diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index d8ef4dccf0c1..adf9bc8ec820 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -790,6 +790,7 @@ intel_dp_output_format(struct intel_connector *connector,
 		       bool ycbcr_420_output)
 {
 	struct intel_dp *intel_dp = intel_attached_dp(connector);
+	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 
 	if (!connector->base.ycbcr_420_allowed || !ycbcr_420_output)
 		return INTEL_OUTPUT_FORMAT_RGB;
@@ -798,6 +799,10 @@ intel_dp_output_format(struct intel_connector *connector,
 	    intel_dp->dfp.ycbcr_444_to_420)
 		return INTEL_OUTPUT_FORMAT_RGB;
 
+	/* Prefer 4:2:0 passthrough over 4:4:4->4:2:0 conversion */
+	if (DISPLAY_VER(i915) >= 11 && intel_dp->dfp.ycbcr420_passthrough)
+		return INTEL_OUTPUT_FORMAT_YCBCR420;
+
 	if (intel_dp->dfp.ycbcr_444_to_420)
 		return INTEL_OUTPUT_FORMAT_YCBCR444;
 	else
@@ -2660,6 +2665,8 @@ void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
 					   const struct intel_crtc_state *crtc_state)
 {
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+	bool ycbcr444_to_420 = false;
+	bool rgb_to_ycbcr = false;
 	u8 tmp;
 
 	if (intel_dp->dpcd[DP_DPCD_REV] < 0x13)
@@ -2676,8 +2683,34 @@ void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
 		drm_dbg_kms(&i915->drm, "Failed to %s protocol converter HDMI mode\n",
 			    str_enable_disable(intel_dp->has_hdmi_sink));
 
-	tmp = crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR444 &&
-		intel_dp->dfp.ycbcr_444_to_420 ? DP_CONVERSION_TO_YCBCR420_ENABLE : 0;
+	if (crtc_state->sink_format == INTEL_OUTPUT_FORMAT_YCBCR420) {
+		switch (crtc_state->output_format) {
+		case INTEL_OUTPUT_FORMAT_YCBCR420:
+			/*
+			 * sink_format is YCBCR420, output_format is also YCBCR420:
+			 * Passthrough.
+			 */
+			break;
+		case INTEL_OUTPUT_FORMAT_YCBCR444:
+			/*
+			 * sink_format is YCBCR420, output_format is YCBCR444:
+			 * Downsample.
+			 */
+			ycbcr444_to_420 = true;
+			break;
+		case INTEL_OUTPUT_FORMAT_RGB:
+			/*
+			 * sink_format is YCBCR420, output_format is RGB:
+			 * Convert to YCBCR444 and Downsample.
+			 */
+			rgb_to_ycbcr = true;
+			ycbcr444_to_420 = true;
+		default:
+			break;
+		}
+	}
+
+	tmp = ycbcr444_to_420 ? DP_CONVERSION_TO_YCBCR420_ENABLE : 0;
 
 	if (drm_dp_dpcd_writeb(&intel_dp->aux,
 			       DP_PROTOCOL_CONVERTER_CONTROL_1, tmp) != 1)
@@ -2685,13 +2718,12 @@ void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
 			    "Failed to %s protocol converter YCbCr 4:2:0 conversion mode\n",
 			    str_enable_disable(intel_dp->dfp.ycbcr_444_to_420));
 
-	tmp = intel_dp->dfp.rgb_to_ycbcr ?
-		DP_CONVERSION_BT709_RGB_YCBCR_ENABLE : 0;
+	tmp = rgb_to_ycbcr ? DP_CONVERSION_BT709_RGB_YCBCR_ENABLE : 0;
 
 	if (drm_dp_pcon_convert_rgb_to_ycbcr(&intel_dp->aux, tmp) < 0)
 		drm_dbg_kms(&i915->drm,
-			   "Failed to %s protocol converter RGB->YCbCr conversion mode\n",
-			   str_enable_disable(tmp));
+			    "Failed to %s protocol converter RGB->YCbCr conversion mode\n",
+			    str_enable_disable(tmp));
 }
 
 bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp)
@@ -4541,7 +4573,7 @@ intel_dp_update_420(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 	struct intel_connector *connector = intel_dp->attached_connector;
-	bool is_branch, ycbcr_420_passthrough, ycbcr_444_to_420, rgb_to_ycbcr;
+	bool is_branch;
 
 	/* No YCbCr output support on gmch platforms */
 	if (HAS_GMCH(i915))
@@ -4555,38 +4587,21 @@ intel_dp_update_420(struct intel_dp *intel_dp)
 		return;
 
 	is_branch = drm_dp_is_branch(intel_dp->dpcd);
-	ycbcr_420_passthrough =
+	intel_dp->dfp.ycbcr420_passthrough =
 		drm_dp_downstream_420_passthrough(intel_dp->dpcd,
 						  intel_dp->downstream_ports);
 	/* on-board LSPCON always assumed to support 4:4:4->4:2:0 conversion */
-	ycbcr_444_to_420 =
+	intel_dp->dfp.ycbcr_444_to_420 =
 		dp_to_dig_port(intel_dp)->lspcon.active ||
 		drm_dp_downstream_444_to_420_conversion(intel_dp->dpcd,
 							intel_dp->downstream_ports);
-	rgb_to_ycbcr = drm_dp_downstream_rgb_to_ycbcr_conversion(intel_dp->dpcd,
-								 intel_dp->downstream_ports,
-								 DP_DS_HDMI_BT709_RGB_YCBCR_CONV);
-
-	if (DISPLAY_VER(i915) >= 11) {
-		/* Let PCON convert from RGB->YCbCr if possible */
-		if (is_branch && rgb_to_ycbcr && ycbcr_444_to_420) {
-			intel_dp->dfp.rgb_to_ycbcr = true;
-			intel_dp->dfp.ycbcr_444_to_420 = true;
-			connector->base.ycbcr_420_allowed = true;
-		} else {
-		/* Prefer 4:2:0 passthrough over 4:4:4->4:2:0 conversion */
-			intel_dp->dfp.ycbcr_444_to_420 =
-				ycbcr_444_to_420 && !ycbcr_420_passthrough;
+	intel_dp->dfp.rgb_to_ycbcr =
+		drm_dp_downstream_rgb_to_ycbcr_conversion(intel_dp->dpcd,
+							  intel_dp->downstream_ports,
+							  DP_DS_HDMI_BT709_RGB_YCBCR_CONV);
 
-			connector->base.ycbcr_420_allowed =
-				!is_branch || ycbcr_444_to_420 || ycbcr_420_passthrough;
-		}
-	} else {
-		/* 4:4:4->4:2:0 conversion is the only way */
-		intel_dp->dfp.ycbcr_444_to_420 = ycbcr_444_to_420;
-
-		connector->base.ycbcr_420_allowed = ycbcr_444_to_420;
-	}
+	if (!is_branch || intel_dp->dfp.ycbcr420_passthrough || intel_dp->dfp.ycbcr_444_to_420)
+		connector->base.ycbcr_420_allowed = true;
 
 	drm_dbg_kms(&i915->drm,
 		    "[CONNECTOR:%d:%s] RGB->YcbCr conversion? %s, YCbCr 4:2:0 allowed? %s, YCbCr 4:4:4->4:2:0 conversion? %s\n",
