Re: [RFC] Make AGP work with IOMMU

From: David Woodhouse
Date: Wed Jul 29 2009 - 05:36:59 EST


On Wed, 2009-07-29 at 18:43 +1000, Dave Airlie wrote:
> >> don't suppose we want page_to_gart or is the double function nicer?
> >
> > I pondered that briefly. But then observed that phys_to_gart() and
> > gart_to_phys() _always_ describe an identity mapping, so perhaps they
> > could just be ditched completely?
>
> Yeah that could work too, no idea why they were introduced, well before my time.

http://git.infradead.org/users/dwmw2/iommu-agp.git?a=commitdiff;h=8bf2f3a9

It was introduced by Keir in 2005 for Xen (commit 07eee78e). I suspect
it can die though, and that the right answer there is also to use the
DMA API correctly.

--
David Woodhouse Open Source Technology Centre
David.Woodhouse@xxxxxxxxx Intel Corporation

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