[PATCH 2/2] drm/amdgpu: handle CPU access for split VRAM buffers

[Nicolai Hähnle]

On 04.04.2017 14:48, Christian König wrote:
> From: Christian König <christian.koenig at amd.com>
>
> This avoids merging them together on page fault.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Acked-by: Michel Dänzer <michel.daenzer at amd.com>

Thanks for the explanations in the earlier thread. Both patches are

Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com>


> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c |  4 +---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 16 ++++++++++++----
>  2 files changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 387d190..10237a8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -927,8 +927,7 @@ int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo)
>  	size = bo->mem.num_pages << PAGE_SHIFT;
>  	offset = bo->mem.start << PAGE_SHIFT;
>  	/* TODO: figure out how to map scattered VRAM to the CPU */
> -	if ((offset + size) <= adev->mc.visible_vram_size &&
> -	    (abo->flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS))
> +	if ((offset + size) <= adev->mc.visible_vram_size)
>  		return 0;
>
>  	/* Can't move a pinned BO to visible VRAM */
> @@ -936,7 +935,6 @@ int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo)
>  		return -EINVAL;
>
>  	/* hurrah the memory is not visible ! */
> -	abo->flags |= AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS;
>  	amdgpu_ttm_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_VRAM);
>  	lpfn =	adev->mc.visible_vram_size >> PAGE_SHIFT;
>  	for (i = 0; i < abo->placement.num_placement; i++) {
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 524abca..10b793a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -529,9 +529,6 @@ static int amdgpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_
>  	case TTM_PL_TT:
>  		break;
>  	case TTM_PL_VRAM:
> -		if (mem->start == AMDGPU_BO_INVALID_OFFSET)
> -			return -EINVAL;
> -
>  		mem->bus.offset = mem->start << PAGE_SHIFT;
>  		/* check if it's visible */
>  		if ((mem->bus.offset + mem->bus.size) > adev->mc.visible_vram_size)
> @@ -549,6 +546,17 @@ static void amdgpu_ttm_io_mem_free(struct ttm_bo_device *bdev, struct ttm_mem_re
>  {
>  }
>
> +static unsigned long amdgpu_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
> +					   unsigned long page_offset)
> +{
> +	struct drm_mm_node *mm = bo->mem.mm_node;
> +	uint64_t size = mm->size;
> +
> +	mm += page_offset / size;
> +	page_offset %= size;
> +	return (bo->mem.bus.base >> PAGE_SHIFT) + mm->start + page_offset;
> +}
> +
>  /*
>   * TTM backend functions.
>   */
> @@ -1064,7 +1072,7 @@ static struct ttm_bo_driver amdgpu_bo_driver = {
>  	.fault_reserve_notify = &amdgpu_bo_fault_reserve_notify,
>  	.io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
>  	.io_mem_free = &amdgpu_ttm_io_mem_free,
> -	.io_mem_pfn = ttm_bo_default_io_mem_pfn,
> +	.io_mem_pfn = amdgpu_ttm_io_mem_pfn,
>  };
>
>  int amdgpu_ttm_init(struct amdgpu_device *adev)
>


-- 
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.