[PATCH 1/2] drm/amdgpu: remove pointless ttm_eu usage from vkms

[Alex Deucher]

On Tue, Apr 19, 2022 at 10:55 AM Christian König
<christian.koenig at amd.com> wrote:
>
> Am 19.04.22 um 16:49 schrieb Alex Deucher:
> > On Tue, Apr 19, 2022 at 10:19 AM Christian König
> > <ckoenig.leichtzumerken at gmail.com> wrote:
> >> We just need to reserve the BO here, no need for using ttm_eu.
> > Can you include a more detailed description as to why it's not
> > necessary?
>
> Well the logic in ttm_eu is for reserving multiple buffers.

With the commit message fixed up to include that detail, the series is:
Acked-by: Alex Deucher <alexander.deucher at amd.com>

>
> > Most of this code was copied from radeon originally.  Does
> > radeon need a similar cleanup?
>
> Most likely yes.
>
> Christian.
>
> >
> > Alex
> >
> >> Signed-off-by: Christian König <christian.koenig at amd.com>
> >> ---
> >>   drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c | 32 +++++++++++++-----------
> >>   1 file changed, 17 insertions(+), 15 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
> >> index 5224d9a39737..576849e95296 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
> >> @@ -302,9 +302,6 @@ static int amdgpu_vkms_prepare_fb(struct drm_plane *plane,
> >>          struct drm_gem_object *obj;
> >>          struct amdgpu_device *adev;
> >>          struct amdgpu_bo *rbo;
> >> -       struct list_head list;
> >> -       struct ttm_validate_buffer tv;
> >> -       struct ww_acquire_ctx ticket;
> >>          uint32_t domain;
> >>          int r;
> >>
> >> @@ -316,18 +313,19 @@ static int amdgpu_vkms_prepare_fb(struct drm_plane *plane,
> >>          obj = new_state->fb->obj[0];
> >>          rbo = gem_to_amdgpu_bo(obj);
> >>          adev = amdgpu_ttm_adev(rbo->tbo.bdev);
> >> -       INIT_LIST_HEAD(&list);
> >>
> >> -       tv.bo = &rbo->tbo;
> >> -       tv.num_shared = 1;
> >> -       list_add(&tv.head, &list);
> >> -
> >> -       r = ttm_eu_reserve_buffers(&ticket, &list, false, NULL);
> >> +       r = amdgpu_bo_reserve(rbo, true);
> >>          if (r) {
> >>                  dev_err(adev->dev, "fail to reserve bo (%d)\n", r);
> >>                  return r;
> >>          }
> >>
> >> +       r = dma_resv_reserve_fences(rbo->tbo.base.resv, 1);
> >> +       if (r) {
> >> +               dev_err(adev->dev, "allocating fence slot failed (%d)\n", r);
> >> +               goto error_unlock;
> >> +       }
> >> +
> >>          if (plane->type != DRM_PLANE_TYPE_CURSOR)
> >>                  domain = amdgpu_display_supported_domains(adev, rbo->flags);
> >>          else
> >> @@ -337,25 +335,29 @@ static int amdgpu_vkms_prepare_fb(struct drm_plane *plane,
> >>          if (unlikely(r != 0)) {
> >>                  if (r != -ERESTARTSYS)
> >>                          DRM_ERROR("Failed to pin framebuffer with error %d\n", r);
> >> -               ttm_eu_backoff_reservation(&ticket, &list);
> >> -               return r;
> >> +               goto error_unlock;
> >>          }
> >>
> >>          r = amdgpu_ttm_alloc_gart(&rbo->tbo);
> >>          if (unlikely(r != 0)) {
> >> -               amdgpu_bo_unpin(rbo);
> >> -               ttm_eu_backoff_reservation(&ticket, &list);
> >>                  DRM_ERROR("%p bind failed\n", rbo);
> >> -               return r;
> >> +               goto error_unpin;
> >>          }
> >>
> >> -       ttm_eu_backoff_reservation(&ticket, &list);
> >> +       amdgpu_bo_unreserve(rbo);
> >>
> >>          afb->address = amdgpu_bo_gpu_offset(rbo);
> >>
> >>          amdgpu_bo_ref(rbo);
> >>
> >>          return 0;
> >> +
> >> +error_unpin:
> >> +       amdgpu_bo_unpin(rbo);
> >> +
> >> +error_unlock:
> >> +       amdgpu_bo_unreserve(rbo);
> >> +       return r;
> >>   }
> >>
> >>   static void amdgpu_vkms_cleanup_fb(struct drm_plane *plane,
> >> --
> >> 2.25.1
> >>
>