Some logging of stuff I had to do to haxx0r ATI's driver to make it work. Even then it didn't work 
Reference: http://gentoo-wiki.com/index.php?title=HOWTO_ATI_Drivers&redirect=no
First get the damn thing, which is trouble enough in itself....
Hack the DETAILS so that the versions are right....
Try the cast and see if it has problems, it may not fail the cast, even if the driver doesn't get built successfully...
if it cannot find stuff and you have to add it from the kernel headers use delve:
delve -c ati_driver start config_loc --haxx0r your sources--- delve -c ati_driver config_loc end
do that lots of times, and copy in functions from the kernel headers that it cannot seem to find
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or you can do some voodoo with the xorg drivers extract xorg tarball in /usr/src and build the r300 mesa drivers by hand --- semi-insane instructions follow
cd xc/Extras/drm bash # opens a subshell for sorcery's environment . /etc/sorcery/config ./autogen.sh make; make install
- note the install to /usr/local/lib/pkgconfig/
- export PKG_CONFIG_PATH='/usr/local/lib/pkgconfig
cd ../Mesa make linux-dri
- sit back and wait until it appears to be looping
- ctrl-c it
cd #to the dir with r300 in it make # if possible
- if you end up with some .so file with r300 in it's name, copy it to the dir with the other mesa drivers
- /usr/X11R6/lib/modules/dri
- then pray and see if it works