Ubuntu
lightdm package

  1. Bug #969489
  2. Comment #130

Comment 130 for bug 969489

Revision history for this message
Ciprian Enache (ciprian-enache) wrote :

Avius: When lightdm fails to start, do you get sometimes X started up in "safe mode" as per Comment 2 from Serge ?

Your problem seems different as your your logs show that lightdm can successfully start and connect to the X server, and something happens during your login. Relevant extract from your logs below:
[+3.06s] DEBUG: Seat: Display server ready, starting session authentication
[...]
[+5.80s] DEBUG: Session pid=1330: Started with service 'lightdm', username 'avius'
[+5.80s] DEBUG: Session pid=1032: Greeter start authentication for avius
[+5.80s] DEBUG: Session pid=1330: Sending SIGTERM
[+5.80s] DEBUG: Seat: Setting XDG_SEAT=seat0
[+5.80s] DEBUG: Session: Setting XDG_VTNR=7
[+5.80s] DEBUG: Session pid=1331: Started with service 'lightdm', username 'avius'
[+5.80s] DEBUG: Got signal 15 from process 991
[+5.80s] DEBUG: Caught Terminated signal, shutting down

Could your problem be related to authentication ? Is your system set to autologin?
Have you tried logging into the console and running 'start lightdm'?

As per comment #97, lightdm (which in turn starts X) can be started before the display kernel modules are fully loaded (creating a race). The problem is most apparent to people running Ubuntu from an SSD. On my PC, the "one line fix" delays the lightdm start sufficiently for the kernel display modules to be fully loaded. It's really working on my system:

ls -ltr /var/log/Xorg*
-rw-r--r-- 1 root root 69099 Sep 13 2013 /var/log/Xorg.failsafe.log.old <-penultimate start of X into failsafe mode before performing the workaround
-rw-r--r-- 1 root root 69514 Mar 8 14:17 /var/log/Xorg.failsafe.log <- last start of X into failsafe mode while getting this down to a one liner in March
-rw-r--r-- 1 root root 31975 Mar 28 19:11 /var/log/Xorg.0.log.old
-rw-r--r-- 1 root root 30869 Mar 30 10:58 /var/log/Xorg.0.log

There are other workarounds from other people in this thread, which seem to have the same effect - for example someone suggests in comment #114 to make the startup verbose, which seems to solve the problem for that person.