function to change the sample rate (of a + given register such as + <constant>AC97_PCM_FRONT_DAC_RATE</constant>) when VRA or + DRA is supported by the codec: + <function>snd_ac97_set_rate()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + snd_ac97_set_rate(ac97, AC97_PCM_FRONT_DAC_RATE, 44100); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The following registers are available to set the rate: + <constant>AC97_PCM_MIC_ADC_RATE</constant>, + <constant>AC97_PCM_FRONT_DAC_RATE</constant>, + <constant>AC97_PCM_LR_ADC_RATE</constant>, + <constant>AC97_SPDIF</constant>. When + <constant>AC97_SPDIF</constant> is specified, the register is + not really changed but the corresponding IEC958 status bits will + be updated. + </para> + </section> + + <section id="api-ac97-clock-adjustment"> + <title>Clock Adjustment</title> + <para> + In some chips, the clock of the codec isn't 48000 but using a + PCI clock (to save a quartz!). In this case, change the field + bus->clock to the corresponding + value. For example, intel8x0 + and es1968 drivers have their own function to read from the clock. + </para> + </section> + + <section id="api-ac97-proc-files"> + <title>Proc Files</title> + <para> + The ALSA AC97 interface will create a proc file such as + <filename>/proc/asound/card0/codec97#0/ac97#0-0</filename> and + <filename>ac97#0-0+regs</filename>. You can refer to these files to + see the current status and registers of the codec. + </para> + </section> + + <section id="api-ac97-multiple-codecs"> + <title>Multiple Codecs</title> + <para> + When there are several codecs on the same card, you need to + call <function>snd_ac97_mixer()</function> multiple times with + ac97.num=1 or greater. The <structfield>num</structfield> field + specifies the codec number. + </para> + + <para> + If you set up multiple codecs, you either need to write + different callbacks for each codec or check + ac97->num in the callback routines. + </para> + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- MIDI (MPU401-UART) Interface --> +<!-- ****************************************************** --> + <chapter id="midi-interface"> + <title>MIDI (MPU401-UART) Interface</title> + + <section id="midi-interface-general"> + <title>General</title> + <para> + Many soundcards have built-in MIDI (MPU401-UART) + interfaces. When the soundcard supports the standard MPU401-UART + interface, most likely you can use the ALSA MPU401-UART API. The + MPU401-UART API is defined in + <filename><sound/mpu401.h></filename>. + </para> + + <para> + Some soundchips have a similar but slightly different + implementation of mpu401 stuff. For example, emu10k1 has its own + mpu401 routines. + </para> + </section> + + <section id="midi-interface-constructor"> + <title>Constructor</title> + <para> + To create a rawmidi object, call + <function>snd_mpu401_uart_new()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_rawmidi *rmidi; + snd_mpu401_uart_new(card, 0, MPU401_HW_MPU401, port, info_flags, + irq, &rmidi); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The first argument is the card pointer, and the second is the + index of this component. You can create up to 8 rawmidi + devices. + </para> + + <para> + The third argument is the type of the hardware, + <constant>MPU401_HW_XXX</constant>. If it's not a special one, + you can use <constant>MPU401_HW_MPU401</constant>. + </para> + + <para> + The 4th argument is the I/O port address. Many + backward-compatible MPU401 have an I/O port such as 0x330. Or, it + might be a part of its own PCI I/O region. It depends on the + chip design. + </para> + + <para> + The 5th argument is a bitflag for additional information. + When the I/O port address above is part of the PCI I/O + region, the MPU401 I/O port might have been already allocated + (reserved) by the driver itself. In such a case, pass a bit flag + <constant>MPU401_INFO_INTEGRATED</constant>, + and the mpu401-uart layer will allocate the I/O ports by itself. + </para> + + <para> + When the controller supports only the input or output MIDI stream, + pass the <constant>MPU401_INFO_INPUT</constant> or + <constant>MPU401_INFO_OUTPUT</constant> bitflag, respectively. + Then the rawmidi instance is created as a single stream. + </para> + + <para> + <constant>MPU401_INFO_MMIO</constant> bitflag is used to change + the access method to MMIO (via readb and writeb) instead of + iob and outb. In this case, you have to pass the iomapped address + to <function>snd_mpu401_uart_new()</function>. + </para> + + <para> + When <constant>MPU401_INFO_TX_IRQ</constant> is set, the output + stream isn't checked in the default interrupt handler. The driver + needs to call <function>snd_mpu401_uart_interrupt_tx()</function> + by itself to start processing the output stream in the irq handler. + </para> + + <para> + If the MPU-401 interface shares its interrupt with the other logical + devices on the card, set <constant>MPU401_INFO_IRQ_HOOK</constant> + (see <link linkend="midi-interface-interrupt-handler"><citetitle> + below</citetitle></link>). + </para> + + <para> + Usually, the port address corresponds to the command port and + port + 1 corresponds to the data port. If not, you may change + the <structfield>cport</structfield> field of + struct <structname>snd_mpu401</structname> manually + afterward. However, <structname>snd_mpu401</structname> pointer is not + returned explicitly by + <function>snd_mpu401_uart_new()</function>. You need to cast + rmidi->private_data to + <structname>snd_mpu401</structname> explicitly, + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_mpu401 *mpu; + mpu = rmidi->private_data; +]]> + </programlisting> + </informalexample> + + and reset the cport as you like: + + <informalexample> + <programlisting> +<![CDATA[ + mpu->cport = my_own_control_port; +]]> + </programlisting> + </informalexample> + </para> + + <para> + The 6th argument specifies the ISA irq number that will be + allocated. If no interrupt is to be allocated (because your + code is already allocating a shared interrupt, or because the + device does not use interrupts), pass -1 instead. + For a MPU-401 device without an interrupt, a polling timer + will be used instead. + </para> + </section> + + <section id="midi-interface-interrupt-handler"> + <title>Interrupt Handler</title> + <para> + When the interrupt is allocated in + <function>snd_mpu401_uart_new()</function>, an exclusive ISA + interrupt handler is automatically used, hence you don't have + anything else to do than creating the mpu401 stuff. Otherwise, you + have to set <constant>MPU401_INFO_IRQ_HOOK</constant>, and call + <function>snd_mpu401_uart_interrupt()</function> explicitly from your + own interrupt handler when it has determined that a UART interrupt + has occurred. + </para> + + <para> + In this case, you need to pass the private_data of the + returned rawmidi object from + <function>snd_mpu401_uart_new()</function> as the second + argument of <function>snd_mpu401_uart_interrupt()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + snd_mpu401_uart_interrupt(irq, rmidi->private_data, regs); +]]> + </programlisting> + </informalexample> + </para> + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- RawMIDI Interface --> +<!-- ****************************************************** --> + <chapter id="rawmidi-interface"> + <title>RawMIDI Interface</title> + + <section id="rawmidi-interface-overview"> + <title>Overview</title> + + <para> + The raw MIDI interface is used for hardware MIDI ports that can + be accessed as a byte stream. It is not used for synthesizer + chips that do not directly understand MIDI. + </para> + + <para> + ALSA handles file and buffer management. All you have to do is + to write some code to move data between the buffer and the + hardware. + </para> + + <para> + The rawmidi API is defined in + <filename><sound/rawmidi.h></filename>. + </para> + </section> + + <section id="rawmidi-interface-constructor"> + <title>Constructor</title> + + <para> + To create a rawmidi device, call the + <function>snd_rawmidi_new</function> function: + <informalexample> + <programlisting> +<![CDATA[ + struct snd_rawmidi *rmidi; + err = snd_rawmidi_new(chip->card, "MyMIDI", 0, outs, ins, &rmidi); + if (err < 0) + return err; + rmidi->private_data = chip; + strcpy(rmidi->name, "My MIDI"); + rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT | + SNDRV_RAWMIDI_INFO_INPUT | + SNDRV_RAWMIDI_INFO_DUPLEX; +]]> + </programlisting> + </informalexample> + </para> + + <para> + The first argument is the card pointer, the second argument is + the ID string. + </para> + + <para> + The third argument is the index of this component. You can + create up to 8 rawmidi devices. + </para> + + <para> + The fourth and fifth arguments are the number of output and + input substreams, respectively, of this device (a substream is + the equivalent of a MIDI port). + </para> + + <para> + Set the <structfield>info_flags</structfield> field to specify + the capabilities of the device. + Set <constant>SNDRV_RAWMIDI_INFO_OUTPUT</constant> if there is + at least one output port, + <constant>SNDRV_RAWMIDI_INFO_INPUT</constant> if there is at + least one input port, + and <constant>SNDRV_RAWMIDI_INFO_DUPLEX</constant> if the device + can handle output and input at the same time. + </para> + + <para> + After the rawmidi device is created, you need to set the + operators (callbacks) for each substream. There are helper + functions to set the operators for all the substreams of a device: + <informalexample> + <programlisting> +<![CDATA[ + snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_mymidi_output_ops); + snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_mymidi_input_ops); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The operators are usually defined like this: + <informalexample> + <programlisting> +<![CDATA[ + static struct snd_rawmidi_ops snd_mymidi_output_ops = { + .open = snd_mymidi_output_open, + .close = snd_mymidi_output_close, + .trigger = snd_mymidi_output_trigger, + }; +]]> + </programlisting> + </informalexample> + These callbacks are explained in the <link + linkend="rawmidi-interface-callbacks"><citetitle>Callbacks</citetitle></link> + section. + </para> + + <para> + If there are more than one substream, you should give a + unique name to each of them: + <informalexample> + <programlisting> +<![CDATA[ + struct snd_rawmidi_substream *substream; + list_for_each_entry(substream, + &rmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT].substreams, + list { + sprintf(substream->name, "My MIDI Port %d", substream->number + 1); + } + /* same for SNDRV_RAWMIDI_STREAM_INPUT */ +]]> + </programlisting> + </informalexample> + </para> + </section> + + <section id="rawmidi-interface-callbacks"> + <title>Callbacks</title> + + <para> + In all the callbacks, the private data that you've set for the + rawmidi device can be accessed as + substream->rmidi->private_data. + <!