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

[Christian König]

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.

> 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
>>