lightdm will not start

[Marius Lund]

systemctl status lightdm.service posts this:

lightdm.service - Light Display Manager
   Loaded: loaded (/lib/systemd/system/lightdm.service; enabled; vendor preset: enabled)
  Drop-In: /lib/systemd/system/display-manager.service.d
           └─xdiagnose.conf
   Active: inactive (dead) (Result: exit-code) since sø. 2016-05-08 19:22:51 CEST; 43min ago
     Docs: man:lightdm(1)
  Process: 7709 ExecStart=/usr/sbin/lightdm (code=exited, status=1/FAILURE)
  Process: 7702 ExecStartPre=/bin/sh -c [ "$(basename $(cat /etc/X11/default-display-manager 2>/dev/null))" = "lightdm" ] (co
 Main PID: 7709 (code=exited, status=1/FAILURE)

mai 08 19:22:51 rowena2 systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
mai 08 19:22:51 rowena2 systemd[1]: Stopped Light Display Manager.
mai 08 19:22:51 rowena2 systemd[1]: lightdm.service: Start request repeated too quickly.
mai 08 19:22:51 rowena2 systemd[1]: Failed to start Light Display Manager.

journalctl -xe posts this:

mai 08 19:22:51 rowena2 systemd[1]: gpu-manager.service: Start request repeated too quickly.
mai 08 19:22:51 rowena2 systemd[1]: Failed to start Detect the available GPUs and deal with any system changes.
-- Subject: Unit gpu-manager.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit gpu-manager.service has failed.
--
-- The result is failed.
mai 08 19:22:51 rowena2 systemd[1]: lightdm.service: Start request repeated too quickly.
mai 08 19:22:51 rowena2 systemd[1]: Failed to start Light Display Manager.
-- Subject: Unit lightdm.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit lightdm.service has failed.

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: lightdm 1.19.0-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic i686
ApportVersion: 2.20.1-0ubuntu3
Architecture: i386
Date: Sun May 8 19:24:25 2016
InstallationDate: Installed on 2012-04-22 (1476 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120421)
LightdmConfig:
 [SeatDefaults]
 user-session=ubuntu
 greeter-session=unity-greeter
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Rexhumus Dei (rexhumus)]

Im sorry, but is there any update to this error?

[Thomas Schweikle (tps)]

Same here. "dpkg-reconfigure lightdm" does not help out.
Lightdm seems to be started, but then is terminated because of "respawning to fast".

lightdm log:
[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.22.0, UID=0 PID=2079
[+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-disable-guest.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-disable-log-backup.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/60-xubuntu.conf
[+0.00s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf.d/10-xubuntu.conf
[+0.00s] DEBUG: [SeatDefaults] is now called [Seat:*], please update this configuration
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.00s] DEBUG: [SeatDefaults] is now called [Seat:*], please update this configuration
[+0.00s] DEBUG: Registered seat module local
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Registered seat module unity
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.01s] DEBUG: Monitoring logind for seats
[+0.01s] DEBUG: New seat added from logind: seat0
[+0.01s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.01s] DEBUG: Seat seat0: Starting
[+0.01s] DEBUG: Seat seat0: Creating greeter session
[+0.01s] DEBUG: Seat seat0: Creating display server of type x
[+0.02s] DEBUG: Using VT 7
[+0.02s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.02s] DEBUG: XServer 0: Logging to /var/log/lightdm/x-0.log
[+0.02s] DEBUG: XServer 0: Writing X server authority to /var/run/lightdm/root/:0
[+0.02s] DEBUG: XServer 0: Launching X Server
[+0.02s] DEBUG: Launching process 2087: /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.02s] DEBUG: XServer 0: Waiting for ready signal from X server :0
[+0.02s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.02s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.02s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.73s] DEBUG: Got signal 10 from process 2087
[+0.73s] DEBUG: XServer 0: Got signal from X server :0
[+0.73s] DEBUG: XServer 0: Connecting to XServer :0
[+0.73s] DEBUG: Launching process 2215: /usr/share/lightdm_xrandr
[+0.75s] DEBUG: Process 2215 exited with return value 1
[+0.75s] DEBUG: Seat seat0: Exit status of /usr/share/lightdm_xrandr: 1
[+0.75s] DEBUG: Seat seat0: Stopping display server due to failed set...