Changing color accuracy to "Prefer accuracy" breaks Kwin on an RX 9070 XT

Reporting here as per asked in KDE's bugzilla

Brief summary of the problem:

Changing color accuracy in the KDE desktop environement to "Prefer accuracy" on an RX 9070 XT creates artifacts on the screen rending it unusable, note that plugging a screen into the iGPU does not produce this, while it does to screens plugged to the GPU

Hardware description:

• CPU: AMD R7 7800x3D
• GPU: AMD RX 9070 XT
• System Memory: 32GB DDR5
• Display(s): 1440p 144hz (on iGPU) + 1440p 360hz (on GPU)
• Type of Display Connection: DP

System information:

• Distro name and Version: EndeavourOS (Arch based)
• Kernel version: Linux 6.13.7-arch1-1
• Driver: Mesa 25.0.1

How to reproduce the issue:

STEPS TO REPRODUCE

1. Own an RX 9070 XT
2. Make sure your monitors are plugged into it
3. Change color accuracy to "Prefer accuracy" in the KDE Desktop Environement

Screenshots/video files

https://bugsfiles.kde.org/attachment.cgi?id=179430

added 9000 dGPU series DC labels

Can confirm this. Interestingly, taking screenshots of the desktop render them normally, it's the video output itself that gets garbled.

Same on my end. I've got pretty much the same setup. The only difference are the monitors. There was no issue with my RTX 3080.

same issue one my end! my system:

Operating System: Nobara Linux 41
KDE Plasma Version: 6.3.3
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.2
Kernel Version: 6.13.7-200.nobara.fc41.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800X3D 8-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon Graphics
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7C84
System Version: 1.0

Same issue here on a RX 9070 XT, but here's another twist: If you run KWin Wayland with direct scanout enabled (this is the default), mpv (tested from 0.39.0 up to the latest git) with --no-config --vo=gpu --gpu-api=vulkan any-video.mkv, then enter fullscreen and make sure no OSD is rendered, KWin can switch its window to direct scanout, and the same display glitching occurs. This was reported separately to mpv (with a video) and mesa. Same behavior on Linux 6.13.8 and 6.14.0.

I can also confirm that looks exactly like on my system with an RX 9070 XT.

Operating System: Arch Linux KDE Plasma Version: 6.3.4 KDE Frameworks Version: 6.12.0 Qt Version: 6.8.3 Kernel Version: 6.13.8-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 12 × AMD Ryzen 5 7500F 6-Core Processor Memory: 30.9 GiB of RAM Graphics Processor: AMD Radeon Graphics Manufacturer: Micro-Star International Co., Ltd. Product Name: MS-7E26 System Version: 1.0

mentioned in issue mesa/mesa#12890 (closed)

changed the description

mentioned in issue #4102 (closed)