Among the work found in Marek's patches for bettering Radeon Gallium3D multi-sample anti-aliasing include fast color clears for integer textures, fast color clears for array/3D/cube textures, fixing color resolves for certain integer formats, cache flushing changes, and other fixes. Fast color clears are an MSAA performance optimization and had earlier come to the Radeon R300 Gallium3D driver earlier in the year.
These patches by the well known independent contributor student to the open-source Radeon Linux graphics driver stack are currently sitting on the Mesa-dev mailing list. Committed by Marek yesterday was also a Mesa patch (that was originally authored by a new contributor, Grigori Goronzy) for initial MSAA fast color clears on AMD Evergreen GPUs and newer. "Allows MSAA colorbuffers, which have a CMASK automatically and don't need any further special handling, to be fast cleared. Instead of clearing the buffer, set the clear color and the CMASK to the cleared state."