On 01/12/2015 07:10 AM, Hans Verkuil wrote: > On 12/18/2014 05:20 PM, Shuah Khan wrote: >> au0828 does video and vbi buffer timeout handling to prevent >> applications such as tvtime from hanging by ensuring that the >> video frames continue to be delivered even when the ITU-656 >> input isn't receiving any data. This work-around is complex >> as it introduces set and clear tier code paths in start/stop >> streaming, and close interfaces. After the vb2 conversion, the >> timeout handling is introducing instability as well as feeding >> too many blank green screens, resulting in degraded video quality. > > Why would this result in degraded video quality? And which instability > exactly?
What I noticed was that I was seeing a few too many green screens and I had to re-tune xawtv when the timeout code is in place. My thinking was that this timeout handling could be introducing blank green frames when there is no need. However, I can't reproduce the problem on 3.19-rc4 base which is what I am using to test the changes to the patch series. Hence, I am not positive if the timeout code indeed was doing anything bad. > >> Without this timeout handling, both xawtv, and tvtime are working >> well with good quality video. I am seeing tvtime hangs. > > Erm, tvtime without the recent 'tvtime: don't block indefinitely waiting > for frames' patch will not work well with au0828 without the timeout code > if there is no valid video data. > > This should at minimum be mentioned in the commit log. I will resend the patch with the updated commit log knowing full well that it might not be accepted. I do have to re-cut the patch after the changes to address your comments on the vb2 conversion patch. It applies, with fuzz, so I decided to re-cut the patch. thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shua...@osg.samsung.com | (970) 217-8978 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
