Color issue (mostly slightly oversaturated) when fresh boot to game mode

[krakerz]

i've got this weird issue with color, i can't give proof because even i tried to record, i'm not sure you can see the differences
but here is the issue

when you do boot normally into gamemode, i noticed the coler is kinda oversaturated,
but it will be fixed if you switch to desktop mode, then switch back again to game mode
the color is fixed

i've tried many things like overwrite gamescope session param to force srgb, with no result
after few hours debugging and helped by Ai to find the root issue, i managed to find a workaround
which is kinda imitate what KDE did, so this is my workaround for now

1. switch to desktop mode / use ssh if you have another device
2. open terminal and do systemctl --user edit gamescope-session.service
3. insert this on top of ### Edits below this comment will be discarded

[Service]
ExecStartPre=-/usr/bin/pkill kwin_wayland
ExecStartPre=/usr/bin/bash -c 'kwin_wayland & KWIN_PID=$!; sleep 2; kill -9 $KWIN_PID'

4. save and exit, and do systemctl --user daemon-reload to reload the daemon
5. do clean reboot to see the effect

what it did was, clean up any kwin process first then launch kde wayland compositor to fix the DRM color state, then kill it after 2 second

---

tbh idk what the root cause is, if anyone has hints feel free to comment

step to reproduce :

1. boot normally > auto enter gamescope / game mode
2. check if you have oversaturated color / kinda washed color
3. switch to desktop mode
4. you might noticed there is ~1s moment that it will either correct the brightness / color, wait a bit for all the startup finished
5. return to game mode
6. you'll see the display color is fixed, probably due kde things earlier

device :

OS: CachyOS x86_64
Host: Claw A8 BZ2EM (REV:1.0)
Kernel: Linux 7.0.12-1-cachyos-deckify
Display (PN8007QB1-2): 1920x1200 in 8", 120]
CPU: AMD Ryzen Z2 Extreme (16) @ 5.09 GHz
GPU: AMD Radeon 890M Graphics [Integrated]