Great slowness with radeon(4x) and AccelMethod "EXA" for X.Org 7.2

Michel Dänzer michel at
Mon Jun 18 08:44:08 PDT 2007

On Mon, 2007-06-18 at 16:34 +0100, Chris Rankin wrote:
> --- Michel Dänzer <michel at> wrote:
> > For compiz, you need someone to implement zero-copy tfp for the r200 3D driver,
> That would be a "someone" at Tungsten Graphics, then ;-). 

Why? It shouldn't be hard for someone with the hardware to port the r300

> And presumably for the radeon and r300 drivers too?

I did the initial implementation for r300 and i915tex.

> > Meanwhile, as you found out, disabling 2D acceleration with Option "XaaNoOffscreenPixmaps"
> > or Option "FBTexPercent" "100" (more or less same effect with EXA) seems to be the least of
> > evils.
> Interesting, because I'm currently not using the "XaaNoOffscreenPixmaps" option at all: compiz
> performance is not amazing, but is OK. 

Fedora used to patch the X server so it enables it on the fly when
compiz starts, maybe they still do.

> Would I lose access to the second 128 MB of my 256 MB Radeon 9200 card
> if I did use it? The Xorg.0.log file says that it can only access the
> first 128 MB on my card directly.

You can't lose it because nothing's currently using it. The drivers
could be extended to use it for 3D textures or EXA offscreen pixmaps
relatively easily though.

Earthling Michel Dänzer           |
Libre software enthusiast         |          Debian, X and DRI developer

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