SFX in future Ubuntu releases

[Sean Middleditch]

On Thu, 2006-06-15 at 12:29 +0200, Étienne Bersac wrote:

> > So far as a security hole... there is no security hole opened by
> > Composite.
> 
> No, the problem in X11 is the driver model which give big power on
> drivers. Especially for drivers not using DRI.

This isn't some inherent property of X11's driver model.  It's simply a
problem in that X needs a lot of hardware access because the kernel
doesn't support the necessary features for managing the video hardware
itself.  X.org itself doesn't force drivers to be insecure.  You could
write a secure driver for X.org today if the kernel supported the
interfaces to make it possible.

> 
> > 2) Why write a whole new X server
> > when you can just write a glitz backend for X.org?
> > This wasn't possible before because the X.org server couldn't directly
> > access the 3D hardware at the same time as client apps, but that's what
> > AIGLX fixed.
> 
> That is a big good news man ! But will that simplify driver
> architecture ? Also, i consider that this is painful to have a
> framebuffer and an Xserver not synced. EGL and an Xserver on top of EGL
> might be a good solution to have a consistent graphic support. Why have
> we so big restriction with usplash (16 colors, etc.) where Xorg work
> fine ?

Because usplash doesn't use X.  Even with a new driver model, most of
the driver code is going to remain in userspace.  No kernel developer
wants huge multi-MiB GL drivers in the kernel proper.  The kernel's job,
though it will likely be extended, isn't going to include the
complexities of GL.  It's going to remain a communication device between
userspace GL and the hardware.


> 
> > And before anyone brings up the "X.org 7.1 w/ AIGLX breaks NVIDIA"
> > argument, note that since Xglx has to run on top of X.org, once Edgy
> > updates to X.org 7.1, Xglx is going to be just as broken until new NVIDIA
> > drivers come out that support X.org 7.1 fully.
> 
> The guilt is to nVidia blob ! Where is the EGL nVidia driver ? nVidia is
> clearly against that driver model, partly because it makes all driver
> the same at the end : OpenGL (modulo the subsets).

Where is EGL?  EGL doesn't exist.  You can't have an EGL driver when EGL
itself is nothing.  It's a half-complete idea, a barely begun
specification.  There needs to be a real EGL spec before you can expect
there to be any real drivers for it.  There also needs to be some actual
X developers working on EGL still for you to expect third part driver
developers to pick it up.  I'm not personally aware of anyone still
working on EGL.  (The dri-egl list at least has been dead.)

That line about NVIDIA being against OpenGL is also flat out silly.  EGL
in no way makes all drivers the same, because OpenGL has a very powerful
extension API.  NVIDIA hardware already supports tons of features using
nothing but the pure OpenGL API which no other hardware supports.  If
you were to force NVIDIA to use EGL, their drivers would retain the same
features and the same edge over their competitors that they do now.
Look up the documentation some time on the *huge* number of OpenGL
extensions NVIDIA developed specifically for their hardware.

> 
> > I think it's pretty clear that I'm against putting XGL into Edgy in any
> > official capacity.
> 
> 100% agree. Xglx is funny, but that's not a solution to push xserver
> over xserver !

See, I disagree.  The X server you pick makes a difference.  Xglx is
known to cause some breakage here and there, especially with certain
exotic configurations.  If Ubuntu chooses to push Xglx, it'll cause
problems for many people that just aren't necessary.  It's true that
X.org/AIGLX still has some performance issues compared to Xglx, but
those are, quite simply, bugs, and can and should be fixed.
-- 
Sean Middleditch <elanthis at awesomeplay.com>