Bug 495545 - Laptop screen brightness changes are not animated smoothly anymore
Summary: Laptop screen brightness changes are not animated smoothly anymore
Status: REPORTED
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (show other bugs)
Version: git master
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: regression
Depends on:
Blocks:
 
Reported: 2024-10-29 20:11 UTC by Jakob Petsovits
Modified: 2024-10-30 16:14 UTC (History)
2 users (show)

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Description Jakob Petsovits 2024-10-29 20:11:37 UTC
SUMMARY

https://invent.kde.org/plasma/powerdevil/-/merge_requests/407, as prerequisite of https://invent.kde.org/plasma/kwin/-/merge_requests/6155, disabled brightness animations for laptop displays when going through KWin.

It's great that KWin can now fade between SDR and fake-HDR with a brightness animation by itself.

However, in the process, these changes broke all other laptop display brightness animations as well, notably for dimming and applet brightness sliders.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma:
KDE Plasma Version: 6.2.80 (around 6.2.2)
KDE Frameworks Version: 6.8
Qt Version: 6.8
Graphics platform: Wayland
Comment 1 Zamundaaa 2024-10-29 20:50:25 UTC
Yes, they are. You're linking to the MR that animates laptop brightness... it's not about HDR or anything like that.

It seems that since that was merged, the animation got really choppy though, with only 3 or 4 steps in it.
Comment 2 Zamundaaa 2024-10-29 21:04:07 UTC
Hmm, so I added some debug logging to KWin, but after restarting it, the animations are completely smooth again.
Comment 3 Jakob Petsovits 2024-10-29 21:11:17 UTC
Ah yes, you're right - it's possible to observe the animation when making large jumps in brightness.

Perhaps the KAuth helper invocation isn't fast enough to handle a high frequency of brightness changes per seconds reliably? If that's the case, then either we revive my PowerDevil branch for SetBrightness via login1 D-Bus, or we extend the Wayland interface to provide more context about the intended animation (or lack thereof).

But if restarting KWin helps, maybe the issue is elsewhere.
Comment 4 Nate Graham 2024-10-30 16:03:50 UTC
I still see brightness animations on my git master setup, FWIW.