-- <code> isn't available before DocBook 4.3 --> + </para> + + <para> + If there is more than one port, your callbacks can determine the + port index from the struct snd_rawmidi_substream data passed to each + callback: + <informalexample> + <programlisting> +<![CDATA[ + struct snd_rawmidi_substream *substream; + int index = substream->number; +]]> + </programlisting> + </informalexample> + </para> + + <section id="rawmidi-interface-op-open"> + <title><function>open</function> callback</title> + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_open(struct snd_rawmidi_substream *substream); +]]> + </programlisting> + </informalexample> + + <para> + This is called when a substream is opened. + You can initialize the hardware here, but you shouldn't + start transmitting/receiving data yet. + </para> + </section> + + <section id="rawmidi-interface-op-close"> + <title><function>close</function> callback</title> + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_xxx_close(struct snd_rawmidi_substream *substream); +]]> + </programlisting> + </informalexample> + + <para> + Guess what. + </para> + + <para> + The <function>open</function> and <function>close</function> + callbacks of a rawmidi device are serialized with a mutex, + and can sleep. + </para> + </section> + + <section id="rawmidi-interface-op-trigger-out"> + <title><function>trigger</function> callback for output + substreams</title> + + <informalexample> + <programlisting> +<![CDATA[ + static void snd_xxx_output_trigger(struct snd_rawmidi_substream *substream, int up); +]]> + </programlisting> + </informalexample> + + <para> + This is called with a nonzero <parameter>up</parameter> + parameter when there is some data in the substream buffer that + must be transmitted. + </para> + + <para> + To read data from the buffer, call + <function>snd_rawmidi_transmit_peek</function>. It will + return the number of bytes that have been read; this will be + less than the number of bytes requested when there are no more + data in the buffer. + After the data have been transmitted successfully, call + <function>snd_rawmidi_transmit_ack</function> to remove the + data from the substream buffer: + <informalexample> + <programlisting> +<![CDATA[ + unsigned char data; + while (snd_rawmidi_transmit_peek(substream, &data, 1) == 1) { + if (snd_mychip_try_to_transmit(data)) + snd_rawmidi_transmit_ack(substream, 1); + else + break; /* hardware FIFO full */ + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + If you know beforehand that the hardware will accept data, you + can use the <function>snd_rawmidi_transmit</function> function + which reads some data and removes them from the buffer at once: + <informalexample> + <programlisting> +<![CDATA[ + while (snd_mychip_transmit_possible()) { + unsigned char data; + if (snd_rawmidi_transmit(substream, &data, 1) != 1) + break; /* no more data */ + snd_mychip_transmit(data); + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + If you know beforehand how many bytes you can accept, you can + use a buffer size greater than one with the + <function>snd_rawmidi_transmit*</function> functions. + </para> + + <para> + The <function>trigger</function> callback must not sleep. If + the hardware FIFO is full before the substream buffer has been + emptied, you have to continue transmitting data later, either + in an interrupt handler, or with a timer if the hardware + doesn't have a MIDI transmit interrupt. + </para> + + <para> + The <function>trigger</function> callback is called with a + zero <parameter>up</parameter> parameter when the transmission + of data should be aborted. + </para> + </section> + + <section id="rawmidi-interface-op-trigger-in"> + <title><function>trigger</function> callback for input + substreams</title> + + <informalexample> + <programlisting> +<![CDATA[ + static void snd_xxx_input_trigger(struct snd_rawmidi_substream *substream, int up); +]]> + </programlisting> + </informalexample> + + <para> + This is called with a nonzero <parameter>up</parameter> + parameter to enable receiving data, or with a zero + <parameter>up</parameter> parameter do disable receiving data. + </para> + + <para> + The <function>trigger</function> callback must not sleep; the + actual reading of data from the device is usually done in an + interrupt handler. + </para> + + <para> + When data reception is enabled, your interrupt handler should + call <function>snd_rawmidi_receive</function> for all received + data: + <informalexample> + <programlisting> +<![CDATA[ + void snd_mychip_midi_interrupt(...) + { + while (mychip_midi_available()) { + unsigned char data; + data = mychip_midi_read(); + snd_rawmidi_receive(substream, &data, 1); + } + } +]]> + </programlisting> + </informalexample> + </para> + </section> + + <section id="rawmidi-interface-op-drain"> + <title><function>drain</function> callback</title> + + <informalexample> + <programlisting> +<![CDATA[ + static void snd_xxx_drain(struct snd_rawmidi_substream *substream); +]]> + </programlisting> + </informalexample> + + <para> + This is only used with output substreams. This function should wait + until all data read from the substream buffer have been transmitted. + This ensures that the device can be closed and the driver unloaded + without losing data. + </para> + + <para> + This callback is optional. If you do not set + <structfield>drain</structfield> in the struct snd_rawmidi_ops + structure, ALSA will simply wait for 50 milliseconds + instead. + </para> + </section> + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- Miscellaneous Devices --> +<!-- ****************************************************** --> + <chapter id="misc-devices"> + <title>Miscellaneous Devices</title> + + <section id="misc-devices-opl3"> + <title>FM OPL3</title> + <para> + The FM OPL3 is still used in many chips (mainly for backward + compatibility). ALSA has a nice OPL3 FM control layer, too. The + OPL3 API is defined in + <filename><sound/opl3.h></filename>. + </para> + + <para> + FM registers can be directly accessed through the direct-FM API, + defined in <filename><sound/asound_fm.h></filename>. In + ALSA native mode, FM registers are accessed through + the Hardware-Dependent Device direct-FM extension API, whereas in + OSS compatible mode, FM registers can be accessed with the OSS + direct-FM compatible API in <filename>/dev/dmfmX</filename> device. + </para> + + <para> + To create the OPL3 component, you have two functions to + call. The first one is a constructor for the <type>opl3_t</type> + instance. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_opl3 *opl3; + snd_opl3_create(card, lport, rport, OPL3_HW_OPL3_XXX, + integrated, &opl3); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The first argument is the card pointer, the second one is the + left port address, and the third is the right port address. In + most cases, the right port is placed at the left port + 2. + </para> + + <para> + The fourth argument is the hardware type. + </para> + + <para> + When the left and right ports have been already allocated by + the card driver, pass non-zero to the fifth argument + (<parameter>integrated</parameter>). Otherwise, the opl3 module will + allocate the specified ports by itself. + </para> + + <para> + When the accessing the hardware requires special method + instead of the standard I/O access, you can create opl3 instance + separately with <function>snd_opl3_new()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_opl3 *opl3; + snd_opl3_new(card, OPL3_HW_OPL3_XXX, &opl3); +]]> + </programlisting> + </informalexample> + </para> + + <para> + Then set <structfield>command</structfield>, + <structfield>private_data</structfield> and + <structfield>private_free</structfield> for the private + access function, the private data and the destructor. + The l_port and r_port are not necessarily set. Only the + command must be set properly. You can retrieve the data + from the opl3->private_data field. + </para> + + <para> + After creating the opl3 instance via <function>snd_opl3_new()</function>, + call <function>snd_opl3_init()</function> to initialize the chip to the + proper state. Note that <function>snd_opl3_create()</function> always + calls it internally. + </para> + + <para> + If the opl3 instance is created successfully, then create a + hwdep device for this opl3. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_hwdep *opl3hwdep; + snd_opl3_hwdep_new(opl3, 0, 1, &opl3hwdep); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The first argument is the <type>opl3_t</type> instance you + created, and the second is the index number, usually 0. + </para> + + <para> + The third argument is the index-offset for the sequencer + client assigned to the OPL3 port. When there is an MPU401-UART, + give 1 for here (UART always takes 0). + </para> + </section> + + <section id="misc-devices-hardware-dependent"> + <title>Hardware-Dependent Devices</title> + <para> + Some chips need user-space access for special + controls or for loading the micro code. In such a case, you can + create a hwdep (hardware-dependent) device. The hwdep API is + defined in <filename><sound/hwdep.h></filename>. You can + find examples in opl3 driver or + <filename>isa/sb/sb16_csp.c</filename>. + </para> + + <para> + The creation of the <type>hwdep</type> instance is done via + <function>snd_hwdep_new()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_hwdep *hw; + snd_hwdep_new(card, "My HWDEP", 0, &hw); +]]> + </programlisting> + </informalexample> + + where the third argument is the index number. + </para> + + <para> + You can then pass any pointer value to the + <parameter>private_data</parameter>. + If you assign a private data, you should define the + destructor, too. The destructor function is set in + the <structfield>private_free</structfield> field. + + <informalexample> + <programlisting> +<![CDATA[ + struct mydata *p = kmalloc(sizeof(*p), GFP_KERNEL); + hw->private_data = p; + hw->private_free = mydata_free; +]]> + </programlisting> + </informalexample> + + and the implementation of the destructor would be: + + <informalexample> + <programlisting> +<![CDATA[ + static void mydata_free(struct snd_hwdep *hw) + { + struct mydata *p = hw->private_data; + kfree(p); + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + The arbitrary file operations can be defined for this + instance. The file operators are defined in + the <parameter>ops</parameter> table. For example, assume that + this chip needs an ioctl. + + <informalexample> + <programlisting> +<![CDATA[ + hw->ops.open = mydata_open; + hw->ops.ioctl = mydata_ioctl; + hw->ops.release = mydata_release; +]]> + </programlisting> + </informalexample> + + And implement the callback functions as you like. + </para> + </section> + + <section id="misc-devices-IEC958"> + <title>IEC958 (S/PDIF)</title> + <para> + Usually the controls for IEC958 devices are implemented via + the control interface. There is a macro to compose a name string for + IEC958 controls, <function>SNDRV_CTL_NAME_IEC958()</function> + defined in <filename><include/asound.h></filename>. + </para> + + <para> + There are some standard controls for IEC958 status bits. These + controls use the type <type>SNDRV_CTL_ELEM_TYPE_IEC958</type>, + and the size of element is fixed as 4 bytes array + (value.iec958.status[x]). For the <structfield>info</structfield> + callback, you don't specify + the value field for this type (the count field must be set, + though). + </para> + + <para> + <quote>IEC958 Playback Con Mask</quote> is used to return the + bit-mask for the IEC958 status bits of consumer mode. Similarly, + <quote>IEC958 Playback Pro Mask</quote> returns the bitmask for + professional mode. They are read-only controls, and are defined + as MIXER controls (iface = + <constant>SNDRV_CTL_ELEM_IFACE_MIXER</constant>). + </para> + + <para> + Meanwhile, <quote>IEC958 Playback Default</quote> control is + defined for getting and setting the current default IEC958 + bits. Note that this one is usually defined as a PCM control + (iface = <constant>SNDRV_CTL_ELEM_IFACE_PCM</constant>), + although in some places it's defined as a MIXER control. + </para> + + <para> + In addition, you can define the control switches to + enable/disable or to set the raw bit mode. The implementation + will depend on the chip, but the control should be named as + <quote>IEC958 xxx</quote>, preferably using + the <function>SNDRV_CTL_NAME_IEC958()</function> macro. + </para> + + <para> + You can find several cases, for example, + <filename>pci/emu10k1</filename>, + <filename>pci/ice1712</filename>, or + <filename>pci/cmipci.c</filename>. + </para> + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- Buffer and Memory Management --> +<!