https://bugs.freedesktop.org/show_bug.cgi?id=73528
--- Comment #43 from EoD EoD@xmw.de --- FTR: the above workaround has been reverted in http://cgit.freedesktop.org/mesa/mesa/commit/?id=de59a40f6898e20a61ac4ea0e59... and there are no more problems on my r600g at least.
Thanks!