Bug#771762: [DEPEND] Dependency failed for X11 Display Manager.

[Michael Biebl]

Am 10.01.2015 um 11:49 schrieb Adrian Immanuel Kiess:
> Package: gdm3
> Version: 3.14.1-3
> Followup-For: Bug #771762
> 
> Dear Maintainer,
> 
>    * What led up to the situation?
>      Trying to run GDM3 at startup or with service gdm3 restart
>    * What exactly did you do (or not do) that was effective (or
>      ineffective)?
>      service kdm stop; dpkg-reconfigure gdm3; service gdm3 start
>    * What was the outcome of this action?
>      GDM3 does not work in Debian/testing
>    * What outcome did you expect instead?
>      Running and working GDM3
> 
> currently in Debian/testing GDM3 is broken for me.
> 
> It seems it tries to spawn a Xorg instance but fails with that.
> 
> I'll give the system logs below:
> 
> adrian at g6 (~) % systemctl status gdm3.service
> ● gdm.service - GNOME Display Manager
>    Loaded: loaded (/lib/systemd/system/gdm.service; static)
>   Drop-In: /run/systemd/generator/gdm3.service.d
>            └─50-gdm3-$x-display-manager.conf
>    Active: failed (Result: start-limit) since Sat 2015-01-10 11:38:47 CET; 6min
> ago
>   Process: 7364 ExecStartPre=/bin/sh -c [ "$(cat /etc/X11/default-display-
> manager 2>/dev/null)" = "/usr/sbin/gdm3" ] (code=exited, status=1/FAILURE)
> 

I think we can consider that a systemd bug and how it implements the LSB
$x-display-manager facility

Currently, this is a target, where every display manager can hook into
via a insserv override snippet.

Whenever another service requests the start of $x-display-manager, all
display managers hooked up into x-display-manager.target will be started.

Since gdm is not your default display-manager (but kdm), the
ExecStartPre= check will fail and thus the unit as a whole will be
marked as failed.

That's obviously not really the behaviour we want.

After careful consideration, I think it's better, to map
$x-display-manager to display-manager.service, which will be a symlink
to the default display manager.

With Didier's systemd-default-display-manager-generator, it should be
guaranteed, that /etc/systemd/system/display-manager.service points to
something sensible.

I'd propose something like the attached patch.

CCing the pkg-systemd-maintainers mailing list for input/review.






-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?
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