Re: [PATCH] drm/amd/display: add FB_DAMAGE_CLIPS support

[Leo Li <sunpeng.li@amd.com>]

On 11/15/22 15:24, Hamza Mahfooz wrote:
> Currently, userspace doesn't have a way to communicate selective updates
> to displays. So, enable support for FB_DAMAGE_CLIPS for DCN ASICs newer
> than DCN301, convert DRM damage clips to dc dirty rectangles and fill
> them into dirty_rects in fill_dc_dirty_rects().
> 
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
> ---
>   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 91 +++++++++++--------
>   .../amd/display/amdgpu_dm/amdgpu_dm_plane.c   |  4 +
>   2 files changed, 58 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 185d09c760ba..18b710ba802d 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -4842,6 +4842,31 @@ static int fill_dc_plane_attributes(struct amdgpu_device *adev,
>   	return 0;
>   }
>   
> +static inline void fill_dc_dirty_rect(struct drm_plane *plane,
> +				      struct rect *dirty_rect, int32_t x,
> +				      int32_t y, int32_t width, int32_t height,
> +				      int *i, bool ffu)
> +{
> +	WARN_ON(*i >= DC_MAX_DIRTY_RECTS);

Hi Hamza,

Since dc_flip_addrs->dirty_rects has a fixed length of 
DC_MAX_DIRTY_RECTS per pipe (a restriction by DMUB FW), I think it makes 
more sense to fallback to a full-frame-update (FFU) if num_clips > 
DC_MAX_DIRTY_RECTS. An alternative would be to reject the atomic commit, 
but that sounds heavy handed.


> +
> +	dirty_rect->x = x;
> +	dirty_rect->y = y;
> +	dirty_rect->width = width;
> +	dirty_rect->height = height;
> +
> +	if (ffu)
> +		drm_dbg(plane->dev,
> +			"[PLANE:%d] PSR FFU dirty rect size (%d, %d)\n",
> +			plane->base.id, width, height);
> +	else
> +		drm_dbg(plane->dev,
> +			"[PLANE:%d] PSR SU dirty rect at (%d, %d) size (%d, %d)",
> +			plane->base.id, x, y, width, height);
> +
> +	(*i)++;
> +}
> +
> +
>   /**
>    * fill_dc_dirty_rects() - Fill DC dirty regions for PSR selective updates
>    *
> @@ -4862,10 +4887,6 @@ static int fill_dc_plane_attributes(struct amdgpu_device *adev,
>    * addition, certain use cases - such as cursor and multi-plane overlay (MPO) -
>    * implicitly provide damage clips without any client support via the plane
>    * bounds.
> - *
> - * Today, amdgpu_dm only supports the MPO and cursor usecase.
> - *
> - * TODO: Also enable for FB_DAMAGE_CLIPS
>    */
>   static void fill_dc_dirty_rects(struct drm_plane *plane,
>   				struct drm_plane_state *old_plane_state,
> @@ -4876,12 +4897,11 @@ static void fill_dc_dirty_rects(struct drm_plane *plane,
>   	struct dm_crtc_state *dm_crtc_state = to_dm_crtc_state(crtc_state);
>   	struct rect *dirty_rects = flip_addrs->dirty_rects;
>   	uint32_t num_clips;
> +	struct drm_mode_rect *clips;
>   	bool bb_changed;
>   	bool fb_changed;
>   	uint32_t i = 0;
>   
> -	flip_addrs->dirty_rect_count = 0;
> -
>   	/*
>   	 * Cursor plane has it's own dirty rect update interface. See
>   	 * dcn10_dmub_update_cursor_data and dmub_cmd_update_cursor_info_data
> @@ -4894,15 +4914,11 @@ static void fill_dc_dirty_rects(struct drm_plane *plane,
>   	 * requested, and there is a plane update, do FFU.
>   	 */
>   	if (!dm_crtc_state->mpo_requested) {
> -		dirty_rects[0].x = 0;
> -		dirty_rects[0].y = 0;
> -		dirty_rects[0].width = dm_crtc_state->base.mode.crtc_hdisplay;
> -		dirty_rects[0].height = dm_crtc_state->base.mode.crtc_vdisplay;
> -		flip_addrs->dirty_rect_count = 1;
> -		DRM_DEBUG_DRIVER("[PLANE:%d] PSR FFU dirty rect size (%d, %d)\n",
> -				 new_plane_state->plane->base.id,
> -				 dm_crtc_state->base.mode.crtc_hdisplay,
> -				 dm_crtc_state->base.mode.crtc_vdisplay);
> +		fill_dc_dirty_rect(new_plane_state->plane, &dirty_rects[0], 0,
> +				   0, dm_crtc_state->base.mode.crtc_hdisplay,
> +				   dm_crtc_state->base.mode.crtc_vdisplay, &i,
> +				   true);
> +		flip_addrs->dirty_rect_count = i;
>   		return;
>   	}

Previously, we always do FFU on plane updates if no MPO has been 
requested. Now, since we want to look at user-provided DRM damage clips, 
this bit needs a bit of a rework.

