Index: sys/dev/acpica/acpi_hpet.c
===================================================================
--- sys/dev/acpica/acpi_hpet.c
+++ sys/dev/acpica/acpi_hpet.c
@@ -841,15 +841,28 @@
 static int
 hpet_suspend(device_t dev)
 {
-//	struct hpet_softc *sc;
+	struct hpet_softc *sc;
+	struct hpet_timer *t;
+	int i;
 
 	/*
 	 * Disable the timer during suspend.  The timer will not lose
 	 * its state in S1 or S2, but we are required to disable
 	 * it.
 	 */
-//	sc = device_get_softc(dev);
-//	hpet_disable(sc);
+	sc = device_get_softc(dev);
+	hpet_disable(sc);
+	for (i = 0; i < sc->num_timers; i++) {
+		t = &sc->t[i];
+
+		/*
+		 * Clear timer state to minimize chances of confusing
+		 * the firmware after resuming from S3.
+		 */
+		bus_write_4(sc->mem_res, HPET_TIMER_CAP_CNF(t->num),
+		    t->caps & ~(HPET_TCNF_INT_ENB | HPET_TCNF_TYPE));
+		bus_write_4(sc->mem_res, HPET_ISR, 1 << t->num);
+	}
 
 	return (0);
 }