Comment # 7 on bug 101325 from Julien Isorce

Hi Luke, any chance you can try the apitrace
https://bugs.freedesktop.org/show_bug.cgi?id=100712#c7 ?
What worked for me on that bug was to disable write-combining by setting the
env var R600_DEBUG=nowc for both Xorg and for the gl application. It affects
performance a lot on some situations but this gives some hints were to look at
for debugging.