From 871480933a1c28f8a9fed4c4d34d06c439a7a422 Mon Sep 17 00:00:00 2001 From: Srikant Patnaik Date: Sun, 11 Jan 2015 12:28:04 +0530 Subject: Moved, renamed, and deleted files The original directory structure was scattered and unorganized. Changes are basically to make it look like kernel structure. --- .../DocBook/media/v4l/vidioc-querybuf.xml | 102 +++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 Documentation/DocBook/media/v4l/vidioc-querybuf.xml (limited to 'Documentation/DocBook/media/v4l/vidioc-querybuf.xml') 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 @@ + + + ioctl VIDIOC_QUERYBUF + &manvol; + + + + VIDIOC_QUERYBUF + Query the status of a buffer + + + + + + int ioctl + int fd + int request + struct v4l2_buffer *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QUERYBUF + + + + argp + + + + + + + + + Description + + This ioctl is part of the memory +mapping 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. + + Applications set the type field + of a &v4l2-buffer; to the same buffer type as was previously used with +&v4l2-format; type and &v4l2-requestbuffers; +type, and the index + field. Valid index numbers range from zero +to the number of buffers allocated with &VIDIOC-REQBUFS; + (&v4l2-requestbuffers; count) minus one. +The reserved field should to set to 0. +When using the multi-planar API, the +m.planes field must contain a userspace pointer to an +array of &v4l2-plane; and the length field has +to be set to the number of elements in that array. +After calling VIDIOC_QUERYBUF with a pointer to + this structure drivers return an error code or fill the rest of +the structure. + + In the flags field the +V4L2_BUF_FLAG_MAPPED, +V4L2_BUF_FLAG_QUEUED and +V4L2_BUF_FLAG_DONE flags will be valid. The +memory field will be set to the current +I/O method. For the single-planar API, the m.offset +contains the offset of the buffer from the start of the device memory, +the length field its size. For the multi-planar API, +fields m.mem_offset and +length in the m.planes +array elements will be used instead. The driver may or may not set the remaining +fields and flags, they are meaningless in this context. + + The v4l2_buffer structure is + specified in . + + + + &return-value; + + + + EINVAL + + The buffer type is not +supported, or the index is out of bounds. + + + + + -- cgit