Bug 509524 - Brightness level in UI not does not reflect level of monitor when it's changed while the computer is powered off
Summary: Brightness level in UI not does not reflect level of monitor when it's change...
Status: CONFIRMED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Power management & brightness (other bugs)
Version First Reported In: 6.4.5
Platform: Arch Linux Linux
: NOR minor
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-09-15 15:53 UTC by gudvinr+kde
Modified: 2025-09-16 22:08 UTC (History)
1 user (show)

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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