Re: IOMMU and graphics cards

FUJITA Tomonori
2009-05-07T13:01:20Z

On Thu, 7 May 2009 14:15:35 +0200
Joerg Roedel <joerg.roedel@amd.com> wrote:

> On Thu, May 07, 2009 at 11:22:01AM +0100, David Woodhouse wrote:
> > On Thu, 2009-05-07 at 12:01 +0200, Joerg Roedel wrote:
> > > > Looks like the DRM code uses the DMA API.
> > >
> > > The proprietary drivers make problems so far. For the ATI one I am in
> > > contact with the developers to try to fix it. But I can't do anything
> > > about the other proprietary driver I am aware of :-(
> >
> > I see no harm in "breaking" code which was already broken. If that's the
> > only reason we're enabling the graphics workaround, let's turn it off.
>
> Well, it is not that simple. Having no workaround at all will not result
> in working proprietary drivers. More likely is that distros just disable
> the IOMMU because their customers want to use these drivers for working
> 3d acceleration.

Have you already discussed this issue with distribution people?

I'm not sure if they would just disable the IOMMU. They want it for
exotic virtualization features?

> As I wrote in the original mail I think we should just make sure that
> these drivers still work with an IOMMU without disabling device
> isolation.