[PATCH xf86-video-ati 0/3] Initial glamor and SI support.

Michel Dänzer michel at daenzer.net
Tue Jul 10 06:08:36 PDT 2012

On Die, 2012-07-10 at 14:06 +0200, Rafał Miłecki wrote: 
> 2012/7/10 Michel Dänzer <michel at daenzer.net>:
> > The main purpose of these changes is to allow using this driver on SI hardware
> > and playing with the (still quite limited) Gallium radeonsi driver in an X
> > environment.
> >
> > Longer term, glamor might be interesting for older Radeons as well. Right now,
> > its main drawbacks are missing XVideo support (shouldn't be hard to add to
> > glamor), and occasionally quite annoying diagonal tearing.
> Ups, I got lost. So do we drop idea of using xf86-video-modesetting
> for SI? I though we want to use xf86-video-modesetting and some
> Gallium state tracker for 2D acceleration.

I'm afraid you read things into what we wrote that weren't there. :) We
wrote that we'd like to use the Gallium driver for 2D acceleration as
well. We evaluated several alternatives for doing that and decided that
glamor seems to provide the best tradeoff right now. It's still not set
in stone, but it's basically working now (with surprisingly little
effort) and we'll see how it goes.

> What's the difference between handling 2D acceleration in:
> 1) xf86-video-ati

The big advantage for this is that it allows for the most consistent
user experience across all Radeon hardware.

> 2) xf86-video-modesetting + X/Gallium?

This was never really an option, the point of xf86-video-modesetting is
to be a simple, generic fallback without hardware acceleration.

> > [The SI support] Defaults to shadowfb. 3D acceleration is available
> > with glamor. 2D acceleration is disabled until the radeonsi driver
> > can handle glamor's shaders. 
> Could you explain what is glamor? I was sure it is supposed to provide
> 2D acceleration using OpenGL.

Right, see http://www.freedesktop.org/wiki/Software/Glamor .

> What do you mean by providing 3D acceleration with glamor?

That enabling glamor also enables the DRI, so you can run e.g. OpenGL
apps using GLX.

Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer

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