black screen after enabling nvidia drivers

[Peter Silva]

This is for 16.04... I had all of this working with primus on 14.04. I upgraded to xenial in December, and since then I have no proprietary nvidia drivers. Whenever the proprietary drivers are enabled (tried 35x a while ago, just repeated with 361, behaviour exactly the same.) I reboot, and I get a black screen. I can switch to a tty, and there is no obvious error in the Xorg.0.log, sometimes even lightdm is running, but there is nothing I can see. I tried various sorts of uninstall/re-install combinations, but always end up resolving by just removing all nvidia drivers to go back to nouveau. But steam games are not really playable with nouveau.