diff --git a/sys/dev/drm/i915/dvo_sil164.c b/sys/dev/drm/i915/dvo_sil164.c
@@ -175,7 +175,8 @@
 {
 	u8 reg9;
 
-	sil164_readb(dvo, SIL164_REG9, &reg9);
+	if (!sil164_readb(dvo, SIL164_REG9, &reg9))
+		return connector_status_unknown;
 
 	if (reg9 & SIL164_9_HTPLG)
 		return connector_status_connected;