> Great! You are the guy who also did the fan control patches aren't you?

Yep, that's me, thanks!
I also stalkered Michel Dänzer for explanations of GTT and VMM at some time :)

> As first step please try to catch an apitrace of it.
> 
> If that doesn't work and you still want to get your hands dirty with the
> code again contact me by mail (christian.koenig@amd.com) and we can discuss
> how to dig deeper into this issue.
> 
> Best regards,
> Christian.

Will do on weekend and mail you about results.