-- ****************************************************** --> + <chapter id="buffer-and-memory"> + <title>Buffer and Memory Management</title> + + <section id="buffer-and-memory-buffer-types"> + <title>Buffer Types</title> + <para> + ALSA provides several different buffer allocation functions + depending on the bus and the architecture. All these have a + consistent API. The allocation of physically-contiguous pages is + done via + <function>snd_malloc_xxx_pages()</function> function, where xxx + is the bus type. + </para> + + <para> + The allocation of pages with fallback is + <function>snd_malloc_xxx_pages_fallback()</function>. This + function tries to allocate the specified pages but if the pages + are not available, it tries to reduce the page sizes until + enough space is found. + </para> + + <para> + The release the pages, call + <function>snd_free_xxx_pages()</function> function. + </para> + + <para> + Usually, ALSA drivers try to allocate and reserve + a large contiguous physical space + at the time the module is loaded for the later use. + This is called <quote>pre-allocation</quote>. + As already written, you can call the following function at + pcm instance construction time (in the case of PCI bus). + + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV, + snd_dma_pci_data(pci), size, max); +]]> + </programlisting> + </informalexample> + + where <parameter>size</parameter> is the byte size to be + pre-allocated and the <parameter>max</parameter> is the maximum + size to be changed via the <filename>prealloc</filename> proc file. + The allocator will try to get an area as large as possible + within the given size. + </para> + + <para> + The second argument (type) and the third argument (device pointer) + are dependent on the bus. + In the case of the ISA bus, pass <function>snd_dma_isa_data()</function> + as the third argument with <constant>SNDRV_DMA_TYPE_DEV</constant> type. + For the continuous buffer unrelated to the bus can be pre-allocated + with <constant>SNDRV_DMA_TYPE_CONTINUOUS</constant> type and the + <function>snd_dma_continuous_data(GFP_KERNEL)</function> device pointer, + where <constant>GFP_KERNEL</constant> is the kernel allocation flag to + use. + For the PCI scatter-gather buffers, use + <constant>SNDRV_DMA_TYPE_DEV_SG</constant> with + <function>snd_dma_pci_data(pci)</function> + (see the + <link linkend="buffer-and-memory-non-contiguous"><citetitle>Non-Contiguous Buffers + </citetitle></link> section). + </para> + + <para> + Once the buffer is pre-allocated, you can use the + allocator in the <structfield>hw_params</structfield> callback: + + <informalexample> + <programlisting> +<![CDATA[ + snd_pcm_lib_malloc_pages(substream, size); +]]> + </programlisting> + </informalexample> + + Note that you have to pre-allocate to use this function. + </para> + </section> + + <section id="buffer-and-memory-external-hardware"> + <title>External Hardware Buffers</title> + <para> + Some chips have their own hardware buffers and the DMA + transfer from the host memory is not available. In such a case, + you need to either 1) copy/set the audio data directly to the + external hardware buffer, or 2) make an intermediate buffer and + copy/set the data from it to the external hardware buffer in + interrupts (or in tasklets, preferably). + </para> + + <para> + The first case works fine if the external hardware buffer is large + enough. This method doesn't need any extra buffers and thus is + more effective. You need to define the + <structfield>copy</structfield> and + <structfield>silence</structfield> callbacks for + the data transfer. However, there is a drawback: it cannot + be mmapped. The examples are GUS's GF1 PCM or emu8000's + wavetable PCM. + </para> + + <para> + The second case allows for mmap on the buffer, although you have + to handle an interrupt or a tasklet to transfer the data + from the intermediate buffer to the hardware buffer. You can find an + example in the vxpocket driver. + </para> + + <para> + Another case is when the chip uses a PCI memory-map + region for the buffer instead of the host memory. In this case, + mmap is available only on certain architectures like the Intel one. + In non-mmap mode, the data cannot be transferred as in the normal + way. Thus you need to define the <structfield>copy</structfield> and + <structfield>silence</structfield> callbacks as well, + as in the cases above. The examples are found in + <filename>rme32.c</filename> and <filename>rme96.c</filename>. + </para> + + <para> + The implementation of the <structfield>copy</structfield> and + <structfield>silence</structfield> callbacks depends upon + whether the hardware supports interleaved or non-interleaved + samples. The <structfield>copy</structfield> callback is + defined like below, a bit + differently depending whether the direction is playback or + capture: + + <informalexample> + <programlisting> +<![CDATA[ + static int playback_copy(struct snd_pcm_substream *substream, int channel, + snd_pcm_uframes_t pos, void *src, snd_pcm_uframes_t count); + static int capture_copy(struct snd_pcm_substream *substream, int channel, + snd_pcm_uframes_t pos, void *dst, snd_pcm_uframes_t count); +]]> + </programlisting> + </informalexample> + </para> + + <para> + In the case of interleaved samples, the second argument + (<parameter>channel</parameter>) is not used. The third argument + (<parameter>pos</parameter>) points the + current position offset in frames. + </para> + + <para> + The meaning of the fourth argument is different between + playback and capture. For playback, it holds the source data + pointer, and for capture, it's the destination data pointer. + </para> + + <para> + The last argument is the number of frames to be copied. + </para> + + <para> + What you have to do in this callback is again different + between playback and capture directions. In the + playback case, you copy the given amount of data + (<parameter>count</parameter>) at the specified pointer + (<parameter>src</parameter>) to the specified offset + (<parameter>pos</parameter>) on the hardware buffer. When + coded like memcpy-like way, the copy would be like: + + <informalexample> + <programlisting> +<![CDATA[ + my_memcpy(my_buffer + frames_to_bytes(runtime, pos), src, + frames_to_bytes(runtime, count)); +]]> + </programlisting> + </informalexample> + </para> + + <para> + For the capture direction, you copy the given amount of + data (<parameter>count</parameter>) at the specified offset + (<parameter>pos</parameter>) on the hardware buffer to the + specified pointer (<parameter>dst</parameter>). + + <informalexample> + <programlisting> +<![CDATA[ + my_memcpy(dst, my_buffer + frames_to_bytes(runtime, pos), + frames_to_bytes(runtime, count)); +]]> + </programlisting> + </informalexample> + + Note that both the position and the amount of data are given + in frames. + </para> + + <para> + In the case of non-interleaved samples, the implementation + will be a bit more complicated. + </para> + + <para> + You need to check the channel argument, and if it's -1, copy + the whole channels. Otherwise, you have to copy only the + specified channel. Please check + <filename>isa/gus/gus_pcm.c</filename> as an example. + </para> + + <para> + The <structfield>silence</structfield> callback is also + implemented in a similar way. + + <informalexample> + <programlisting> +<![CDATA[ + static int silence(struct snd_pcm_substream *substream, int channel, + snd_pcm_uframes_t pos, snd_pcm_uframes_t count); +]]> + </programlisting> + </informalexample> + </para> + + <para> + The meanings of arguments are the same as in the + <structfield>copy</structfield> + callback, although there is no <parameter>src/dst</parameter> + argument. In the case of interleaved samples, the channel + argument has no meaning, as well as on + <structfield>copy</structfield> callback. + </para> + + <para> + The role of <structfield>silence</structfield> callback is to + set the given amount + (<parameter>count</parameter>) of silence data at the + specified offset (<parameter>pos</parameter>) on the hardware + buffer. Suppose that the data format is signed (that is, the + silent-data is 0), and the implementation using a memset-like + function would be like: + + <informalexample> + <programlisting> +<![CDATA[ + my_memcpy(my_buffer + frames_to_bytes(runtime, pos), 0, + frames_to_bytes(runtime, count)); +]]> + </programlisting> + </informalexample> + </para> + + <para> + In the case of non-interleaved samples, again, the + implementation becomes a bit more complicated. See, for example, + <filename>isa/gus/gus_pcm.c</filename>. + </para> + </section> + + <section id="buffer-and-memory-non-contiguous"> + <title>Non-Contiguous Buffers</title> + <para> + If your hardware supports the page table as in emu10k1 or the + buffer descriptors as in via82xx, you can use the scatter-gather + (SG) DMA. ALSA provides an interface for handling SG-buffers. + The API is provided in <filename><sound/pcm.h></filename>. + </para> + + <para> + For creating the SG-buffer handler, call + <function>snd_pcm_lib_preallocate_pages()</function> or + <function>snd_pcm_lib_preallocate_pages_for_all()</function> + with <constant>SNDRV_DMA_TYPE_DEV_SG</constant> + in the PCM constructor like other PCI pre-allocator. + You need to pass <function>snd_dma_pci_data(pci)</function>, + where pci is the struct <structname>pci_dev</structname> pointer + of the chip as well. + The <type>struct snd_sg_buf</type> instance is created as + substream->dma_private. You can cast + the pointer like: + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_sg_buf *sgbuf = (struct snd_sg_buf *)substream->dma_private; +]]> + </programlisting> + </informalexample> + </para> + + <para> + Then call <function>snd_pcm_lib_malloc_pages()</function> + in the <structfield>hw_params</structfield> callback + as well as in the case of normal PCI buffer. + The SG-buffer handler will allocate the non-contiguous kernel + pages of the given size and map them onto the virtually contiguous + memory. The virtual pointer is addressed in runtime->dma_area. + The physical address (runtime->dma_addr) is set to zero, + because the buffer is physically non-contiguous. + The physical address table is set up in sgbuf->table. + You can get the physical address at a certain offset via + <function>snd_pcm_sgbuf_get_addr()</function>. + </para> + + <para> + When a SG-handler is used, you need to set + <function>snd_pcm_sgbuf_ops_page</function> as + the <structfield>page</structfield> callback. + (See <link linkend="pcm-interface-operators-page-callback"> + <citetitle>page callback section</citetitle></link>.) + </para> + + <para> + To release the data, call + <function>snd_pcm_lib_free_pages()</function> in the + <structfield>hw_free</structfield> callback as usual. + </para> + </section> + + <section id="buffer-and-memory-vmalloced"> + <title>Vmalloc'ed Buffers</title> + <para> + It's possible to use a buffer allocated via + <function>vmalloc</function>, for example, for an intermediate + buffer. Since the allocated pages are not contiguous, you need + to set the <structfield>page</structfield> callback to obtain + the physical address at every offset. + </para> + + <para> + The implementation of <structfield>page</structfield> callback + would be like this: + + <informalexample> + <programlisting> +<![CDATA[ + #include <linux/vmalloc.h> + + /* get the physical page pointer on the given offset */ + static struct page *mychip_page(struct snd_pcm_substream *substream, + unsigned long offset) + { + void *pageptr = substream->runtime->dma_area + offset; + return vmalloc_to_page(pageptr); + } +]]> + </programlisting> + </informalexample> + </para> + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- Proc Interface --> +<!-- ****************************************************** --> + <chapter id="proc-interface"> + <title>Proc Interface</title> + <para> + ALSA provides an easy interface for procfs. The proc files are + very useful for debugging. I recommend you set up proc files if + you write a driver and want to get a running status or register + dumps. The API is found in + <filename><sound/info.h></filename>. + </para> + + <para> + To create a proc file, call + <function>snd_card_proc_new()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + struct snd_info_entry *entry; + int err = snd_card_proc_new(card, "my-file", &entry); +]]> + </programlisting> + </informalexample> + + where the second argument specifies the name of the proc file to be + created. The above example will create a file + <filename>my-file</filename> under the card directory, + e.g. <filename>/proc/asound/card0/my-file</filename>. + </para> + + <para> + Like other components, the proc entry created via + <function>snd_card_proc_new()</function> will be registered and + released automatically in the card registration and release + functions. + </para> + + <para> + When the creation is successful, the function stores a new + instance in the pointer given in the third argument. + It is initialized as a text proc file for read only. To use + this proc file as a read-only text file as it is, set the read + callback with a private data via + <function>snd_info_set_text_ops()</function>. + + <informalexample> + <programlisting> +<![CDATA[ + snd_info_set_text_ops(entry, chip, my_proc_read); +]]> + </programlisting> + </informalexample> + + where the second argument (<parameter>chip</parameter>) is the + private data to be used in the callbacks. The third parameter + specifies the read buffer size and the fourth + (<parameter>my_proc_read</parameter>) is the callback function, which + is defined like + + <informalexample> + <programlisting> +<![CDATA[ + static void my_proc_read(struct snd_info_entry *entry, + struct snd_info_buffer *buffer); +]]> + </programlisting> + </informalexample> + + </para> + + <para> + In the read callback, use <function>snd_iprintf()</function> for + output strings, which works just like normal + <function>printf()</function>. For example, + + <informalexample> + <programlisting> +<![CDATA[ + static void my_proc_read(struct snd_info_entry *entry, + struct snd_info_buffer *buffer) + { + struct my_chip *chip = entry->private_data; + + snd_iprintf(buffer, "This is my chip!\n"); + snd_iprintf(buffer, "Port = %ld\n", chip->port); + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + The file permissions can be changed afterwards. As default, it's + set as read only for all users. If you want to add write + permission for the user (root as default), do as follows: + + <informalexample> + <programlisting> +<![CDATA[ + entry->mode = S_IFREG | S_IRUGO | S_IWUSR; +]]> + </programlisting> + </informalexample> + + and set the write buffer size and the callback + + <informalexample> + <programlisting> +<![CDATA[ + entry->c.text.write = my_proc_write; +]]> + </programlisting> + </informalexample> + </para> + + <para> + For the write callback, you can use + <function>snd_info_get_line()</function> to get a text line, and + <function>snd_info_get_str()</function> to retrieve a string from + the line. Some examples are found in + <filename>core/oss/mixer_oss.c</filename>, core/oss/and + <filename>pcm_oss.c</filename>. + </para> + + <para> + For a raw-data proc-file, set the attributes as follows: + + <informalexample> + <programlisting> +<![CDATA[ + static struct snd_info_entry_ops my_file_io_ops = { + .read = my_file_io_read, + }; + + entry->content = SNDRV_INFO_CONTENT_DATA; + entry->private_data = chip; + entry->c.ops = &my_file_io_ops; + entry->size = 4096; + entry->mode = S_IFREG | S_IRUGO; +]]> + </programlisting> + </informalexample> + + For the raw data, <structfield>size</structfield> field must be + set properly. This specifies the maximum size of the proc file access. + </para> + + <para> + The read/write callbacks of raw mode are more direct than the text mode. + You need to use a low-level I/O functions such as + <function>copy_from/to_user()</function> to transfer the + data. + + <informalexample> + <programlisting> +<![CDATA[ + static ssize_t my_file_io_read(struct snd_info_entry *entry, + void *file_private_data, + struct file *file, + char *buf, + size_t count, + loff_t pos) + { + if (copy_to_user(buf, local_data + pos, count)) + return -EFAULT; + return count; + } +]]> + </programlisting> + </informalexample> + + If the size of the info entry has been set up properly, + <structfield>count</structfield> and <structfield>pos</structfield> are + guaranteed to fit within 0 and the given size. + You don't have to check the range in the callbacks unless any + other condition is required. + + </para> + + </chapter> + + +<!-- ****************************************************** --> +<!-- Power Management --> +<!-- ****************************************************** --> + <chapter id="power-management"> + <title>Power Management</title> + <para> + If the chip is supposed to work with suspend/resume + functions, you need to add power-management code to the + driver. The additional code for power-management should be + <function>ifdef</function>'ed with + <constant>CONFIG_PM</constant>. + </para> + + <para> + If the driver <emphasis>fully</emphasis> supports suspend/resume + that is, the device can be + properly resumed to its state when suspend was called, + you can set the <constant>SNDRV_PCM_INFO_RESUME</constant> flag + in the pcm info field. Usually, this is possible when the + registers of the chip can be safely saved and restored to + RAM. If this is set, the trigger callback is called with + <constant>SNDRV_PCM_TRIGGER_RESUME</constant> after the resume + callback completes. + </para> + + <para> + Even if the driver doesn't support PM fully but + partial suspend/resume is still possible, it's still worthy to + implement suspend/resume callbacks. In such a case, applications + would reset the status by calling + <function>snd_pcm_prepare()</function> and restart the stream + appropriately. Hence, you can define suspend/resume callbacks + below but don't set <constant>SNDRV_PCM_INFO_RESUME</constant> + info flag to the PCM. + </para> + + <para> + Note that the trigger with SUSPEND can always be called when + <function>snd_pcm_suspend_all</function> is called, + regardless of the <constant>SNDRV_PCM_INFO_RESUME</constant> flag. + The <constant>RESUME</constant> flag affects only the behavior + of <function>snd_pcm_resume()</function>. + (Thus, in theory, + <constant>SNDRV_PCM_TRIGGER_RESUME</constant> isn't needed + to be handled in the trigger callback when no + <constant>SNDRV_PCM_INFO_RESUME</constant> flag is set. But, + it's better to keep it for compatibility reasons.) + </para> + <para> + In the earlier version of ALSA drivers, a common + power-management layer was provided, but it has been removed. + The driver needs to define the suspend/resume hooks according to + the bus the device is connected to. In the case of PCI drivers, the + callbacks look like below: + + <informalexample> + <programlisting> +<![CDATA[ + #ifdef CONFIG_PM + static int snd_my_suspend(struct pci_dev *pci, pm_message_t state) + { + .... /* do things for suspend */ + return 0; + } + static int snd_my_resume(struct pci_dev *pci) + { + .... /* do things for suspend */ + return 0; + } + #endif +]]> + </programlisting> + </informalexample> + </para> + + <para> + The scheme of the real suspend job is as follows. + + <orderedlist> + <listitem><para>Retrieve the card and the chip data.</para></listitem> + <listitem><para>Call <function>snd_power_change_state()</function> with + <constant>SNDRV_CTL_POWER_D3hot</constant> to change the + power status.</para></listitem> + <listitem><para>Call <function>snd_pcm_suspend_all()</function> to suspend the running PCM streams.</para></listitem> + <listitem><para>If AC97 codecs are used, call + <function>snd_ac97_suspend()</function> for each codec.</para></listitem> + <listitem><para>Save the register values if necessary.</para></listitem> + <listitem><para>Stop the hardware if necessary.</para></listitem> + <listitem><para>Disable the PCI device by calling + <function>pci_disable_device()</function>. Then, call + <function>pci_save_state()</function> at last.</para></listitem> + </orderedlist> + </para> + + <para> + A typical code would be like: + + <informalexample> + <programlisting> +<![CDATA[ + static int mychip_suspend(struct pci_dev *pci, pm_message_t state) + { + /* (1) */ + struct snd_card *card = pci_get_drvdata(pci); + struct mychip *chip = card->private_data; + /* (2) */ + snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); + /* (3) */ + snd_pcm_suspend_all(chip->pcm); + /* (4) */ + snd_ac97_suspend(chip->ac97); + /* (5) */ + snd_mychip_save_registers(chip); + /* (6) */ + snd_mychip_stop_hardware(chip); + /* (7) */ + pci_disable_device(pci); + pci_save_state(pci); + return 0; + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + The scheme of the real resume job is as follows. + + <orderedlist> + <listitem><para>Retrieve the card and the chip data.