lxdm selected causes gdm and lxdm both to run

Bug #579538 reported by Jim Petersen on 2010-05-12
This bug affects 3 people
Affects Status Importance Assigned to Milestone
lxdm (Ubuntu)

Bug Description

Binary package hint: lxdm

I have Ubuntu 10.04 32-bit installed on my desktop PC and used "sudo apt-get install lubuntu-desktop" to add LUbuntu as a choice, since it is an older P4 2.4 MHz PC. I first selected "gdm" as my chosen login manager instead of "lxdm" in the dpkg configure screen that popped up during install of meta-package lubuntu-desktop. Later, I thought it would be nice to use "sudo dpkg-reconfigure lxdm" and select "lxdm" for a lightweight login manager. However, after rebooting, both lxdm and gdm start up, and cause various login and LXDE usage problems (once logged in), and sometimes gdm appears, sometimes lxdm. I saw by using "ps -aef | grep dm" that lxdm and gdm both were running.

If I use "sudo dpkg-reconfigure gdm" I also get the same choice of gdm or lxdm. However, setting lxdm in the dpkg setup for gdm causes the same behavior after rebooting: Both gdm and lxdm are running.

By setting back to gdm and rebooting, everything works normally again (only one login manager running), although at that point gdm is once again the chosen and running login manager.

One behavior I see when gdm and lxdm are both running is that after login to LUbuntu desktop, CPU usage is at 100% and the system is very unresponsive. Trying to open any window (e.g. lxterm) causes a flashing window and titlebar, and it's very hard to get it to close (system is almost unresponsive).

Lionel Le Folgoc (mrpouit) wrote :

I've experienced that when switching to lxdm as well. I think this is a bug in gdm though, that doesn't respect the default login manager chosen, and starts unconditionally.

Changed in lxdm (Ubuntu):
status: New → Confirmed
Jim Petersen (jpeter20) wrote :

I've solved this issue. Upstart launches /etc/init/gdm.conf during boot, which causes a conflict with an already-running login manager such as lxdm. By simply renaming gdm.conf to gdm.conf.save, gdm doesn't get launched and lxdm is allowed to do its thing.

Good find. For the record, that script checks if /etc/X11/default-display-manager is /usr/sbin/gdm, so you can go that route too. I guess d-d-m is not created automatically anymore, is it deprecated?

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