In short, if there are valid clips for this plane 
(drm_plane_get_damage_clips_count() > 0), they should be added to 
dc_dirty_rects. Otherwise, fallback to old FFU logic.

With MPO, the damage clips are more interesting, since the entire 
plane's bounding box can be moved. I wonder if that is reflected in 
DRM's damage clips. Do you know if a plane bb change will be reflected 
in drm_plane_get_damage_clips()?

Thanks,
Leo
>   
> @@ -4914,6 +4930,7 @@ static void fill_dc_dirty_rects(struct drm_plane *plane,
>   	 * rects.
>   	 */
>   	num_clips = drm_plane_get_damage_clips_count(new_plane_state);
> +	clips = drm_plane_get_damage_clips(new_plane_state);
>   	fb_changed = old_plane_state->fb->base.id !=
>   		     new_plane_state->fb->base.id;
>   	bb_changed = (old_plane_state->crtc_x != new_plane_state->crtc_x ||
> @@ -4921,33 +4938,33 @@ static void fill_dc_dirty_rects(struct drm_plane *plane,
>   		      old_plane_state->crtc_w != new_plane_state->crtc_w ||
>   		      old_plane_state->crtc_h != new_plane_state->crtc_h);
>   
> -	DRM_DEBUG_DRIVER("[PLANE:%d] PSR bb_changed:%d fb_changed:%d num_clips:%d\n",
> -			 new_plane_state->plane->base.id,
> -			 bb_changed, fb_changed, num_clips);
> +	drm_dbg(plane->dev,
> +		"[PLANE:%d] PSR bb_changed:%d fb_changed:%d num_clips:%d\n",
> +		new_plane_state->plane->base.id,
> +		bb_changed, fb_changed, num_clips);
>   
> -	if (num_clips || fb_changed || bb_changed) {
> -		dirty_rects[i].x = new_plane_state->crtc_x;
> -		dirty_rects[i].y = new_plane_state->crtc_y;
> -		dirty_rects[i].width = new_plane_state->crtc_w;
> -		dirty_rects[i].height = new_plane_state->crtc_h;
> -		DRM_DEBUG_DRIVER("[PLANE:%d] PSR SU dirty rect at (%d, %d) size (%d, %d)\n",
> -				 new_plane_state->plane->base.id,
> -				 dirty_rects[i].x, dirty_rects[i].y,
> -				 dirty_rects[i].width, dirty_rects[i].height);
> -		i += 1;
> +	if (num_clips) {
> +		for (; i < num_clips; i++, clips++) {
> +			fill_dc_dirty_rect(new_plane_state->plane,
> +					   &dirty_rects[i], clips->x1,
> +					   clips->y1, clips->x2 - clips->x1,
> +					   clips->y2 - clips->y1, &i, false);
> +		}
> +	} else if (fb_changed || bb_changed) {
> +		fill_dc_dirty_rect(new_plane_state->plane, &dirty_rects[i],
> +				   new_plane_state->crtc_x,
> +				   new_plane_state->crtc_y,
> +				   new_plane_state->crtc_w,
> +				   new_plane_state->crtc_h, &i, false);
>   	}
>   
>   	/* Add old plane bounding-box if plane is moved or resized */
>   	if (bb_changed) {
> -		dirty_rects[i].x = old_plane_state->crtc_x;
> -		dirty_rects[i].y = old_plane_state->crtc_y;
> -		dirty_rects[i].width = old_plane_state->crtc_w;
> -		dirty_rects[i].height = old_plane_state->crtc_h;
> -		DRM_DEBUG_DRIVER("[PLANE:%d] PSR SU dirty rect at (%d, %d) size (%d, %d)\n",
> -				old_plane_state->plane->base.id,
> -				dirty_rects[i].x, dirty_rects[i].y,
> -				dirty_rects[i].width, dirty_rects[i].height);
> -		i += 1;
> +		fill_dc_dirty_rect(new_plane_state->plane, &dirty_rects[i],
> +				   old_plane_state->crtc_x,
> +				   old_plane_state->crtc_y,
> +				   old_plane_state->crtc_w,
> +				   old_plane_state->crtc_h, &i, false);
>   	}
>   
>   	flip_addrs->dirty_rect_count = i;
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> index e6854f7270a6..3c50b3ff7954 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> @@ -1600,6 +1600,10 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
>   		drm_plane_create_rotation_property(plane, DRM_MODE_ROTATE_0,
>   						   supported_rotations);
>   
> +	if (dm->adev->ip_versions[DCE_HWIP][0] > IP_VERSION(3, 0, 1) &&
> +	    plane->type != DRM_PLANE_TYPE_CURSOR)
> +		drm_plane_enable_fb_damage_clips(plane);
> +
>   	drm_plane_helper_add(plane, &dm_plane_helper_funcs);
>   
>   #ifdef CONFIG_DRM_AMD_DC_HDR