Created attachment 84671 [details]
Kwin backtrace

I run Slackware64-current systems on several workstations using AMD processors
and graphic cards. I usually compile my own very recent kernels (currently
3.11-rc*) and I regularly (about once every two weeks) compile git version of
libdrm, mesa and xf86-video-ati.
I noticed that with recent versions of mesa, kwin, KDE's compositor and windows
manager, crashed immediately at boot and only worked when I disabled the OpenGL
effects. The last version of mesa that worked was of the 2013/08/08. By just
changing mesa to a more recent version, kwin would segfault, for the first time
in years, with KDE 4.10.5 as well as 4.11.
My other systems, which have a fairly similar OS settings, do not have these
issues but they use the r600g driver while my old laptop, the one which crash,
still use r300g.
I've attached to this kwin backtrace which clearly shows that kwin crash while
working with r300_dri.so, as well as the startx output.
I don't have debug binaries unfortunately.