https://bugs.freedesktop.org/show_bug.cgi?id=36099
--- Comment #3 from vand2@gmx.de 2011-04-09 05:45:07 PDT --- With the current git version the distortions are gone and all looks ok.
glxinfo now: glxinfo | grep string
server glx vendor string: SGI server glx version string: 1.2 client glx vendor string: Mesa Project and SGI client glx version string: 1.4 OpenGL vendor string: X.Org R300 Project OpenGL renderer string: Gallium 0.4 on ATI RV570 OpenGL version string: 2.1 Mesa 7.11-devel (git-d27ff8c) OpenGL shading language version string: 1.20