Thanks. Perhaps we jumped the gun though... On your login screen do you see two options "Ubuntu" and "Ubuntu on Xorg", or only one?
It looks like you might be experiencing a problem with Xorg judging by comment #4: Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (WW) RADEON(0): flip queue failed: Invalid argument Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (WW) RADEON(0): Page flip failed: Invalid argument Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (EE) RADEON(0): present flip failed Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (WW) RADEON(0): flip queue failed: Invalid argument Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (WW) RADEON(0): Page flip failed: Invalid argument Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (EE) RADEON(0): present flip failed Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (WW) RADEON(0): flip queue failed: Invalid argument Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (WW) RADEON(0): Page flip failed: Invalid argument Oct 23 08:21:34 hostname /usr/lib/gdm3/gdm-x-session[1533]: (EE) RADEON(0): present flip failed ** Bug watch added: GNOME Bug Tracker #789540 https://bugzilla.gnome.org/show_bug.cgi?id=789540 ** Also affects: mutter via https://bugzilla.gnome.org/show_bug.cgi?id=789540 Importance: Unknown Status: Unknown ** Also affects: xorg-server (Ubuntu) Importance: Undecided Status: New ** Changed in: xorg-server (Ubuntu) Status: New => Incomplete ** Changed in: gnome-shell (Ubuntu) Status: New => Incomplete ** Changed in: mutter (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1725836 Title: No more than 2 displays work simultaneously To manage notifications about this bug go to: https://bugs.launchpad.net/mutter/+bug/1725836/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs