Modesetting artifacts on x11

Created an account just to report this bug. Only seems to happens under X11, usually when transitioning tabs. Installing the old DDX driver fixes the issue, but I read it's better to let it fallback to modesetting. Here's a video of the issue: 2025-02-27_14-19-24 I've made sure it isn't a compositor or wm issue, as it happens on other distros and WM/DEs as well, but as long as its under X11. Wayland is perfect, but I need x11 to drive a CRT monitor I use for gaming.

My machine specs are: CPU: Celeron n4020 GPU: UHD 600 8GB of RAM 256gb SSD OS: Arch Linux, 6.13.4 kernel

The circular looking artifacts definitely look like render compressed data that's not been decompressed.

Looks like it's always happening on some kind of transition effect. Who is rendering that transition?

Please

• attach the Xorg.log
• boot with drm.debug=0xe log_buf_len=4M passed to the kernel cmdline and attach the resulting dmesg after boot
• attach results of cat /sys/kernel/debug/dri/0/i915_display_info once you've reproduced the problem

There you go: Xorg.0.logdmesg.logdinfo.log

That version of Xorg shouldn't use modifiers by default, and I don't see any evidence in the log that you forced them on. Also the display was just using plain old X-tile (at least at the time when you grabbed the display_info). So this feels more like a potential Mesa bug where it's sometimes forgetting to decompress something.

What happens if you enable modifier support for X by placing something like this in your xorg.conf?

Section "ServerLayout"
        Identifier "default"
        Option "Debug" "dmabuf_capable"
EndSection

There should be some message in Xorg.log to indicate that it actually picked up the option, so verify that you see that.

Behaves about the same. Made sure to also verify xorg picked it up in log.

added Community feature: display/Other platform: GLK labels