[PATCH] drm/amdgpu: fix AGP addressing when GART is not at 0

[Alex Deucher]

On Sat, Nov 11, 2023 at 2:17 AM Christian König
<christian.koenig at amd.com> wrote:
>
> Am 10.11.23 um 15:47 schrieb Alex Deucher:
> > This worked by luck if the GART aperture ended up at 0.  When
> > we ended up moving GART on some chips, the GART aperture ended
> > up offsetting the the AGP address since the resource->start is
> > a GART offset, not an MC address.  Fix this by moving the AGP
> > address setup into amdgpu_bo_gpu_offset_no_check().
> >
> > Reported-by: Jesse Zhang <Jesse.Zhang at amd.com>
> > Reported-by: Yifan Zhang <yifan1.zhang at amd.com>
> > Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> > Cc: christian.koenig at amd.com
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 10 +++++++---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    |  4 +---
> >   2 files changed, 8 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> > index cef920a93924..1b3e97522838 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> > @@ -1527,10 +1527,14 @@ u64 amdgpu_bo_gpu_offset(struct amdgpu_bo *bo)
> >   u64 amdgpu_bo_gpu_offset_no_check(struct amdgpu_bo *bo)
> >   {
> >       struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> > -     uint64_t offset;
> > +     uint64_t offset, addr;
> >
> > -     offset = (bo->tbo.resource->start << PAGE_SHIFT) +
> > -              amdgpu_ttm_domain_start(adev, bo->tbo.resource->mem_type);
> > +     addr = amdgpu_gmc_agp_addr(&bo->tbo);
>
> IIRC you must check bo->tbo.resource->mem_type before calling
> amdgpu_gmc_agp_addr().

Yes, this was fixed in v2.

Alex

>
> Regards,
> Christian.
>
> > +     if (addr != AMDGPU_BO_INVALID_OFFSET)
> > +             offset = addr;
> > +     else
> > +             offset = (bo->tbo.resource->start << PAGE_SHIFT) +
> > +                     amdgpu_ttm_domain_start(adev, bo->tbo.resource->mem_type);
> >
> >       return amdgpu_gmc_sign_extend(offset);
> >   }
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > index 05991c5c8ddb..ab4a762aed5b 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > @@ -959,10 +959,8 @@ int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
> >               return 0;
> >
> >       addr = amdgpu_gmc_agp_addr(bo);
> > -     if (addr != AMDGPU_BO_INVALID_OFFSET) {
> > -             bo->resource->start = addr >> PAGE_SHIFT;
> > +     if (addr != AMDGPU_BO_INVALID_OFFSET)
> >               return 0;
> > -     }
> >
> >       /* allocate GART space */
> >       placement.num_placement = 1;
>