[Post-Install] Monitor is going to sleep after splash screen

[srllucas]

Hi everyone,

I have an issue with KDE + Wayland (X11 works normally). I can’t run any recent KDE + Wayland distribution (KDE + Wayland + Debian 12 is ok (kernel 6.1)).

ISSUE: After the splash screen, the monitor goes to sleep. The system itself is still running — for example, I can access it through TTY (and the monitor wakes up again after switching to a TTY). In KDE, there is no active display in "echo $DISPLAY" (it returns blank).

GNOME works normally, and I’m currently using Ubuntu 26.04 LTS (even though I love Kubuntu!).

My setup:

System:
Host: luciano-X99-B9 Kernel: 7.0.0-15-generic arch: x86_64 bits: 64
Desktop: GNOME v: 50.1 Distro: Ubuntu 26.04 (Resolute Raccoon)
Machine:
Type: Desktop Mobo: MACHINIST model: X99 B9 serial: <superuser required>
Firmware: UEFI vendor: American Megatrends v: 5.11 date: 06/07/2024
CPU:
Info: 14-core Intel Xeon E5-2680 v4 [MT MCP] speed (MHz): avg: 1200
min/max: 1200/3300
Graphics:
Device-1: Advanced Micro Devices [AMD/ATI] Ellesmere [Radeon RX
470/480/570/570X/580/580X/590] driver: amdgpu v: kernel
Display: wayland server: X.Org v: 24.1.10 with: Xwayland v: 24.1.10
compositor: gnome-shell driver: dri: radeonsi gpu: amdgpu
resolution: 1920x1080~60Hz
API: OpenGL v: 4.6 compat-v: 4.5 vendor: amd mesa v: 26.0.3-1ubuntu1
renderer: AMD Radeon RX 570 Series (radeonsi polaris10 ACO DRM 3.64
7.0.0-15-generic)
Info: Tools: api: eglinfo, glxinfo, vulkaninfo gpu: corectrl x11: xdriinfo,
xdpyinfo, xprop, xrandr
Network:
Device-1: Realtek RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet
driver: r8169
Drives:
Local Storage: total: 1.35 TiB used: 63.36 GiB (4.6%)
Info:
Memory: total: 64 GiB available: 61.63 GiB used: 3.44 GiB (5.6%)
Processes: 497 Uptime: 25m Shell: Bash inxi: 3.3.40

[INVICTRA]

Before it loads up KDE you should see the login screen (SDDM). Can you confirm the login screen is showing up?

[srllucas]

Before it loads up KDE you should see the login screen (SDDM). Can you confirm the login screen is showing up?

The monitor goes to sleep before the SDDM... the splash apears in low resolution, than the video driver is loaded and it changes to high resolution... few seconds after, the monitor goes to sleep...

[die.boer]

At GRUB: Press e on the boot entry and add this to the linux line:

amdgpu.dc=0

Then boot with Ctrl+X.

If KDE Wayland then works we can make it permanant,let us know

[srllucas]

At GRUB: Press e on the boot entry and add this to the linux line:

amdgpu.dc=0

Then boot with Ctrl+X.

If KDE Wayland then works we can make it permanant,let us know

I already tried it... same behaviour

[die.boer]

ok next , from a TTY:
run these

mkdir -p ~/.config/environment.d

nano ~/.config/environment.d/kwin.conf​

put this inside KWIN_DRM_NO_AMS=1
save (ctrl+O - enter - ctrl+X) , and reboot

[INVICTRA]

Hi everyone,

I have an issue with KDE + Wayland (X11 works normally). I can’t run any recent KDE + Wayland distribution (KDE + Wayland + Debian 12 is ok (kernel 6.1)).

There is no X11 installed on a fresh Kubuntu 26.04 so I haven't tried this yet. It would be interesting to know if you could set SDDM to run in X11 and then try to continue to a Wayland desktop.