Comment 19 for bug 969489

This looks like it might be a duplicate of bug 615549.

I've done some digging and although I'm not sure this will fully resolve the issue observed, I have found a bug in lightdm.conf which could cause the behaviour seen...

As Clint intimates in #11, the current 'start on' condition...

    drm-device-added card0 PRIMARY_DEVICE_FOR_DISPLAY=1

... is *NOT* valid. What this condition is asking Upstart to do is match on an event whose first _positional_ environment variable *exactly matches* the string 'card0' and which also has an environment variable called 'PRIMARY_DEVICE_FOR_DISPLAY' with value '1'.

However, if you look at /var/log/udev:

$ awk 'BEGIN{RS="";ORS="\n\n"}; /UDEV *\[/ && /PRIMARY_DEVICE_FOR_DISPLAY=1/ { print; }' /var/log/udev
UDEV [34.559987] add /devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0 (drm)
ACTION=add
DEVNAME=/dev/dri/card0
DEVPATH=/devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0
DEVTYPE=drm_minor
MAJOR=226
MINOR=0
PRIMARY_DEVICE_FOR_DISPLAY=1
SEQNUM=2231
SUBSYSTEM=drm
TAGS=:udev-acl:
UDEV_LOG=3
USEC_INITIALIZED=34559916
$

... you'll see that there are no variables that exactly match 'card0'! The fix is as simple as adding an asterisk to perform a wild-card match:

  drm-device-added *card0 PRIMARY_DEVICE_FOR_DISPLAY=1

However, my preference would to make our intent explicit and say:

  drm-device-added DEVPATH=*card0 PRIMARY_DEVICE_FOR_DISPLAY=1

This would protect against a change to the way the upstart-udev-bridge handles udev environment variable ordering and is much easier to understand.

@serge - could you add the missing asterisk and report back?