Index: sys/dev/uart/uart_core.c
===================================================================
--- sys/dev/uart/uart_core.c
+++ sys/dev/uart/uart_core.c
@@ -540,6 +540,8 @@
 		/* No interrupt resource. Force polled mode. */
 		sc->sc_polled = 1;
 		callout_init(&sc->sc_timer, 1);
+		callout_reset(&sc->sc_timer, hz / uart_poll_freq,
+		    (timeout_t *)uart_intr, sc);
 	}
 
 	if (bootverbose && (sc->sc_fastintr || sc->sc_polled)) {