I can also verify this issue. A few things to further note (just in case there may be other involved components):
1) This issue also affects Ubuntu 17.10 out of the box, as well as Fedora 27. 2) The issue is not just with the login screen; this "vertical asynchronization" is also present during bootup, as well as during the desktop session if logged in. (It is even present during boot with Ubuntu 16.04, which I clean-installed when I encountered this issue initially with 17.10 after purchasing my ultrawide monitor) 3) The issue is not present if I am able to change the resolution to 1920x1080 (of course, this negates the benefit of the ultrawide monitor) 4) If it weren't for it also being present during the bootup sequence, I would say that it seems to be constrained to Wayland; if Wayland is disabled, the issue is not present at the login screen nor during the desktop session. I understand this makes pinning the culprit down more difficult; if it weren't for everything working fine in X.org, I would point the finger at the AMDGPU driver. If it weren't for the issue being present during the bootup sequence, I would point the finger at Wayland. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/1748871 Title: GDM horizontal scanline corruption with an ultra wide monitor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1748871/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
