Lightdm failed to start again

[lolis4thewin]

So every time i dont use my computer to 7 or so days this happens:

Any idea what to do? I tried to reinstall lightdm but nothing.

I would like to use light dm cause i use xfce’s login manager (but only i3 as wm, no de). But i may be considering a switch to ssdm.

[Nachlese]

If you disable the lightdm.service (for the time being)
and reboot
you could boot normally, to a TTY prompt.

Log in there (not as root - you’ll be prompted for the password) and start lightdm.service
perhaps the output will tell you something.

systemctl disable lightdm.service

reboot

systemctl start lightdm.service
once rebooted and logged in

[lolis4thewin]

Same…

[Nachlese]

Why use sudo?
You will get prompted.

There must be a log about why it fails somewhere - but I can’t tell you where off the top of my head.

There is a chance that you are in a partial update state.
Run a system update.

… you’ll need sudo here

sudo pacman -Syyu

[lolis4thewin]

Without sudo i have to authenticate myself that does the same.

But the same happens

[lolis4thewin]

@Nachlese

Run a system update

I did that too earlier

[Nachlese]

Then perhaps someone else can help you - I currently cannot.

[lolis4thewin]

Thank you for your help!

[Nachlese]

there are log files in /var/log/lightdm/

sudo ls -l /var/log/lightdm/

look through them:
sudo less /var/log/lightdm/lightdm.log
sudo less /var/log/lightdm/seat0-greeter.log
sudo less /var/log/lightdm/x-0.log

[maycne.sonahoz]

It should also trace in the system journal:

journalctl --boot=0 --unit=lightdm

---

[HowTo] Find error logs

Difficulty: ★☆☆☆☆ The first step for troubleshooting an issue is to find an error log: a trace produced by an application when failing/crashing, and providing the first trail a user/developer can follow to fix it. 1. Reach a usable system Obviously, it will be impossible to acquire those logs if you can’t have access to a usable system. See: [HowTo] Reach a minimal system 2. Find the faulty application If you don’t know which application failed – this is usually the case on a system or gra…

[Jim.B]

It appears that the error is gtk greeter related. have you tried removing the gtk greeter and install the lightdm-slick-greeter?

[lolis4thewin]

i3hunor@HunorT480 ~]$ journalctl --boot=0 --unit=lightdm
Jan 22 09:52:39 HunorT480 systemd[1]: Starting Light Display Manager...
Jan 22 09:52:39 HunorT480 lightdm[290272]: Failed to use bus name org.freedesktop.DisplayMan>
Jan 22 09:52:39 HunorT480 systemd[1]: lightdm.service: Main process exited, code=exited, sta>
Jan 22 09:52:39 HunorT480 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jan 22 09:52:39 HunorT480 systemd[1]: Failed to start Light Display Manager.
Jan 22 09:52:39 HunorT480 systemd[1]: lightdm.service: Scheduled restart job, restart counte>
Jan 22 09:52:39 HunorT480 systemd[1]: Stopped Light Display Manager.
Jan 22 09:52:39 HunorT480 systemd[1]: Starting Light Display Manager...
Jan 22 09:52:40 HunorT480 lightdm[290289]: Failed to use bus name org.freedesktop.DisplayMan>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Main process exited, code=exited, sta>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jan 22 09:52:40 HunorT480 systemd[1]: Failed to start Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Scheduled restart job, restart counte>
Jan 22 09:52:40 HunorT480 systemd[1]: Stopped Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: Starting Light Display Manager...
Jan 22 09:52:40 HunorT480 lightdm[290299]: Failed to use bus name org.freedesktop.DisplayMan>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Main process exited, code=exited, sta>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jan 22 09:52:40 HunorT480 systemd[1]: Failed to start Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Scheduled restart job, restart counte>
Jan 22 09:52:40 HunorT480 systemd[1]: Stopped Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: Starting Light Display Manager...
Jan 22 09:52:40 HunorT480 lightdm[290310]: Failed to use bus name org.freedesktop.DisplayMan>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Main process exited, code=exited, sta>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jan 22 09:52:40 HunorT480 systemd[1]: Failed to start Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Scheduled restart job, restart counte>
Jan 22 09:52:40 HunorT480 systemd[1]: Stopped Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: Starting Light Display Manager...
Jan 22 09:52:40 HunorT480 lightdm[290326]: Failed to use bus name org.freedesktop.DisplayMan>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Main process exited, code=exited, sta>
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jan 22 09:52:40 HunorT480 systemd[1]: Failed to start Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Scheduled restart job, restart counte>
Jan 22 09:52:40 HunorT480 systemd[1]: Stopped Light Display Manager.
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Start request repeated too quickly.
Jan 22 09:52:40 HunorT480 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jan 22 09:52:40 HunorT480 systemd[1]: Failed to start Light Display Manager.

[lolis4thewin]

I cant remove gtk-greeter, but i installed lightdm-slick-greeter.

 yay -R lightdm-gtk-greeter
[sudo] password for i3hunor: 
checking dependencies...
error: failed to prepare transaction (could not satisfy dependencies)
:: removing lightdm-gtk-greeter breaks dependency 'lightdm-gtk-greeter' required by lightdm-gtk-greeter-settings
 -> exit status 1

[Nachlese]

Just removing the gtk-greeter will not magically lead to the other one being used.
You can keep it - no need to remove it.

You need to adapt the configuration file /etc/lightdm/lightdm.conf

swap one entry for the other - in this example here, the slick greeter is active (no # at the start of the line)

grep -E 'greeter-session=' /etc/lightdm/lightdm.conf
#greeter-session=lightdm-webkit2-greeter
greeter-session=lightdm-slick-greeter

You’ll have to put that in yourself.
it is in /etc/lightdm/lightdm.conf
around line nr. 103

just add another line and comment what was there, that will make it easy to switch back should you want to

…
ps:

The lines of the log you posted are truncated (cut short)

@lolis4thewin

journalctl --boot=0 --unit=lightdm

… important things might be missing due to that

what looks relevant is this line here:

@lolis4thewin

Failed to use bus name org.freedesktop.DisplayMan>

something informative has likely been cut off

…

another ps:
did you find anything when looking through these?

@Nachlese

there are log files in /var/log/lightdm/

sudo ls -l /var/log/lightdm/

look through them:
sudo less /var/log/lightdm/lightdm.log
sudo less /var/log/lightdm/seat0-greeter.log
sudo less /var/log/lightdm/x-0.log

[lolis4thewin]

Okay, i dont really understand, but now everything was fine.
I dont know what happened, but it works now altough i just changed to ssdm back to lightdm and thats all.
Anyway, thank you all!