Bug 504965

Summary: Allow disabling software dimming of screens
Product: [Plasma] kwin Reporter: zocker.network
Component: colour-managementAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DOWNSTREAM    
Severity: wishlist CC: nate
Priority: NOR Keywords: multiscreen
Version First Reported In: 6.2.5   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description zocker.network 2025-05-29 15:31:19 UTC 
SUMMARY
I like KDE’s new approach to dim multiple screens together. However, I dislike that the output to my TV is software-dimmed (because it does not support DDCCI). Especially because this makes the image quality on the TV worse than required, and also because earlier it was possible to quickly dim down the laptop screen to save battery while the content on the TV continues to play. But also on my PCs and other outputs, I would like to disable software dimming just because I would rather like to change it manually on the screen to preserve quality.

STEPS TO REPRODUCE
1. Have a laptop with an integrated screen
2. Connect a TV (or other non-DDCCI capable screen)
3. Dim down brightness with special keyboard keys

OBSERVED RESULT
Starting from a certain step, the brightness of the TV goes also down, but that is obviously emulated in software.

EXPECTED RESULT
Only dim the laptop screen and do never dim in software-emulated (as option).

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: NixOS 24.11
KDE Plasma Version: 6.2.5
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.3

ADDITIONAL INFORMATION
none
Comment 1 Bug Janitor Service 2025-05-29 16:33:39 UTC 
Thank you for the bug report!

However Plasma 6.2.5 is no longer eligible for support or maintenance from KDE; supported versions are 5.27. (LTS), and 6.3 (non-LTS) or newer. Please upgrade to a supported version as soon as your distribution makes it available to you. Plasma is a fast-moving project, and bugs in one version are often fixed in the next one.

If you need support for Plasma 6.2.5, please contact your distribution, who bears the responsibility of providing support for older releases that are no longer supported by KDE.

If you can reproduce the issue after upgrading to a supported version, feel free to re-open this bug report.