I upgraded to Ubuntu 15.04 which was just released. After reboot, I get as far as the login screen but it only appears for a second, then it goes to an infinite loop of screen flickering. How could I fix it?
Here is a video of what I'm seeing: https://youtu.be/NCtCw267v8Y
(The tag "Nvidia" is added to this question as that is, or at least was, my graphics driver.)
Note that switching to
upstart does not fix this, nor am I able to enter the command line with
Update: when I boot with recovery mode,
/var/log/Xorg.0.log is empty, and I can at least enter my password (which in normal mode is impossible) but then it starts the same flickering, see this second video recording: https://youtu.be/AdOqBKPnUKA
Valid workaround: go to recovery mode, open a root shell, get list of relevant packages with
dpkg -l | grep -i nvidia and remove them all with
apt-get remove --purge [package] (for me, they were versions 340 and 331 while the one nvidia itself recommends me – 350 – is not in any ubuntu package)
Solution: upgrade your kernel like this.