</para></listitem> + <listitem><para>Set up PCI. First, call <function>pci_restore_state()</function>. + Then enable the pci device again by calling <function>pci_enable_device()</function>. + Call <function>pci_set_master()</function> if necessary, too.</para></listitem> + <listitem><para>Re-initialize the chip.</para></listitem> + <listitem><para>Restore the saved registers if necessary.</para></listitem> + <listitem><para>Resume the mixer, e.g. calling + <function>snd_ac97_resume()</function>.</para></listitem> + <listitem><para>Restart the hardware (if any).</para></listitem> + <listitem><para>Call <function>snd_power_change_state()</function> with + <constant>SNDRV_CTL_POWER_D0</constant> to notify the processes.</para></listitem> + </orderedlist> + </para> + + <para> + A typical code would be like: + + <informalexample> + <programlisting> +<![CDATA[ + static int mychip_resume(struct pci_dev *pci) + { + /* (1) */ + struct snd_card *card = pci_get_drvdata(pci); + struct mychip *chip = card->private_data; + /* (2) */ + pci_restore_state(pci); + pci_enable_device(pci); + pci_set_master(pci); + /* (3) */ + snd_mychip_reinit_chip(chip); + /* (4) */ + snd_mychip_restore_registers(chip); + /* (5) */ + snd_ac97_resume(chip->ac97); + /* (6) */ + snd_mychip_restart_chip(chip); + /* (7) */ + snd_power_change_state(card, SNDRV_CTL_POWER_D0); + return 0; + } +]]> + </programlisting> + </informalexample> + </para> + + <para> + As shown in the above, it's better to save registers after + suspending the PCM operations via + <function>snd_pcm_suspend_all()</function> or + <function>snd_pcm_suspend()</function>. It means that the PCM + streams are already stoppped when the register snapshot is + taken. But, remember that you don't have to restart the PCM + stream in the resume callback. It'll be restarted via + trigger call with <constant>SNDRV_PCM_TRIGGER_RESUME</constant> + when necessary. + </para> + + <para> + OK, we have all callbacks now. Let's set them up. In the + initialization of the card, make sure that you can get the chip + data from the card instance, typically via + <structfield>private_data</structfield> field, in case you + created the chip data individually. + + <informalexample> + <programlisting> +<![CDATA[ + static int __devinit snd_mychip_probe(struct pci_dev *pci, + const struct pci_device_id *pci_id) + { + .... + struct snd_card *card; + struct mychip *chip; + int err; + .... + err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card); + .... + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + .... + card->private_data = chip; + .... + } +]]> + </programlisting> + </informalexample> + + When you created the chip data with + <function>snd_card_create()</function>, it's anyway accessible + via <structfield>private_data</structfield> field. + + <informalexample> + <programlisting> +<![CDATA[ + static int __devinit snd_mychip_probe(struct pci_dev *pci, + const struct pci_device_id *pci_id) + { + .... + struct snd_card *card; + struct mychip *chip; + int err; + .... + err = snd_card_create(index[dev], id[dev], THIS_MODULE, + sizeof(struct mychip), &card); + .... + chip = card->private_data; + .... + } +]]> + </programlisting> + </informalexample> + + </para> + + <para> + If you need a space to save the registers, allocate the + buffer for it here, too, since it would be fatal + if you cannot allocate a memory in the suspend phase. + The allocated buffer should be released in the corresponding + destructor. + </para> + + <para> + And next, set suspend/resume callbacks to the pci_driver. + + <informalexample> + <programlisting> +<![CDATA[ + static struct pci_driver driver = { + .name = KBUILD_MODNAME, + .id_table = snd_my_ids, + .probe = snd_my_probe, + .remove = __devexit_p(snd_my_remove), + #ifdef CONFIG_PM + .suspend = snd_my_suspend, + .resume = snd_my_resume, + #endif + }; +]]> + </programlisting> + </informalexample> + </para> + + </chapter> + + +<!-- ****************************************************** --> +<!-- Module Parameters --> +<!-- ****************************************************** --> + <chapter id="module-parameters"> + <title>Module Parameters</title> + <para> + There are standard module options for ALSA. At least, each + module should have the <parameter>index</parameter>, + <parameter>id</parameter> and <parameter>enable</parameter> + options. + </para> + + <para> + If the module supports multiple cards (usually up to + 8 = <constant>SNDRV_CARDS</constant> cards), they should be + arrays. The default initial values are defined already as + constants for easier programming: + + <informalexample> + <programlisting> +<![CDATA[ + static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; + static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; + static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP; +]]> + </programlisting> + </informalexample> + </para> + + <para> + If the module supports only a single card, they could be single + variables, instead. <parameter>enable</parameter> option is not + always necessary in this case, but it would be better to have a + dummy option for compatibility. + </para> + + <para> + The module parameters must be declared with the standard + <function>module_param()()</function>, + <function>module_param_array()()</function> and + <function>MODULE_PARM_DESC()</function> macros. + </para> + + <para> + The typical coding would be like below: + + <informalexample> + <programlisting> +<![CDATA[ + #define CARD_NAME "My Chip" + + module_param_array(index, int, NULL, 0444); + MODULE_PARM_DESC(index, "Index value for " CARD_NAME " soundcard."); + module_param_array(id, charp, NULL, 0444); + MODULE_PARM_DESC(id, "ID string for " CARD_NAME " soundcard."); + module_param_array(enable, bool, NULL, 0444); + MODULE_PARM_DESC(enable, "Enable " CARD_NAME " soundcard."); +]]> + </programlisting> + </informalexample> + </para> + + <para> + Also, don't forget to define the module description, classes, + license and devices. Especially, the recent modprobe requires to + define the module license as GPL, etc., otherwise the system is + shown as <quote>tainted</quote>. + + <informalexample> + <programlisting> +<![CDATA[ + MODULE_DESCRIPTION("My Chip"); + MODULE_LICENSE("GPL"); + MODULE_SUPPORTED_DEVICE("{{Vendor,My Chip Name}}"); +]]> + </programlisting> + </informalexample> + </para> + + </chapter> + + +<!-- ****************************************************** --> +<!-- How To Put Your Driver --> +<!-- ****************************************************** --> + <chapter id="how-to-put-your-driver"> + <title>How To Put Your Driver Into ALSA Tree</title> + <section> + <title>General</title> + <para> + So far, you've learned how to write the driver codes. + And you might have a question now: how to put my own + driver into the ALSA driver tree? + Here (finally :) the standard procedure is described briefly. + </para> + + <para> + Suppose that you create a new PCI driver for the card + <quote>xyz</quote>. The card module name would be + snd-xyz. The new driver is usually put into the alsa-driver + tree, <filename>alsa-driver/pci</filename> directory in + the case of PCI cards. + Then the driver is evaluated, audited and tested + by developers and users. After a certain time, the driver + will go to the alsa-kernel tree (to the corresponding directory, + such as <filename>alsa-kernel/pci</filename>) and eventually + will be integrated into the Linux 2.6 tree (the directory would be + <filename>linux/sound/pci</filename>). + </para> + + <para> + In the following sections, the driver code is supposed + to be put into alsa-driver tree. The two cases are covered: + a driver consisting of a single source file and one consisting + of several source files. + </para> + </section> + + <section> + <title>Driver with A Single Source File</title> + <para> + <orderedlist> + <listitem> + <para> + Modify alsa-driver/pci/Makefile + </para> + + <para> + Suppose you have a file xyz.c. Add the following + two lines + <informalexample> + <programlisting> +<![CDATA[ + snd-xyz-objs := xyz.o + obj-$(CONFIG_SND_XYZ) += snd-xyz.o +]]> + </programlisting> + </informalexample> + </para> + </listitem> + + <listitem> + <para> + Create the Kconfig entry + </para> + + <para> + Add the new entry of Kconfig for your xyz driver. + <informalexample> + <programlisting> +<![CDATA[ + config SND_XYZ + tristate "Foobar XYZ" + depends on SND + select SND_PCM + help + Say Y here to include support for Foobar XYZ soundcard. + + To compile this driver as a module, choose M here: the module + will be called snd-xyz. +]]> + </programlisting> + </informalexample> + + the line, select SND_PCM, specifies that the driver xyz supports + PCM. In addition to SND_PCM, the following components are + supported for select command: + SND_RAWMIDI, SND_TIMER, SND_HWDEP, SND_MPU401_UART, + SND_OPL3_LIB, SND_OPL4_LIB, SND_VX_LIB, SND_AC97_CODEC. + Add the select command for each supported component. + </para> + + <para> + Note that some selections imply the lowlevel selections. + For example, PCM includes TIMER, MPU401_UART includes RAWMIDI, + AC97_CODEC includes PCM, and OPL3_LIB includes HWDEP. + You don't need to give the lowlevel selections again. + </para> + + <para> + For the details of Kconfig script, refer to the kbuild + documentation. + </para> + + </listitem> + + <listitem> + <para> + Run cvscompile script to re-generate the configure script and + build the whole stuff again. + </para> + </listitem> + </orderedlist> + </para> + </section> + + <section> + <title>Drivers with Several Source Files</title> + <para> + Suppose that the driver snd-xyz have several source files. + They are located in the new subdirectory, + pci/xyz. + + <orderedlist> + <listitem> + <para> + Add a new directory (<filename>xyz</filename>) in + <filename>alsa-driver/pci/Makefile</filename> as below + + <informalexample> + <programlisting> +<![CDATA[ + obj-$(CONFIG_SND) += xyz/ +]]> + </programlisting> + </informalexample> + </para> + </listitem> + + <listitem> + <para> + Under the directory <filename>xyz</filename>, create a Makefile + + <example> + <title>Sample Makefile for a driver xyz</title> + <programlisting> +<![CDATA[ + ifndef SND_TOPDIR + SND_TOPDIR=../.. + endif + + include $(SND_TOPDIR)/toplevel.config + include $(SND_TOPDIR)/Makefile.conf + + snd-xyz-objs := xyz.o abc.o def.o + + obj-$(CONFIG_SND_XYZ) += snd-xyz.o + + include $(SND_TOPDIR)/Rules.make +]]> + </programlisting> + </example> + </para> + </listitem> + + <listitem> + <para> + Create the Kconfig entry + </para> + + <para> + This procedure is as same as in the last section. + </para> + </listitem> + + <listitem> + <para> + Run cvscompile script to re-generate the configure script and + build the whole stuff again. + </para> + </listitem> + </orderedlist> + </para> + </section> + + </chapter> + +<!-- ****************************************************** --> +<!