It looks like modesetting, or at least a destructive probe of the attached displays.
There's nothing KMS related in dmesg corresponding to the blanking, so I don't think it's an invalid FB (I'd expect i915 to spit something in dmesg in that case) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1842009 Title: [Wayland] Screen blanks for a second whenever discrete GPU is powered up To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1842009/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs