SDDM Not Launching at Startup

English Install/Boot/Login
1

Recently I’ve been having some issues with Plasma resource usage skyrocketing after hibernation that I’ve been trying to fix (which seems partially resolved) although in the process I may have broken SDDM but not exactly sure. I was previously having some issues with PAM and logins being stored which I think I also fixed but may have been related. The plasma issues seem to be related to NVIDIA drivers, I’m on 570 version now but rolling back to 550 the problem persists.

I used to start up fine, be met by the login screen and login fine. Now however, I don’t get this far and duped to tty console and login from there. If I login and startx manually I’m back to where I wanted to be but can’t understand why SDDM won’t launch. I tried chaging to LightDM and this worked fine.

Here is the output from:

journalctl -u sddm

Mar 28 10:19:00 localhost.localdomain systemd[1]: Starting Simple Desktop Display Manager...
Mar 28 10:19:00 localhost.localdomain systemd[1]: Started Simple Desktop Display Manager.
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Initializing...
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Starting...
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Logind interface found
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Adding new display...
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Loaded empty theme configuration
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Xauthority path: "/run/sddm/xauth_PCYtMw"
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Using VT 2
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Display server starting...
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Writing cookie to "/run/sddm/xauth_PCYtMw"
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Running: /usr/bin/X -nr -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_PCYtMw -noreset -displayfd 16
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Failed to read display number from pipe
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Display server stopping...
Mar 28 10:19:00 localhost.localdomain sddm[2050]: Attempt 1 starting the Display server on vt 2 failed
Mar 28 10:19:02 localhost.localdomain sddm[2050]: Display server starting...
Mar 28 10:19:02 localhost.localdomain sddm[2050]: Writing cookie to "/run/sddm/xauth_PCYtMw"
Mar 28 10:19:02 localhost.localdomain sddm[2050]: Running: /usr/bin/X -nr -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_PCYtMw -noreset -displayfd 16
Mar 28 10:19:02 localhost.localdomain sddm[2050]: Failed to read display number from pipe
Mar 28 10:19:02 localhost.localdomain sddm[2050]: Display server stopping...
Mar 28 10:19:02 localhost.localdomain sddm[2050]: Attempt 2 starting the Display server on vt 2 failed
Mar 28 10:19:04 localhost.localdomain sddm[2050]: Display server starting...
Mar 28 10:19:04 localhost.localdomain sddm[2050]: Writing cookie to "/run/sddm/xauth_PCYtMw"
Mar 28 10:19:04 localhost.localdomain sddm[2050]: Running: /usr/bin/X -nr -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_PCYtMw -noreset -displayfd 16
Mar 28 10:19:04 localhost.localdomain sddm[2050]: Failed to read display number from pipe
Mar 28 10:19:04 localhost.localdomain sddm[2050]: Display server stopping...
Mar 28 10:19:04 localhost.localdomain sddm[2050]: Attempt 3 starting the Display server on vt 2 failed
Mar 28 10:19:04 localhost.localdomain sddm[2050]: Could not start Display server on vt 2
2

Also wanted to include my Xorg.0 log

I asked chatgpt to have a look at it and suggested I restart systemd-logind

sudo systemctl restart systemd-logind

but when I run that the whole system freezes and needs a restart

based on this error

(EE) systemd-logind: failed to get session: PID 2060 does not belong to any known session .

Had to link xorg log because it was too long.

Xorg.0.log

Edit: also running

sudo systemctl restart display-manager.service

Causes the system to crash but takes me to non-gui command line with haphazardly formatting text across the screen and needs a reboot, I will try and take a photo and post it.

3

I recently had SDDM problems as well … it was caused by Budgie … once I removed it all back to normal

4

Xorg.0.log seem old:
7.965] (==) Log file: "/var/log/Xorg.0.log", Time: Sat Mar 8 14:34:28 2025

Also the Kernel is not up to date.

5

I did notice before I updated that it was last edited on 08/03 but not sure I can affect that, strangely I made some changes and it’s update.

Here’s the latest one (replaced): Xorg.0.log

I also just tried the following steps which has got me to a login screen but it doesn’t seem to be the SDDM screen and have a large onscreen keyboard overlay

image
image694×813 61 KB

6

Where do you have these strange settings for Nvidia from? They are not required for a standard setup.

The default ssdm.conf is empty on all my systems (Tumbleweed). And i also use Nvidia GPUs in all of them.

7

They were suggested by chatGPT and I agree I’ve not seen them before but they seem to have remidied. The login screen is back to the proper SDDM one after I changed it in plasma.

My sddm.d.conf folder was empty too but this wasn’t the case previously there were some nvidia configs from the default initialisation, the above steps mean only the scripts folder is there now but the sddm.conf (in /var) is popoulated now with:

[General]
DisplayServer=x11
GreeterEnvironment=
InputMethod=qtvirtualkeyboard
Namespaces=
Numlock=none

[Theme]
CursorSize=
CursorTheme=
DisableAvatarsThreshold=7
EnableAvatars=true
FacesDir=/usr/share/sddm/faces
Font=
ThemeDir=/usr/share/sddm/themes

[Users]
DefaultPath=/usr/local/bin:/usr/bin:/bin
HideShells=
HideUsers=
RememberLastSession=true
RememberLastUser=true
ReuseSession=true

[Wayland]
CompositorCommand=weston --shell=kiosk
EnableHiDPI=true
SessionCommand=/usr/share/sddm/scripts/wayland-session
SessionDir=/usr/local/share/wayland-sessions,/usr/share/wayland-sessions
SessionLogFile=.local/share/sddm/wayland-session.log

[X11]
DisplayCommand=/etc/sddm/scripts/Xsetup
DisplayStopCommand=/usr/share/sddm/scripts/Xstop
EnableHiDPI=true
ServerArguments=-nolisten tcp
ServerPath=/usr/bin/X
SessionCommand=/etc/X11/xdm/Xsession
SessionDir=/usr/local/share/xsessions,/usr/share/xsessions
SessionLogFile=.local/share/sddm/xorg-session.log
XephyrPath=/usr/bin/Xephyr
8

I should note the first chatGPT command didn’t work (something about passing permissions for sudo) but this seemed a valid alternative:

sddm --example-config | sudo tee /etc/sddm.conf
9

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