[CentOS] intel_iommu=on => No root device found

[Nils Caspar]

> I did some experimenting with and without the RAID card installed. There are no DMAR errors, when the RAID card isn't present... Too bad!

Just got this confirmed by Adaptec Support:

> VT-D is not supported with our Adaptec RAID Controllers. You will need to disable this in the BIOS of the mainboard in order for the system to run in a stable way. This applies mainly to VMWARE but also to other linux configuration as you have seen.