I tried disabling nouveau drivers in Ubuntu 18.04 by putting these lines in
#Blacklist nouveau drivers blacklist nouveau blacklist lbm-nouveau alias nouveau off alias lbm-nouveau off
and updating initramfs.
On reboot the gdm won't start, blocked in the last line:
Trying to enter any tty, I get the same error (I had to undo changes from rescue mode).
The same procedure was working on 17.10 (with xorg).
My PC is an Asus ux430uq with clean install of ubuntu 18.04 (4.15.0-20 kernel).
I am afraid of uninstalling
xserver-xorg-video-nouveau drivers since I don't know how to reinstall them if something go wrong (I can't get internet working in rescue mode).
Uninstalling the above package lead to the same error. Trying to boot ubuntu with the kernel flag
nouveau.modeset=0 gives the same error too.