diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb new file mode 100644 index 00000000..7c22a532 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -0,0 +1,195 @@ +What: /sys/bus/usb/devices/.../power/autosuspend +Date: March 2007 +KernelVersion: 2.6.21 +Contact: Alan Stern <stern@rowland.harvard.edu> +Description: + Each USB device directory will contain a file named + power/autosuspend. This file holds the time (in seconds) + the device must be idle before it will be autosuspended. + 0 means the device will be autosuspended as soon as + possible. Negative values will prevent the device from + being autosuspended at all, and writing a negative value + will resume the device if it is already suspended. + + The autosuspend delay for newly-created devices is set to + the value of the usbcore.autosuspend module parameter. + +What: /sys/bus/usb/devices/.../power/persist +Date: May 2007 +KernelVersion: 2.6.23 +Contact: Alan Stern <stern@rowland.harvard.edu> +Description: + If CONFIG_USB_PERSIST is set, then each USB device directory + will contain a file named power/persist. The file holds a + boolean value (0 or 1) indicating whether or not the + "USB-Persist" facility is enabled for the device. Since the + facility is inherently dangerous, it is disabled by default + for all devices except hubs. For more information, see + Documentation/usb/persist.txt. + +What: /sys/bus/usb/device/.../power/connected_duration +Date: January 2008 +KernelVersion: 2.6.25 +Contact: Sarah Sharp <sarah.a.sharp@intel.com> +Description: + If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file + is present. When read, it returns the total time (in msec) + that the USB device has been connected to the machine. This + file is read-only. +Users: + PowerTOP <power@bughost.org> + http://www.lesswatts.org/projects/powertop/ + +What: /sys/bus/usb/device/.../power/active_duration +Date: January 2008 +KernelVersion: 2.6.25 +Contact: Sarah Sharp <sarah.a.sharp@intel.com> +Description: + If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file + is present. When read, it returns the total time (in msec) + that the USB device has been active, i.e. not in a suspended + state. This file is read-only. + + Tools can use this file and the connected_duration file to + compute the percentage of time that a device has been active. + For example, + echo $((100 * `cat active_duration` / `cat connected_duration`)) + will give an integer percentage. Note that this does not + account for counter wrap. +Users: + PowerTOP <power@bughost.org> + http://www.lesswatts.org/projects/powertop/ + +What: /sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend +Date: January 2008 +KernelVersion: 2.6.27 +Contact: Sarah Sharp <sarah.a.sharp@intel.com> +Description: + When read, this file returns 1 if the interface driver + for this interface supports autosuspend. It also + returns 1 if no driver has claimed this interface, as an + unclaimed interface will not stop the device from being + autosuspended if all other interface drivers are idle. + The file returns 0 if autosuspend support has not been + added to the driver. +Users: + USB PM tool + git://git.moblin.org/users/sarah/usb-pm-tool/ + +What: /sys/bus/usb/device/.../authorized +Date: July 2008 +KernelVersion: 2.6.26 +Contact: David Vrabel <david.vrabel@csr.com> +Description: + Authorized devices are available for use by device + drivers, non-authorized one are not. By default, wired + USB devices are authorized. + + Certified Wireless USB devices are not authorized + initially and should be (by writing 1) after the + device has been authenticated. + +What: /sys/bus/usb/device/.../wusb_cdid +Date: July 2008 +KernelVersion: 2.6.27 +Contact: David Vrabel <david.vrabel@csr.com> +Description: + For Certified Wireless USB devices only. + + A devices's CDID, as 16 space-separated hex octets. + +What: /sys/bus/usb/device/.../wusb_ck +Date: July 2008 +KernelVersion: 2.6.27 +Contact: David Vrabel <david.vrabel@csr.com> +Description: + For Certified Wireless USB devices only. + + Write the device's connection key (CK) to start the + authentication of the device. The CK is 16 + space-separated hex octets. + +What: /sys/bus/usb/device/.../wusb_disconnect +Date: July 2008 +KernelVersion: 2.6.27 +Contact: David Vrabel <david.vrabel@csr.com> +Description: + For Certified Wireless USB devices only. + + Write a 1 to force the device to disconnect + (equivalent to unplugging a wired USB device). + +What: /sys/bus/usb/drivers/.../new_id +Date: October 2011 +Contact: linux-usb@vger.kernel.org +Description: + Writing a device ID to this file will attempt to + dynamically add a new device ID to a USB device driver. + This may allow the driver to support more hardware than + was included in the driver's static device ID support + table at compile time. The format for the device ID is: + idVendor idProduct bInterfaceClass. + The vendor ID and device ID fields are required, the + interface class is optional. + Upon successfully adding an ID, the driver will probe + for the device and attempt to bind to it. For example: + # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id + +What: /sys/bus/usb-serial/drivers/.../new_id +Date: October 2011 +Contact: linux-usb@vger.kernel.org +Description: + For serial USB drivers, this attribute appears under the + extra bus folder "usb-serial" in sysfs; apart from that + difference, all descriptions from the entry + "/sys/bus/usb/drivers/.../new_id" apply. + +What: /sys/bus/usb/drivers/.../remove_id +Date: November 2009 +Contact: CHENG Renquan <rqcheng@smu.edu.sg> +Description: + Writing a device ID to this file will remove an ID + that was dynamically added via the new_id sysfs entry. + The format for the device ID is: + idVendor idProduct. After successfully + removing an ID, the driver will no longer support the + device. This is useful to ensure auto probing won't + match the driver to the device. For example: + # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id + +What: /sys/bus/usb/device/.../avoid_reset_quirk +Date: December 2009 +Contact: Oliver Neukum <oliver@neukum.org> +Description: + Writing 1 to this file tells the kernel that this + device will morph into another mode when it is reset. + Drivers will not use reset for error handling for + such devices. +Users: + usb_modeswitch + +What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm +Date: September 2011 +Contact: Andiry Xu <andiry.xu@amd.com> +Description: + If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device + is plugged in to a xHCI host which support link PM, it will + perform a LPM test; if the test is passed and host supports + USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will + be enabled for the device and the USB device directory will + contain a file named power/usb2_hardware_lpm. The file holds + a string value (enable or disable) indicating whether or not + USB2 hardware LPM is enabled for the device. Developer can + write y/Y/1 or n/N/0 to the file to enable/disable the + feature. + +What: /sys/bus/usb/devices/.../removable +Date: February 2012 +Contact: Matthew Garrett <mjg@redhat.com> +Description: + Some information about whether a given USB device is + physically fixed to the platform can be inferred from a + combination of hub decriptor bits and platform-specific data + such as ACPI. This file will read either "removable" or + "fixed" if the information is available, and "unknown" + otherwise.
\ No newline at end of file |