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| author | Pawel Osciak <p.osciak@samsung.com> | 2010-04-28 09:05:23 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-05-19 17:58:38 +0200 |
| commit | 21636363be97725432591071d26dc0dca088ecbb (patch) | |
| tree | 3448192f320a6385fb57c2e4585d4443dcd11696 /Documentation/DocBook/v4l/vidioc-qbuf.xml | |
| parent | V4L/DVB: videobuf: Add support for V4L2_BUF_FLAG_ERROR (diff) | |
| download | linux-21636363be97725432591071d26dc0dca088ecbb.tar.xz linux-21636363be97725432591071d26dc0dca088ecbb.zip | |
V4L/DVB: Add documentation for the new error flag
Add documentation for V4L2_BUF_FLAG_ERROR.
Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-qbuf.xml')
| -rw-r--r-- | Documentation/DocBook/v4l/vidioc-qbuf.xml | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/DocBook/v4l/vidioc-qbuf.xml b/Documentation/DocBook/v4l/vidioc-qbuf.xml index b843bd7b3897..ab691ebf3b93 100644 --- a/Documentation/DocBook/v4l/vidioc-qbuf.xml +++ b/Documentation/DocBook/v4l/vidioc-qbuf.xml @@ -111,7 +111,11 @@ from the driver's outgoing queue. They just set the 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.</para> +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.</para> <para>By default <constant>VIDIOC_DQBUF</constant> blocks when no buffer is in the outgoing queue. When the @@ -158,7 +162,13 @@ enqueue a user pointer buffer.</para> <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.</para> +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> |