https://bugs.kde.org/show_bug.cgi?id=511793

--- Comment #8 from username <[email protected]> ---
(In reply to william.drumright from comment #7)
> (In reply to captainskelly0 from comment #6)
> > (In reply to william.drumright from comment #4)
> > > On KDE Plasma Wayland (KWin 6.5.4) with AMD GPU, games that grab/release 
> > > the
> > > mouse cursor (e.g. World of Warcraft WOTLK / Classic) show severe 
> > > frametime
> > > stalls when right-clicking to control the camera.
> > > 
> > > This does not occur on NVIDIA hardware.
> > > 
> > > Environment (affected system)
> > > OS: Archy
> > > KDE Plasma: 6.5.4
> > > Session: Wayland
> > > GPU: AMD RX 7900 XTX
> > > Driver: amdgpu + Mesa
> > > Monitor: 165 Hz
> > > Mouse: 1000 Hz polling
> > > Game runtime: Wine / Proton GE (DXVK)
> > > Game: World of Warcraft WOTLK (legacy client)
> > > 
> > > Symptoms
> > > Right-clicking to rotate camera causes a visible hitch / microstutter
> > > MangoHud FPS briefly drops to 0 exactly when the mouse button is pressed 
> > > or
> > > released
> > > 
> > > What fixes the issue
> > > KWIN_DRM_NO_DIRECT_SCANOUT=1
> > > → Completely resolves the stutter and FPS→0 drops
> > > 
> > > Gamescope
> > > → Also resolves it, but causes alt-tab issues and occasional mouse/camera
> > > desync
> > > 
> > > Partial workaround
> > > Disabling in-game hardware cursor (adds mouse latency)
> > > 
> > > 
> > > Control test (no issue)
> > > Tested on a laptop with NVIDIA GPU using the same game and runtime:
> > > CPU: Intel i7 (12th gen)
> > > GPU: RTX 3070 Ti
> > > OS: Archy
> > > Session: KDE Wayland
> > > Mouse: 1000 Hz polling
> > > Same Wine/Proton GE runner
> > > → No stutter, no FPS drops, no Gamescope or env vars needed
> > > 
> > > 
> > > Likely cause
> > > Appears related to KWin Direct Scanout being invalidated by cursor
> > > visibility / pointer grab changes, causing a brief present stall. 
> > > Disabling
> > > Direct Scanout globally avoids the issue.
> > 
> > Where are you adding `KWIN_DRM_NO_DIRECT_SCANOUT=1` to?
> 
> I may have spoken too soon. While enabling the KWIN_DRM did smooth out the
> FPS stutter, moving to a busy part of the game causes the mouse to have
> really bad latency. Going back to GameScope may be the best option until
> this bug gets addressed upstream.
> 
> If you want to test it yourself:
> 
>     Create an environment directory and file:
> mkdir -p ~/.config/environment.d
> nano ~/.config/environment.d/kwin.conf
> 
> Add this line to the file:
> 
> KWIN_DRM_NO_DIRECT_SCANOUT=1
> 
> Log out and back in

Still didn't work for me. I use KDE Wayland/Proton GE 10.26/RX 6900 XT if it
matters.

Currenlty the best workaroud I found is to keep Battle.net Launcher running in
system tray. It blocks direct scanout because of this
https://bugs.kde.org/show_bug.cgi?id=513203

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