Hi Hans, On 24-03-2017 12:28, Hans Verkuil wrote: > On 03/24/17 13:21, Jose Abreu wrote: >> Hi Hans, >> >> >> On 24-03-2017 12:12, Hans Verkuil wrote: >>> On 03/24/17 12:52, Jose Abreu wrote: >>>> Hi Hans, >>>> >>>> >>>>>> Can you please review this series, when possible? And if you >>>>>> could test it on cobalt it would be great :) >>>>> Hopefully next week. >>>> Thanks :) >>>> >>>>> Did you have some real-world numbers w.r.t. measured >>>>> pixelclock frequencies and 60 vs 59.94 Hz and 24 vs 23.976 Hz? >>>> I did make some measurements but I'm afraid I didn't yet test >>>> with many sources (I mostly tested with signal generators which >>>> should have a higher precision clock than real sources). I have a >>>> bunch of players here, I will test them as soon as I can. >>>> Regarding precision: for our controller is theoretically and >>>> effectively enough: The worst case is for 640x480, and even in >>>> that case the difference between 60Hz and 59.94Hz is > 1 unit of >>>> the measuring register. This still doesn't solve the problem of >>>> having a bad source with a bad clock, but I don't know if we can >>>> do much more about that. >>> I would really like to see a table with different sources sending >>> these different framerates and the value that your HW detects. >>> >>> If there is an obvious and clear difference, then this feature makes >>> sense. If it is all over the place, then I need to think about this >>> some more. >>> >>> To be honest, I expect that you will see 'an obvious and clear' >>> difference, but that is no more than a gut feeling at the moment and >>> I would like to see some proper test results. >> Ok, I will make a table. The test procedure will be like this: >> - Measure pixel clock value using certified HDMI analyzer >> - Measure pixel clock using our controller >> - Compare the values obtained from analyzer, controller and >> the values that the source is telling to send (the value >> displayed in source menu for example [though, some of them may >> not discriminate the exact frame rate, thats why analyzer should >> be used also]). >> >> Seems ok? I will need some time, something like a week because my >> setup was "borrowed". > That sounds good. Sorry for adding to your workload, but there is no > point to have a flag that in practice is meaningless. > > I'm actually very curious about the results! I managed to do the tests but unfortunately I can't publish the full results (at least until I get approval). I can say that the results look good. As you expected we have some sources with a bad clock but this is correctly detected by the controller (and also by the HDMI analyzer). Using the v4l2_calc_framerate function I managed to get this: | Source | Resolution | v4l2_calc_framerate() ------------------------------------------------------------------------------ | Analyzer 1 | 640x480@59.94 | 59.92 | Analyzer 1 | 640x480@60 | 60 | Analyzer 1 | 1920x1080@60 | 60 | Player 1 | 1920x1080@59.94 | 59.94 | Player 2 | 1920x1080@59.94 | 59.93 | Player 3 | 3840x2160@59.94 | 59.94 | Player 4 | 1920x1080@59.94 | 59.94 | Player 5 | 1920x1080@59.94 | 59.93 | Player 6 | 1280x720@50 | 50 | Player 7 | 1920x1080@59.94 | 59.93 | Player 8 | 1920x1080@60 | 60 | Analyzer 2 | 720x480@59.94 | 59.94 | Analyzer 2 | 720x480@60 | 60 | Analyzer 2 | 1920x1080@59.94 | 59.93 | Analyzer 2 | 1920x180@60 | 60 | Analyzer 2 | 3840x2160@23.98 | 23.97 | Analyzer 2 | 3840x2160@24 | 24 | Analyzer 2 | 3840x2160@29.97 | 29.96 | Analyzer 2 | 3840x2160@30 | 30 | Analyzer 2 | 3840x2160@59.94 | 59.93 | Analyzer 2 | 3840x2160@60 | 60 ------------------------------------------------------------------------------ What do you think? Shall we continue integrating this new patch or drop it? Best regards, Jose Miguel Abreu > > Regards, > > Hans > >> Best regards, >> Jose Miguel Abreu >> >>>>> I do want to see that, since this patch series only makes sense if you can >>>>> actually make use of it to reliably detect the difference. >>>>> >>>>> I will try to test that myself with cobalt, but almost certainly I won't >>>>> be able to tell the difference; if memory serves it can't detect the freq >>>>> with high enough precision. >>>> Ok, thanks, this would be great because I didn't test the series >>>> exactly "as is" because I'm using 4.10. I did look at vivid >>>> driver but it already handles reduced frame rate, so it kind of >>>> does what it is proposed in this series. If this helper is >>>> integrated in the v4l2 core then I can send the patch to vivid. >>> That would be nice to have in vivid. >>> >>> Regards, >>> >>> Hans >>>
