[PATCH v5 15/39] [media] v4l2: add a frame interval error event

Russell King - ARM Linux linux at armlinux.org.uk
Sat Mar 11 10:51:37 PST 2017

On Sat, Mar 11, 2017 at 10:14:49AM -0800, Steve Longerbeam wrote:
> On 03/11/2017 03:39 AM, Hans Verkuil wrote:
> >It's fine to use an internal event as long as the end-user doesn't
> >see it. But if you lose vsyncs, then you never capture another frame,
> >right?
> No, that's not correct. By loss of vertical sync, I mean the IPU
> captures portions of two different frames, resulting in a permanent
> "split image", with one frame containing portions of two consecutive
> images. Or, the video rolls continuously, if you remember the old CRT
> television sets of yore, it's the same rolling effect.

I have seen that rolling effect, but the iMX6 regains correct sync
within one complete "roll" just fine here with IMX219.  However, it
has always recovered.

So, I don't think there's a problem with the iMX6 part of the
processing, and so I don't think we should cripple the iMX6 capture
drivers for this problem.

It seems to me that the problem is with the source.

RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

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