Arch Linux

ironhak

Member

Registered: 2025-08-10

Posts: 40

Plasma don't start trough a DM, only via TTY

Hi.

If I try to start Plasma via SSDM/Lightdm I get a black screen and then I'm back to the DM. However if I start it via TTY with startplasma-wayland eveyrhitng works...

Can someone help me understand what's happening here?

Thanks a lot

Scimmia

Fellow

Registered: 2012-09-01

Posts: 13,418

Re: Plasma don't start trough a DM, only via TTY

What does the journal say?

ironhak

Member

Registered: 2025-08-10

Posts: 40

Re: Plasma don't start trough a DM, only via TTY

What does the journal say?

Hi, there are lots of lines... What command should I run?

Erwin Iosef

Member

Registered: 2024-05-22

Posts: 99

Re: Plasma don't start trough a DM, only via TTY

After logging again into plasma via SDDM, enter

journalctl -e > output.txt |  curl --data-binary https://paste.rs/

and post the output link here.

Remember that the data in the paste can be seen by anybody.

Refer to https://wiki.archlinux.org/title/Genera … s_and_code for more guidance.

Last edited by Erwin Iosef (2026-01-10 08:39:22)

5hridhyan

Member

From: 127.0.0.1

Registered: 2025-12-25

Posts: 73

Re: Plasma don't start trough a DM, only via TTY

journalctl -b -u sddm --no-pager #if using sddm
coredumpctl list kwin_wayland 

please share the output of these.
edit : journalctl -b | grep -Ei "sddm|plasma|kwin|wayland|failed|error"
my bad

Last edited by 5hridhyan (2026-01-10 11:15:48)

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We don’t finish life. We just learn to love the unfinished lines.  — Grok

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 72,057

Re: Plasma don't start trough a DM, only via TTY

Don't grep unless you exactly know what you're grepping for.
Not for errors, not for services (journalct btw. has a built-in grep and service selection) and also not for strings (could be localized)

The symptoms suggest that whatever session gets started terminates immediately but we don't even know what that is, let alone whether it crashes, whether this is pam specific, a problem with unlocking/mounting $HOME …

Please post your complete system journal for the boot:

sudo journalctl -b | curl -F 'file=@-' 0x0.st

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How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

ironhak

Member

Registered: 2025-08-10

Posts: 40

Re: Plasma don't start trough a DM, only via TTY

Hello, sorry for late.

https://0x0.st/PXvu.txt

Here is the outout. What I did: turn on pc, boot into plasma, boot not successful and back to light dm, boot into sway and ran the command

sudo journalctl -b | curl -F 'file=@-' 0x0.st

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 72,057

Re: Plasma don't start trough a DM, only via TTY

Jan 12 10:48:05 ThinkPad-T14 kwin_wayland[2149]: cannot open display: 
Jan 12 10:48:05 ThinkPad-T14 kcminit_startup[2091]: Loading shell integration failed.
Jan 12 10:48:06 ThinkPad-T14 kcminit_startup[2091]: could not connect to display :0
Jan 12 10:48:06 ThinkPad-T14 ksplashqml[2090]: Authorization required, but no authorization protocol specified
Jan 12 10:48:06 ThinkPad-T14 ksplashqml[2090]: could not connect to display :0
Jan 12 10:48:06 ThinkPad-T14 kcminit_startup[2091]: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
Jan 12 10:48:06 ThinkPad-T14 kcminit_startup[2091]: Could not load the Qt platform plugin "xcb" in "" even though it was found.
Jan 12 10:48:06 ThinkPad-T14 ksplashqml[2090]: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
Jan 12 10:48:06 ThinkPad-T14 kcminit_startup[2091]: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Looks like lightdm or the session you start exports some environment trying to move stuff to xwayland?
Can you log into a KDE/wayland session w/ a fresh user account?

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How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc