https://bugs.kde.org/show_bug.cgi?id=527725
Bug ID: 527725
Summary: HDR output severely washed out on Acer Predator X27U
Z1 since KWin 6.8.0 (AMD RX 6900 XT)
Classification: Plasma
Product: kwin
Version First 6.8.0
Reported In:
Platform: openSUSE
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: colour-management
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected]
Target Milestone: ---
**SUMMARY**
HDR on my Acer Predator X27U Z1 stopped working correctly after upgrading from
KWin 6.7.x to 6.8.0.
With KWin 6.8.0, enabling HDR caused severe visual corruption, including
rainbow-colored static covering approximately half the screen. After updating
to KWin 6.8.1, the static disappeared, but HDR now produces an extremely
washed-out image with incorrect gamma, contrast, and brightness.
The issue only affects the Acer monitor. HDR continues working correctly on my
ASUS VG27AQL5A and Gigabyte G27Q.
Screenshots taken while the issue occurs look normal, despite the physical
monitor displaying incorrect colors.
**STEPS TO REPRODUCE**
1. Start a KDE Plasma Wayland session using an AMD Radeon RX 6900 XT.
2. Connect an Acer Predator X27U Z1 via DisplayPort.
3. Open System Settings > Display & Monitor.
4. Enable HDR on the Acer.
**OBSERVED RESULT**
The Acer's HDR output becomes severely washed out and excessively bright.
Disabling HDR restores normal SDR output.
**EXPECTED RESULT**
HDR should display normally, as it did under KWin 6.7.x.
**SYSTEM INFORMATION**
- Distribution: openSUSE Tumbleweed
- Session: Wayland
- KWin: 6.8.1
- GPU: AMD Radeon RX 6900 XT
- Monitor: Acer Predator X27U Z1, 2560x1440, 280 Hz, DisplayPort
- Additional monitors: ASUS VG27AQL5A and Gigabyte G27Q
**TROUBLESHOOTING**
The following did not resolve the issue:
- Testing refresh rates of 60, 120, and 280 Hz
- Switching between 8-bit and automatic 10-bit color depth
- Changing KWin color-processing preferences
- Adjusting HDR brightness and SDR brightness/saturation
- Disabling direct scanout with KWIN_DRM_NO_DIRECT_SCANOUT=1
- Enabling KWIN_DRM_USE_COLOR_PIPELINE=1
- Resetting kwinoutputconfig.json
- Checking EDID information and kernel logs
**REGRESSION HISTORY**
- KWin 6.7.x: HDR worked normally.
- KWin 6.8.0: Rainbow static and severe display corruption.
- KWin 6.8.1: No rainbow static, but severely washed-out HDR.
The issue persists after extensive configuration troubleshooting.
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