Bug 514857

Summary:	Unable to change the real brightness of Samsung Odyssey G5 from the plasma panel.
Product:	[Plasma] plasmashell	Reporter:	alesar032
Component:	Power management & brightness	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	kdedev
Priority:	NOR
Version First Reported In:	6.5.90
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description alesar032 2026-01-20 09:38:38 UTC

SUMMARY
Unable to change the real brightness of Samsung Odyssey G5 27" 1440p from the Plasma panel.

STEPS TO REPRODUCE
1. Change the brightness of the monitor from the Brightness and colour menu.

OBSERVED RESULT
The brightness of the monitor does not change, it only lowers the "virtual" contrast.

EXPECTED RESULT
The monitor brightness does change.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.5.90
KDE Frameworks Version: 6.22.0
Qt Version: 6.11.0
Kernel Version: 6.18.5-arch1-1 (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
The new version of the firmware fixes the issue where the monitor was crashing when changing the brightness via ddc, so we should be able to change it from the plasma panel. (see https://bugs.kde.org/show_bug.cgi?id=494522)

Comment 1 TraceyC 2026-01-20 20:57:23 UTC

Thanks for the bug report. Can you please  run `kscreen-doctor -o | grep -i bright` and paste the results?

Comment 2 alesar032 2026-01-20 22:00:20 UTC

(In reply to TraceyC from comment #1)
> Thanks for the bug report. Can you please  run `kscreen-doctor -o | grep -i
> bright` and paste the results?

 kscreen-doctor -o | grep -i bright
        Brightness control: supported, set to 100% and dimming to 100%
        Automatic brightness: unsupported
        Brightness control: supported, set to 20% and dimming to 100%
        Automatic brightness: unsupported
I have two monitors, the first one is the one that has the issue with the brightness control, the second one works fine.