diff --git a/sys/dev/tpm/tpm20.h b/sys/dev/tpm/tpm20.h
--- a/sys/dev/tpm/tpm20.h
+++ b/sys/dev/tpm/tpm20.h
@@ -136,6 +136,7 @@
 };
 
 int tpm20_suspend(device_t dev);
+int tpm20_resume(device_t dev);
 int tpm20_shutdown(device_t dev);
 int32_t tpm20_get_timeout(uint32_t command);
 int tpm20_init(struct tpm_sc *sc);
diff --git a/sys/dev/tpm/tpm20.c b/sys/dev/tpm/tpm20.c
--- a/sys/dev/tpm/tpm20.c
+++ b/sys/dev/tpm/tpm20.c
@@ -242,9 +242,28 @@
 		destroy_dev(sc->sc_cdev);
 }
 
+int
+tpm20_resume(device_t dev)
+{
+#if defined TPM_HARVEST || defined RANDOM_ENABLE_TPM
+	struct tpm_sc *sc;
+
+	sc = device_get_softc(dev);
+	taskqueue_enqueue_timeout(taskqueue_thread, &sc->harvest_task,
+	    hz * TPM_HARVEST_INTERVAL);
+#endif
+	return (0);
+}
+
 int
 tpm20_suspend(device_t dev)
 {
+#if defined TPM_HARVEST || defined RANDOM_ENABLE_TPM
+	struct tpm_sc *sc;
+
+	sc = device_get_softc(dev);
+	taskqueue_drain_timeout(taskqueue_thread, &sc->harvest_task);
+#endif
 	return (tpm20_save_state(dev, true));
 }
 
diff --git a/sys/dev/tpm/tpm_crb.c b/sys/dev/tpm/tpm_crb.c
--- a/sys/dev/tpm/tpm_crb.c
+++ b/sys/dev/tpm/tpm_crb.c
@@ -449,6 +449,7 @@
 	DEVMETHOD(device_detach,	tpmcrb_detach),
 	DEVMETHOD(device_shutdown,	tpm20_shutdown),
 	DEVMETHOD(device_suspend,	tpm20_suspend),
+	DEVMETHOD(device_resume,	tpm20_resume),
 	DEVMETHOD(tpm_transmit,		tpmcrb_transmit),
 	{0, 0}
 };
diff --git a/sys/dev/tpm/tpm_tis_core.c b/sys/dev/tpm/tpm_tis_core.c
--- a/sys/dev/tpm/tpm_tis_core.c
+++ b/sys/dev/tpm/tpm_tis_core.c
@@ -487,6 +487,7 @@
 	DEVMETHOD(device_detach,	tpmtis_detach),
 	DEVMETHOD(device_shutdown,	tpm20_shutdown),
 	DEVMETHOD(device_suspend,	tpm20_suspend),
+	DEVMETHOD(device_resume,	tpm20_resume),
 	DEVMETHOD(tpm_transmit,		tpmtis_transmit),
 	DEVMETHOD_END
 };