[20.04] X session fails to start on 440 and kernel 5.4.0-21 (but 5.4.0-18 works)

[Simos Xenitellis ]

I am testing Ubuntu 20.04. This system has an NVidia GPU, with nvidia-driver 440.64.

With Linux kernel 5.4.0-18, I can login successfully to an X session (default GNOME).
With Linux kernel 5.4.0-21, I fail to login to an X session. When I put my password and press Enter to login, the screen blanks, and within a second returns back to the login screen.

With Linux kernel 5.4.0-21 and Wayland session, it works and I can login.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Martin Vernay (magean)]

I am having a similar issue. My graphics card is a Geforce GTX 1060 and the kernel is 5.4.0-21. By default, Ubuntu 20.04 was using `nouveau` drivers, but nouveau doesn't behave well with some applications I need, in particular RStudio (which tends to crash under nouveau).

So, I enabled NVidia 440 series proprietary drivers through Software and Updates. Then, I rebooted.

First odd thing: I rebooted into GDM while normally auto-login is enabled. I should have been auto-logged into my default session, which is Gnome on Xorg (not Ubuntu default) but I wasn't.

Second odd thing: the little gear at the bottom right corner of GDM - used to switch desktop session - was gone.

Third odd thing: after I typed my password into GDM, nothing happened. At all. Not even a flicker.

So I switched to a virtual console, logged in and entered `startx`. Screen went black for an instant, then I was back to the console with a brief log output telling me that X had successfully stopped.

I rebooted, same issue. So, I rebooted again, but in GRUB I picked Advanced Options, then Rescue Mode, then Resume boot as normal in the ncurse box. This time, I was automatically logged in to my default session (GNOME on Xorg, not Ubuntu).

I logged out to GDM. Now, the session gear is back in the corner of the screen... However, Wayland sessions are no longer listed - maybe this is a default behavior when NVidia proprietary drivers are enabled since Wayland support isn't exactly spot on yet?

Anyway, if you're having this problem too, the workaround is a rescue boot from GRUB. Then, you can either re-enable nouveau or get used to rescue booting... But this can only be a temporary solution.

[Simos Xenitellis  (simosx)]

I have installed from scratch Ubuntu Daily 20200412, which is still at the Linux 5.4.0-21 kernel.

I was not able to replicate the issue that I was facing, therefore for me I would mark this report as INVALID.

@magean: I have just reinstalled Ubuntu Daily and I got the proprietary drivers instead of nouveau. During the installation, I ticked the option to receive proprietary graphics drivers and WiFi firmware.

The little gear to switch between an X11 and Wayland session should appear as soon as you start typing the password. It does not appear by default.

In your case, I would try to install again the fresh Daily, and try to figure out a reproducible list of steps.

Do you want to create a new report that specifically describes the issue that you are facing?
As far as I understand, the issue you are getting is related to switching between nouveau and proprietary NVidia?

[Martin Vernay (magean)]

Thanks for your reply. I did tick the "proprietary drivers" checkbox during the installation, but for some reason nouveau was enabled afterwards. As for the session-switching gear, it doesn't appear at all when NVidia drivers are enabled.

Now, the problem persists even on a fully up-to-date beta. But at the same time, if there was a widespread issue of such a magnitude (it does prevent booting in normal conditions) affecting NVidia users, other people should be affected...

I'm going to assume that I just picked the wrong beta build at the wrong time. If I have some time to spare, I'll check if the issue persists on a fresh install with the latest daily build. Otherwise, I'll just cross fingers and hope that I was simply unlucky and that, when the final release hits next week, everything will be fine on a fresh install.

[Martin Vernay (magean)]

I installed the last batch of upgrades which included a number of Xorg and kernel-related packages, and now I can successfully reboot and login after enabling NVidia drivers. However, I'm stuck at 1024*768 resolution, Gnome display settings don't let me pick anything else and NVidia X Server Settings opens an empty window. So... back to nouveau.

I'll definitely try a fresh install this week-end and see if the problem persists.

[Martin Vernay (magean)]

I was able to pinpoint my problem as well as a workaround:
https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/1845801

`splash` needs to be removed from grub options: edit `/etc/default/grub`, remove `splash`, then sudo update-grub

[Martin Vernay (magean)]

And in fact, someone has just found a better solution:
https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/1845801/comments/71

[mabovo (mabovo)]

The problem persists with kernel 5.4.0-34, same problem even with workaround in GRUB: "nvidia-drm.modeset=1"

[aimanehob (aimanehoballah)]

Same problem with kernel 5.4.0-33
Tried "nvidia-drm.modeset=1" and splash removal