Lightdm doesn't launch Plasma on Kubuntu Trusty anymore

[Rohan Garg]

When trying to start the KDE Desktop using lightdm on a Live Kubuntu CD, lightdm fails to start the session.

[Steps to reproduce]
* Download the latest Kubuntu Trusty ISO
* Click on "Try Kubuntu"
* Plasma fails to come up

Lightdm Log :
[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.9.4, UID=0 PID=5237
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf.d/50-guest-wrapper.conf
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf.d/50-xserver-command.conf
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Registered seat module xlocal
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Registered seat module unity
[+0.00s] DEBUG: Registered seat module surfaceflinger
[+0.00s] DEBUG: Adding default seat
[+0.00s] DEBUG: Seat: Starting
[+0.00s] DEBUG: Seat: Creating user session
[+0.09s] DEBUG: Seat: Failed to find session configuration ubuntu
[+0.09s] DEBUG: Seat: Can't find session 'ubuntu'
[+0.09s] DEBUG: Seat: Creating greeter session
[+0.09s] DEBUG: Seat: Failed to find session configuration default
[+0.09s] DEBUG: Seat: Failed to create greeter session

[Robert Ancell (robert-ancell)]

This is because the lightdm has removed lightdm-set-defaults - now you should provide configuration into /usr/share/lightdm/lightdm.conf.d (patches attached)

[Robert Ancell (robert-ancell)]

I haven't tested these patches but this is essentially what you should do - please ping me if you have any problems.

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1257760

[Jonathan Riddell (jr)]

Thanks, uploaded