On 01/12/2015 09:44 PM, Devin Heitmueller wrote: > Hi Shuah, > > On Mon, Jan 12, 2015 at 9:56 PM, Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> 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 timer code paths in start/stop >> streaming, and close interfaces. However, tvtime will hang >> without the following tvtime change: > > I'm confused. When we last debated whether this patch would be > accepted, the last message from Mauro said the following: > >> That means that we'll need to keep holding such timeout code for >> years, until all distros update to a new tvtime, of course assuming >> that this is the only one application with such issue. > > In other words, the timeout code has to stay in there since otherwise > it will cause ABI breakage. It's great that Hans has submitted a > patch to improve tvtime, and over the next couple of years that patch > might actually start to appear in distributions. That unfortunately > doesn't change the fact that everybody who updates their kernel (or > has it updated for them as part of their distribution) will go from > "works fine" to "completely broken". > > The driver was working before the VB2 conversion, so if there is now > instability then it's likely that some bug was introduced during the > conversion to VB2. Simply ripping out the timeout code seems like the > wrong approach to addressing a regression likely caused by your own > VB2 conversion patch. > I couldn't reproduce what I was seeing when I did patch v2 series work. 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. I am seeing tvtime hangs without the timeout. I am fine with this patch not going. It does make the code cleaner and also reduces buffer handling during streaming. However, there is a clear regression to tvtime. thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@xxxxxxxxxxxxxxx | (970) 217-8978 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
