diff options
| author | Hans Verkuil <hans.verkuil@cisco.com> | 2012-09-19 11:14:39 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-10-05 22:25:17 -0300 |
| commit | e3b1b4e732e18befcfa428bac1c487f681fbc36a (patch) | |
| tree | d79f2e6f15a27b0ecf8c6f6c4a4e1feee241bc9f /Documentation/DocBook/media/v4l/vidioc-querybuf.xml | |
| parent | 96b1a70226cd43f69c63a7ba2a769bece08cf64e (diff) | |
[media] DocBook: various updates w.r.t. v4l2_buffer and multiplanar
Clarify the behavior of v4l2_buffer in the multiplanar case,
including fixing a false statement: you can't set m.planes to NULL
when calling DQBUF.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-querybuf.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-querybuf.xml | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml index 6e414d7b6df..a597155c052 100644 --- a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml +++ b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml @@ -48,8 +48,8 @@ <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 + <para>This ioctl is part of the <link linkend="mmap">streaming +</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> @@ -71,6 +71,7 @@ the structure.</para> <para>In the <structfield>flags</structfield> field the <constant>V4L2_BUF_FLAG_MAPPED</constant>, +<constant>V4L2_BUF_FLAG_PREPARED</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 @@ -79,8 +80,10 @@ 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> +array elements will be used instead and the <structfield>length</structfield> +field of &v4l2-buffer; is set to the number of filled-in array elements. +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> |