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Subject: RE: PCI-DMA: high address but no IOMMU - nForce4
Date: Mon, 31 Oct 2005 09:50:40 -0800
Message-ID: <DBFABB80F7FD3143A911F9E6CFD477B004FAE5EE@hqemmail02.nvidia.com>
Thread-Topic: PCI-DMA: high address but no IOMMU - nForce4
Thread-Index: AcXeLtEJjJcwueMkQkCiX87Yq2r5hwAFHubg
From: "Allen Martin" <AMartin@nvidia.com>
To: "Matti Aarnio" <matti.aarnio@zmailer.org>, "Andi Kleen" <ak@suse.de>
Cc: "Michael Madore" <michael.madore@gmail.com>,
       <linux-kernel@vger.kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
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> This board has no AGP at all in it, but it does have lots
> of PCIE, and a bit of PCI-X thrown in for "legacy cards". 
> Somehow that detail breaks things when the machine really
> should use bounce-buffering, or something similar -- I don't
> know if Nvidia  nForce4 chipset does have IOMMU, though...
> 
> If Nvidia did omit such essential piece of hardware from
> a modern chipset, I do find it amazingly short-sighted...
> (Of course they don't yield documentation of the chips to
> public so that I can't quickly verify this detail...)

nForce4 does not contain an IOMMU, neither does any K8 chipset, because
the IOMMU is in the CPU.

-Allen
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