On Sun Apr 2, 2023 at 12:49 PM CEST, Frank Oltmanns wrote: > > When apply this to drm-next my panel stays dark. I haven't figured out > yet why, though. The other two patches in this series work fine, i.e. > they have no effect as they are just a refactoring. > > I'm testing this on my pinephone. It's the same with the patch I > submitted. For whatever reason, it no longer works on drm-next. I've reproduced the issue on my PinePhone and noticed that tcon0 had set pll-video0-2x as its parent instead of pll-mipi. Having tried a whole range of pll-video0 rates, I'm now convinced that DSI only works when tcon0 has pll-mipi as its parent. As little a change as setting .clock in the default mode of PP's panel to 73500 can fix it. Better yet, dropping pll-video0-2x from the set of acceptable parents for tcon0 fixes it universally. And that's what megi's kernel does, though the measure was introduced with a different rationale: <https://github.com/megous/linux/commit/7374d5756aa0cc3f11e494e3cbc54f6c7c01e1a8> Roman
