i915 hang and large allocation (~3.7-rc4)

[Dave Hansen]

I've been seeing a little goofiness with i915 video under the 3.7-rc's.
It looks like I'm seeing two separate issues.  One, that the video
hardware hangs, spits some errors in dmesg, and then video acceleration
seems to stop working.  Two, when it does this, apport goes digging in
debugfs for information about the hang.  When it does this, something
does an order-9 (2MB) kmalloc() which fails.

While debugfs is expected to be a _bit_ rickety, I do think order-9
is a bit excessive for an in-kernel allocation, even a temporary
one.  I'm not quite sure if it has done this for a long time, and I'm
only hitting it now since I'm seeing a _separate_ i915 hang.

Relevant parts of dmesg, lspci, and kernel config are here:

	http://sr71.net/~dave/linux/i915-wonky/