For me this is still broken with -proposed packages although this bug has "Fix Released" status: When I have xserver-xorg-video-nvidia-390 390.48-0ubuntu1 installed, the system boots into a back screen. Without, LightDM comes up as expected.
lspci excerpt (on a ThinkPad T460p): 00:02.0 VGA compatible controller: Intel Corporation HD Graphics 530 (rev 06) 02:00.0 3D controller: NVIDIA Corporation GM108M [GeForce 940MX] (rev a2) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1752053 Title: nvidia-390 fails to boot graphical display To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1752053/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp