Ubuntu – Systemctl, graphic login did not show up, why

Ubuntu 16.04. I booted into my system but I landed in the console login. Why did it not start my graphical login? How can I fix that? How can I debug that?

Some messages from journalctl -xb:

Jul 30 17:44:58 gcomputer dbus[2494]: [system] Failed to activate service 'org.freesmartphone.ogsmd': timed out
Jul 30 17:44:58 gcomputer dbus[2494]: [system] Activating service name='org.freesmartphone.ogsmd' (using servicehelper)
Jul 30 17:44:58 gcomputer org.freesmartphone.ogsmd[2494]: 2016-07-30T15:44:58.105551Z [WARN]  subsystem : Could not load plugin: Could not load /us
Jul 30 17:45:07 gcomputer kdm[2881]: X server termination timeout, killing
Jul 30 17:45:07 gcomputer kdm[2881]: X server for display :0 cannot be started, session disabled
Jul 30 17:45:23 gcomputer dbus[2494]: [system] Failed to activate service 'org.freesmartphone.ogsmd': timed out
Jul 30 17:45:23 gcomputer dbus[2494]: [system] Activating service name='org.freesmartphone.ogsmd' (using servicehelper)
Jul 30 17:45:23 gcomputer org.freesmartphone.ogsmd[2494]: 2016-07-30T15:45:23.129582Z [WARN]  subsystem : Could not load plugin: Could not load /us
Jul 30 17:45:48 gcomputer dbus[2494]: [system] Failed to activate service 'org.freesmartphone.ogsmd': timed out
Jul 30 17:45:48 gcomputer dbus[2494]: [system] Activating service name='org.freesmartphone.ogsmd' (using servicehelper)
Jul 30 17:45:48 gcomputer org.freesmartphone.ogsmd[2494]: 2016-07-30T15:45:48.156545Z [WARN]  subsystem : Could not load plugin: Could not load /us
Jul 30 17:46:13 gcomputer dbus[2494]: [system] Failed to activate service 'org.freesmartphone.ogsmd': timed out
Jul 30 17:46:14 gcomputer dbus[2494]: [system] Rejected send message, 1 matched rules; type="method_call", sender=":1.20" (uid=0 pid=2803 comm="/us
Jul 30 17:47:13 gcomputer systemd[1]: Reloading.
...
Jul 30 17:48:19 gcomputer console-kit-daemon[4607]: (process:4671): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
Jul 30 17:48:19 gcomputer console-kit-daemon[4607]: missing action
Jul 30 17:48:19 gcomputer dbus[2494]: [system] Successfully activated service 'org.freedesktop.ConsoleKit'
Jul 30 17:48:19 gcomputer systemd[1]: Started Console Manager.

Maybe also relevant:

root@gcomputer:~# systemctl get-default
graphical.target

root@gcomputer:~# systemctl status kdm
● kdm.service - LSB: X display manager for KDE
   Loaded: loaded (/etc/init.d/kdm; bad; vendor preset: enabled)
   Active: active (running) since Sun 2016-07-31 01:41:27 CEST; 7h left
     Docs: man:systemd-sysv-generator(8)
   CGroup: /system.slice/kdm.service
           └─2881 /usr/bin/kdm

Jul 31 01:41:27 gcomputer systemd[1]: Starting LSB: X display manager for KDE...
Jul 31 01:41:27 gcomputer kdm[2562]:  * Starting K Display Manager kdm
Jul 31 01:41:27 gcomputer kdm[2562]:    ...done.
Jul 31 01:41:27 gcomputer systemd[1]: Started LSB: X display manager for KDE.
Jul 31 01:41:57 gcomputer kdm[2881]: X server startup timeout, terminating
Jul 30 17:45:07 gcomputer kdm[2881]: X server termination timeout, killing
Jul 30 17:45:07 gcomputer kdm[2881]: X server for display :0 cannot be started, session disabled

root@gcomputer:~# systemctl status lightdm.service
● lightdm.service - Light Display Manager
   Loaded: loaded (/lib/systemd/system/lightdm.service; static; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:lightdm(1)

Jul 30 18:24:22 gcomputer systemd[1]: Stopped Light Display Manager.
Jul 30 18:24:22 gcomputer systemd[1]: Starting Light Display Manager...
Jul 30 18:24:22 gcomputer systemd[1]: lightdm.service: Control process exited, code=exited status=1
Jul 30 18:24:22 gcomputer systemd[1]: Failed to start Light Display Manager.
Jul 30 18:24:22 gcomputer systemd[1]: lightdm.service: Unit entered failed state.
Jul 30 18:24:22 gcomputer systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jul 30 18:24:22 gcomputer systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Jul 30 18:24:22 gcomputer systemd[1]: Stopped Light Display Manager.
Jul 30 18:24:22 gcomputer systemd[1]: lightdm.service: Start request repeated too quickly.
Jul 30 18:24:22 gcomputer systemd[1]: Failed to start Light Display Manager.

There is not a single error in /var/log/Xorg.0.log. Not sure where else to look:

root@gcomputer:~# grep EE /var/log/Xorg.0.log
    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
root@gcomputer:~# tail -n 10 /var/log/Xorg.0.log
    i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G,
    915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM,
    Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33,
    GM45, 4 Series, G45/G43, Q45/Q43, G41, B43
[     3.709] (II) intel: Driver for Intel(R) HD Graphics: 2000-6000
[     3.709] (II) intel: Driver for Intel(R) Iris(TM) Graphics: 5100, 6100
[     3.709] (II) intel: Driver for Intel(R) Iris(TM) Pro Graphics: 5200, 6200, P6300
[     3.709] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[     3.709] (II) FBDEV: driver for framebuffer: fbdev
[     3.709] (II) VESA: driver for VESA chipsets: vesa