Re: New module proposal: LightDM

[Ray Strode <halfline gmail com>]

Hi,

(speaking as one of the 3 maintainers of GDM)

On Thu, Oct 21, 2010 at 12:02 AM, Robert Ancell <robert ancell gmail com> wrote:
> - The GDM greeter is slow due to it loading the GNOME session, the
> example GTK+ LightDM greeter is very lightweight (so is comparable to
> the speed of the old GDM and newer display managers like LXDM).
Using GNOME session / g-s-d /etc  is one of GDMs main features.  The
point is for there to be consistent experience on the login screen and
in the session.
If GDM is too slow because of GNOME session then GNOME session needs
to be fixed, otherwise login after GDM will be too slow too.  Anyway,
if gnome-session is slow on your machine we should start by profiling
it and figuring out why.

> - The GDM greeter has very limited themeing capabilities.  A
> contributor to LightDM (PCMan) was able to quickly write a new greeter
> that used GtkBuilder and provided comparable themeing support to the
> old GDM.
GDM uses the standard theming mechanism as the rest of GNOME.  This a
good thing.

Making GDM use GNOME components and integrate with GNOME is not a bad
thing. It used to not do that and was explicitly changed...

Of course, things will need to be rethought about in a post- GNOME 3
world (use mutter / clutter?)

> - While it is technically possible to write an alternate greeter for
> GDM, in practise it is too difficult.  LightDM has been designed from
> the start to make writing a greeter no harder than a standard X
> application.
Granted, the interface between greeter and daemon isn't
as clean as it could be.  Still,

1) it's obviously not too difficult, or there couldn't be one
functioning greeter
2) When writing a new greeter becomes a priority to someone, the
interface is completely changeable. It's a private interface so it can
be changed in any way that's needed.

> - All X server users have pretty much the same requirements beyond the
> login GUI.  By using LightDM the development effort of maintaining the
> display manager can be shared between projects (GNOME, KDE, LXDE,
> XFCE).
So you're not proposing LightDM to become part of GNOME, you're just
proposing GDM get dropped and LightDM become an external dependency?

Have you talked to the other projects about this?  We had some
discussions some time back with Oswald (KDE developer) about
standardizing on one display manager a few years ago:

http://mail.gnome.org/archives/gdm-list/2007-October/msg00013.html
(added him to cc list)

Anyway, I'm obviously in favor of keeping GDM in GNOME.  I admit it
has some baggage (some of it removed and added back later by popular
demand), but overall GDM is in really good shape as a project.. FWIW,
your various patches over the years have been a part of getting GDM to
where it is.

--Ray