* On 21.01.2013 07:11 PM, Mihai Moldovan wrote:
I'm also currently testing a kernel without the Intel IOMMU feature [CONFIG_INTEL_IOMMU=n, but CONFIG_IOMMU_SUPPORT=y]. [...] At least not seeing USB and PCI(e) issues. I'll leave the box running for some more [time] [...]
No freezes for >22h, seems to be fine.
[...] and will afterwards disable IOMMU as a whole to see if I hit USB and PCI(e) issues again with that combination.
The systems seems to run stable with CONFIG_IOMMU_SUPPORT=n set, too. This is expected. However: unlike during earlier tests when I disabled IOMMU and Intel IOMMU via kernel/boot parameters, I am not seeing any DMA mapping errors.
There seems to be a difference between disabling IOMMU/Intel IOMMU statically in the kernel compared to disabling it via kernel parameter. Is this another bug?
I've attached both kernel ring buffer logs (minus the timings for easier diffing.)
[*] kern-new-iommu_off.log.bz2 disables IOMMU and Intel IOMMU via boot parameter [*] kern-iommu_static_off.log.bz2 has CONFIG_IOMMU_SUPPORT=n set and any IOMMU support statically disabled (also consequently DMAR)
Mihai