This still happens but it seems to have happened while switching from lightdm to gnome-session. Here it changes the display resolution and shows the background of lightdm several times as mosaik across the screen.
[ 44.805941] EXT4-fs (dm-3): re-mounted. Opts: commit=0 [ 51.624571] [drm] force priority to high [ 51.626145] [drm] force priority to high [ 54.848254] eth0: no IPv6 routers present [ 87.672273] [drm:drm_mode_getfb] *ERROR* invalid framebuffer id [ 98.128006] [drm:atom_op_jump] *ERROR* atombios stuck in loop for more than 5secs aborting [ 98.128013] [drm:atom_execute_table_locked] *ERROR* atombios stuck executing E1E8 (len 2585, WS 4, PS 4) @ 0xE8D2 [ 102.324596] [drm] force priority to high [ 102.336424] [drm:radeon_dp_get_link_status] *ERROR* displayport link status failed [ 102.336426] [drm:radeon_dp_link_train_cr] *ERROR* clock recovery failed [ 119.680350] init: tty2 main process ended, respawning [ 121.851756] [drm:drm_mode_getfb] *ERROR* invalid framebuffer id [ 121.851830] [drm] force priority to high [ 158.560036] eth0: no IPv6 routers present the mouse hanging could be at the time of [drm] force priority to high ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/859171 Title: [ATI Radeon] System unresponsive for short time within Lightdm To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/859171/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs