From 6bd4dd27f926519527b9c39709df13ad120d63f9 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Mon, 3 Sep 2012 09:21:59 -0300 Subject: [PATCH] [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 Reviewed-by: Sylwester Nawrocki Acked-by: Laurent Pinchart Acked-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/vidioc-streamon.xml | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/DocBook/media/v4l/vidioc-streamon.xml b/Documentation/DocBook/media/v4l/vidioc-streamon.xml index 81cca4569050..716ea15e54a1 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; type. - Note applications can be preempted for unknown periods right + If VIDIOC_STREAMON is called when streaming +is already in progress, or if VIDIOC_STREAMOFF is called +when streaming is already stopped, then the ioctl does nothing and 0 is +returned. + + Note that applications can be preempted for unknown periods right before or after the VIDIOC_STREAMON or VIDIOC_STREAMOFF calls, there is no notion of starting or stopping "now". Buffer timestamps can be used to -- 2.20.1