[PATCH] drm/amdgpu/gmc6: fix DMA mask

[Alex Deucher]

On Thu, Oct 28, 2021 at 4:33 AM Paul Menzel <pmenzel at molgen.mpg.de> wrote:
>
> Dear Alex,
>
>
> On 28.10.21 00:19, Paul Menzel wrote:
>
> > On 27.10.21 20:23, Alex Deucher wrote:
> >> On Wed, Oct 27, 2021 at 2:22 PM Alex Deucher
> >> <alexander.deucher at amd.com> wrote:
> >>>
> >>> The DMA mask on SI parts is 40 bits not 44.  Looks like a copy
> >>> paste typo.
> >>
> >> Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1762
> >>
> >> Fixed locally.
> >
> > As I have no way to reproduce this, as the ring gfx timeout error is
> > logged ten seconds after the IO_PAGE_FAULT, is very likely to be related?
> >
> > Hopefully I am going to be able to test this on Friday. Does AMD’s QA
> > team have the cards to test the `iommu.forcedac=1` case? Is that test
> > case going to be added to the “test protocol”?
> >
> > Lastly, should a Fixes tag be added, so it’s picked up for the stable
> > series?
>
> Does the value of 44 need to be changed to 40 also five lines below?
>
> -       adev->need_swiotlb = drm_need_swiotlb(44);
> +       adev->need_swiotlb = drm_need_swiotlb(40);
>

Good catch.  I'll fix that too for consistency, but the driver is not
functional with the swiotlb due to the amount of memory the driver
maps.

Thanks!

Alex

>
> Kind regards,
>
> Paul