Ubuntu 18.04, login screen loops

After upgrade from 16.04 to 18.04, on the login screen, enter password, the login screen keeps coming back. Thanks for help.
nvidia-bug-report.log.gz (1.21 MB)

It’s a bit odd, the driver is running fine, the Xserver starts after login and immediatly stops cleanly again. Like no user session is selected. Can you select a different session?

What did you mean by select different session?

It’s hard to tell for me if you’re running lightdm or GDM after upgrade from 16.04 to 18.04 but I suspect you’re still using lightdm. Don’t you have a chooser for the desktop session like in the picture in the answer?:

Ah, I got what you meant. I tried both gdm3 and lightdm and had the same issue.

I tried to downgrade the driver to 396 that is used by cuda9.2 and it worked. However, both 418 and 430 won’t work.

Now my issue became that I can’t use cuda. I tried install cuda 9.2 but cuda didn’t work. I tried 10.1 without replacing driver, then I got "driver version insufficient " error. Is there any way that I use one version of driver for display and different version for CUDA? I don’t know if there is a version can make both working.

The 384 driver is a cuda 10 compat driver. Though I would rather recommend upgrading the Ubuntu HWE stack and then re-try the current 430 driver. https://wiki.ubuntu.com/Kernel/LTSEnablementStack

After upgrade to 5.0 kernel, install 430 driver didn’t work.

nvidia-bug-report.log.gz (722 KB)
nvidia-bug-report.log.gz (1.16 MB)

Driver seems to run fine, maybe gdm is freaking out. Please check if this helps:

I’m affected too. The problem is disabling modeset=1 gives tearing. Nvidia should fix that damn fence signaling bug.