[BUG] Heavy lagging on desktop while running SteamVR under KDE Plasma Wayland

[the-bukkit]

Describe the bug When I launch SteamVR my entire desktop only seems to update very sporadically (see spinner in top right of the video.) Once SteamVR is closed, everything works like normal again.

To Reproduce Steps to reproduce the behavior:

1. Launch SteamVR
2. Interact with any application

Expected behavior I expected for my system to behave about the same as prior to launching SteamVR.

System Information (please complete the following information):

• Steam client version (build number or date): 1731112063

• SteamVR version: Version 2.8.6 (1729556249)

• Distribution (e.g. Ubuntu): Arch Linux

• Steam runtime diagnostics: Steam Runtime Diagnostics.txt

• Steam and SteamVR logs: steam-logs.tar.gz

• Minidumps: steam-minidumps.tar.gz

Screenshots

https://github.com/user-attachments/assets/ea57c8ec-0e1b-4574-b447-87220bda33ac

Additional context I'm running a 3 monitor setup via a Displayport MST hub

Neither my CPU nor my GPU are fully utilized when this happens.

[wallcarpet40]

I have the same issue. I see you are also using KDE Plasma Wayland. This might be a regression in KDE Plasma, specifically in Wayland. When I run the session in X11, it works. There's already a bug report here: https://bugs.kde.org/show_bug.cgi?id=495400 And possible fix is pending here: https://invent.kde.org/plasma/kwin/-/merge_requests/6756

[the-bukkit]

I can confirm that it works normally under X11. So it looks like you're right about it being an issue with KDE Plasma Wayland.