Description of problem:
Since kernel upgrade machine freezes after Fedora progress bar before login. Found DMA issue. Workaround is kernel option iommu=soft. For a newbie this would be a show stopper for using this version Linux on this big iron.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Software Update to kernel 18.104.22.168-67.fc12, from 22.214.171.124-174.2.22.fc12, which was working.
Soon after initial Fedora progress bar goes to black screen, no login.
ssh in from other machine shows dmesg keeps repeating
DRHD: handling fault status reg 2
DMAR:[DMA Read] Request device [01:00.0] fault addr 215da0000
DMAR:[fault reason 01] Present bit in root entry is clear
Log in normally and use computer.
The akmod-nvidia.x86_64 195.36.08-1.fc12 that is installed works fine with kernel 126.96.36.199-174.2.22.fc12.
Workaround is on relevant kernel line, i.e. for 188.8.131.52-67.fc12, to append iommu=soft
Closing NOTABUG. If you can reproduce without the broken nvidia module (i.e. if nouveau has similar problems), then please re-open.