KDE desktop environment not loading after login

[Johan1830]

Hi there,
Relative beginner here. Here's the basic information for my setup. I'm sure thatthere is more I should/could be providing but I'm not sure what's most useful. I'm using KDE as the desktop environment.
--------------
OS: Debian GNU/Linux 12 (bookworm) x86_64
Host: Vostro 7500
Kernel: 6.1.0-18-amd64
CPU: Intel i7-10750H (12) @ 5.000GHz
GPU: Intel CometLake-H GT2 [UHD Graphics]
GPU: NVIDIA GeForce GTX 1650 Ti Mobile
---------------

I've probably missed something obvious but the issue I'm facing arose overnight between March 28-29. The login screen loads just fine after booting up the system. So SDDM appears to be working. After login to a Wayland session though, it just reverts back to the login screen. After login into an X11 session, the KDE splash screen will load, the gear will turn for a minute, and then freeze. The DE never actually loads. If I use `startx` from the terminal to attempt it, the same thing happens, but I will eventually get a black screen with a working cursor. Nothing else. As it happens, I can remote into it with chrome remote desktop and get the gui just fine.
At first I thought it was just the nvidia drivers, and sure enough, a search found that everything *nvidia* had been completely removed overnight. It took HOURS of digging and trying things out, but I was finally able to get the drivers installed. Unfortunately the GUI still doesn't load. Any suggestions?

[FreewheelinFrank]

Sounds like this issue. The kernel seems to be the one affected. See second bug report here:

viewtopic.php?p=792730#p792730

Boot into previous kernel from grub. Not sure why you would be affected, as I thought this had been fixed, but I'm not a Bookworm or Nvidia user so I haven't been following the issue.

[Johan1830]

Thanks so much for the response! That and related posts came up in my investigation of potential kernel/driver issues. The only trick is that from the grub menu, I only have kernel 6.1.0-18 as an option. As for resetting to a before-update status, in looking elsewhere (https://wiki.debian.org/SystemDowngrade) I'm been a little nervous to try. Not sure I've got the chops to make sure I don't break something.

[FreewheelinFrank]

Can you boot to a command line with networking, multi-user.target formerly know as runlevel3?

https://syslog.me/2020/04/30/how-to-boo ... ux-system/

(See table here for explanation of targets and equivalence to run levels.)

https://opensource.com/article/20/5/systemd-startup

If you can do that it might be possible to install a newer kernel either from bookworm-updates or bookworm-backports. (I've never been in this situation.)

[Johan1830]

I'll look into that and give it a try.

In the meantime, maybe this gives some additional clues. I'm pretty sure a kernel update is still at play here, but I found something of a solution by installing GNOME alongside KDE. After installing gnome (which worked just fine), I could get into my KDE DE from the Gnome login screen. Interestingly, after a reboot, my very first attempt was straight into KDE (it defaulted to SDDM for the login screen). It didn't work. Froze as usual. Rebooted and tried Gnome first (still SDDM default). It worked fine. Logged out, and then successfully logged into KDE without a problem. It was then that I noticed that all the only sound output option on both DEs is Chrome Remote Desktop. I logged into that from another device and sure enough, all sound it being ported through there. But the chrome remote desktop is black and unusable again. It's making me wonder if maybe chrome remote was ultimately a proximate cause for some of the issues. Though again, my initially troubleshooting revolved completely around what I think was the -18 kernel update and an associated wipe of nvidia drivers.

Happy to have the GUI back at least, but still definitely puzzled about the whole thing.

[Johan1830]

I purged the system of chrome-remote-desktop and after a reboot, was able to get straight into KDE without first logging into gnome. And sound was all correct. Maybe that was the main problem.

[rrf2024]

I'm having a similar problem in my Debian10 + TDE (fork from KDE3.5). Similar issues I've found searching in forums, was: trying to open startx with root user, thus it will create the file .Xauthority and/or .ICEauthority with permissions, owner and group to root only. fixes are either "chown" in these files, or simply removing them.

try to check what both logs files are telling. "/var/log/syslog" (or maybe also "/var/log/Xorg.0.log") and "~/.xsession-errors"

In my Debian 10, says "unable to open display: permission denied" and in my Debian 12, I haven't found the reason, yet. All the DE's I have, only gdm3 is working; all the other (including my favorite "trinity-tdm") the screen goes black and the monitor displays the message "out of reach". (and in my other monitor, translated from local language, says "out of scale")