Turns out lightdm is working after all, almost. If you wait patiently when the black screen appears after the Ubuntu 5 dots boot screen, possibly as much as 4 minutes, then the desktop eventually appears, albeit somewhat messed up, with a message box asking you to "unlock the login keychain" because it "was not unlocked when you logged in". After entering the password, the desktop is redrawn correctly and everything works. I'm still on kernel 126.96.36.199. It seems lightdm is just very slow as noted by njsf.
I think, if you touch the mouse during this black screen period, the login screen appears and, if you login you see a black screen for several seconds then it logs you out again. A cycle you can't get out of. That's what led to my comment that lightdm wasn't working for me. Daniel, I will create a bug of my own. Thanks for the explanation. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gdm3 in Ubuntu. https://bugs.launchpad.net/bugs/1779476 Title: Ubuntu 18.04: gdm3 does not switch to graphics after update To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1779476/+subscriptions -- desktop-bugs mailing list firstname.lastname@example.org https://lists.ubuntu.com/mailman/listinfo/desktop-bugs