When I enable MSI for the nvidia driver 180.44, a few seconds after logging in, X freezes. I can still use magic sysrq to shut off the pc. This is what I found in the log:
NVRM: Xid (0000:05): 26, Ch 00000000 M 0000021c D 00001c00 intr 00400000
A log with *disabled* MSI is attached. In disabled MSI config my setup is stable - using a composite kde 4.2 desktop. Please let me know if you need more infos. Btw I experienced the same issue with earlier drivers and other (stable) kernels.