drm/i915/display: Selective fetch Y position on Region Early Transport

Selective fetch Y position differs when Region Early Transport is
used. Use formula from Bspec for this.

Bspec: 68927
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240529093849.1016172-5-jouni.hogander@intel.com

drivers/gpu/drm/i915/display/skl_universal_plane.c

@@ -1302,7 +1302,11 @@ static void icl_plane_update_sel_fetch_noarm(struct intel_plane *plane,
 
 	clip = &plane_state->psr2_sel_fetch_area;
 
-	val = (clip->y1 + plane_state->uapi.dst.y1) << 16;
+	if (crtc_state->enable_psr2_su_region_et)
+		y = max(0, plane_state->uapi.dst.y1 - crtc_state->psr2_su_area.y1);
+	else
+		y = (clip->y1 + plane_state->uapi.dst.y1);
+	val = y << 16;
 	val |= plane_state->uapi.dst.x1;
 	intel_de_write_fw(i915, SEL_FETCH_PLANE_POS(pipe, plane->id), val);