Created attachment 65183 [details]
Xorg.0.log.old

on my T61 with SNA my system hangs.

This happen almost always when I start FF. 
Everything is ok with 2.20.1

I'm using:
kde - 4.9
kernel - 3.5.0
mesa-8.1_rc1_pre20120724
xorg-server-1.12.99.903


lspci -v

00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (primary) (rev 0c) (prog-if 00 [VGA controller])
        Subsystem: Lenovo T61
        Flags: bus master, fast devsel, latency 0, IRQ 45
        Memory at f8100000 (64-bit, non-prefetchable) [size=1M]
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at 1800 [size=8]
        Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
        Capabilities: [d0] Power Management version 3
        Kernel driver in use: i915



Now I'm able to attach only Xorg.0.log but later I will attach i915_error_state and dmesg.

Any more information do you need?