"dpkg-reconfigure lightdm" fails

[Yann Dìnendal]

GDM was used instead of lightdm, so I uninstalled it (sudo aptitude remove gdm), it told me to uninstall also gdm-guest-session. And it told me to run "dpkg-reconfigure lightdm". But it fails, so I have to manually launch "sudo lightdm" from TTY1 to log in.

$ sudo dpkg-reconfigure lightdm
dpkg-maintscript-helper: warning: environment variable DPKG_MAINTSCRIPT_NAME missing
dpkg-maintscript-helper: warning: environment variable DPKG_MAINTSCRIPT_PACKAGE missing
$

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: lightdm 0.9.7-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4
Uname: Linux 3.0.0-11-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu1
Architecture: i386
Date: Tue Sep 20 02:39:48 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110330)
SourcePackage: lightdm
UpgradeStatus: Upgraded to oneiric on 2011-09-03 (16 days ago)

[Daniel Holbach (dholbach)]

Confirmed. Same problem here, full log:

daniel@daydream:~$ LC_ALL=C sudo apt-get install xdm
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  xdm
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/164 kB of archives.
After this operation, 926 kB of additional disk space will be used.
Preconfiguring packages ...
Selecting previously deselected package xdm.
(Reading database ... 172392 files and directories currently installed.)
Unpacking xdm (from .../xdm_1%3a1.1.10-3ubuntu1_amd64.deb) ...
Processing triggers for man-db ...
Processing triggers for ureadahead ...
Setting up xdm (1:1.1.10-3ubuntu1) ...
 Adding system startup for /etc/init.d/xdm ...
   /etc/rc0.d/K01xdm -> ../init.d/xdm
   /etc/rc1.d/K01xdm -> ../init.d/xdm
   /etc/rc6.d/K01xdm -> ../init.d/xdm
   /etc/rc2.d/S99xdm -> ../init.d/xdm
   /etc/rc3.d/S99xdm -> ../init.d/xdm
   /etc/rc4.d/S99xdm -> ../init.d/xdm
   /etc/rc5.d/S99xdm -> ../init.d/xdm
daniel@daydream:~$ LC_ALL=C sudo dpkg -P xdm
(Reading database ... 172427 files and directories currently installed.)
Removing xdm ...
xdm prerm warning: new default display manager has been selected; please be
   sure to run "dpkg-reconfigure lightdm" to ensure that it is configured
Purging configuration files for xdm ...
 Removing any system startup links for /etc/init.d/xdm ...
   /etc/rc0.d/K01xdm
   /etc/rc1.d/K01xdm
   /etc/rc2.d/S99xdm
   /etc/rc3.d/S99xdm
   /etc/rc4.d/S99xdm
   /etc/rc5.d/S99xdm
   /etc/rc6.d/K01xdm
Processing triggers for ureadahead ...
Processing triggers for man-db ...
daniel@daydream:~$ LC_ALL=C sudo dpkg-reconfigure lightdm
dpkg-maintscript-helper: warning: environment variable DPKG_MAINTSCRIPT_NAME missing
dpkg-maintscript-helper: warning: environment variable DPKG_MAINTSCRIPT_PACKAGE missing
daniel@daydream:~$

[Yann Dìnendal (yannbreliere)]

Do you know how I can configure lightdm to launch automatically, before bug #706354 is fixed?

[Bilal Akhtar (bilalakhtar)]

Yann,

There's a simple fix, which avoids running any dpkg-* commands:

sudo su
echo "/usr/sbin/lightdm" > /etc/X11/default-display-manager
exit

That should do it.

[Yann Dìnendal (yannbreliere)]

Thanks, Bilal!
The file /etc/X11/default-display-manager only contained "lightdm", I don't know why. With the full path, it works!