-- Useful Functions --> +<!-- ****************************************************** --> + <chapter id="useful-functions"> + <title>Useful Functions</title> + + <section id="useful-functions-snd-printk"> + <title><function>snd_printk()</function> and friends</title> + <para> + ALSA provides a verbose version of the + <function>printk()</function> function. If a kernel config + <constant>CONFIG_SND_VERBOSE_PRINTK</constant> is set, this + function prints the given message together with the file name + and the line of the caller. The <constant>KERN_XXX</constant> + prefix is processed as + well as the original <function>printk()</function> does, so it's + recommended to add this prefix, e.g. + + <informalexample> + <programlisting> +<![CDATA[ + snd_printk(KERN_ERR "Oh my, sorry, it's extremely bad!\n"); +]]> + </programlisting> + </informalexample> + </para> + + <para> + There are also <function>printk()</function>'s for + debugging. <function>snd_printd()</function> can be used for + general debugging purposes. If + <constant>CONFIG_SND_DEBUG</constant> is set, this function is + compiled, and works just like + <function>snd_printk()</function>. If the ALSA is compiled + without the debugging flag, it's ignored. + </para> + + <para> + <function>snd_printdd()</function> is compiled in only when + <constant>CONFIG_SND_DEBUG_VERBOSE</constant> is set. Please note + that <constant>CONFIG_SND_DEBUG_VERBOSE</constant> is not set as default + even if you configure the alsa-driver with + <option>--with-debug=full</option> option. You need to give + explicitly <option>--with-debug=detect</option> option instead. + </para> + </section> + + <section id="useful-functions-snd-bug"> + <title><function>snd_BUG()</function></title> + <para> + It shows the <computeroutput>BUG?</computeroutput> message and + stack trace as well as <function>snd_BUG_ON</function> at the point. + It's useful to show that a fatal error happens there. + </para> + <para> + When no debug flag is set, this macro is ignored. + </para> + </section> + + <section id="useful-functions-snd-bug-on"> + <title><function>snd_BUG_ON()</function></title> + <para> + <function>snd_BUG_ON()</function> macro is similar with + <function>WARN_ON()</function> macro. For example, + + <informalexample> + <programlisting> +<![CDATA[ + snd_BUG_ON(!pointer); +]]> + </programlisting> + </informalexample> + + or it can be used as the condition, + <informalexample> + <programlisting> +<![CDATA[ + if (snd_BUG_ON(non_zero_is_bug)) + return -EINVAL; +]]> + </programlisting> + </informalexample> + + </para> + + <para> + The macro takes an conditional expression to evaluate. + When <constant>CONFIG_SND_DEBUG</constant>, is set, the + expression is actually evaluated. If it's non-zero, it shows + the warning message such as + <computeroutput>BUG? (xxx)</computeroutput> + normally followed by stack trace. It returns the evaluated + value. + When no <constant>CONFIG_SND_DEBUG</constant> is set, this + macro always returns zero. + </para> + + </section> + + </chapter> + + +<!-- ****************************************************** --> +<!-- Acknowledgments --> +<!-- ****************************************************** --> + <chapter id="acknowledgments"> + <title>Acknowledgments</title> + <para> + I would like to thank Phil Kerr for his help for improvement and + corrections of this document. + </para> + <para> + Kevin Conder reformatted the original plain-text to the + DocBook format. + </para> + <para> + Giuliano Pochini corrected typos and contributed the example codes + in the hardware constraints section. + </para> + </chapter> +</book> diff --git a/Documentation/DocBook/writing_usb_driver.tmpl b/Documentation/DocBook/writing_usb_driver.tmpl new file mode 100644 index 00000000..bd97a13f --- /dev/null +++ b/Documentation/DocBook/writing_usb_driver.tmpl @@ -0,0 +1,412 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="USBDeviceDriver"> + <bookinfo> + <title>Writing USB Device Drivers</title> + + <authorgroup> + <author> + <firstname>Greg</firstname> + <surname>Kroah-Hartman</surname> + <affiliation> + <address> + <email>greg@kroah.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2001-2002</year> + <holder>Greg Kroah-Hartman</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + + <para> + This documentation is based on an article published in + Linux Journal Magazine, October 2001, Issue 90. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + The Linux USB subsystem has grown from supporting only two different + types of devices in the 2.2.7 kernel (mice and keyboards), to over 20 + different types of devices in the 2.4 kernel. Linux currently supports + almost all USB class devices (standard types of devices like keyboards, + mice, modems, printers and speakers) and an ever-growing number of + vendor-specific devices (such as USB to serial converters, digital + cameras, Ethernet devices and MP3 players). For a full list of the + different USB devices currently supported, see Resources. + </para> + <para> + The remaining kinds of USB devices that do not have support on Linux are + almost all vendor-specific devices. Each vendor decides to implement a + custom protocol to talk to their device, so a custom driver usually needs + to be created. Some vendors are open with their USB protocols and help + with the creation of Linux drivers, while others do not publish them, and + developers are forced to reverse-engineer. See Resources for some links + to handy reverse-engineering tools. + </para> + <para> + Because each different protocol causes a new driver to be created, I have + written a generic USB driver skeleton, modeled after the pci-skeleton.c + file in the kernel source tree upon which many PCI network drivers have + been based. This USB skeleton can be found at drivers/usb/usb-skeleton.c + in the kernel source tree. In this article I will walk through the basics + of the skeleton driver, explaining the different pieces and what needs to + be done to customize it to your specific device. + </para> + </chapter> + + <chapter id="basics"> + <title>Linux USB Basics</title> + <para> + If you are going to write a Linux USB driver, please become familiar with + the USB protocol specification. It can be found, along with many other + useful documents, at the USB home page (see Resources). An excellent + introduction to the Linux USB subsystem can be found at the USB Working + Devices List (see Resources). It explains how the Linux USB subsystem is + structured and introduces the reader to the concept of USB urbs + (USB Request Blocks), which are essential to USB drivers. + </para> + <para> + The first thing a Linux USB driver needs to do is register itself with + the Linux USB subsystem, giving it some information about which devices + the driver supports and which functions to call when a device supported + by the driver is inserted or removed from the system. All of this + information is passed to the USB subsystem in the usb_driver structure. + The skeleton driver declares a usb_driver as: + </para> + <programlisting> +static struct usb_driver skel_driver = { + .name = "skeleton", + .probe = skel_probe, + .disconnect = skel_disconnect, + .fops = &skel_fops, + .minor = USB_SKEL_MINOR_BASE, + .id_table = skel_table, +}; + </programlisting> + <para> + The variable name is a string that describes the driver. It is used in + informational messages printed to the system log. The probe and + disconnect function pointers are called when a device that matches the + information provided in the id_table variable is either seen or removed. + </para> + <para> + The fops and minor variables are optional. Most USB drivers hook into + another kernel subsystem, such as the SCSI, network or TTY subsystem. + These types of drivers register themselves with the other kernel + subsystem, and any user-space interactions are provided through that + interface. But for drivers that do not have a matching kernel subsystem, + such as MP3 players or scanners, a method of interacting with user space + is needed. The USB subsystem provides a way to register a minor device + number and a set of file_operations function pointers that enable this + user-space interaction. The skeleton driver needs this kind of interface, + so it provides a minor starting number and a pointer to its + file_operations functions. + </para> + <para> + The USB driver is then registered with a call to usb_register, usually in + the driver's init function, as shown here: + </para> + <programlisting> +static int __init usb_skel_init(void) +{ + int result; + + /* register this driver with the USB subsystem */ + result = usb_register(&skel_driver); + if (result < 0) { + err("usb_register failed for the "__FILE__ "driver." + "Error number %d", result); + return -1; + } + + return 0; +} +module_init(usb_skel_init); + </programlisting> + <para> + When the driver is unloaded from the system, it needs to deregister + itself with the USB subsystem. This is done with the usb_deregister + function: + </para> + <programlisting> +static void __exit usb_skel_exit(void) +{ + /* deregister this driver with the USB subsystem */ + usb_deregister(&skel_driver); +} +module_exit(usb_skel_exit); + </programlisting> + <para> + To enable the linux-hotplug system to load the driver automatically when + the device is plugged in, you need to create a MODULE_DEVICE_TABLE. The + following code tells the hotplug scripts that this module supports a + single device with a specific vendor and product ID: + </para> + <programlisting> +/* table of devices that work with this driver */ +static struct usb_device_id skel_table [] = { + { USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) }, + { } /* Terminating entry */ +}; +MODULE_DEVICE_TABLE (usb, skel_table); + </programlisting> + <para> + There are other macros that can be used in describing a usb_device_id for + drivers that support a whole class of USB drivers. See usb.h for more + information on this. + </para> + </chapter> + + <chapter id="device"> + <title>Device operation</title> + <para> + When a device is plugged into the USB bus that matches the device ID + pattern that your driver registered with the USB core, the probe function + is called. The usb_device structure, interface number and the interface ID + are passed to the function: + </para> + <programlisting> +static int skel_probe(struct usb_interface *interface, + const struct usb_device_id *id) + </programlisting> + <para> + The driver now needs to verify that this device is actually one that it + can accept. If so, it returns 0. + If not, or if any error occurs during initialization, an errorcode + (such as <literal>-ENOMEM</literal> or <literal>-ENODEV</literal>) + is returned from the probe function. + </para> + <para> + In the skeleton driver, we determine what end points are marked as bulk-in + and bulk-out. We create buffers to hold the data that will be sent and + received from the device, and a USB urb to write data to the device is + initialized. + </para> + <para> + Conversely, when the device is removed from the USB