I have realized, that my issue is not related to GDM, rather with X detection of my monitor. But it should be related to libxrandr (if I understand it well).
-- [Hardy] GDM starts with wrong display resolution https://bugs.launchpad.net/bugs/194552 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs