Arch Linux

tomzooi

Member

Registered: 2010-05-01

Posts: 24

Lightdm flashes twice at startup

Hello all,

On both my laptops, running the latest arch(4.1.6.1-1) I have a weird issue with my login manager, lightdm.
After booting it fully shows, only to dissappear after two seconds and restart (and stay there properly until I login). My journalctl says this:

[tom@tomtop ~]$ journalctl -u lightdm
-- Logs begin at Sun 2015-09-20 21:33:57 CEST, end at Sun 2015-09-20 21:50:24 CEST. --
Sep 20 21:46:31 tomtop systemd[1]: Stopping Light Display Manager...
Sep 20 21:46:31 tomtop lightdm[2741]: Failed to get D-Bus connection
Sep 20 21:46:32 tomtop systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Sep 20 21:46:32 tomtop systemd[1]: Stopped Light Display Manager.
Sep 20 21:46:32 tomtop systemd[1]: lightdm.service: Unit entered failed state.
Sep 20 21:46:32 tomtop systemd[1]: lightdm.service: Failed with result 'exit-code'.
-- Reboot --
Sep 20 21:46:55 tomtop systemd[1]: Starting Light Display Manager...
Sep 20 21:46:56 tomtop systemd[1]: Started Light Display Manager.
Sep 20 21:46:56 tomtop lightdm[2520]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Sep 20 21:47:00 tomtop systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Sep 20 21:47:00 tomtop systemd[1]: lightdm.service: Unit entered failed state.
Sep 20 21:47:00 tomtop systemd[1]: lightdm.service: Failed with result 'exit-code'.
Sep 20 21:47:00 tomtop systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Sep 20 21:47:00 tomtop systemd[1]: Stopped Light Display Manager.
Sep 20 21:47:00 tomtop systemd[1]: Starting Light Display Manager...
Sep 20 21:47:00 tomtop systemd[1]: Started Light Display Manager.
Sep 20 21:47:01 tomtop lightdm[2780]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Sep 20 21:47:03 tomtop lightdm[2803]: pam_unix(lightdm:session): session opened for user tom by (uid=0)
[tom@tomtop ~]$ uname -r
4.1.6-1-ARCH

I cannot find anything about that weird hold-off time over error, this is the (standard) service file:

[tom@tomtop ~]$ cat /usr/lib/systemd/system/lightdm.service 
[Unit]
Description=Light Display Manager
Documentation=man:lightdm(1)
After=systemd-user-sessions.service plymouth-quit.service

[Service]
ExecStart=/usr/bin/lightdm
Restart=always
IgnoreSIGPIPE=no
BusName=org.freedesktop.DisplayManager

[Install]
Alias=display-manager.service

So far that was all the information I can think of that might lead to a solution, but since it didn't ring any bells for me, I'm guessing there is more places to look?

hpgisler

Member

Registered: 2015-11-07

Posts: 2

Re: Lightdm flashes twice at startup

I observe exactly the same behavior with most recent arch: pacman -Syu.

Did you find the cause for this yet?

tomzooi

Member

Registered: 2010-05-01

Posts: 24

Re: Lightdm flashes twice at startup

I have not found the cause yet unfortunately, it appears all my linux systems (both my laptops and barebone) have the exact same issue...

tomzooi

Member

Registered: 2010-05-01

Posts: 24

Re: Lightdm flashes twice at startup

I switched to lxdm since I wasn't able to fix this weird flicker.

hpgisler

Member

Registered: 2015-11-07

Posts: 2

Re: Lightdm flashes twice at startup

I've checked my /etc/lightdm folder and saw that I had two differing (by format) config files there for lightdm:
a) lightdm.conf (modified somewhat by myself from an earlier ligthdm version)
b) lightdm.conf.pacnew (created by pacman, but not overwriting a) )

In my case, it seems, that the conf file format mismatch was the case for the flickering.

Overwriting a) with b) solved the problem for me. 

now journalctl shows correct behavior:

Jan 19 17:23:06 silverstone lightdm[668]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Jan 19 17:23:06 silverstone systemd[1]: Created slice User Slice of lightdm.
Jan 19 17:23:06 silverstone systemd[1]: Starting User Manager for UID 620...
Jan 19 17:23:06 silverstone systemd-logind[482]: New session c1 of user lightdm.
Jan 19 17:23:06 silverstone systemd[1]: Started Session c1 of user lightdm.

silasdavis

Member

Registered: 2013-02-13

Posts: 17

Re: Lightdm flashes twice at startup

Could you post working config. I seem to be getting this behaviour with fresh config

ngagun

Member

Registered: 2012-05-07

Posts: 17

Re: Lightdm flashes twice at startup

Has anyone figured out a solution for this? It's annoying!