Comment # 6 on bug 1170399 from David Hodgson

This went away with a recent (approx 2 months ago) update to the kernel and was
OK up to 4.12.14-lp151.28.79-default.  It has just come back with
4.12.14-lp151.28.83-default.

NVIDIA driver is unchanged throughout.

# gnome --version
/usr/lib/gnome-session-binary 3.26.1 

/etc/gdm/custom.conf:
[daemon]
InitialSetupEnable=False
WaylandEnable=false

/etc/sysconfig/displaymanager:
DISPLAYMANAGER_XSERVER="Xorg"
DISPLAYMANAGER="gdm"