[Nouveau] launching Firefox causes system crash

[Grant]

Launching firefox is causing a system crash with a black or white
screen and diagonal lines across it.  I've tried the latest nouveau
from git and the latest kernel.  I can't find anything in the logs
unfortunately.  Any ideas?

00:0d.0 VGA compatible controller: NVIDIA Corporation C61 [GeForce
6150SE nForce 430] (rev a2) (prog-if 00 [VGA controller])
    Subsystem: Micro-Star International Co., Ltd. Device 7309
    Flags: bus master, 66MHz, fast devsel, latency 0, IRQ 40
    Memory at de000000 (32-bit, non-prefetchable) [size=16M]
    Memory at c0000000 (64-bit, prefetchable) [size=256M]
    Memory at dd000000 (64-bit, non-prefetchable) [size=16M]
    Expansion ROM at dfd40000 [disabled] [size=128K]
    Capabilities: [48] Power Management version 2
    Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Kernel driver in use: nouveau

- Grant