bus, the disconnect + function is called with the device pointer. The driver needs to clean any + private data that has been allocated at this time and to shut down any + pending urbs that are in the USB system. + </para> + <para> + Now that the device is plugged into the system and the driver is bound to + the device, any of the functions in the file_operations structure that + were passed to the USB subsystem will be called from a user program trying + to talk to the device. The first function called will be open, as the + program tries to open the device for I/O. We increment our private usage + count and save a pointer to our internal structure in the file + structure. This is done so that future calls to file operations will + enable the driver to determine which device the user is addressing. All + of this is done with the following code: + </para> + <programlisting> +/* increment our usage count for the module */ +++skel->open_count; + +/* save our object in the file's private structure */ +file->private_data = dev; + </programlisting> + <para> + After the open function is called, the read and write functions are called + to receive and send data to the device. In the skel_write function, we + receive a pointer to some data that the user wants to send to the device + and the size of the data. The function determines how much data it can + send to the device based on the size of the write urb it has created (this + size depends on the size of the bulk out end point that the device has). + Then it copies the data from user space to kernel space, points the urb to + the data and submits the urb to the USB subsystem. This can be seen in + the following code: + </para> + <programlisting> +/* we can only write as much as 1 urb will hold */ +bytes_written = (count > skel->bulk_out_size) ? skel->bulk_out_size : count; + +/* copy the data from user space into our urb */ +copy_from_user(skel->write_urb->transfer_buffer, buffer, bytes_written); + +/* set up our urb */ +usb_fill_bulk_urb(skel->write_urb, + skel->dev, + usb_sndbulkpipe(skel->dev, skel->bulk_out_endpointAddr), + skel->write_urb->transfer_buffer, + bytes_written, + skel_write_bulk_callback, + skel); + +/* send the data out the bulk port */ +result = usb_submit_urb(skel->write_urb); +if (result) { + err("Failed submitting write urb, error %d", result); +} + </programlisting> + <para> + When the write urb is filled up with the proper information using the + usb_fill_bulk_urb function, we point the urb's completion callback to call our + own skel_write_bulk_callback function. This function is called when the + urb is finished by the USB subsystem. The callback function is called in + interrupt context, so caution must be taken not to do very much processing + at that time. Our implementation of skel_write_bulk_callback merely + reports if the urb was completed successfully or not and then returns. + </para> + <para> + The read function works a bit differently from the write function in that + we do not use an urb to transfer data from the device to the driver. + Instead we call the usb_bulk_msg function, which can be used to send or + receive data from a device without having to create urbs and handle + urb completion callback functions. We call the usb_bulk_msg function, + giving it a buffer into which to place any data received from the device + and a timeout value. If the timeout period expires without receiving any + data from the device, the function will fail and return an error message. + This can be shown with the following code: + </para> + <programlisting> +/* do an immediate bulk read to get data from the device */ +retval = usb_bulk_msg (skel->dev, + usb_rcvbulkpipe (skel->dev, + skel->bulk_in_endpointAddr), + skel->bulk_in_buffer, + skel->bulk_in_size, + &count, HZ*10); +/* if the read was successful, copy the data to user space */ +if (!retval) { + if (copy_to_user (buffer, skel->bulk_in_buffer, count)) + retval = -EFAULT; + else + retval = count; +} + </programlisting> + <para> + The usb_bulk_msg function can be very useful for doing single reads or + writes to a device; however, if you need to read or write constantly to a + device, it is recommended to set up your own urbs and submit them to the + USB subsystem. + </para> + <para> + When the user program releases the file handle that it has been using to + talk to the device, the release function in the driver is called. In this + function we decrement our private usage count and wait for possible + pending writes: + </para> + <programlisting> +/* decrement our usage count for the device */ +--skel->open_count; + </programlisting> + <para> + One of the more difficult problems that USB drivers must be able to handle + smoothly is the fact that the USB device may be removed from the system at + any point in time, even if a program is currently talking to it. It needs + to be able to shut down any current reads and writes and notify the + user-space programs that the device is no longer there. The following + code (function <function>skel_delete</function>) + is an example of how to do this: </para> + <programlisting> +static inline void skel_delete (struct usb_skel *dev) +{ + kfree (dev->bulk_in_buffer); + if (dev->bulk_out_buffer != NULL) + usb_free_coherent (dev->udev, dev->bulk_out_size, + dev->bulk_out_buffer, + dev->write_urb->transfer_dma); + usb_free_urb (dev->write_urb); + kfree (dev); +} + </programlisting> + <para> + If a program currently has an open handle to the device, we reset the flag + <literal>device_present</literal>. For + every read, write, release and other functions that expect a device to be + present, the driver first checks this flag to see if the device is + still present. If not, it releases that the device has disappeared, and a + -ENODEV error is returned to the user-space program. When the release + function is eventually called, it determines if there is no device + and if not, it does the cleanup that the skel_disconnect + function normally does if there are no open files on the device (see + Listing 5). + </para> + </chapter> + + <chapter id="iso"> + <title>Isochronous Data</title> + <para> + This usb-skeleton driver does not have any examples of interrupt or + isochronous data being sent to or from the device. Interrupt data is sent + almost exactly as bulk data is, with a few minor exceptions. Isochronous + data works differently with continuous streams of data being sent to or + from the device. The audio and video camera drivers are very good examples + of drivers that handle isochronous data and will be useful if you also + need to do this. + </para> + </chapter> + + <chapter id="Conclusion"> + <title>Conclusion</title> + <para> + Writing Linux USB device drivers is not a difficult task as the + usb-skeleton driver shows. This driver, combined with the other current + USB drivers, should provide enough examples to help a beginning author + create a working driver in a minimal amount of time. The linux-usb-devel + mailing list archives also contain a lot of helpful information. + </para> + </chapter> + + <chapter id="resources"> + <title>Resources</title> + <para> + The Linux USB Project: <ulink url="http://www.linux-usb.org">http://www.linux-usb.org/</ulink> + </para> + <para> + Linux Hotplug Project: <ulink url="http://linux-hotplug.sourceforge.net">http://linux-hotplug.sourceforge.net/</ulink> + </para> + <para> + Linux USB Working Devices List: <ulink url="http://www.qbik.ch/usb/devices">http://www.qbik.ch/usb/devices/</ulink> + </para> + <para> + linux-usb-devel Mailing List Archives: <ulink url="http://marc.theaimsgroup.com/?l=linux-usb-devel">http://marc.theaimsgroup.com/?l=linux-usb-devel</ulink> + </para> + <para> + Programming Guide for Linux USB Device Drivers: <ulink url="http://usb.cs.tum.edu/usbdoc">http://usb.cs.tum.edu/usbdoc</ulink> + </para> + <para> + USB Home Page: <ulink url="http://www.usb.org">http://www.usb.org</ulink> + </para> + </chapter> + +</book> diff --git a/Documentation/DocBook/z8530book.tmpl b/Documentation/DocBook/z8530book.tmpl new file mode 100644 index 00000000..6f3883be --- /dev/null +++ b/Documentation/DocBook/z8530book.tmpl @@ -0,0 +1,371 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="Z85230Guide"> + <bookinfo> + <title>Z8530 Programming Guide</title> + + <authorgroup> + <author> + <firstname>Alan</firstname> + <surname>Cox</surname> + <affiliation> + <address> + <email>alan@lxorguk.ukuu.org.uk</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>2000</year> + <holder>Alan Cox</holder> + </copyright> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="intro"> + <title>Introduction</title> + <para> + The Z85x30 family synchronous/asynchronous controller chips are + used on a large number of cheap network interface cards. The + kernel provides a core interface layer that is designed to make + it easy to provide WAN services using this chip. + </para> + <para> + The current driver only support synchronous operation. Merging the + asynchronous driver support into this code to allow any Z85x30 + device to be used as both a tty interface and as a synchronous + controller is a project for Linux post the 2.4 release + </para> + </chapter> + + <chapter id="Driver_Modes"> + <title>Driver Modes</title> + <para> + The Z85230 driver layer can drive Z8530, Z85C30 and Z85230 devices + in three different modes. Each mode can be applied to an individual + channel on the chip (each chip has two channels). + </para> + <para> + The PIO synchronous mode supports the most common Z8530 wiring. Here + the chip is interface to the I/O and interrupt facilities of the + host machine but not to the DMA subsystem. When running PIO the + Z8530 has extremely tight timing requirements. Doing high speeds, + even with a Z85230 will be tricky. Typically you should expect to + achieve at best 9600 baud with a Z8C530 and 64Kbits with a Z85230. + </para> + <para> + The DMA mode supports the chip when it is configured to use dual DMA + channels on an ISA bus. The better cards tend to support this mode + of operation for a single channel. With DMA running the Z85230 tops + out when it starts to hit ISA DMA constraints at about 512Kbits. It + is worth noting here that many PC machines hang or crash when the + chip is driven fast enough to hold the ISA bus solid. + </para> + <para> + Transmit DMA mode uses a single DMA channel. The DMA channel is used + for transmission as the transmit FIFO is smaller than the receive + FIFO. it gives better performance than pure PIO mode but is nowhere + near as ideal as pure DMA mode. + </para> + </chapter> + + <chapter id="Using_the_Z85230_driver"> + <title>Using the Z85230 driver</title> + <para> + The Z85230 driver provides the back end interface to your board. To + configure a Z8530 interface you need to detect the board and to + identify its ports and interrupt resources. It is also your problem + to verify the resources are available. + </para> + <para> + Having identified the chip you need to fill in a struct z8530_dev, + which describes each chip. This object must exist until you finally + shutdown the board. Firstly