its and xorg/ati/kernel problem not desktop or distribution problem.
if you are comfortable with compiling, git and know how to recover from an x hard crash then then you may try this if not you will have to wait like everyone else.
First off you need some extra packages.
autoconf xorg-server-devel kernel-source gcc make git
if X crashes and you do a hard reset you can append your kernel line with xorg=safe to reboot to a vesa display or xorg=off to boot to command line only.
next get latest mesa source
git clone git://anongit.freedesktop.org/git/mesa/mesa
this may take a little while
next select the radeon-rewrite branch
cd mesa then
git branch radeon-rewrite origin/radeon-rewrite
ensure is latest
git checkout radeon-rewrite
no we dont want to build the whole thing as we we can specify the models
./autogen.sh --prefix=/usr --with-dri-drivers=radeon,r200,r300
the r200 r300 are the only supported cards for dri but the group includes x1xxx series
once that is done just sudo make install any voila
if you do not have much success or find the driver unstable you can reinstall mesa through pisi.
now add some info to xorg.conf
lspci | grep VGA will tell you the pci address of you card
so use you prefered editor for editing xorg.conf is use nano
sudo nano /etc/X11/xorg.conf
some option may lock your card it is trial and error
here is my device section
Identifier "ATI Technologies Inc RS482 [Radeon Xpress 200]"
Option "AGPFastWrite" "true"
Option "AccelMethod" "EXA"
Option "MigrationHeuristic" "greedy"
Option "DRI" "true"
Option "AGPMode" "4"
Option "EnablePageFlip" "on"
Option "ColorTiling" "on"
#Option "DynamicClocks" "on"
VendorName "ATI Technologies Inc"
BoardName "RS482 [Radeon Xpress 200]"
some more info on the options and a dual screen confighttp://www.thinkwiki.org/wiki/Additional_options_for_the_radeon_driver