Cannot start X on Archlinux 3.12.3 and with driver 331.20-2 while SLI and BaseMosaic are enabled

I am having what seems like this EXACT issue with xubuntu 14.04, 2 EVGA GTX580’s and 3 AOC 1080p monitors. I have tried many different driver versions and they all fall flat on their face when trying to use base mosaic. I see from your first post that you are using XFCE with arch as I am with Xubuntu. Have your tried other desktop environments like gnome, cinnamon or kde?

Im going to shove a spare HDD in my sata dock and load up some other environments and see what I can come up with.

I fixed mine. see post over there -> https://devtalk.nvidia.com/default/topic/752307/linux/331-334-337-gt-3-monitors-gt-base-mosaic-gt-fails-to-initialize-dma/

ekroboi:

THAT WORKED PERFECTLY.

Thank you.

Can you tell me how you stumbled upon setting the iommu flags?