I’m on tumbleweed and since sometime last fall the boot screen and SDDM have not loaded i’ve only had a black screen, my monitor says no signal. I have been able to login. Even though the screen is black i can still put in the password unencrypt my SSD and then put in the password to login. Once i do both of those KDE loads and i can see everything. If i logout of KDE it goes back to a black screen SDDM does not load. i thought by now some update might have fixed what was broken. I’m running an AMD 7900 xtx for my GPU.
Are you using SDDM Wayland?
Run
grep -R DisplayServer /etc/sddm.conf.d/
sudo journalctl -b -u sddm | grep -i wayland
Also share the results from
systemctl status display-manager-legacy display-manager
Another thought I had - from a working KDE Plasma session, can you switch to a VT (eg Ctrl+Alt+F3) ok, or does it fail?
I’m not sure if SDDM is running on wayland. I ran the commands
Running grep -R DisplayServer /etc/sddm.conf.d/ didn’t give me anything.
Running sudo journalctl -b -u sddm | grep -i wayland gave me the following:
Feb 11 19:03:06 localhost.localdomain sddm[2749]: Reading from "/usr/share/wayland-sessions/plasmawayland.desktop"
Feb 11 19:03:06 localhost.localdomain sddm[2749]: Session "/usr/share/wayland-sessions/plasmawayland.desktop" selected, command: "/usr/libexec/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland" for VT 1
Feb 11 19:03:07 localhost.localdomain sddm-helper[3038]: Starting Wayland user session: "/usr/share/sddm/scripts/wayland-session" "/usr/libexec/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland"
And for systemctl status display-manager-legacy display-manager if get:
○ display-manager-legacy.service - X Display Manager
Loaded: loaded (/usr/lib/systemd/system/display-manager-legacy.service; disabled; preset: enabled)
Active: inactive (dead)
● sddm.service - Simple Desktop Display Manager
Loaded: loaded (/usr/lib/systemd/system/sddm.service; enabled; preset: disabled)
Active: active (running) since Wed 2026-02-11 19:03:01 EST; 3min 52s ago
Invocation: 29403a48ad6d4a81822bd5152f98b77f
Docs: man:sddm(1)
man:sddm.conf(5)
Main PID: 2749 (sddm)
Tasks: 24 (limit: 76032)
CPU: 561ms
CGroup: /system.slice/sddm.service
├─2749 /usr/bin/sddm
└─2754 /usr/bin/Xorg.bin -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_UdukYf -noreset -displayfd 16
Warning: some journal files were not opened due to insufficient permissions.
when trying to switch a VT i got a blank screen again.
The output confirms SDDM staring on X11…
CGroup: /system.slice/sddm.service
├─2749 /usr/bin/sddm
└─2754 /usr/bin/Xorg.bin -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_UdukYf -noreset -displayfd 16
Ok, the output suggests that SDDM and Xorg are starting correctly, but for some reason there is an issue with display detection, or modesetting during VT switching.
How is the monitor connected? DisplayPort? Resolution + refresh rate?
Examine System Settings > Display and report back, or share the results from kscreen-doctor -o.
If it is a high refresh rate display (eg 144Hz), try setting it to 60Hz, and attempt to VT switch again. Does it succeed?
Setting it to 60 didn’t fix it VT was still blank
This is what i get for kscreen-doctor -o
Output: 1 DP-2 340ab0f0-a67a-4e10-be4c-c189950e924f
enabled
connected
priority 1
DisplayPort
replication source:0
Modes: 1:3440x1440@99.98! 2:3440x1440@84.96 3:3440x1440@74.98 4:3440x1440@59.97* 5:1920x1080@60.00 6:1920x1080@60.00 7:1920x1080@59.94 8:1920x1080@50.00 9:1680x1050@59.95 10:1280x1024@75.03 11:1280x1024@60.02 12:1440x900@59.89 13:1280x960@60.00 14:1152x864@75.00 15:1280x720@60.00 16:1280x720@60.00 17:1280x720@59.94 18:1280x720@50.00 19:1440x576@50.00 20:1440x576@50.00 21:1024x768@75.03 22:1024x768@70.07 23:1024x768@60.00 24:1440x480@60.00 25:1440x480@60.00 26:1440x480@59.94 27:1440x480@59.94 28:800x600@75.00 29:800x600@72.19 30:800x600@60.32 31:800x600@56.25 32:720x576@50.00 33:720x576@50.00 34:720x480@60.00 35:720x480@60.00 36:720x480@59.94 37:720x480@59.94 38:640x480@75.00 39:640x480@72.81 40:640x480@66.67 41:640x480@60.00 42:640x480@59.94 43:640x480@59.94 44:720x400@70.08 45:1600x1200@59.87 46:1600x1200@99.89 47:1280x1024@99.83 48:1024x768@99.75 49:1920x1200@59.88 50:1920x1200@99.90 51:1280x800@59.81 52:1280x800@99.91 53:2560x1440@59.96 54:2560x1440@99.97 55:1920x1080@99.82 56:1600x900@59.95 57:1600x900@99.87 58:1368x768@59.88 59:1368x768@99.80 60:1280x720@99.72
Geometry: 0,0 3440x1440
Scale: 1
Rotation: 1
Overscan: 0
Vrr: Automatic
RgbRange: Automatic
HDR: incapable
Wide Color Gamut: incapable
ICC profile: none
Color profile source: sRGB
Color power preference: prefer efficiency and performance
Brightness control: supported, set to 100% and dimming to 100%
DDC/CI: allowed
Color resolution: automatic (10), range: [8; 16] bits per color
Allow EDR: unsupported
Sharpness control: unsupported
Thanks for the update. From a working KDE session, open a terminal and do
sudo journalctl -b | grep -Ei "amdgpu|drm|dc|failed|link"
If desired you can save to a file for easier reviewing
journalctl -b | grep -Ei "amdgpu|drm|dc|failed|link" > ~/log.txt
Hopefully catch something that is failing in the GPU stack (for example when SDDM login screen was active).
If you switch away can you switch back to the graphical desktop session again?
It’s actually working now, the boot screen and SDDM are loading. I’m not sure what was wrong but after changing to 60hz switch to VT didn’t fix things and i couldn’t switch back it just stayed blank. After rebooting and changing it back to 100hz the screen went blank again. And after rebooting again I can see the boot screen and SDDM again. I can even switch back and forth between VT and GUI. THX
Thanks for the update. That strongly suggests this was a DisplayPort modeset / link training issue rather than SDDM itself. No need to dig any deeper now if it’s now working as expected. 