https://bugs.freedesktop.org/show_bug.cgi?id=57875
--- Comment #22 from Stefan Dösinger stefandoesinger@gmx.at --- Are you sure? I see nothing in the r300g git history that I'd expect to have fixed this bug. Unless of course the hw does what ARB_depth_clamp requires when you set CLIP_DISABLE and the rendering problems had nothing to do with depth_clamp in the first place.
If the bug is indeed fixed a bisect for the commit fixing it might be interesting.