Comment 11 for bug 996008

For the record, I have tried booting with the irqpoll option, does not help.

Doing echo 'options nvidia NVreg_EnableMSI=1' > /etc/modprobe.d/nvidia.conf as recommended in that post you linked does apparently not activate MSI for nvidia as intended. There was no file with that name in that directory, but several otehr nvidia* files (nvidia-current-updates_hybrid.conf, nvidia-current_hybrid.conf, nvidia-graphics-drivers.conf). I did not know which one to add that option to, if necessary.

However, using dmesg | grep MSI to check for enabled MSI, the following drew my attention:
hda_intel: Disabling MSI
hda_intel is one of the modules which conflicts on irq11, I think (/proc/interrupts says on 11: ohci_hcd:usb2, snd_hda_intel, nvidia), so I'll further investigate. I have a theory that on precise, the MSI for the sound driver has been disabled for some reason, creating this conflict in the first place.

I have to be a bit careful about wildly changing system settings, as this is a production machine and I can't currently afford to lose it for an extended period of time if I have to nuke the system and reinstall or whatever.