zero the active field. This ensures + nothing goes off without you intending it. The irq field should + be set to the interrupt number of the chip. (Each chip has a single + interrupt source rather than each channel). You are responsible + for allocating the interrupt line. The interrupt handler should be + set to <function>z8530_interrupt</function>. The device id should + be set to the z8530_dev structure pointer. Whether the interrupt can + be shared or not is board dependent, and up to you to initialise. + </para> + <para> + The structure holds two channel structures. + Initialise chanA.ctrlio and chanA.dataio with the address of the + control and data ports. You can or this with Z8530_PORT_SLEEP to + indicate your interface needs the 5uS delay for chip settling done + in software. The PORT_SLEEP option is architecture specific. Other + flags may become available on future platforms, eg for MMIO. + Initialise the chanA.irqs to &z8530_nop to start the chip up + as disabled and discarding interrupt events. This ensures that + stray interrupts will be mopped up and not hang the bus. Set + chanA.dev to point to the device structure itself. The + private and name field you may use as you wish. The private field + is unused by the Z85230 layer. The name is used for error reporting + and it may thus make sense to make it match the network name. + </para> + <para> + Repeat the same operation with the B channel if your chip has + both channels wired to something useful. This isn't always the + case. If it is not wired then the I/O values do not matter, but + you must initialise chanB.dev. + </para> + <para> + If your board has DMA facilities then initialise the txdma and + rxdma fields for the relevant channels. You must also allocate the + ISA DMA channels and do any necessary board level initialisation + to configure them. The low level driver will do the Z8530 and + DMA controller programming but not board specific magic. + </para> + <para> + Having initialised the device you can then call + <function>z8530_init</function>. This will probe the chip and + reset it into a known state. An identification sequence is then + run to identify the chip type. If the checks fail to pass the + function returns a non zero error code. Typically this indicates + that the port given is not valid. After this call the + type field of the z8530_dev structure is initialised to either + Z8530, Z85C30 or Z85230 according to the chip found. + </para> + <para> + Once you have called z8530_init you can also make use of the utility + function <function>z8530_describe</function>. This provides a + consistent reporting format for the Z8530 devices, and allows all + the drivers to provide consistent reporting. + </para> + </chapter> + + <chapter id="Attaching_Network_Interfaces"> + <title>Attaching Network Interfaces</title> + <para> + If you wish to use the network interface facilities of the driver, + then you need to attach a network device to each channel that is + present and in use. In addition to use the generic HDLC + you need to follow some additional plumbing rules. They may seem + complex but a look at the example hostess_sv11 driver should + reassure you. + </para> + <para> + The network device used for each channel should be pointed to by + the netdevice field of each channel. The hdlc-> priv field of the + network device points to your private data - you will need to be + able to find your private data from this. + </para> + <para> + The way most drivers approach this particular problem is to + create a structure holding the Z8530 device definition and + put that into the private field of the network device. The + network device fields of the channels then point back to the + network devices. + </para> + <para> + If you wish to use the generic HDLC then you need to register + the HDLC device. + </para> + <para> + Before you register your network device you will also need to + provide suitable handlers for most of the network device callbacks. + See the network device documentation for more details on this. + </para> + </chapter> + + <chapter id="Configuring_And_Activating_The_Port"> + <title>Configuring And Activating The Port</title> + <para> + The Z85230 driver provides helper functions and tables to load the + port registers on the Z8530 chips. When programming the register + settings for a channel be aware that the documentation recommends + initialisation orders. Strange things happen when these are not + followed. + </para> + <para> + <function>z8530_channel_load</function> takes an array of + pairs of initialisation values in an array of u8 type. The first + value is the Z8530 register number. Add 16 to indicate the alternate + register bank on the later chips. The array is terminated by a 255. + </para> + <para> + The driver provides a pair of public tables. The + z8530_hdlc_kilostream table is for the UK 'Kilostream' service and + also happens to cover most other end host configurations. The + z8530_hdlc_kilostream_85230 table is the same configuration using + the enhancements of the 85230 chip. The configuration loaded is + standard NRZ encoded synchronous data with HDLC bitstuffing. All + of the timing is taken from the other end of the link. + </para> + <para> + When writing your own tables be aware that the driver internally + tracks register values. It may need to reload values. You should + therefore be sure to set registers 1-7, 9-11, 14 and 15 in all + configurations. Where the register settings depend on DMA selection + the driver will update the bits itself when you open or close. + Loading a new table with the interface open is not recommended. + </para> + <para> + There are three standard configurations supported by the core + code. In PIO mode the interface is programmed up to use + interrupt driven PIO. This places high demands on the host processor + to avoid latency. The driver is written to take account of latency + issues but it cannot avoid latencies caused by other drivers, + notably IDE in PIO mode. Because the drivers allocate buffers you + must also prevent MTU changes while the port is open. + </para> + <para> + Once the port is open it will call the rx_function of each channel + whenever a completed packet arrived. This is invoked from + interrupt context and passes you the channel and a network + buffer (struct sk_buff) holding the data. The data includes + the CRC bytes so most users will want to trim the last two + bytes before processing the data. This function is very timing + critical. When you wish to simply discard data the support + code provides the function <function>z8530_null_rx</function> + to discard the data. + </para> + <para> + To active PIO mode sending and receiving the <function> + z8530_sync_open</function> is called. This expects to be passed + the network device and the channel. Typically this is called from + your network device open callback. On a failure a non zero error + status is returned. The <function>z8530_sync_close</function> + function shuts down a PIO channel. This must be done before the + channel is opened again and before the driver shuts down + and unloads. + </para> + <para> + The ideal mode of operation is dual channel DMA mode. Here the + kernel driver will configure the board for DMA in both directions. + The driver also handles ISA DMA issues such as controller + programming and the memory range limit for you. This mode is + activated by calling the <function>z8530_sync_dma_open</function> + function. On failure a non zero error value is returned. + Once this mode is activated it can be shut down by calling the + <function>z8530_sync_dma_close</function>. You must call the close + function matching the open mode you used. + </para> + <para> + The final supported mode uses a single DMA channel to drive the + transmit side. As the Z85C30 has a larger FIFO on the receive + channel this tends to increase the maximum speed a little. + This is activated by calling the <function>z8530_sync_txdma_open + </function>. This returns a non zero error code on failure. The + <function>z8530_sync_txdma_close</function> function closes down + the Z8530 interface from this mode. + </para> + </chapter> + + <chapter id="Network_Layer_Functions"> + <title>Network Layer Functions</title> + <para> + The Z8530 layer provides functions to queue packets for + transmission. The driver internally buffers the frame currently + being transmitted and one further frame (in order to keep back + to back transmission running). Any further buffering is up to + the caller. + </para> + <para> + The function <function>z8530_queue_xmit</function> takes a network + buffer in sk_buff format and queues it for transmission. The + caller must provide the entire packet with the exception of the + bitstuffing and CRC. This is normally done by the caller via + the generic HDLC interface layer. It returns 0 if the buffer has been + queued and non zero values for queue full. If the function accepts + the buffer it becomes property of the Z8530 layer and the caller + should not free it. + </para> + <para> + The function <function>z8530_get_stats</function> returns a pointer + to an internally maintained per interface statistics block. This + provides most of the interface code needed to implement the network + layer get_stats callback. + </para> + </chapter> + + <chapter id="Porting_The_Z8530_Driver"> + <title>Porting The Z8530 Driver</title> + <para> + The Z8530 driver is written to be portable. In DMA mode it makes + assumptions about the use of ISA DMA. These are probably warranted + in most cases as the Z85230 in particular was designed to glue to PC + type machines. The PIO mode makes no real assumptions. + </para> + <para> + Should you need to retarget the Z8530 driver to another architecture + the only code that should need changing are the port I/O functions. + At the moment these assume PC I/O port accesses. This may not be + appropriate for all platforms. Replacing + <function>z8530_read_port</function> and <function>z8530_write_port + </function> is intended to be all that is required to port this + driver layer. + </para> + </chapter> + + <chapter id="bugs"> + <title>Known Bugs And Assumptions</title> + <para> + <variablelist> + <varlistentry><term>Interrupt Locking</term> + <listitem> + <para> + The locking in the driver is done via the global cli/sti lock. This + makes for relatively poor SMP performance. Switching this to use a + per device spin lock would probably materially improve performance. + </para> + </listitem></varlistentry> + + <varlistentry><term>Occasional Failures</term> + <listitem> + <para> + We have reports of occasional failures when run for very long + periods of time and the driver starts to receive junk frames. At + the moment the cause of this is not clear. + </para> + </listitem></varlistentry> + </variablelist> + + </para> + </chapter> + + <chapter id="pubfunctions"> + <title>Public Functions Provided</title> +!Edrivers/net/wan/z85230.c + </chapter> + + <chapter id="intfunctions"> + <title>Internal Functions</title> +!Idrivers/net/wan/z85230.c + </chapter> + +</book> |
