Marek's latest patch-set that was published on Monday night is for refactoring and clean-up of the driver. There's 19 patches as part of this series that touches several hundred lines of code within the R600g code-base.
Aside from the code bath, Marek worked out fine-grained sampler state updates, support for geometry shader resources (GL geometry shaders are soon to hit Mesa), atomization of some states, and some other bug-fixes.
The patch series can currently be found on the mesa-dev list. The work will be merged to Git master for the eventual Mesa 9.1/10.0 release come early 2013 now that Mesa 9.0 has already been branched.
For those that missed it, last week marked five years of official open-source AMD Linux graphics under which there's been the open-source driver strategy with Bridgman & Co.