lightdm crash/loop after recent 12.04 beta updates

[professordes]

Lightdm is crashing/looping on two multi-monitor machines, one 64bit one 32bit, both Intel graphics. It had been stable on 12.04 beta1 and subsequent updates until beta2.

It is still possible to set an automatic login and get to a gui desktop on startup, but logging out after this goes back again to the crash/loop in lightdm.

1) release: 12.04 beta2 (upgraded initially from 11.10 to 12.04beta1)

2) package: lightdm 1.1.9-0ubuntu1

3) expected behaviour: lightdm greeter screen appears after startup allowing standard login

4) what happens: greeter screen briefly flashes up, then black screen (with cursor), and back to greeter ->loop

[professordes (d-a-johnston-hw)]

/var/log/lightdm/lightdm.log is full of stuff like this....

in particular:

[+8758.58s] DEBUG: Greeter start authentication for guest account
[+8759.00s] DEBUG: Session 19998 exited with return value 0
[+8759.00s] DEBUG: Greeter quit

-------------------------------------------------------------------------------------------------------------------------------------------------

[+8757.20s] DEBUG: Greeter authorized
[+8757.20s] DEBUG: Logging to /var/log/lightdm/x-0-greeter.log
[+8757.20s] DEBUG: Session 19998 running command /usr/lib/lightdm/lightdm-greeter-session /usr/sbin/unity-greeter
[+8757.43s] DEBUG: Greeter connected version=1.1.9
[+8757.43s] DEBUG: Greeter connected, display is ready
[+8757.43s] DEBUG: New display ready, switching to it
[+8757.43s] DEBUG: Activating VT 7
[+8757.43s] DEBUG: Stopping greeter display being switched from
[+8758.58s] DEBUG: Greeter start authentication for guest account
[+8759.00s] DEBUG: Session 19998 exited with return value 0
[+8759.00s] DEBUG: Greeter quit
[+8759.00s] DEBUG: Failed to start greeter
[+8759.00s] DEBUG: Stopping display
[+8759.00s] DEBUG: Sending signal 15 to process 19994
[+8759.04s] DEBUG: Greeter closed communication channel
[+8759.62s] DEBUG: Process 19994 exited with return value 0
[+8759.62s] DEBUG: X server stopped
[+8759.62s] DEBUG: Removing X server authority /var/run/lightdm/root/:0
[+8759.62s] DEBUG: Releasing VT 7
[+8759.62s] DEBUG: Display server stopped
[+8759.62s] DEBUG: Display stopped
[+8759.62s] DEBUG: Active display stopped, switching to greeter
[+8759.62s] DEBUG: Switching to greeter
[+8759.62s] DEBUG: Starting new display for greeter
[+8759.62s] DEBUG: Starting local X display
[+8759.62s] DEBUG: Using VT 7
[+8759.62s] DEBUG: Logging to /var/log/lightdm/x-0.log
[+8759.62s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0
[+8759.62s] DEBUG: Launching X Server
[+8759.62s] DEBUG: Launching process 20111: /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+8759.62s] DEBUG: Waiting for ready signal from X server :0

[tylerjwilk (tylerjwilk)]

I can confirm this on a AMD 64 with 32-bit install. Greet screen shows then crashes. Loops. This happened directly after the latest batch of updates. Machine is unusable. No work around found.

[tylerjwilk (tylerjwilk)]

Work around.
If you have multiple users you can try hitting the up and down arrow keys to try and stop the crash from happening. It seems like something about the default selected user account being already selected is crashing it. Once navigated away from the user you can hen go back to that user and login normally.

The greeter still crashes post login. I believe this maybe related to wallpaper selected by user.

Does greeter try and preload he users background image? What if its on an externally mounted device and not available prior to login ?

[professordes (d-a-johnston-hw)]

My typing isn't fast enough to make the workaround work, so I've had to stick to Plan B and continue to use auto-login :)
When the greeter flashes up it is:
1) showing the default purple
2) sitting on the guest user
I don't know if either of these is significant.....

I still have the problem with a background in a "standard" location (/usr/share/wallpapers or my Pictures/ folder) or when
the user background is made unavailable by changing permissions.

The problem is only showing up at the minute on two dual monitor machines with Intel graphics, everything else I have tried (including another dual monitor setup with an nvidia card) is still OK.

[tylerjwilk (tylerjwilk)]

This is a duplicate bug. See this bug for more details:
https://bugs.launchpad.net/ubuntu/+source/unity-greeter/+bug/946674

This should be marked as duplicate.