[Tips] Debian boot hanging at 'started cups scheduler'

[atommo999]

Thought it was worth posting this as just had to go through a troubleshooting session. To summarise the issue:

- Debian 12 that was up to date and was working fine, however following the most recent updates from a few days ago this issue started following a reboot.
- I have an Nvidia GTX 1650 running the official Nvidia driver (4.6.0 NVIDIA 525.125.06)

The issue is the boot-up process hangs as soon as you see the text 'Started CUPS Scheduler'.

After a lot of Googling, I did Ctrl + Alt + F3 to get into the terminal, then logged in and ran 'startx'. This loaded into the desktop environment but resolution was very low. This made me suspect a graphics driver issue.

After further investigation, I purged the nvidia driver from my system (sudo apt remove --purge nvidia-*)

Then rebooted and it loaded the desktop environment without hanging! However, I then had a new issue... a black bar at the top of my screen- coming down to about the point where it would obscure the back/forward buttons of web browsers.

After even more investigation (tried changing display resolution to no avail) I re-installed the Nvidia driver. This didn't break the bootup again, but the black area was still showing.

Finally, I changed the display setting refresh rate from 60Hz to 75Hz and that got rid of the black bar.

Weirdly, despite that being the fix, when I check the display settings now it says '60Hz is the only refresh rate supported by this display' despite the display definitely supporting 75Hz (it has a label saying as such).

Hope this helps others! The Nvidia driver has caused me a bunch of weird issues so far, with this just being the latest one. For example, had to change my KDE mode from Weyland to X11 and turn off Compositor due to it.

[pugwall]

I had this problem too - hanging at CUPS. Seems the Nouveau driver didn't like my Geforce 4070 ti. The official NVIDIA driver in the repository didn't appear to support the 4000 series either.

Ended up Ctrl + Alt + F* into a new console and installing Lynx text-based browser haha. It was a bit clunky, but managed to navigate to the Nvidia website and download the latest driver. Installed and everything worked.

So if you have a 4000 series card, you'll probably have to manually download/install the latest NVIDIA driver too at this point in time. It's an easy Google to find the exact commands/steps.

Also beware of KDE Plasma/Wayland with these GPUs. I chose that environment during install and it froze after logging in. Choose Plasma X11 instead (click bottom left of log-in screen to change).

Anyway, I'm a noob but this worked for me. Hope it helps someone!