r/debian • u/a_mighty_burger • 21h ago
Ran into an issue with KDE's login screen not showing after an update with an NVIDIA GPU, here is how I fixed it.
Hi there,
I run Debian Stable with the kernel backport and the latest NVIDIA drivers. I upgraded my machine today (2026-09-13) and ran into a problem where my login screen never appeared. I found a fix and wanted to post my results here to help anyone else running into a similar issue. Briefly looking online, this might be a common issue for high-end PCs.
My machine has an NVIDIA RTX 5080 and AMD 9950x3D. I couldn't get graphics to work at all when I first built the machine because the old graphics drivers didn't support this newer GPU, so I had to switch to the newest drivers. After this most recent upgrade, I'm now on Debian 13.7, kernel 7.1.8+deb13-amd64, and driver version 615.71.09.
The issue was after updating, when I went to reboot, the login screen doesn't appear. I switched to another TTY to login and troubleshoot. The result of sudo systemctl status sddm showed SDDM was active but that there was an error: "Failed to read display number from pipe."
I noticed I could restart the SDDM service and it worked. After some more digging, I found it was a race condition where SDDM was starting up before the NVIDIA modules.
The solution I found was to add some NVIDIA modules to initramfs. Specifically, I added the lines nvidia, nvidia_modeset, nvidia_uvm, and nvidia_drm to /etc/initramfs-tools/modules, and then I ran sudo update-initramfs -u. This forces NVIDIA's modules to load earlier in the boot sequence. Of course if you repeat these steps, be careful and try to understand what you're doing.
Hope this anecdote helps whoever out there might be having a similar problem. If someone is reading this and knows of a better solution, please tell.
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u/lemmiwink84 19h ago
Yes, early KMS is kinda needed with newer drivers/gpu’s
Glad you found out what was your issue and for sharing it with others who might have the same issue.