Hello, I've been noticing what sounds like the same issue as the original post. This is brand new install of Ubuntu 20.04 after running all updates and restarting. A clean boot show has no display problems but after I suspend my system I get a lot of tearing/flashing. If I drop the rate on the larger monitor from 144Hz to 59.95Hz the problem goes away. I have also tried the other supported rates of 120.00 and 99.95 which still have tearing.
If I try the same process but with just my larger screen enabled, the resume doesn't have the flickering. This does not seem to be happening in Fedora 32 in the same system. Since that runs 5.6 and 3.36 on Wayland maybe the issue is in the kernel. I am mostly a user so I can't really draw better conclusions. I can provide a video and logs as needed. My setup: AMD® Ryzen 5 2600x six-core processor × 12 AMD® Radeon rx 5600 xt GNOME version 3.36.3 Kernel: 5.4.0-40-generic #44-Ubuntu SMP Tue Jun 23 00:01:04 UTC 2020 Windowing System X11 (also happens when using Wayland) 2 monitors: Samsung 32" with resolution 3840x2160 @ 144.00 Hz Asus 24" 1920x1080 at 60Hz -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1874588 Title: Flickering screen after waking up from Suspend To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1874588/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
