Re: [PATCH v2 1/4] drm/i915/psr: Repeat Selective Update area alignment

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 3/3/2026 6:24 PM, Jouni Högander wrote:
> Currently we are aligning Selective Update area to cover cursor fully if
> needed only once. It may happen that cursor is in Selective Update area
> after pipe alignment and after that covering cursor plane only
> partially. Fix this by looping alignment as long as alignment isn't needed
> anymore.
>
> v2:
>    - do not unecessarily loop if cursor was already fully covered
>    - rename aligned as su_area_changed
>
> Fixes: 1bff93b8bc27 ("drm/i915/psr: Extend SU area to cover cursor fully if needed")
> Cc: <stable@vger.kernel.org> # v6.9+
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>


Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>


> ---
>   drivers/gpu/drm/i915/display/intel_psr.c | 50 ++++++++++++++++++------
>   1 file changed, 38 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 5bea2eda744b..7b197e84e77d 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -2688,11 +2688,12 @@ static void clip_area_update(struct drm_rect *overlap_damage_area,
>   		overlap_damage_area->y2 = damage_area->y2;
>   }
>   
> -static void intel_psr2_sel_fetch_pipe_alignment(struct intel_crtc_state *crtc_state)
> +static bool intel_psr2_sel_fetch_pipe_alignment(struct intel_crtc_state *crtc_state)
>   {
>   	struct intel_display *display = to_intel_display(crtc_state);
>   	const struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config;
>   	u16 y_alignment;
> +	bool su_area_changed = false;
>   
>   	/* ADLP aligns the SU region to vdsc slice height in case dsc is enabled */
>   	if (crtc_state->dsc.compression_enable &&
> @@ -2701,10 +2702,18 @@ static void intel_psr2_sel_fetch_pipe_alignment(struct intel_crtc_state *crtc_st
>   	else
>   		y_alignment = crtc_state->su_y_granularity;
>   
> -	crtc_state->psr2_su_area.y1 -= crtc_state->psr2_su_area.y1 % y_alignment;
> -	if (crtc_state->psr2_su_area.y2 % y_alignment)
> +	if (crtc_state->psr2_su_area.y1 % y_alignment) {
> +		crtc_state->psr2_su_area.y1 -= crtc_state->psr2_su_area.y1 % y_alignment;
> +		su_area_changed = true;
> +	}
> +
> +	if (crtc_state->psr2_su_area.y2 % y_alignment) {
>   		crtc_state->psr2_su_area.y2 = ((crtc_state->psr2_su_area.y2 /
>   						y_alignment) + 1) * y_alignment;
> +		su_area_changed = true;
> +	}
> +
> +	return su_area_changed;
>   }
>   
>   /*
> @@ -2838,7 +2847,7 @@ int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
>   	struct intel_crtc_state *crtc_state = intel_atomic_get_new_crtc_state(state, crtc);
>   	struct intel_plane_state *new_plane_state, *old_plane_state;
>   	struct intel_plane *plane;
> -	bool full_update = false, cursor_in_su_area = false;
> +	bool full_update = false, su_area_changed;
>   	int i, ret;
>   
>   	if (!crtc_state->enable_psr2_sel_fetch)
> @@ -2945,15 +2954,32 @@ int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
>   	if (ret)
>   		return ret;
>   
> -	/*
> -	 * Adjust su area to cover cursor fully as necessary (early
> -	 * transport). This needs to be done after
> -	 * drm_atomic_add_affected_planes to ensure visible cursor is added into
> -	 * affected planes even when cursor is not updated by itself.
> -	 */
> -	intel_psr2_sel_fetch_et_alignment(state, crtc, &cursor_in_su_area);
> +	do {
> +		bool cursor_in_su_area;
>   
> -	intel_psr2_sel_fetch_pipe_alignment(crtc_state);
> +		/*
> +		 * Adjust su area to cover cursor fully as necessary
> +		 * (early transport). This needs to be done after
> +		 * drm_atomic_add_affected_planes to ensure visible
> +		 * cursor is added into affected planes even when
> +		 * cursor is not updated by itself.
> +		 */
> +		intel_psr2_sel_fetch_et_alignment(state, crtc, &cursor_in_su_area);
> +
> +		su_area_changed = intel_psr2_sel_fetch_pipe_alignment(crtc_state);
> +
> +		/*
> +		 * If the cursor was outside the SU area before
> +		 * alignment, the alignment step (which only expands
> +		 * SU) may pull the cursor partially inside, so we
> +		 * must run ET alignment again to fully cover it. But
> +		 * if the cursor was already fully inside before
> +		 * alignment, expanding the SU area won't change that,
> +		 * so no further work is needed.
> +		 */
> +		if (cursor_in_su_area)
> +			break;
> +	} while (su_area_changed);
>   
>   	/*
>   	 * Now that we have the pipe damaged area check if it intersect with