From: Andi Kleen <ak@muc.de>
To: Boszormenyi Zoltan <zboszor@freemail.hu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: x86_64 IOMMU question
Date: Thu, 18 Mar 2004 00:14:09 +0100 [thread overview]
Message-ID: <m3ptbbawxq.fsf@averell.firstfloor.org> (raw)
In-Reply-To: <1yxkz-6ct-31@gated-at.bofh.it> (Boszormenyi Zoltan's message of "Thu, 11 Mar 2004 13:20:15 +0100")
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
next parent reply other threads:[~2004-03-11 13:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1yxkz-6ct-31@gated-at.bofh.it>
2004-03-17 23:14 ` Andi Kleen [this message]
2004-03-11 12:14 x86_64 IOMMU question Boszormenyi Zoltan
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