iommu needs to be disabled on AMD boards with multiple iommu units
Trying to enable iommu on AMD boards that have multiple iommu units will lead to errors and the system not working properly.
Updated by Christopher Chan about 9 years ago
The kernel will report one iommu unit being enabled but then report an error for the other one and then things just go haywire with endless reports from the kernel. It is a production box so I do not have the luxury of stopping it and booting an usb image to collect data on the errors and sorry about the fuzzy report because I tried enabling the iommu in Q4 of last year.