XGI had worked to provide a full open-source driver stack for the Volari 8300 series, but that graphics card never ended up being widely available. As XGI faded away, IBM worked on the XGI Linux driver and wrote the XG40 GPU support along with other changes as some XGI graphics processors wound up in some IBM systems. Ian Romanick was the one working on this unpopular Linux driver at IBM, but in 2008 he went to work for Intel, which meant a final blow to XGI's Linux support.
There hasn't been much to say about XGI or their Linux support since that time. The only work going into the xf86-video-xgi driver has been small fixes and updates so the driver remains compatible with current X.Org Server releases. However, this morning, to much surprise, there is actually some signs of life left for xf86-video-xgi.
XGI's Jong Lin has written patches for xf86-video-xgi so that it can work on ARM-based systems, supports EXA acceleration, can handle EDID with I2C function, supports custom modes, and the unification of more code between the x86/PowerPC/ARM architectures. Confirmation of this work can be found here. This isn't exactly huge like the XGI driver picking up kernel mode-setting support or any really exciting features, but up to this point only XAA has been available for 2D acceleration and now there's EXA.
Providing support for the ARM architecture so late in the game is rather interesting, unless XGI Technology is looking to revive itself by providing GPUs for new mobile/netbook devices. XGI's most recent press release is from May 2009 where they announced the Volari Z11 GPU for embedded ARM-based systems such as the Marvell Kirkwood.
Jong Lin is a long-time XGI employee and someone that I had communicated with some five years ago. We're awaiting comment to find out whether XGI Technology plans to relaunch itself in some fashion or they are just looking to spice up their Linux driver for those few out there that still have a Volari graphics card.