summaryrefslogtreecommitdiff
path: root/Documentation/DocBook/v4l/vidioc-qbuf.xml
diff options
context:
space:
mode:
authorJens Axboe <jens.axboe@oracle.com>2010-05-21 23:27:26 +0400
committerJens Axboe <jens.axboe@oracle.com>2010-05-21 23:27:26 +0400
commitee9a3607fb03e804ddf624544105f4e34260c380 (patch)
treece41b6e0fa10982a306f6c142a92dbf3c9961284 /Documentation/DocBook/v4l/vidioc-qbuf.xml
parentb492e95be0ae672922f4734acf3f5d35c30be948 (diff)
parentd515e86e639890b33a09390d062b0831664f04a2 (diff)
downloadlinux-ee9a3607fb03e804ddf624544105f4e34260c380.tar.xz
Merge branch 'master' into for-2.6.35
Conflicts: fs/ext3/fsync.c Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-qbuf.xml')
-rw-r--r--Documentation/DocBook/v4l/vidioc-qbuf.xml14
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>