glxcompgr without Xgl ?

[Luca Dionisi]

Hi all
Is it possible to use glxcompmgr without using (and
even installing) Xgl ?
When I try to launch glxcompmgr it says something like
it needs double buffered visual. What does it mean?

I'm using a fresh installation of Xorg 7.0.
"xcompmgr" works, but it is quite slow, in particular
if I set transparency in a window.
I've got a Radeon card, DRI works well.

Please, any advice.

Luca