diff --git a/sys/amd64/acpica/acpi_wakeup.c b/sys/amd64/acpica/acpi_wakeup.c
--- a/sys/amd64/acpica/acpi_wakeup.c
+++ b/sys/amd64/acpica/acpi_wakeup.c
@@ -74,7 +74,7 @@
 extern struct susppcb	**susppcbs;
 static cpuset_t		suspcpus;
 
-static void		acpi_stop_beep(void *);
+static void		acpi_stop_beep(void *, enum sleep_type);
 
 static int		acpi_wakeup_ap(struct acpi_softc *, int);
 static void		acpi_wakeup_cpus(struct acpi_softc *);
@@ -88,7 +88,7 @@
 } while (0)
 
 static void
-acpi_stop_beep(void *arg)
+acpi_stop_beep(void *arg, enum sleep_type stype)
 {
 
 	if (acpi_resume_beep != 0)
diff --git a/sys/cam/ata/ata_da.c b/sys/cam/ata/ata_da.c
--- a/sys/cam/ata/ata_da.c
+++ b/sys/cam/ata/ata_da.c
@@ -878,8 +878,8 @@
 				uint32_t sense_flags);
 static callout_func_t	adasendorderedtag;
 static void		adashutdown(void *arg, int howto);
-static void		adasuspend(void *arg);
-static void		adaresume(void *arg);
+static void		adasuspend(void *arg, int stype);
+static void		adaresume(void *arg, int stype);
 
 #ifndef ADA_DEFAULT_TIMEOUT
 #define ADA_DEFAULT_TIMEOUT 30	/* Timeout in seconds */
@@ -3747,7 +3747,7 @@
 }
 
 static void
-adasuspend(void *arg)
+adasuspend(void *arg, int stype)
 {
 
 	adaflush();
@@ -3760,7 +3760,7 @@
 }
 
 static void
-adaresume(void *arg)
+adaresume(void *arg, int stype)
 {
 	struct cam_periph *periph;
 	struct ada_softc *softc;
diff --git a/sys/cam/nvme/nvme_da.c b/sys/cam/nvme/nvme_da.c
--- a/sys/cam/nvme/nvme_da.c
+++ b/sys/cam/nvme/nvme_da.c
@@ -159,7 +159,7 @@
 static  int		ndaerror(union ccb *ccb, uint32_t cam_flags,
 				uint32_t sense_flags);
 static void		ndashutdown(void *arg, int howto);
-static void		ndasuspend(void *arg);
+static void		ndasuspend(void *arg, int stype);
 
 #ifndef	NDA_DEFAULT_SEND_ORDERED
 #define	NDA_DEFAULT_SEND_ORDERED	1
@@ -1365,7 +1365,7 @@
 }
 
 static void
-ndasuspend(void *arg)
+ndasuspend(void *arg, int stype)
 {
 
 	ndaflush();
diff --git a/sys/compat/linuxkpi/common/src/linux_acpi.c b/sys/compat/linuxkpi/common/src/linux_acpi.c
--- a/sys/compat/linuxkpi/common/src/linux_acpi.c
+++ b/sys/compat/linuxkpi/common/src/linux_acpi.c
@@ -112,21 +112,33 @@
 }
 
