diff --git a/sys/dev/ppbus/lpt.c b/sys/dev/ppbus/lpt.c
index e4288fcb500..4c885082530 100644
--- a/sys/dev/ppbus/lpt.c
+++ b/sys/dev/ppbus/lpt.c
@@ -447,7 +447,9 @@ lptout(void *arg)
 {
 	struct lpt_data *sc = arg;
 	device_t dev = sc->sc_dev;
+#if defined(INVARIANTS) || defined(LPT_DEBUG)
 	device_t ppbus = device_get_parent(dev);
+#endif
 
 	ppb_assert_locked(ppbus);
 	lprintf(("T %x ", ppb_rstr(ppbus)));