Re: [Intel-gfx] [PATCH 1/2] drm/i915/display: Add initial selective fetch support for biplanar formats

["Souza, Jose" <jose.souza@intel.com>]

On Thu, 2021-10-21 at 13:10 +0300, Jouni Högander wrote:
> Biplanar formats are using two planes (Y and UV). This patch adds handling
> of Y selective fetch area by utilizing existing linked plane mechanism.
> Also UV plane Y offset configuration is modified according to Bspec.
> 
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 30 +++++++++++++++++++++---
>  1 file changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 49c2dfbd4055..469bf95178f3 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -1467,10 +1467,19 @@ void intel_psr2_program_plane_sel_fetch(struct intel_plane *plane,
>  	val |= plane_state->uapi.dst.x1;
>  	intel_de_write_fw(dev_priv, PLANE_SEL_FETCH_POS(pipe, plane->id), val);
>  
> -	/* TODO: consider auxiliary surfaces */
> -	x = plane_state->uapi.src.x1 >> 16;
> -	y = (plane_state->uapi.src.y1 >> 16) + clip->y1;
> +	x = plane_state->view.color_plane[color_plane].x;
> +
> +	/*
> +	 * From Bspec: UV surface Start Y Position = half of Y plane Y
> +	 * start position.
> +	 */
> +	if (!color_plane)
> +		y = plane_state->view.color_plane[color_plane].y + clip->y1;
> +	else
> +		y = plane_state->view.color_plane[color_plane].y + clip->y1 / 2;

Matches bspec but I'm not an expert in colorimetry not sure if it is missing handling for other non-RGB format.
Let ship with it and fix on top but would be nice to ask around if we are missing cases for other formats.

> +
>  	val = y << 16 | x;
> +
>  	intel_de_write_fw(dev_priv, PLANE_SEL_FETCH_OFFSET(pipe, plane->id),
>  			  val);
>  
> @@ -1700,6 +1709,7 @@ int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
>  	for_each_oldnew_intel_plane_in_state(state, plane, old_plane_state,
>  					     new_plane_state, i) {
>  		struct drm_rect *sel_fetch_area, inter;
> +		struct intel_plane *linked = new_plane_state->planar_linked_plane;
>  
>  		if (new_plane_state->uapi.crtc != crtc_state->uapi.crtc ||
>  		    !new_plane_state->uapi.visible)
> @@ -1718,6 +1728,20 @@ int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
>  		sel_fetch_area->y1 = inter.y1 - new_plane_state->uapi.dst.y1;
>  		sel_fetch_area->y2 = inter.y2 - new_plane_state->uapi.dst.y1;
>  		crtc_state->update_planes |= BIT(plane->id);
> +
> +		/*
> +		 * Sel_fetch_area is calculated for UV plane. Use
> +		 * same area for Y plane as well.
> +		 */
> +		if (linked) {
> +			struct intel_plane_state *linked_new_plane_state =
> +			  intel_atomic_get_new_plane_state(state, linked);
> +			struct drm_rect *linked_sel_fetch_area =
> +			  &linked_new_plane_state->psr2_sel_fetch_area;
> +
> +			linked_sel_fetch_area->y1 = sel_fetch_area->y1;
> +			linked_sel_fetch_area->y2 = sel_fetch_area->y2;

Okay this is needed because the slave plane has visible = false.

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

> +		}
>  	}
>  
>  skip_sel_fetch_set_loop: