Same problem here with a Dell XPS 15 9560 after Kubuntu 17.10 -> 18.04 upgrade.
Finally solved after lots of retries and reboots. I have now:
Graphics Drivers PPA (https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa)
- sudo add-apt-repository ppa:graphics-drivers/ppa
- sudo apt update
- sudo apt dist-upgrade
Replaced manually nvidia 390 drivers by the newest 396
Purged nouveau package because I saw a "segmentation fault" log in /var/log/Xorg.0.log
- sudo apt purge xserver-xorg-video-nouveau
- sudo vi /etc/X11/xorg.conf -> uncomment line #Driver "nvidia" of Section "Device". So my xorg.conf file is exactly the same as the pasted in comment #77 without the last Section "Monitor".
- sudo reboot
After the reboot I see my previous sddm login screen instead of a tty and I can login normally :)
Same problem here with a Dell XPS 15 9560 after Kubuntu 17.10 -> 18.04 upgrade. /launchpad. net/~graphics- drivers/ +archive/ ubuntu/ ppa) drivers/ ppa xorg-video- nouveau
Finally solved after lots of retries and reboots. I have now:
Graphics Drivers PPA (https:/
- sudo add-apt-repository ppa:graphics-
- sudo apt update
- sudo apt dist-upgrade
Replaced manually nvidia 390 drivers by the newest 396
Purged nouveau package because I saw a "segmentation fault" log in /var/log/Xorg.0.log
- sudo apt purge xserver-
- sudo vi /etc/X11/xorg.conf -> uncomment line #Driver "nvidia" of Section "Device". So my xorg.conf file is exactly the same as the pasted in comment #77 without the last Section "Monitor".
- sudo reboot
After the reboot I see my previous sddm login screen instead of a tty and I can login normally :)