Re: Question about iommu on x86_64 and radeon driver.

[Daniel Haid]

> Look in the source code. I somehow assumed it would activate it
> but maybe it isn't. And the problem you have is related to
> something else?

If I have read the code correctly the only way to get
swiotlb_force=1 in lib/swiotlb.c is to add the "swiotlb=force"
argument to the kernel parameters.

Without it on VIA chipsets swiotlb gets activated, but with
swiotlb_force=0. In this case DMA to addresses below 4GB should be
direct.

But since I still get the error the radeon driver must (incorrectly)
allocate memory above 4GB somewhere, but where?


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