Comment # 1 on bug 66551 from octoploid

OK, I've just double checked and the issue doesn't depend on
DPM being enabled.
A vanilla Linus kernel (latest git) with DPM disabled will also hang.

I'm using:

x11-drivers/xf86-video-ati-7.1.0
media-libs/mesa-9.1.4
x11-libs/libdrm-2.4.46

Any idea on how to further debug this issue?