I upgraded my RAM from 2GB to 8GB today, and I'm no longer able to run 
X. My guess is this is a bug in the xen.git kernel (the dom0 kernel) in 
the i915 module. Other kernels (vanilla 2.6.32.x) work fine.

I have attached the full dmesg log. The problem is completely 
reproducible on my machine.

Thanks
Yasir