SUMMARY Downstream issue: https://gitlab.postmarketos.org/postmarketOS/pmaports/-/issues/3271 We tend to use a lot of lower end devices when testing Plasma Mobile, and so any graphics performance degradation becomes quite noticeable. Night color especially appears to cause much lower fps with animations which is noticeable when we interact and scroll widgets using touch. Suspected to have started happening in Plasma 6.2, but I haven't confirmed for myself, only the reporter of the downstream issue had caught it then. I can confirm the issue on Plasma 6.3 STEPS TO REPRODUCE 1. Enable night color (either through the kcm, or in the Plasma Mobile quicksettings which does the same thing) 2. Scroll webpages in firefox, or interact with the shell 3. Disable night color 4. Scroll webpages in firefox, or interact with the shell OBSERVED RESULT There is a lot of frames dropped when night color is enabled. EXPECTED RESULT The performance when night color is enabled matches the performance when night color is disabled. SOFTWARE/OS VERSIONS Linux/KDE Plasma: postmarketOS edge KDE Plasma Version: 6.3.0 KDE Frameworks Version: 6.11.0 Qt Version: 6.8.2
Created attachment 178561 [details] video
Does that device have a CTM and/or GAMMA_LUT? You can check with drm_info if they're supported, and while night light is on, if they're also actually used
(In reply to Zamundaaa from comment #2) > Does that device have a CTM and/or GAMMA_LUT? You can check with drm_info if > they're supported, and while night light is on, if they're also actually used It appears so, I attached the output of drm_info for google-krane (Lenovo Chromebook Duet)
Created attachment 178598 [details] drm_info of google-krane
hmm, did you get that drm_info output while night light is active? If so, KWin neither used the gamma lut (it's size is only 512, so that's expected - though we should probably relax that requirement a bit) nor the CTM, which would clearly explain the performance difference. If you could re-test on 6.3.2, that would also be good. There were some fixes for KMS offloading in there.
🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME. For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging. Thank you for helping us make KDE software even better for everyone!
🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.
(In reply to Zamundaaa from comment #5) > If you could re-test on 6.3.2, that would also be good. There were some > fixes for KMS offloading in there. The issue persists on Plasma Mobile 6.3.5.
Alright. Please attach the output of both drm_info and kscreen-doctor -o while night light is enabled. If KWin is now using KMS offloading (like it should), then this could just be the GPU being so severely slow that the few additional shader instructions kill performance. I'm not sure there's a whole lot that can be done in that case... If it's still not using KMS offloading though, then that should be much easier to fix.
Created attachment 182871 [details] drm_info on Plasma Mobile 6.4.1 on Google-Krane
Created attachment 182872 [details] `kscreen-doctor -o` on Plasma Mobile 6.4.1 on Google-Krane
(In reply to Zamundaaa from comment #9) > Please attach the output of both drm_info and kscreen-doctor -o > while night light is enabled. Both of them should now be attached to this issue.
> │ │ ├───"CTM": blob = 0 > │ │ ├───"GAMMA_LUT": blob = 0 Alright, still no KMS offloading, and no option is enabled that would prevent it. That explains the performance problems. Maybe the driver is rejecting our config? Please follow https://invent.kde.org/plasma/kwin/-/wikis/Debugging/Debugging-DRM-issues to get a drm debug log of enabling night light.
Created attachment 182873 [details] drm-debug log while enabling night light
Created attachment 182901 [details] add some logging to kwin Hmm, there's nothing relevant in there :/ Could you run with that patch, enable night light and then attach KWin's log here?
(In reply to Zamundaaa from comment #15) > Created attachment 182901 [details] > add some logging to kwin > > Hmm, there's nothing relevant in there :/ > Could you run with that patch, enable night light and then attach KWin's log > here? Ah, I forgot about this after holidays. I can't really run a patch for a component such a KWin. Last time I tried building KDE software, it was extremely complicated and didn't work in the end. And even if I was to get it to build, I wouldn't know how to run it. Maybe Devin Lin would be up for testing it? (I have no idea how to ping someone here.) They are a Plasma Mobile developer, so I assume they have experience building KWin and running it on postmarketOS.