Messages in this thread | | | From | Dave Airlie <> | Subject | Re: IOMMU and graphics cards | Date | Tue, 7 Jul 2009 08:00:01 +1000 |
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On 07/07/2009, at 7:35, Dave Airlie <airlied@linux.ie> wrote:
> > > On Mon, 6 Jul 2009, David Woodhouse wrote: > >> On Mon, 2009-07-06 at 15:11 +0200, Joerg Roedel wrote: >>> Ok, cool, that sounds good. Which in-kernel DRM drivers break with >>> IOMMU >>> for you? I'll may probably add a similar temporary workaround for >>> AMD >>> IOMMU too... >> >> The Intel one definitely broke -- I don't know about the others. >> There >> are some old patches at http://people.freedesktop.org/~zhen/agp-mm-* >> which make it look like _all_ AGP drivers are broken. >> >> I wouldn't bother adding the workaround -- as I said, I'm planning to >> rip it out of 2.6.32 (and in linux-next as soon as it's reasonable >> to do >> so). Let's just let them fix it. > > cc'ing Eric, > > My memory of this is graphics becomes totally useless and can be > 10x-50x > slower. I think ripping this out without the person doing the ripping > taking responsiblity for doing speed regression testing is totally > insane. > > I personally have no IOMMU hw from Intel or AMD and nobody has seen > it fit > to supply me with any at any point in time, I'm not on the correct > gravy > train. So I suspect the people with the hw will have to do the work > and > the regression testing.
Could you also enumerate any limitations of the IOMMUs on the amount of memory they can remap per device if any.
Dave
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