deactivating gdm service breaks grahical authentication

[loz]

Binary package hint: gnome-system-tools

In Xubuntu x64 8.04 with gnome-system-tools 2.22.0 :
In services settings, if I uncheck gdm, some things are broken whereas it is supposed to just "allow users to login locally" :
Of course it deactivate graphical login as one would expect, but also breaks user switching, and graphical authentication.
This is a big problem because graphical authentication is required to unlock services pannel, necessary step to reactivate gdm service.
From this point command line is required to rollback the action.

If you want details, I can do it again but it would be nice to give me first the command line to activate gdm service (I'm not a Debian guy so far, more a RedHat one), since it was a pain to fix the problem last time...

I think this option (deactivating gdm service) should just deactivate graphical login as stated, or at least warn that it will stop other functionnalities, and won't be rollable back graphically.

[Charlie Kravetz (cjkgeek)]

I reproduced this bug in VirtualBox, using Hardy 8.04. Unfortunately, while Applications -> System -> Services -> Graphical login manager (GDM) ¨Allows users to login graphically¨ gives a definite warning:
    Are you sure you want to deactivate gdm?

    This may affect your system behavior in
    several ways, possibly leading to data loss.

                                                    No Yes

Marking ¨Yes¨ and proceeding completely stops gdm, leaving me with at the screens I would have using Ctl+Alt+F8, the terminal used for data messages. There is no indication of how to get a desktop back. Switching to tty2, I logged in and used 'sudo gdm start' to get the desktop back and could then enter Services again to allow gdm to be used.

I would expect ¨Allows users to login graphically¨ to mean I just can´t login, not that my desktop will immediately shutdown.

I am confirming this bug based on this and the reporters comments. Thanks for reporting this bug.

[Milan Bouchet-Valat (nalimilan)]

Maybe we could improve that by changing the UI and adding some "start/stop now" buttons, that would be disabled for GDM. Unlike D-Bus (bug 112102, though we may still discuss that), it does not make sense at all to kill GDM while you're connected graphically.

[EdDantes (rod1995)]

Im running Linux 2.6.28-15-generic #52-Ubuntu SMP i686 GNU/Linux on an Asus laptop with Geoforce Go 7300, unfortunately I did kill GDM..
Now I cant log-in in graphical mode:

"Ubuntu is running in low-graphics mode
(EE) Failed to inialize GLX extention (Compatible NVIDIA X driver not found)"

Already reconfigured xserver and updated nvidia driver, reconfigure gdm, and nothing. If I run startx it works.

I do not find an effective rollback action, could you help with some details?
Thanks

[Milan Bouchet-Valat (nalimilan)]

EdDantes: I guess you can re-enable GDM on start typing
sudo update-rc.d defaults gdm

If that does not work, do
sudo rm /etc/rc?.d/S*gdm
and retry the first step.

BTW, I think the error message you pointed has no link with your problem.

[Milan Bouchet-Valat (nalimilan)]

Since Karmic services-admin is not shipped, and this is fixed upstream by hiding GDM from the list. If you're using a graphical tool, you're not likely to want to disabled it; and if you want to do so, you have to know how to do it from the command line, else you'd be unable to change that back.