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| author | Pawel Osciak <p.osciak@samsung.com> | 2010-04-28 04:05:23 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-05-19 12:58:38 -0300 |
| commit | 21636363be97725432591071d26dc0dca088ecbb (patch) | |
| tree | 3448192f320a6385fb57c2e4585d4443dcd11696 | |
| parent | b2dfd1a45f014e24f0eecc50a7edc954425c348a (diff) | |
| download | linux-21636363be97725432591071d26dc0dca088ecbb.tar.bz2 | |
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>
| -rw-r--r-- | Documentation/DocBook/v4l/io.xml | 10 | ||||
| -rw-r--r-- | Documentation/DocBook/v4l/vidioc-qbuf.xml | 14 |
2 files changed, 22 insertions, 2 deletions
diff --git a/Documentation/DocBook/v4l/io.xml b/Documentation/DocBook/v4l/io.xml index bb685ed6fe7b..d424886beda0 100644 --- a/Documentation/DocBook/v4l/io.xml +++ b/Documentation/DocBook/v4l/io.xml @@ -702,6 +702,16 @@ They can be both cleared however, then the buffer is in "dequeued" state, in the application domain to say so.</entry> </row> <row> + <entry><constant>V4L2_BUF_FLAG_ERROR</constant></entry> + <entry>0x0040</entry> + <entry>When this flag is set, the buffer has been dequeued + successfully, although the data might have been corrupted. + This is recoverable, streaming may continue as normal and + the buffer may be reused normally. + Drivers set this flag when the <constant>VIDIOC_DQBUF</constant> + ioctl is called.</entry> + </row> + <row> <entry><constant>V4L2_BUF_FLAG_KEYFRAME</constant></entry> <entry>0x0008</entry> <entry>Drivers set or clear this flag when calling the 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> |