 static void
-linux_handle_power_suspend_event(void *arg __unused)
+linux_handle_power_suspend_event(void *arg __unused, enum sleep_type stype)
 {
-	/*
-	 * Only support S3 for now.
-	 * acpi_sleep_event isn't always called so we use power_suspend_early
-	 * instead which means we don't know what state we're switching to.
-	 * TODO: Make acpi_sleep_event consistent
-	 */
-	linux_acpi_target_sleep_state = ACPI_STATE_S3;
-	pm_suspend_target_state = PM_SUSPEND_MEM;
+
+	switch (stype) {
+	case STYPE_SUSPEND_TO_IDLE:
+		/* XXX: obiwac Not 100% sure this is correct, but
+		 * acpi_target_sleep_state does seem to be set to
+		 * ACPI_STATE_S3 during s2idle on Linux.
+		 */
+		linux_acpi_target_sleep_state = ACPI_STATE_S3;
+		pm_suspend_target_state = PM_SUSPEND_TO_IDLE;
+		break;
+	case STYPE_SUSPEND:
+		linux_acpi_target_sleep_state = ACPI_STATE_S3;
+		pm_suspend_target_state = PM_SUSPEND_MEM;
+		break;
+	default:
+		printf("%s: sleep type %d not yet supported\n",
+		    __func__, stype);
+		break;
+	}
 }
 
 static void
-linux_handle_power_resume_event(void *arg __unused)
+linux_handle_power_resume_event(void *arg __unused, enum sleep_type stype)
 {
+
 	linux_acpi_target_sleep_state = ACPI_STATE_S0;
 	pm_suspend_target_state = PM_SUSPEND_ON;
 }
diff --git a/sys/dev/acpica/acpi.c b/sys/dev/acpica/acpi.c
--- a/sys/dev/acpica/acpi.c
+++ b/sys/dev/acpica/acpi.c
@@ -3671,10 +3671,10 @@
 	return_ACPI_STATUS (AE_OK);
     }
 
-    EVENTHANDLER_INVOKE(power_suspend_early);
+    EVENTHANDLER_INVOKE(power_suspend_early, stype);
     stop_all_proc();
     suspend_all_fs();
-    EVENTHANDLER_INVOKE(power_suspend);
+    EVENTHANDLER_INVOKE(power_suspend, stype);
 
 #ifdef EARLY_AP_STARTUP
     MPASS(mp_ncpus == 1 || smp_started);
@@ -3828,7 +3828,7 @@
     resume_all_fs();
     resume_all_proc();
 
-    EVENTHANDLER_INVOKE(power_resume);
+    EVENTHANDLER_INVOKE(power_resume, stype);
 
     /* Allow another sleep request after a while. */
     callout_schedule(&acpi_sleep_timer, hz * ACPI_MINIMUM_AWAKETIME);
diff --git a/sys/dev/acpica/acpi_timer.c b/sys/dev/acpica/acpi_timer.c
--- a/sys/dev/acpica/acpi_timer.c
+++ b/sys/dev/acpica/acpi_timer.c
@@ -69,8 +69,9 @@
 static void	acpi_timer_identify(driver_t *driver, device_t parent);
 static int	acpi_timer_probe(device_t dev);
 static int	acpi_timer_attach(device_t dev);
-static void	acpi_timer_resume_handler(struct timecounter *);
-static void	acpi_timer_suspend_handler(struct timecounter *);
+static void	acpi_timer_resume_handler(struct timecounter *, enum sleep_type);
+static void	acpi_timer_suspend_handler(struct timecounter *,
+    enum sleep_type);
 static u_int	acpi_timer_get_timecount(struct timecounter *tc);
 static u_int	acpi_timer_get_timecount_safe(struct timecounter *tc);
 static int	acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
@@ -235,7 +236,7 @@
 }
 
 static void
-acpi_timer_resume_handler(struct timecounter *newtc)
+acpi_timer_resume_handler(struct timecounter *newtc, enum sleep_type stype)
 {
 	struct timecounter *tc;
 
@@ -251,7 +252,7 @@
 }
 
 static void
-acpi_timer_suspend_handler(struct timecounter *newtc)
+acpi_timer_suspend_handler(struct timecounter *newtc, enum sleep_type stype)
 {
 	struct timecounter *tc;
 
diff --git a/sys/dev/vt/vt_core.c b/sys/dev/vt/vt_core.c
--- a/sys/dev/vt/vt_core.c
+++ b/sys/dev/vt/vt_core.c
@@ -195,8 +195,8 @@
 #ifndef SC_NO_CUTPASTE
 static void vt_mouse_paste(void);
 #endif
-static void vt_suspend_handler(void *priv);
-static void vt_resume_handler(void *priv);
+static void vt_suspend_handler(void *priv, int stype);
+static void vt_resume_handler(void *priv, int stype);
 
