Re: New module proposal: LightDM

[Brian Cameron <brian cameron oracle com>]

Ray:

> On Sun, May 15, 2011 at 2:30 PM, Brian Cameron<brian cameron oracle com>  wrote:
> > Yes, you are right.  GDM does not currently use OpenGL.
> >
> > My comment was meant to be understood as an example of how GDM may be
> > moving in a direction that requires certain hardware or only works on
> > certain operating systems.  Sorry if I was not clear.  For example, I
> > also raised concerns that the GDM/ConsoleKit evolution may be moving in
> > a Linux-focused direction.
> So to be concrete (for clairty to those following along that don't
> already know).  Oracle ships a product called SunRay.  It's a thin
> client system where the individual thin clients are treated as black
> box hardware devices that speak the X protocol.  Some of these devices
> don't support certain X extensions GNOME rely on like RENDER and GLX.
> I think this is what Brian is alluding to (Brian, correct me if i'm
> wrong on any of the above).

These sorts of hardware concerns are not specific to Sun Ray.  I believe
GNOME 3 will support a fallback mode to support such hardware.  It is
not clear, though, if GDM will follow suit.

From a Sun Ray perspective, a more serious issue is that GDM does not
support MultiSeat configurations in general.

> > If GDM is evolving into a display manager with tight GNOME integration
> > that works only with specific hardware and/or operating systems, then
> > an alternative display manager may be needed by some users.
> Of course, that's fine.  I don't think many would disagree with that.
> When developing your platform for SunRay, you've got to make choices
> that are appropriate for the technology you have.  And it may be
> LightDM is the way to go for that product.  Certainly, getting LightDM
> vetted through the ARC review process would be a good thing for it.

It is hard to predict the future.  The Oracle Desktop team has already
invested a lot of time to make ConsoleKit and GDM work well with Sun Ray
on Solaris.  Oracle is now using a patched GDM 2.30 and it works
reasonably well.  What makes sense in the future depends a lot on how
GDM and LightDM modules evolve going forward.

> SunRay is proprietary, though, and so kind of sits outside the focus
> of GNOME.

Yes, Sun Ray is a proprietary product that runs on Solaris and many
Linux operating systems.  To what degree GNOME supports proprietary
software, or how far it sits outside the "focus of GNOME" I do not know.

That said, Sun Ray needs a display manager that supports MultiSeat and
the ability to dynamically trigger when a seat is started or stopped
(and the ability to specify an Xserver command to use).  These features
seem generally useful and not what I would characterize as
"proprietary".

Sun/Oracle worked to implement these features into ConsoleKit and GDM.
See GNOME bug #536355 for more details.  It seems that now ConsoleKit
is being rewritten with a goal to better support MultiSeat.  Perhaps it
will be more straightforward to integrate Sun Ray with GDM after it has
better native MultiSeat support.

> But we've talked about this before, and I think we both
> agreed (right?) the choices you make for that platform may sometimes
> be orthogonal to and contrary with the choices we make together for
> GNOME.   We all have several hats to wear and juggle I guess.

Sure, but if we have identified a few cases where GDM can not be used,
then it could make sense for the GNOME community to recommend an
alternative in these cases.  Or is Solaris the only distro that has
these sorts of issues?

Brian