Description: Running linux mainline kernel 3.12 rcX in arch linux with nouveau driver causes crash soon after boot

I have been testing the linux mainline kernel version 3.12 rc1, rc2 and rc3 - this report is being entered so that the upstream bug reported at https://bugs.freedesktop.org/show_bug.cgi?id=69982 can be tracked, and a known temporary workaround implemented until the problem is resolved upstream.

In my case the graphics hardware is:
01:00.0 VGA compatible controller: NVIDIA Corporation G86GLM [Quadro FX 360M] (rev a1)

But this bug may also impact other Nvidia graphics cards older than NV50 due to the recent implementation of MSI interrupts as default in the nouveau driver.

Additional info:
* package version(s)

$ sudo pacman -Ss nouveau
extra/nouveau-dri 9.2.0-2 [installed]
Mesa drivers for Nouveau
extra/xf86-video-nouveau 1.0.9-1 (xorg-drivers xorg) [installed]
Open Source 2D acceleration driver for nVidia cards

Kernel is linux mainline 3.12 rc3

* config and/or log files etc.
Log files are available in my upstream report referenced above.

Steps to reproduce: Boot to 3.12 rc3, login to KDE - system locks up within a few seconds with no access to alternative text consoles, and the only known recovery is reboot.

There are two known workarounds:

1) Boot with nouveau.config=NvMSI=0 in the kernel line

or

2) Make a file /etc/modprobe.d/nouveau.conf containing one line:

option nouveau config:NvMSI=0

Then boot.

With either of these the system runs without any crash once booted.