Update (June 22nd): The issue now consistently appears ~10 minutes after boot (earlier testing likely just didn’t run under full load).
The “unplug/replug” suggestion didn’t help, but it led to a reliable workaround: boot with only the DP 4K display connected, wait a few minutes, then connect the first HDMI display, wait again, then connect the second HDMI display. This results in a stable session and has provided ~20 hours of uptime without flickering or GBM errors. I’ve reverted all system tweaks and returned displays to: DP-1: 3840×2160 @ 60Hz, 200% scaling HDMI-1: 3840×2160 @ 60Hz, 200% scaling HDMI-2: 1920×1080 @ 60Hz, 100% scaling (Previous all at 1080p configuration was part of testing.) Driver and desktop tests: Tried Intel Xe driver → same issue Tried KDE Plasma and Budgie → no flickering/GBM errors, but DP 4K display stayed black until forcing 30Hz via CLI (GUI wouldn’t allow it), so I reverted back to GNOME Current conclusion: GNOME + Intel display stack on this hardware appears unstable only in full 3-display configurations. Any 1–2 display combination is stable for long periods, but stability on 3 displays only occurs with the staged hotplug sequence (DP first, then HDMIs). Adding DP last reliably triggers the issue. At this point, this is a workaround rather than a fix. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2156644 Title: GNOME Panel & Activities Overview workspace thumbnails flickering issue To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2156644/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
