Almost every ATI board is supported by Xfree86, at least for the 2D accelerated features. The 3D support is provided either by the DRI project, which is already present inside XFree86, or by closed source drivers provided by ATI.

The multimedia features are actually supported by the GATOS project.

You have almost the same xfree support on ppc or alpha platform but you can't use the ATI closed source drivers. That means that you can't use the r300 3d features at all. If you have such a board and you want it supported by xfree, you should contact ATI and ask them to open the specs.

It should be but you may have a configuration issue due to the OEM PCI id that such chips may have. In most cases you may have to write the configuration file yourself or use the xf86config.

The xfree ebuild provides XFree86. xfree-drm provides the kernel modules required by DRI and ati-drivers provides the ATI closed source X drivers and kernel modules.

If you want just the Rage128 drivers and modules
installed with xfree

# VIDEO_CARDS="rage128" emerge xfree-drm
To have just the Radeon support
(r100, r200, r250, but not r300 yet)
# VIDEO_CARDS="radeon" emerge xfree-drm
To install the ATI closed source drivers
(r200,r250 and r300 only)
# emerge ati-drivers
To install just XFree86 but not install
any kernel module
# emerge xfree

It is suggested the use of xf86cfg, xf86config or directly by using the XFree86 auto configuration option:

# X -configure