Starting gdm (manually or during boot) doesn't do anything

Question

At my wit's end here! I can't get gdm to run. Not just not at boot-time, but at all. There's no error message. tty7 stays blank. It doesn't seem to attempt to start an X server. It doesn't log anything in /var/log/gdm or /var/log/Xorg.0.log (anywhere else I should look?).

$ sudo start gdm
gdm start/running, process 17747
$ sudo start gdm
gdm start/running, process 17769
$ sudo start gdm
gdm start/running, process 17791
$ sudo stop gdm
stop: Unknown instance: 

I've purged gdm, installed gdm, reinstalled gdm with -f and -m for good measure, wiped /usr/share/gdm, /etc/gdm, /etc/dconf/db/gdm.d and even ~/.config/dconf/user... nothing! Upgrading to 14.10 didn't help, either.

Running the gdm binary itself starts up some sort of miniature Gnome-Shell with nothing to do.

Gnome-Shell itself works fine with lightdm... minus the screen lock functionality, which I want. Besides, it just bothers me that something doesn't work. :þ

I'm having this issue on a regular desktop as well as an Eee PC 1215 N with intel/nvidia hybrid graphics. Both have KDE in addition to Gnome-Shell. (Well, I reinstalled the Eee PC with elementary OS yesterday).

Update: sudo start gdm says "gdm start/running" and provides a pid even with the gdm binary itself removed.

Solution

I suspect a bug. Maybe gdm's crashing on launch.

In theory sudo apt-get update; sudo apt-get --purge --reinstall install gdm might help if it's corrupted or (more likely as it was likely upgraded when you upgraded your release to Utopic) its config is bad. So I'd try that first.

When that fails, I suggest enabling automated bug reporting to Launchpad, then see if you're offered the chance to submit a bug report when you launch gdm with sudo start gdm. (On 14.10, you likely do not need to do this, as development releases are set up to let you report bugs in this way.)

• That works for the typical case of checking to see if a program that doesn't appear to run properly is crashing. But since a GUI is likely not running when you attempt to start gdm (if one is, maybe that's the problem!), you may have to manually check to see if Apport generated any data on the crash.

  Assuming you're running sudo start gdm from a text-based virtual console, which is the usual case, you will likely not actually be informed explicitly of the crash. But assuming you set up Apport as detailed above, you can then check to see if there is a .crash file in /var/crash for gdm.

  You can then continue the bug reporting process by running ubuntu-bug ... (from in a GUI) or apport-cli ... (non-graphical), with ... replaced by the name of the .crash file, including the .crash suffix. Either do this from the /var/crash directory or start the filename with /var/crash/.

If Apport generated .crash file and/or prompted you to report a bug, that confirms it's a crash (and thus almost certainly a bug). You can go through with the report, but please read this first.

Comments

[Eliah Kagan]

Anything on tty8? Also, can you clarify what you mean by "with nothing to do"?

[Anj Tuesday]

Nothing on tty8. (Except once or twice or so on the netbook when it gave me the "low graphics mode" dialogue. This has stopped happening, though, and I've never had trouble starting a full resolution, 3D-accelerated X session with lightdm or startx.) By "with nothing to do" I mean it looks like the usual gdm login screen, just without the parts that would actually let you pick a user, enter a password, select a session, and login. Maybe that's the usual result of running /usr/sbin/gdm directly.

[Anj Tuesday]

There's nothing (new) in /var/crash, but I'm unsure how to do the suggested modifications to /var/apport/crashdb.conf since there's no 'problem_types' line to edit. Where exactly does it go?

[Anj Tuesday]

It's Utopic, although the problem with gdm goes back to at least Trusty. The Eee PC has elementary 0.3 (based on Trusty), and its crashdb.conf does indeed have problem_types (but elementary's own packages conflict with gdm, so I can't try anything there any more)

[Anj Tuesday]

sudo start gdm says "gdm start/running" even when I remove /usr/sbin/gdm. Hmmm.

[Anj Tuesday]

Nothing (no output)

[Anj Tuesday]

The reinstalled system is working better so far, although not perfectly. gdm starts every time but occasionally turns up in this dysfunctional top-bar-only state that's missing the username/password/session chooser UI. But that might be an entirely different problem. I'll see what happens as I restore more of my usual setup. Thanks for the advice and patience! PS: I did say /usr/sbin/gdm :)

[Eliah Kagan]

@AnjTuesday Sorry about my misreading of sbin as bin! I'm glad you have it working better now. You may want to edit this question to update it about what you're currently trying to get fixed. By the way, since my answer here wasn't the solution and I don't anticipate it will particularly help others people much either, I'd like to delete it (I can always reuse content of it in future answers instead). But I don't want to make any of your comments here invisible to you if you're still using them for reference. Please let me know if/when it's OK with you for me to remove this answer. Thanks!

[Eliah Kagan]

@AnjTuesday On the other hand, the current problem has only happened on Utopic, right? Problems with development versions of Ubuntu are considered off-topic on Ask Ubuntu. So rather than having you edit this question, it might be better to file a bug on Launchpad. If you do, and provide the bug number, I'll subscribe to the bug. We could then close this question as "a problem that cannot be reproduced" (this is a different sub-reason under "off topic") since the reinstalled system doesn't have the same problem as it originally described.

[Eliah Kagan]

@AnjTuesday I have no problem keeping this answer if it may help at least one person in the future (and that person can be you). Please just keep in mind that (1) comments are considered second-class citizens and are often removed by moderators or just by community-flagging if they're considered obsolete or insufficiently related to the post being commented on--I wouldn't count on these sticking around. Note also that I had already removed some of my comments here. And (2) this question itself will likely be closed and may, after that, be deleted (deleting this answer and comments with it).