Cursor movement causes corruption with Gamescope in HDR

[njdom24]

• Sway Version:

  • 1.12-dev (sway_git from chaotic-nyx)

• Debug Log:

  • https://gist.github.com/njdom24/ef5911855e6a5968ba8ae762c588a6e6

• Configuration File:

  • Occurs (and logged) with the default config

• Stack Trace:

  • N/A

GPU: 9070 XT (Mesa 25.2.4)
OS: NixOS 25.11 (unstable)
Kernel: Linux 6.17.1-cachyos

• Description:
  • Running a game with Gamescope for HDR causes cursor movement, when visible, to corrupt the screen. I know Gamescope's nested Wayland backend has to composite a cursor, so I figure it's causing rapid direct scanout state changes.

Not seeing this occur on KDE, using their direct scanout Effect to confirm.

Doesn't seem to happen when I switch my game to SDR (and therefore require color management), nor does it happen with Gamescope SDR-on-SDR.

Seems we should probably keep direct scanout disabled while Gamescope's composited cursor is visible, instead of just while moving.

8mb.video-LXE-hNZnMdex.mp4

[njdom24]

Update: Gamescope logs are spamming:
[gamescope] [Error] xdg_backend: Compositor released us but we were not acquired. Oh no.
With every cursor movement.

No issues with PROTON_ENABLE_WAYLAND, PROTON_ENABLE_HDR options with community Proton builds, and no issues with SDR content (even in HDR mode) in Gamescope.

Update 2: It's --force-grab-cursor. Without this option, the corruption is both much rarer and harder to see.