Comment 127 for bug 969489

Currently I've been running without issues with the following configuration in /etc/init/lightdm.conf since September 2013.

[...]
start on ((filesystem
           and runlevel [!06]
           and started dbus
           and plymouth-ready
           and stopped udevtrigger) # <- one line fix
          or runlevel PREVLEVEL=S)
[...]

My configuration is:
Ubuntu 12.04 64bit
Intel SSD 335
Nvidia GTS 650 with NVIDIA drivers.
lightdm version 1.2.3-0ubuntu2.4

Additionally, dependencies on the following were not helping to solve the problem:
graphics-device-added PRIMARY_DEVICE_FOR_DISPLAY=1 - this event is not fired on my machine
graphics-device-added - this event is fired too early - possibly on vesafb load - ligthdm crashes and the fallback mode kicks in.
drm-device-added PRIMARY_DEVICE_FOR_DISPLAY=1 - is not fired on my machine