Comment # 24 on bug 91268 from Laurento Frittella

I'm trying the attached patch to disable WC on my r6xx and it seems to help
here as well.

01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
RV620/M82 [Mobility Radeon HD 3450/3470]

Linux mybox 4.2.1-custom #3 SMP PREEMPT Mon Oct 26 22:05:24 CET 2015 x86_64
GNU/Linux

Debian stretch/sid