* x86_64 IOMMU question
@ 2004-03-11 12:14 Boszormenyi Zoltan
0 siblings, 0 replies; 2+ messages in thread
From: Boszormenyi Zoltan @ 2004-03-11 12:14 UTC (permalink / raw)
To: linux-kernel
Hi,
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?
--
Best regards,
Zoltán Böszörményi
---------------------
What did Hussein say about his knife?
One in Bush worth two in the hand.
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* Re: x86_64 IOMMU question
[not found] <1yxkz-6ct-31@gated-at.bofh.it>
@ 2004-03-17 23:14 ` Andi Kleen
0 siblings, 0 replies; 2+ messages in thread
From: Andi Kleen @ 2004-03-17 23:14 UTC (permalink / raw)
To: Boszormenyi Zoltan; +Cc: linux-kernel
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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2004-03-17 23:14 ` x86_64 IOMMU question Andi Kleen
2004-03-11 12:14 Boszormenyi Zoltan
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