nvidia-config-display should manage nvidia libGL enablement

[Matt McCutchen]

Nicolas,

I'm continuing the discussion from
https://bugzilla.rpmfusion.org/show_bug.cgi?id=860 here at your request.

I propose that nvidia-config-display should manage the enablement of the
nvidia libGL along with the X driver, instead of leaving the nvidia
libGL enabled all the time.  This will allow GL programs to work when
the nvidia driver is disabled using another installed GL library, such
as mesa.

This is something I expected to just work, but if you would prefer to
consider it an enhancement request, that's fine with me.  I recognize
that software rendering with mesa is an inferior configuration for
intensive graphics work, but I feel that the value of having a working
(though inferior) configuration when the driver is disabled outweighs
the effort to implement the proposal, especially when much of the
infrastructure is already there.

In reply to https://bugzilla.rpmfusion.org/show_bug.cgi?id=860#c13 :
> A reboot is mandatory for that switch. nvidia recommands to switch to init 3
> while installing the driver, that way none of the drivers components are really
> in use.
> Updating, installing or switching theses components in live will always lead
> weird behaviours, so we will never support that.

That's irrelevant.  As long as nvidia-config-display doesn't change the
library path, the problem will occur regardless of whether I reboot.

> >       I'll grant that supertux is too slow to play with mesa, but blender
> > seems to work.
> Forget about it. Blender upstream doesn't even support intel 3D drivers because
> of lack of hardware 3D acceleration, I don't beleive they will support nouveau
> over nvidia since nouveau uses software emulated 3D.

My request is with a mesa + nv setup in mind, not nouveau.  I'm not sure
what you mean by saying that blender "doesn't support" a particular
driver.  I can start blender just fine with mesa + nv, though I suppose
it would become slow if I tried to do any heavy work.  (I'm not a
blender expert; I just chose it as an example of a well-known GL program
that happened to be on my system.)

-- 
Matt