After upgrade 12.04->14.04 lightdm fails to start

Bug #1297936 reported by Nils Kassube on 2014-03-26
26
This bug affects 5 people
Affects Status Importance Assigned to Milestone
lightdm (Ubuntu)
Undecided
Unassigned

Bug Description

I upgraded this Kubuntu laptop using the command "do-release-upgrade -d" from 12.04 to 14.04. After the reboot, the splash screen did not disappear and lightdm didn't start. Running the command "start lightdm" (as root), I got the error message "start: Job failed to start", which wasn't really helpful. I also tried the command "/etc/init.d/lightdm start" and now there was some more information:

[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.9.13, UID=0 PID=2635
[+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/40-kde-plasma.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/40-lightdm-kde-greeter.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 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
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Using Xephyr for X servers
[+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
[+0.01s] DEBUG: Adding default seat
[+0.01s] DEBUG: Seat: Starting
[+0.01s] DEBUG: Seat: Creating greeter session
[+0.01s] DEBUG: Seat: Failed to find session configuration lightdm-gtk-greeter
[+0.01s] DEBUG: Seat: Failed to create greeter session
 * Starting X display manager lightdm [ OK ]

Even though there was the "[ OK ]" displayed in the last line, lightdm didn't start. Due to the message "Failed to find session configuration lightdm-gtk-greeter" I supposed that the package lightdm-gtk-greeter was missing. And indeed after I installed that package (+ dependencies), lightdm started.

As this is a test-upgrade I could return to the original 12.04 system. On that partition was a file /etc/lightdm/lightdm.conf from 2012 with this contents:

[SeatDefaults]
greeter-session=lightdm-gtk-greeter
user-session=Lubuntu

Obviously this was a leftover of a previous test with the lubuntu-desktop. While I had uninstalled lightdm and most of the other Lubuntu packages, this configuration file was not removed for some reason. And during the upgrade I was not asked if the config file should be replaced but the file stayed untouched.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.219
ProcVersionSignature: Ubuntu 3.13.0-19.40-generic 3.13.6
Uname: Linux 3.13.0-19-generic i686
ApportVersion: 2.13.3-0ubuntu1
Architecture: i386
CrashDB: ubuntu
CurrentDesktop: KDE
Date: Wed Mar 26 17:26:05 2014
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2014-03-26 (0 days ago)

Nils Kassube (kassube) wrote :
Nils Kassube (kassube) wrote :

Further experiments showed that it would be better to remove the stale config file /etc/lightdm/lightdm.conf instead of installing the additional package lightdm-gtk-greeter. Then the much nicer qt version of the login screen is in use and the KDE systemsettings can be used to configure the login screen.

Harald Sitter (apachelogger) wrote :

I am not sure we can do much about broken config files to be honest.

affects: ubuntu-release-upgrader (Ubuntu) → lightdm (Ubuntu)
Nils Kassube (kassube) wrote :

I think the upgrader could check if lightdm was installed before the upgrade. If it wasn't because kdm was in use, then the stale config file could be removed.

Jonathan Riddell (jr) on 2014-04-03
Changed in lightdm (Ubuntu):
milestone: none → ubuntu-14.04
Rohan Garg (rohangarg) on 2014-04-15
tags: removed: kubuntu
Jonathan Riddell (jr) on 2014-04-15
Changed in lightdm (Ubuntu):
milestone: ubuntu-14.04 → none
Launchpad Janitor (janitor) wrote :

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

Changed in lightdm (Ubuntu):
status: New → Confirmed
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