https://bugs.freedesktop.org/show_bug.cgi?id=37262
--- Comment #3 from dE de.techno@gmail.com 2011-07-18 08:27:22 PDT --- I hope you mean the commit. As said, the problem persists with mesa greater than 7.10.x.
This problem appears be of low level, I tried a systemtap script to see what was causing the I/O but there was hardly anything suspicious.