diff --git a/src/i830_hdmi.c b/src/i830_hdmi.c
index 05aa9ac..2528a84 100644
--- a/src/i830_hdmi.c
+++ b/src/i830_hdmi.c
@@ -79,7 +79,8 @@ i830_hdmi_mode_set(xf86OutputPtr output, DisplayModePtr mode,
     sdvox = SDVO_ENCODING_HDMI |
 	SDVO_BORDER_ENABLE |
 	SDVO_VSYNC_ACTIVE_HIGH |
-	SDVO_HSYNC_ACTIVE_HIGH;
+	SDVO_HSYNC_ACTIVE_HIGH |
+        SDVO_NULL_PACKETS_DURING_VSYNC;
 
     if (dev_priv->has_hdmi_sink)
 	    sdvox |= SDVO_AUDIO_ENABLE;