http://bugs.winehq.org/show_bug.cgi?id=14847
--- Comment #19 from Henri Verbeet hverbeet@gmail.com 2011-10-14 13:34:19 CDT --- (In reply to comment #18)
MesaGL and open-source drivers for your GPU. It is well known that the current state of open source GPU drivers is far from perfect so your best bet would be to install Catalyst/fglrx binary drivers blob from AMD and retest the game with it.
While it's true that the free drivers aren't exactly perfect, I generally have better hopes for things working with r600g than with fglrx. The problems with r600g are typically related to performance rather than to rendering correctness or stability.