SDDM login breaks if automatic login is disabled

Legion495 · June 5, 2025, 9:01pm

Hello!

I rather recently switched to Tumbleweed with KDE and autologin.
I set the autologin during install.

I wanted to disable it to autounlock the kdewallet with the login.
So on my desktop I first tried to set the autologin off in the KDE sddm settings.
Also wanted to apply the theme and did that.
After I did that I made a reboot and was unable to login. Only could save it with a snapper rollback.

OKAY I tried again this time without setting any themes or anything. Then it worked on my desktop. And honestly I am quite afraid to apply any changes to sddm at this point.

I do not know why or where to really look.
I am unable to diagnose this without specific guidance.
I will now try to set sddm autologin OFF on my laptop and report back how that goes.

BR

Legion495 · June 5, 2025, 9:16pm

Okay so I noticed it appears my sddm had the sweet theme applied on the laptop.
I set it to breeze. Any other really. If I try to login with autologin first toggled off I just a get a login failed.

And if I switch to the terminal I cannot login.
I am honestly quite shocked a KDE setting is able to wreck my installation.

Legion495 · June 5, 2025, 9:56pm

To add. I have a suspicion that there is no config for the non autologin sddm.
I will try to find the config files tomorrow on my desktop to compare.

nrickert · June 5, 2025, 10:44pm

What’s the output from:

grep AUTO /etc/sysconfig/displaymanager

deano_ferrari · June 5, 2025, 11:27pm

Just to clarify - Are you using “display-manager-legacy.service”? Or the standalone “sddm.service” (which is also possible now)?

systemctl status display-manager-legacy sddm

Legion495 · June 6, 2025, 10:26am

# grep AUTO /etc/sysconfig/displaymanager
DISPLAYMANAGER_AUTOLOGIN="legion495"
# DISPLAYMANAGER_AUTOLOGIN is empty.

On my desktop it is without username.

Legion495 · June 6, 2025, 10:28am

I strongly suspect it is the legacy one.
I did not make any changes from the base installer here.
So I suspect this is default. I did have to set wayland as default. Which I did in the sddm settings in the KDE GUI after I installed it. Otherwise I would start into x11 (broken themes).

··• systemctl status display-manager-legacy sddm
● display-manager-legacy.service - X Display Manager
     Loaded: loaded (/usr/lib/systemd/system/display-manager-legacy.service; enabled; preset: enabled)
     Active: active (running) since Fri 2025-06-06 12:23:25 CEST; 3min 3s ago
 Invocation: 3444e0d101044bb8a771e2002e1c535f
    Process: 1458 ExecStart=/usr/lib/X11/display-manager start (code=exited, status=0/SUCCESS)
   Main PID: 1489 (sddm)
      Tasks: 2 (limit: 18161)
        CPU: 98ms
     CGroup: /system.slice/display-manager-legacy.service
             └─1489 /usr/bin/sddm

Warning: some journal files were not opened due to insufficient permissions.

○ sddm.service - Simple Desktop Display Manager
     Loaded: loaded (/usr/lib/systemd/system/sddm.service; disabled; preset: disabled)
     Active: inactive (dead)
       Docs: man:sddm(1)
             man:sddm.conf(5)

And this matches my Desktop.

Legion495 · June 6, 2025, 10:52am

And I want to say thank you for helping.
In the meantime I checked a few configs.
It appears that /etc/sddm.conf.d/kde_settings.conf doesn’t seem to have any effect.
Maybe changes would need to be applied somehow.

Because I tried just removing the username like I have it on desktop.
It did autologin me anyway after a reboot. No worries I always rollback. hail snapper :3

hui · June 6, 2025, 10:58am

Something different to check: As you always used autologin on this machine and didn’t type it manually, are you sure that you use the correct PW? No typo? Keyboard layout? …

deano_ferrari · June 6, 2025, 11:01am

Please check /var/lib/sddm/state.conf

Legion495 · June 6, 2025, 11:05am

Okay something I did not expect.
I cannot login back into a logged out session yet when I use sudo the PW is correct?
Maybe my laptops sddm was broken from the start o.o

I will try to set my PW again. MAYBE that updates stuff?
And my PW is matched so keyboard differences should have no affect for eng or ger.

Legion495 · June 6, 2025, 11:07am

[Last]
# Name of the last logged-in user.
# This user will be preselected when the login screen appears
User=legion495


# Name of the session for the last logged-in user.
# This session will be preselected when the login screen appears.
Session=/usr/share/wayland-sessions/plasmawayland.desktop

Same as on desktop

hui · June 6, 2025, 11:14am

Can you elaborate on this? Why and where sudo? Do you mean logout from a terminal or GUI session?

sudo shouldn’t be involved at all when you try to login as a user. So the above statement is a little bit confusing.

Legion495 · June 6, 2025, 11:16am

From sddm I get nowhere. My PW is incorrect. I cannot do anything there.
Yet any prompt or command which requires authentication after autologin works perfectly fine.
Shouldn’t it be same password?

hui · June 6, 2025, 11:17am

This depends completely on how you installed your system and which checkmarks you had set when you installed the system. Normally the user and root PW should differ for security reasons.

Legion495 · June 6, 2025, 11:29am

I always have it with my normal account.
I dislike the handling of two passwords. I get why some would not.
And for servers I would opt for disabling any root logins instead.

I just made a new account. Cannot login from sddm.
I did already try to change my pw without any success.
I will now try from terminal with passwd.

Edit I am afraid
sudo passwd legion495
did not change anything.

I mean it is not far that I could not reinstall. It just seems like such a silly issue.

I used the KDE users to create “legion” set pw “123” and that did not work but at least shows up on sddm xD

hui · June 6, 2025, 11:35am

Please try as real root and not with sudo…

su -
passwd legion495

Legion495 · June 6, 2025, 11:43am

Okay I switched to root and tried.
Set the pw. Logged out and still get “Login Failed”.
Upon suspicion I currently check if I did anything for fingerprints but I think they enabled without any changes.

Legion495 · June 6, 2025, 11:51am

I honestly do not know how or when.
I used my earliest snapshot and there it works fine.
I did not install any major things on the device. So color me surprised.

Legion495 · June 6, 2025, 12:13pm

Okay I want to recap something.
As I did that rollback I remembered what happend on my desktop while trying the same.

I changed the sddm stuff to turn off autologin (also made a update) and restarted.
Was locked out. Paniced around . Learned how to rollback. I did a rollback over quite many changes.

And then I could turn it off and since then it has been fine.
I actually think something broke somewhere.

Changes I made in general to the system was.
Installing steamtinkerlaunch over proton-qt so I installed dependencies
the packman codec stuff and repo. And one for a specific yad version.
Starship and the Nobara Theme c:

So take what you will from that. Also fetched some KDE themes.
I highly doubt those packages would break anything.
I just wanted to leave this here if something needs to pick this up again.