[PATCH 2/2] drm/amdgpu: Put page tables to GTT memory for APUs.

[Alex Deucher]

On Tue, Aug 22, 2023 at 8:00 AM Christian König
<christian.koenig at amd.com> wrote:
>
> Am 22.08.23 um 08:17 schrieb Yifan Zhang:
> > To decrease VRAM pressure for APUs, put page tables to
> > GTT domain.
> >
> > Signed-off-by: Yifan Zhang <yifan1.zhang at amd.com>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
> > index 96d601e209b8..26063e611c49 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
> > @@ -515,7 +515,7 @@ int amdgpu_vm_pt_create(struct amdgpu_device *adev, struct amdgpu_vm *vm,
> >       bp.size = amdgpu_vm_pt_size(adev, level);
> >       bp.byte_align = AMDGPU_GPU_PAGE_SIZE;
> >
> > -     if (!adev->gmc.is_app_apu)
> > +     if (!(adev->gmc.is_app_apu || (adev->flags & AMD_IS_APU)))
>
> I've tried this before and it doesn't work in quite a bunch of
> configurations. Especially IOMMU has big problems with that.
>
> Alex do you know which hw generation finally supported that without
> problems?

We ran into issues on raven boards IIRC.  It's probably safe to enable
on Renoir and newer APUs since those should have all been validated
with windows + IOMMU.

Alex

>
> Regards,
> Christian.
>
> >               bp.domain = AMDGPU_GEM_DOMAIN_VRAM;
> >       else
> >               bp.domain = AMDGPU_GEM_DOMAIN_GTT;
>