Re: [PATCH 2/2] drm/xe/display: align framebuffers according to hw requirements

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Oct 09, 2024 at 06:19:47PM +0300, Juha-Pekka Heikkila wrote:
> Align framebuffers in memory according to hw requirements instead of
> default page size alignment.
> 
> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
> ---
>  drivers/gpu/drm/xe/display/xe_fb_pin.c | 57 ++++++++++++++++----------
>  1 file changed, 35 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/display/xe_fb_pin.c b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> index 79dbbbe03c7f..761510ae0690 100644
> --- a/drivers/gpu/drm/xe/display/xe_fb_pin.c
> +++ b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> @@ -79,7 +79,8 @@ write_dpt_remapped(struct xe_bo *bo, struct iosys_map *map, u32 *dpt_ofs,
>  
>  static int __xe_pin_fb_vma_dpt(const struct intel_framebuffer *fb,
>  			       const struct i915_gtt_view *view,
> -			       struct i915_vma *vma)
> +			       struct i915_vma *vma,
> +			       u64 physical_alignment)
>  {
>  	struct xe_device *xe = to_xe_device(fb->base.dev);
>  	struct xe_tile *tile0 = xe_device_get_root_tile(xe);
> @@ -99,23 +100,29 @@ static int __xe_pin_fb_vma_dpt(const struct intel_framebuffer *fb,
>  				 XE_PAGE_SIZE);
>  
>  	if (IS_DGFX(xe))
> -		dpt = xe_bo_create_pin_map(xe, tile0, NULL, dpt_size,
> -					   ttm_bo_type_kernel,
> -					   XE_BO_FLAG_VRAM0 |
> -					   XE_BO_FLAG_GGTT |
> -					   XE_BO_FLAG_PAGETABLE);
> +		dpt = xe_bo_create_pin_map_at_aligned(xe, tile0, NULL,
> +						      dpt_size, ~0ull,
> +						      ttm_bo_type_kernel,
> +						      XE_BO_FLAG_VRAM0 |
> +						      XE_BO_FLAG_GGTT |
> +						      XE_BO_FLAG_PAGETABLE,
> +						      physical_alignment);
>  	else
> -		dpt = xe_bo_create_pin_map(xe, tile0, NULL, dpt_size,
> -					   ttm_bo_type_kernel,
> -					   XE_BO_FLAG_STOLEN |
> -					   XE_BO_FLAG_GGTT |
> -					   XE_BO_FLAG_PAGETABLE);
> +		dpt = xe_bo_create_pin_map_at_aligned(xe, tile0, NULL,
> +						      dpt_size,  ~0ull,
> +						      ttm_bo_type_kernel,
> +						      XE_BO_FLAG_STOLEN |
> +						      XE_BO_FLAG_GGTT |
> +						      XE_BO_FLAG_PAGETABLE,
> +						      physical_alignment);
>  	if (IS_ERR(dpt))
> -		dpt = xe_bo_create_pin_map(xe, tile0, NULL, dpt_size,
> -					   ttm_bo_type_kernel,
> -					   XE_BO_FLAG_SYSTEM |
> -					   XE_BO_FLAG_GGTT |
> -					   XE_BO_FLAG_PAGETABLE);
> +		dpt = xe_bo_create_pin_map_at_aligned(xe, tile0, NULL,
> +						      dpt_size,  ~0ull,
> +						      ttm_bo_type_kernel,
> +						      XE_BO_FLAG_SYSTEM |
> +						      XE_BO_FLAG_GGTT |
> +						      XE_BO_FLAG_PAGETABLE,
> +						      physical_alignment);
>  	if (IS_ERR(dpt))
>  		return PTR_ERR(dpt);
>  
> @@ -184,7 +191,8 @@ write_ggtt_rotated(struct xe_bo *bo, struct xe_ggtt *ggtt, u32 *ggtt_ofs, u32 bo
>  
>  static int __xe_pin_fb_vma_ggtt(const struct intel_framebuffer *fb,
>  				const struct i915_gtt_view *view,
> -				struct i915_vma *vma)
> +				struct i915_vma *vma,
> +				u64 physical_alignment)
>  {
>  	struct drm_gem_object *obj = intel_fb_bo(&fb->base);
>  	struct xe_bo *bo = gem_to_xe_bo(obj);
> @@ -266,7 +274,8 @@ static int __xe_pin_fb_vma_ggtt(const struct intel_framebuffer *fb,
>  }
>  
>  static struct i915_vma *__xe_pin_fb_vma(const struct intel_framebuffer *fb,
> -					const struct i915_gtt_view *view)
> +					const struct i915_gtt_view *view,
> +					u64 physical_alignment)
>  {
>  	struct drm_device *dev = fb->base.dev;
>  	struct xe_device *xe = to_xe_device(dev);
> @@ -315,9 +324,9 @@ static struct i915_vma *__xe_pin_fb_vma(const struct intel_framebuffer *fb,
>  
>  	vma->bo = bo;
>  	if (intel_fb_uses_dpt(&fb->base))
> -		ret = __xe_pin_fb_vma_dpt(fb, view, vma);
> +		ret = __xe_pin_fb_vma_dpt(fb, view, vma, physical_alignment);
>  	else
> -		ret = __xe_pin_fb_vma_ggtt(fb, view, vma);
> +		ret = __xe_pin_fb_vma_ggtt(fb, view, vma,  physical_alignment);
>  	if (ret)
>  		goto err_unpin;
>  
> @@ -358,7 +367,7 @@ intel_fb_pin_to_ggtt(const struct drm_framebuffer *fb,
>  {
>  	*out_flags = 0;
>  
> -	return __xe_pin_fb_vma(to_intel_framebuffer(fb), view);
> +	return __xe_pin_fb_vma(to_intel_framebuffer(fb), view, phys_alignment);
>  }
>  
>  void intel_fb_unpin_vma(struct i915_vma *vma, unsigned long flags)
> @@ -372,11 +381,15 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state)
>  	struct drm_gem_object *obj = intel_fb_bo(fb);
>  	struct xe_bo *bo = gem_to_xe_bo(obj);
>  	struct i915_vma *vma;
> +	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
> +	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
> +	u64 phys_alignment = plane->min_alignment(plane, fb, 0);

.min_alignment() gives you the virtual alignment. Physical alignment
is not covered (except for cursors on ancient hardware since those
don't go through ggtt translation at all).

I don't think we have any real way to even ask for specific physical
alignment with shmem. You get what you get.

>  
>  	/* We reject creating !SCANOUT fb's, so this is weird.. */
>  	drm_WARN_ON(bo->ttm.base.dev, !(bo->flags & XE_BO_FLAG_SCANOUT));
>  
> -	vma = __xe_pin_fb_vma(to_intel_framebuffer(fb), &plane_state->view.gtt);
> +	vma = __xe_pin_fb_vma(intel_fb, &plane_state->view.gtt, phys_alignment);
> +
>  	if (IS_ERR(vma))
>  		return PTR_ERR(vma);
>  
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel