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authorHans Verkuil <hans.verkuil@cisco.com>2012-09-03 09:21:59 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-09-26 09:26:57 -0300
commit6bd4dd27f926519527b9c39709df13ad120d63f9 (patch)
tree9b9f6c0fdf68097c6b63dbcfb023d29c72ae349d /Documentation/DocBook/media/v4l
parent8e19b3475072682312de71f4dddf6d4f4081e143 (diff)
[media] DocBook: improve STREAMON/OFF documentation
Specify that STREAMON/OFF should return 0 if the stream is already started/stopped. The spec never specified what the correct behavior is. This ambiguity was resolved during the 2012 Media Workshop. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Sakari Ailus <sakari.ailus@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l')
-rw-r--r--Documentation/DocBook/media/v4l/vidioc-streamon.xml7
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-streamon.xml b/Documentation/DocBook/media/v4l/vidioc-streamon.xml
index 81cca456905..716ea15e54a 100644
--- a/Documentation/DocBook/media/v4l/vidioc-streamon.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-streamon.xml
@@ -74,7 +74,12 @@ not transmitted yet. I/O returns to the same state as after calling
stream type. This is the same as &v4l2-requestbuffers;
<structfield>type</structfield>.</para>
- <para>Note applications can be preempted for unknown periods right
+ <para>If <constant>VIDIOC_STREAMON</constant> is called when streaming
+is already in progress, or if <constant>VIDIOC_STREAMOFF</constant> is called
+when streaming is already stopped, then the ioctl does nothing and 0 is
+returned.</para>
+
+ <para>Note that applications can be preempted for unknown periods right
before or after the <constant>VIDIOC_STREAMON</constant> or
<constant>VIDIOC_STREAMOFF</constant> calls, there is no notion of
starting or stopping "now". Buffer timestamps can be used to