Comment # 23 on bug 58042 from Simone Scanzoni

Mesa 9.2-devel (git-4deefd9) showed the problem here with TF2, I don't have
CSS.
Added patches:
 r600g: emit a ps partial flush after CP DMA
 r600g: enable CP DMA on r6xx (v3)
and the problem persisted.
Then reverting commit 1eedebc65b02130ef7a27062a1ed67972a317a08 fixed the issue.
Mesa 9.0.3 works.
HD3850 (RV670) AGP, kernel 3.8.0

First comment so I want to thank the devs for their work. :)