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| author | Hans Verkuil <hverkuil@xs4all.nl> | 2010-02-20 09:41:03 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-02-26 15:11:05 -0300 |
| commit | 995f5fefb0c6abba3688b3aadf40e422b64b814a (patch) | |
| tree | 560d626bee9f74cf64c96e1d9ff93bfeb230c686 /Documentation/DocBook/v4l/vidioc-querybuf.xml | |
| parent | 340dde817a4f68af79453ed295ca0e8de7232669 (diff) | |
| download | linux-stable-995f5fefb0c6abba3688b3aadf40e422b64b814a.tar.gz linux-stable-995f5fefb0c6abba3688b3aadf40e422b64b814a.tar.bz2 linux-stable-995f5fefb0c6abba3688b3aadf40e422b64b814a.zip | |
V4L/DVB: media-spec: Fix documentation mistakes regarding I/O streaming
The media spec contains several errors in the description of the
I/O streaming ioctls, in particular with respect to the userptr
I/O method.
The most important change is that you really need to set count
and index in v4l2_requestbuffer and v4l2_buffer when dealing with
user pointer streaming.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-querybuf.xml')
| -rw-r--r-- | Documentation/DocBook/v4l/vidioc-querybuf.xml | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/Documentation/DocBook/v4l/vidioc-querybuf.xml b/Documentation/DocBook/v4l/vidioc-querybuf.xml index d834993e6191..e649805a4908 100644 --- a/Documentation/DocBook/v4l/vidioc-querybuf.xml +++ b/Documentation/DocBook/v4l/vidioc-querybuf.xml @@ -54,12 +54,13 @@ 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 previously + 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. 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> @@ -68,8 +69,8 @@ the structure.</para> <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 -<constant>V4L2_MEMORY_MMAP</constant>, the <structfield>m.offset</structfield> +<structfield>memory</structfield> field will be set to the current +I/O method, 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. The driver may or may not set the remaining fields and flags, they are meaningless in |