Fwd: [xubuntu-users] Replacing LightDM with XDM

Stephen Michael Kellat skellat at fastmail.net
Wed Nov 27 04:48:37 UTC 2013

On Wed, 27 Nov 2013 02:46:05 +0200
Pasi Lallinaho <pasi at shimmerproject.org> wrote:

> Hey George,
> forwarding this to the developer mailing list.
> I'm pretty sure we won't switch at least for 14.04 (we have more
> features and improvements landing for LightDM), but it's always
> possible to rethink this after the LTS. Maybe this will also raise up
> some questions.
> Cheers,
> Pasi
> -------- Original Message --------
> Subject: 	[xubuntu-users] Replacing LightDM with XDM
> Date: 	Tue, 26 Nov 2013 16:14:28 -0500 (EST)
> From: 	George F. Nemeyer <tigerwolf at tigerden.com>
> Reply-To: 	Xubuntu Support and User Discussions
> <xubuntu-users at lists.ubuntu.com>
> To: 	xubuntu-users at lists.ubuntu.com
> I have 30 machines running Xubuntu 13.04 in a public
> kiosk-environment.
> I need to replace the lightDM display manager with XDM, because I
> need to strip all ability to change *anything* on the machines
> (network settings, session settings, decorations,
> logout/reboot/shutdown, etc.) out of the login screen.  LightDM seems
> to be in a constant state of change, and what little configuration
> seems possible either dosen't work as described, or has other issues,
> such as putting a right-click panel option into XFCE which leads to
> options allowing any user to be able to reboot or shut the machines
> down.
> I've had only partial success converting to XDM.  XDM works and is
> configured to look as I want it, and it allows logins, but once a user
> session starts, there's lots of strange behavior:
>  - The package manager starts, allows you to select a package to
> install, but does nothing when you tell it do do so.
>  - Other programs have similar oddities.  These *seem* to be ones
> that do some cross-interfacing with system functions.
>  - Some, but not all, panel icons won't launch the underlying program
> at all.
>  - Wireless, audio volume, and other icons normally in the
> 'notification area' aren't there, even for admin users who should
> have access to those functions.
> I suspect that LightDM is starting something like dbus, session bus,
> or some other daemonish-process(es) that are not started by XDM.  The
> LightDM configuration is not fully documented (no man pages), and
> much of the Internet forum guidance is simply wrong for the versions
> in 13.04.  It uses non-plain-text configuration files, so I haven't
> any real idea of just what all it does when logging in with it.
> Has anyone been able to run with XDM successfully, and if so, what
> did you do?
> Likewise, if anyone has a clue on what LightDM does and insight how
> to get rid of it, I'd be very grateful.
> =^_^=  Tigerwolf
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> -- 
> Pasi Lallinaho (knome)                      » http://open.knome.fi/
> Leader of Shimmer Project and Xubuntu       »
> http://shimmerproject.org/ Graphic artist, webdesigner, Ubuntu
> member  » http://xubuntu.org/

The last time anything happened in Ubuntu's archives with XDM was a merge done by Micah Gersten in December 2011.  The screenshots in the packages.ubuntu.com listing show the Debian graphic very prominently so we'll need to see if that is hard-coded or not.  From the discussion on LP Bug #585853 it looks like Steve Langasek said XDM does not play nice with Upstart ten months prior to Micah's merge.  Debian Bug #615020 talks about a lack of ConsoleKit support which is going to be crippling nowadays.  More details can be found through the portal here: http://packages.qa.debian.org/x/xdm.html

I might suggest considering a different option than XDM if possible.  I might think of some Wednesday once I get a good night's sleep after a day On The Run in Cleveland handling business downton.

Stephen Michael Kellat

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