const struct drm_connector *connector)
 {
        struct dc_crtc_timing *timing_out = &stream->timing;
+       const struct drm_display_info *info = &connector->display_info;
 
        memset(timing_out, 0, sizeof(struct dc_crtc_timing));
 
        timing_out->v_border_top = 0;
        timing_out->v_border_bottom = 0;
        /* TODO: un-hardcode */
-
-       if ((connector->display_info.color_formats & DRM_COLOR_FORMAT_YCRCB444)
+       if (drm_mode_is_420_only(info, mode_in)
+                       && stream->sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A)
+               timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
+       else if ((connector->display_info.color_formats & DRM_COLOR_FORMAT_YCRCB444)
                        && stream->sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A)
                timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR444;
        else