https://bugzilla.kernel.org/show_bug.cgi?id=68571
--- Comment #21 from Alexandre Demers alexandre.f.demers@gmail.com --- (In reply to perry3d from comment #18)
You are right, its not PCIExpress 2.0 vs. 3.0. I forced it in the bios, no improvment.
I also tried the drm-next-3.14 branch from Alex repository. Made it even worse: freeze on boot. Before i reached kdm and sometimes i saw the desktop.
After applying the patch from https://bugzilla.kernel.org/show_bug.cgi?id=68571#c5 i am on the same behaviour like i was with stock kernel 3.13.
I discovered that there is no kernel panic. I can get back to KDM with the SysRQ keys (Alt + Print + K).
Maybe its because my card is slightly overclocked by the factory: http://msi.com/product/vga/R6870-Hawk.html (in compare with the reference card: 930Mhz vs 900Mhz).
Something else i can do?
I may be wrong here, but I think that for now (which is something I worked with Alex Deucher in a different bug), overclocked cards are being limited to the reference values.