 SET_DECLARE(vt_drv_set, struct vt_driver);
 
@@ -3330,7 +3330,7 @@
 }
 
 static void
-vt_suspend_handler(void *priv)
+vt_suspend_handler(void *priv, int stype)
 {
 	struct vt_device *vd;
 
@@ -3341,7 +3341,7 @@
 }
 
 static void
-vt_resume_handler(void *priv)
+vt_resume_handler(void *priv, int stype)
 {
 	struct vt_device *vd;
 
diff --git a/sys/dev/xen/control/control.c b/sys/dev/xen/control/control.c
--- a/sys/dev/xen/control/control.c
+++ b/sys/dev/xen/control/control.c
@@ -175,12 +175,16 @@
 	cpuset_t cpu_suspend_map;
 #endif
 
-	EVENTHANDLER_INVOKE(power_suspend_early);
+	/*
+	 * TODO Once enum sleep_type is made available on non-ACPI, this should
+	 * be STYPE_SUSPEND instead.
+	 */
+	EVENTHANDLER_INVOKE(power_suspend_early, 0);
 	xs_lock();
 	stop_all_proc();
 	xs_unlock();
 	suspend_all_fs();
-	EVENTHANDLER_INVOKE(power_suspend);
+	EVENTHANDLER_INVOKE(power_suspend, 0);
 
 #ifdef EARLY_AP_STARTUP
 	MPASS(mp_ncpus == 1 || smp_started);
@@ -297,7 +301,7 @@
 	resume_all_fs();
 	resume_all_proc();
 
-	EVENTHANDLER_INVOKE(power_resume);
+	EVENTHANDLER_INVOKE(power_resume, 0);
 
 	if (bootverbose)
 		printf("System resumed after suspension\n");
diff --git a/sys/i386/acpica/acpi_wakeup.c b/sys/i386/acpica/acpi_wakeup.c
--- a/sys/i386/acpica/acpi_wakeup.c
+++ b/sys/i386/acpica/acpi_wakeup.c
@@ -84,7 +84,7 @@
 static struct susppcb	**susppcbs;
 #endif
 
-static void		acpi_stop_beep(void *);
+static void		acpi_stop_beep(void *, enum sleep_type);
 
 #ifdef SMP
 static int		acpi_wakeup_ap(struct acpi_softc *, int);
@@ -100,7 +100,7 @@
 } while (0)
 
 static void
-acpi_stop_beep(void *arg)
+acpi_stop_beep(void *arg, enum sleep_type stype)
 {
 
 	if (acpi_resume_beep != 0)
diff --git a/sys/sys/eventhandler.h b/sys/sys/eventhandler.h
--- a/sys/sys/eventhandler.h
+++ b/sys/sys/eventhandler.h
@@ -200,8 +200,13 @@
 EVENTHANDLER_DECLARE(shutdown_post_sync, shutdown_fn);	/* after fs sync */
 EVENTHANDLER_DECLARE(shutdown_final, shutdown_fn);
 
-/* Power state change events */
-typedef void (*power_change_fn)(void *);
+/*
+ * Power state change events.
+ *
+ * TODO Maybe enum sleep_type shouldn't be defined in dev/acpica/acpivar.h, cuz
+ * then I can't use it here/on non-ACPI systems.
+ */
+typedef void (*power_change_fn)(void *, int stype);
 EVENTHANDLER_DECLARE(power_resume, power_change_fn);
 EVENTHANDLER_DECLARE(power_suspend, power_change_fn);
 EVENTHANDLER_DECLARE(power_suspend_early, power_change_fn);