Messages in this thread | | | Subject | Re: x86_64 IOMMU question | From | Andi Kleen <> | Date | Thu, 18 Mar 2004 00:14:09 +0100 |
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Boszormenyi Zoltan <zboszor@freemail.hu> writes:
> is it possible to use the IOMMU to help 32 bit devices > that limit their capabilities with pci_set_dma_mask()? > E.g. the emu10k1 limits itself under 256MB. Can the IOMMU > pass the data to/from the card from/to above 256MB?
It can only remap to the AGP aperture, which is usually just below the 4GB boundary. In theory you could move the aperture to a very low address and remap to that (see arch/x86_64/kernel/aperture.c), but that would waste memory.
-Andi
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