I have an IBM x3850 m2 server, with ibm serveraid mr10k raid card, wich is a lsi megaraid card.
My problme is, if I try to run linux, with 4.4 kernel I need to use iommu=soft kernel arg to make it work. Without this option I get this error:
Calgary: DMA error on CalIOC2 PHB 0x3
I also try pci=nomsi but with this option I get another error:
NMI watchdog: Bug: soft lockup - CPU#1 stuck for 22s! [udevd: 1381]
I can solv this error with this arg: acpi=off but with this the system won't see the raid card.
The problem with iommu=soft is the huge load (around 70 or more). With kernel 3.10 the card work without problem. I'm using proxmox 4.4 on the server and the 3.10 kernel won't work with this version. There is two way for me, downgrade the proxmox or solve the problem with megaraid_sas driver.