IOMMU 3.2 black screen hang fix AMD - FYI

Ignore my sig, having a problem changing it right now…Gigabyte 990xa-ud3, AMD FX-6100 6 core, 8 gig mem, Nvidia 8400gs PCI, Nvidia 2.95.53 drivers, 1 TB sata 3

Yes I know the PCI card is unusual…I had it laying around…

After a wildfire that burned down my house (talk about needing backups!!) and a hiatus with Ubuntu, Mint and such I came back to Suse again and decided to try tumbleweed because I like the idea of rolling updates. The thing is with any distro I always got the dreaded “black screen” after logging in with KDM on kernels >3.1. If I turned off iommu in the bios KDE would boot fine.

Long story short the fix is this…put “amd_iommu=on iommu=on,pt” in your kernel boot parameters in grub and I was able to boot KDE with IOMMU enabled in the bios.

I also downloaded the AMD microcode from here OSRC: Microcode and fixed an annoying cpu error on boot. The microcode that comes with the package seems to be missing the microcode_amd_fam15h.bin file. installing this fixed it.

Dammit…I meant kernel 3.4 not 3.2…but the problem is the same >3.1