X/Wayland issues after latest updates on F27

It had been a while since I performed an update (bad on me) so it was a rather large package set. But after upgrading GDM/Gnome became completely unusable. Everything was very slow to react and the mouse would track for a fraction of a second and the pause for a while. I'm not sure if it was the actual problem but downgrading gnome-shell "fixed" the problem enough that I now have a usable GUI, but only if I run startx from the command line. Trying to use journalctl from a 80 column CLI to figure out the problem was an exercise in futility... The lines are just way too long. I tried booting the previous kernel to no avail so it doesn't look like that was the core problem. gnome-shell core dumped in my last boot but not in the previous two so... The only consistent error has been: Mar 20 17:50:22 hobbes.localdomain kernel: [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [CRTC:32:crtc-0] flip_done timed out Mar 20 17:50:32 hobbes.localdomain kernel: [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [PLANE:30:plane-0] flip_done timed o Mar 20 17:50:42 hobbes.localdomain kernel: [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [CRTC:35:crtc-1] flip_done timed out Mar 20 17:50:52 hobbes.localdomain kernel: [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [PLANE:33:plane-2] flip_done timed o I am running the nvidia binary drivers but there has only been minor updates and I've now updated to the new version in updates-testing (390.40) did not help. Ideas? Thanks, Richard