Bug 508006 - Display brightness improperly set after DPMS display cycle on->off->on
Summary: Display brightness improperly set after DPMS display cycle on->off->on
Status: RESOLVED UPSTREAM
Alias: None
Product: kwin
Classification: Plasma
Component: colour-management (other bugs)
Version First Reported In: 6.4.4
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-08-08 04:47 UTC by Christopher Snowhill
Modified: 2025-08-11 12:47 UTC (History)
2 users (show)

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Description Christopher Snowhill 2025-08-08 04:47:59 UTC 
SUMMARY
As of Plasma 6.4.4, when DPMS powers off my Asus ROG Strix XG27UCS, when it powers on again, the monitor is dimmed. Upon unlocking the screen, the desktop screen is severely darkened, except for the brightest colors, which seem to be relatively normal.

STEPS TO REPRODUCE
1. Enable HDR mode
2. Lock the screen
3. Press escape so the screen shuts off
4. Wait for DPMS to activate and power it off completely
5. Press a key to wake the screen
6. Unlock the desktop

OBSERVED RESULT
Screen is darkened. This effect cannot be captured with a screen shot.

EXPECTED RESULT
Screen is not darkened.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux - kernel 6.16.0-5-cachyos (64-bit)
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.16.0 
Qt Version: 6.9.1

ADDITIONAL INFORMATION
The effect goes away if I reset the display color settings, such as by toggling the accuracy/efficiency setting, or by running the HDR tuning wizard.
Comment 1 Zamundaaa 2025-08-11 12:47:52 UTC 
This is a driver bug, see https://gitlab.freedesktop.org/drm/amd/-/issues/4444#note_3032557