Pasting from other Linux forums (with updates) since I haven’t found the answer yet.
I started to get weird “artifacts” in the form of a bunch of colored squares (mostly green) flickering on screen when anything on screen is changing in Plasma Wayland after running Cachy-Update at some point this past week. This could include moving windows around, scrolling through a website, playing a game, etc. This is also happening in my X11 windows, with my electron programs showing the weird colored squares flickering. I’ve attached a screenshot from a slow-motion video I took to try to capture this behavior.
It doesn’t happen in my Hyprland session and Cinnamon Wayland session, so I don’t believe it is graphics drivers or Wayland (I tried reinstalling them before trying other sessions), but more of a Desktop Environment issue with Plasma. I reinstalled entirely and noticed that it happened in the Live environment as well. Since it doesn’t happen in other sessions or Windows, I don’t think it’s hardware either.
Wendell from L1Tech Forums said it reminded him of the triple buffering issue, but I tried disabling triple buffering which did not solve the issue.
Let me know if there are useful logs or info I can provide to debug this since I’m a newbie when it comes to debugging this.
Since Cachy uses the most current-est things, plus some custom build of stuff in some areas iirc, have you tried a quick dual boot with a different distro? Or a different kernel and/or mesa build if such is available? Just to eliminate this as a problem area on your system for Plasma?
This might be it. I don’t know why it would only show itself in Plasma and not Hyprland/Cinnamon Wayland. Gonna experiment with different mesa drivers to see if I can pinpoint it.
The issue might be subtitle, or mutter/KWin are using the GPU in a way that makes it driver fail, where Hyperland/Cinamon compositors don’t. That or they just have fewer features, VRR… By Hyperland at least should have most of them.
Something I wonder also, this is a per-application issue.
Also there was a link to Making sure you're not a bot! that should be fixed with Linux 7.0, but I don’t know your distro…
Using CachyOS, I would’ve expected it to not appear if it should’ve been fixed in Linux 7.0. Also it was not a per application issue as I was seeing it across the entire screen extending beyond the window of the application being used with practically all applications (like the System settings app). I am happy to report that it was fixed by rolling back the Mesa drivers to 26.0.5. Out of curiosity I updated them back to 26.1.0 and the problem is not reappearing.
