diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 79ebb58afcb28..98da94ab3e244 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -1900,6 +1900,7 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
 	int clock = mode->clock;
 	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 	bool has_hdmi_sink = intel_has_hdmi_sink(hdmi, connector->state);
+	bool ycbcr_420_only;
 
 	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
 		return MODE_NO_DBLESCAN;
@@ -1916,12 +1917,22 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
 		clock *= 2;
 	}
 
-	if (drm_mode_is_420_only(&connector->display_info, mode))
+	ycbcr_420_only = drm_mode_is_420_only(&connector->display_info, mode);
+	if (ycbcr_420_only)
 		clock /= 2;
 
 	status = intel_hdmi_mode_clock_valid(hdmi, clock, has_hdmi_sink);
-	if (status != MODE_OK)
-		return status;
+	if (status != MODE_OK) {
+		if (ycbcr_420_only ||
+		    !connector->ycbcr_420_allowed ||
+		    !drm_mode_is_420_also(&connector->display_info, mode))
+			return status;
+
+		clock /= 2;
+		status = intel_hdmi_mode_clock_valid(hdmi, clock, has_hdmi_sink);
+		if (status != MODE_OK)
+			return status;
+	}
 
 	return intel_mode_valid_max_plane_size(dev_priv, mode, false);
 }
@@ -2129,6 +2140,14 @@ static int intel_hdmi_compute_output_format(struct intel_encoder *encoder,
 	}
 
 	ret = intel_hdmi_compute_clock(encoder, crtc_state);
+	if (ret) {
+		if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_YCBCR420 &&
+		    connector->ycbcr_420_allowed &&
+		    drm_mode_is_420_also(&connector->display_info, adjusted_mode)) {
+			crtc_state->output_format = INTEL_OUTPUT_FORMAT_YCBCR420;
+			ret = intel_hdmi_compute_clock(encoder, crtc_state);
+		}
+	}
 
 	return ret;
 }