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| author | Hans Verkuil <hverkuil@xs4all.nl> | 2018-09-17 07:37:18 -0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2018-10-04 14:26:10 -0400 |
| commit | 1611c686c1245408c3ddb451b2a5fff1dc088d6e (patch) | |
| tree | f1b267cf456b8481fea55e7466b0b06723a6c7ff /Documentation/media | |
| parent | 85e4af0a7ae2f146769b7475ae531bf8a3f3afb4 (diff) | |
| download | linux-0-day-1611c686c1245408c3ddb451b2a5fff1dc088d6e.tar.gz linux-0-day-1611c686c1245408c3ddb451b2a5fff1dc088d6e.tar.xz | |
media: vidioc-dqevent.rst: clarify V4L2_EVENT_SRC_CH_RESOLUTION
Clarify that when you receive V4L2_EVENT_SOURCE_CHANGE with flag
V4L2_EVENT_SRC_CH_RESOLUTION set, and the new resolution appears
identical to the old resolution, then you still must restart the
streaming I/O.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation/media')
| -rw-r--r-- | Documentation/media/uapi/v4l/vidioc-dqevent.rst | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-dqevent.rst b/Documentation/media/uapi/v4l/vidioc-dqevent.rst index cb3565f367933..04416b6943c0b 100644 --- a/Documentation/media/uapi/v4l/vidioc-dqevent.rst +++ b/Documentation/media/uapi/v4l/vidioc-dqevent.rst @@ -379,7 +379,17 @@ call. - 0x0001 - This event gets triggered when a resolution change is detected at an input. This can come from an input connector or from a video - decoder. + decoder. Applications will have to query the new resolution (if + any, the signal may also have been lost). + + *Important*: even if the new video timings appear identical to the old + ones, receiving this event indicates that there was an issue with the + video signal and you must stop and restart streaming + (:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` + followed by :ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>`). The reason is + that many devices are not able to recover from a temporary loss of + signal and so restarting streaming I/O is required in order for the + hardware to synchronize to the video signal. Return Value |