system freeze with kernel 3.2-rc7

[Kai Krakow <hurikhan77@gmail.com>]

Hello!

I found my system freeze mostly during starting up X and KDE. Sometimes it 
works for some minutes, sometimes it freezes immediatly. When the freeze 
happens, everything is dead (even the reset button does not work, I need to 
power cycle).

I was using libdrm-2.4.27 before, system freeze showed some colorful lines 
running down at the left side of the screen after turning black, then some 
blue flicker in the top 10% of the the screen. System no longer reacts, 
network is dead too.

Now, using libdrm-2.4.29, the system freeze shows other effects: Screen does 
not turn black but starts to flicker and occassionally moves some 
centimeters to the right (wrapping the right-most part to the left) for a 
very short time, then jumping back with some distortions. The rest is the 
same: Complete freeze, even reset button stops working.

Before finding out about the libdrm difference, I tried other intel xorg 
driver versions to no avail, I tried with SNA support and without. No 
difference. I'm now back to intel xorg driver 2.17.0.

I read about the semaphores feature, turned it off: No change. Sometimes the 
system even freezes before displaying the framebuffer splash.

I didn't have such issues with early 3.2 rcs (afair), and not with 3.1 
kernels. After some digging through google I've found you enabled RC6 in 
3.2. I disabled it now, and my system runs wonderfully.

Do you need any specs? I'd be happy to send these. The system is a Z68 Pro 
board with Sandybridge i5-2500K processor, 8 GB of RAM and UEFI firmware. 
Looks like RC6 is not ready for roll-out, at least on some mainboards.

Regards,
Kai