Daniel Vetter <daniel@xxxxxxxx> writes: > On Wed, Nov 08, 2017 at 02:21:08PM -0800, Eric Anholt wrote: >> Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> writes: >> >> > On Wed, Nov 08, 2017 at 12:17:28PM -0800, Eric Anholt wrote: >> >> Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> writes: >> >> >> >> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> >> >> > >> >> > Apparently some sinks look at the YQ bits even when receiving RGB, >> >> > and they get somehow confused when they see a non-zero YQ value. >> >> > So we can't just blindly follow CEA-861-F and set YQ to match the >> >> > RGB range. >> >> > >> >> > Unfortunately there is no good way to tell whether the sink >> >> > designer claims to have read CEA-861-F. The CEA extension block >> >> > revision number has generally been stuck at 3 since forever, >> >> > and even a very recently manufactured sink might be based on >> >> > an old design so the manufacturing date doesn't seem like >> >> > something we can use. In lieu of better information let's >> >> > follow CEA-861-F only for HDMI 2.0 sinks, since HDMI 2.0 is >> >> > based on CEA-861-F. For HDMI 1.x sinks we'll always set YQ=0. >> >> > >> >> > The alternative would of course be to always set YQ=0. And if >> >> > we ever encounter a HDMI 2.0+ sink with this bug that's what >> >> > we'll probably have to do. >> >> >> >> Should vc4 be doing anything special for HDMI2 sinks, if it's an HDMI1.4 >> >> source? >> > >> > As long as you stick to < 340 MHz modes you shouldn't have to do >> > anything. For >=340 MHz you'd need to use some new HDMI 2.0 features. >> > >> > Looks like vc4 crtc .mode_valid() doesn't do much. I presume it's up >> > to bridges/encoders to filter out most things that aren't supported? >> >> I had a patch for that at >> https://patchwork.freedesktop.org/series/30680/ -- fedora folks had run >> into trouble with 4k monitors. > > Ack on the clock limiting patch, silly that it's stuck. No idea about CEC, > better for Hans/Boris I guess. Thanks!
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