Created attachment 111050 [details]
screenshot

While the contents of the window seems to be mostly fine, they are composed
inside the window in a completely wrong way (screenshot attached).
There is a visible line going from top left corner to bottom right and both
resulting parts of the window contains rotated and partially stretched content.

Trace to reproduce this at: http://pavel.ondracka.cz/battle.net.trace
or just get the client at battle.net/app/ and run it with wine. 

This is not reproducible with llvmpipe.

GPU: RV530
Mesa: e06b0778f59980429fececb1aa0de0f0a3f23427
libdrm: 2.4.58-3.fc21
Kernel: 3.17.6-300.fc21.i686