Could you try booting with 'drm.debug=0xe' and attach the dmesg log here (or on the upstream bug, if possible).
** Changed in: linux (Ubuntu) Status: Triaged => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/855124 Title: XRANDR operations very slow unless (phantom) HDMI1 disabled To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/855124/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs