[PATCH v4 13/36] [media] v4l2: add a frame timeout event

Steve Longerbeam
2017-03-02T23:07:21Z

On 03/02/2017 07:53 AM, Sakari Ailus wrote:
> Hi Steve,
>
> On Wed, Feb 15, 2017 at 06:19:15PM -0800, Steve Longerbeam wrote:
>> Add a new FRAME_TIMEOUT event to signal that a video capture or
>> output device has timed out waiting for reception or transmit
>> completion of a video frame.
>>
>> Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
>> ---
>> Documentation/media/uapi/v4l/vidioc-dqevent.rst | 5 +++++
>> Documentation/media/videodev2.h.rst.exceptions | 1 +
>> include/uapi/linux/videodev2.h | 1 +
>> 3 files changed, 7 insertions(+)
>>
>> diff --git a/Documentation/media/uapi/v4l/vidioc-dqevent.rst b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
>> index 8d663a7..dd77d9b 100644
>> --- a/Documentation/media/uapi/v4l/vidioc-dqevent.rst
>> +++ b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
>> @@ -197,6 +197,11 @@ call.
>> the regions changes. This event has a struct
>> :c:type:`v4l2_event_motion_det`
>> associated with it.
>> + * - ``V4L2_EVENT_FRAME_TIMEOUT``
>> + - 7
>> + - This event is triggered when the video capture or output device
>> + has timed out waiting for the reception or transmit completion of
>> + a frame of video.
>
> As you're adding a new interface, I suppose you have an implementation
> around. How do you determine what that timeout should be?

The imx-media driver sets the timeout to 1 second, or 30 frame
periods at 30 fps.

Steve