Created attachment 115834 [details]
kernel log with drm.debug=1

Playing in spec ops: the line from steam causes gpu lockup.

Behaviour differs. Firstly system freeze, after a few seconds screen becomes
black. Sometimes works only sysrq, sometimes i can switch to VT and log in
(screen still is black, but sudo reboot works). Sometimes it unfreeze and
everything works again.

System:                  Fedora 22 x86_64
kernel:                  4.0.2-300.fc22.x86_64
mesa:                    10.5.4-1.20150505.fc22
xorg-server:             1.17.1-11.fc22
libdrm:                  2.4.61-3.fc22
xorg-x11-drv-ati.x86_64: 7.5.0-3.fc22
window manager:          kwin-5.3.0-2.fc22

video card Radeon R9 270X
OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD PITCAIRN
OpenGL core profile version string: 3.3 (Core Profile) Mesa 10.5.4
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 10.5.4
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 10.5.4
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.00
OpenGL ES profile extensions:

reproduce always. After 15-40 minutes of playing.