Bug 509524

Summary:	Brightness level in UI not does not reflect level of monitor when it's changed while the computer is powered off
Product:	[Plasma] plasmashell	Reporter:	gudvinr+kde
Component:	Power management & brightness	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	CONFIRMED ---
Severity:	minor	CC:	nate
Priority:	NOR
Version First Reported In:	6.4.5
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description gudvinr+kde 2025-09-15 15:53:01 UTC

SUMMARY

When you turn PC off, then change brightness, then turn on, widget will show all brightness level.

STEPS TO REPRODUCE
1. Set brightness of external monitor to 0%
2. Turn PC off
3. Set brightness to e.g. 70%
4. Turn PC on

OBSERVED RESULT

Brightness level in UI grabbed from DDC/EDID and set to 70%

EXPECTED RESULT

Brightness at 0% as it was before turning PC off.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.2
Kernel Version: 6.16.7-arch1-1 (64-bit)
Graphics Platform: Wayland
Graphics Processor 1: AMD Radeon RX Vega M GL Graphics
Graphics Processor 2: Mesa Intel® HD Graphics 630

ADDITIONAL INFORMATION

This happens with both of my DELL P2418D and BenQ PD2700U