Index: share/man/man4/acpi_thermal.4
===================================================================
--- share/man/man4/acpi_thermal.4
+++ share/man/man4/acpi_thermal.4
@@ -84,6 +84,9 @@
 .It Va hw.acpi.thermal.tz%d._PSV
 Temperature to start passive cooling by throttling down CPU, etc.
 This value can be overridden by the user.
+.It Va hw.acpi.thermal.tz%d._CR3
+Temperature to start critical suspend to RAM (S3).
+This value can be overridden by the user.
 .It Va hw.acpi.thermal.tz%d._HOT
 Temperature to start critical suspend to disk (S4).
 This value can be overridden by the user.
Index: sys/dev/acpica/acpi_thermal.c
===================================================================
--- sys/dev/acpica/acpi_thermal.c
+++ sys/dev/acpica/acpi_thermal.c
@@ -60,7 +60,7 @@
 #define TZ_NOTIFY_TEMPERATURE	0x80 /* Temperature changed. */
 #define TZ_NOTIFY_LEVELS	0x81 /* Cooling levels changed. */
 #define TZ_NOTIFY_DEVICES	0x82 /* Device lists changed. */
-#define TZ_NOTIFY_CRITICAL	0xcc /* Fake notify that _CRT/_HOT reached. */
+#define TZ_NOTIFY_CRITICAL	0xcc /* Fake notify that _CRT/_HOT/_CR3 reached. */
 
 /* Check for temperature changes every 10 seconds by default */
 #define TZ_POLLRATE	10
@@ -78,6 +78,7 @@
     ACPI_BUFFER	al[TZ_NUMLEVELS];
     int		crt;
     int		hot;
+    int		cr3;
     ACPI_BUFFER	psl;
     int		psv;
     int		tc1;
@@ -97,8 +98,9 @@
     int				tz_thflags;	/*Current temp-related flags*/
 #define TZ_THFLAG_NONE		0
 #define TZ_THFLAG_PSV		(1<<0)
-#define TZ_THFLAG_HOT		(1<<2)
-#define TZ_THFLAG_CRT		(1<<3)
+#define TZ_THFLAG_CR3		(1<<2)
+#define TZ_THFLAG_HOT		(1<<3)
+#define TZ_THFLAG_CRT		(1<<4)
     int				tz_flags;
 #define TZ_FLAG_NO_SCP		(1<<0)		/*No _SCP method*/
 #define TZ_FLAG_GETPROFILE	(1<<1)		/*Get power_profile in timeout*/
@@ -282,6 +284,10 @@
         OID_AUTO, "_PSV", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
 	offsetof(struct acpi_tz_softc, tz_zone.psv), acpi_tz_temp_sysctl, "IK",
 	"passive cooling temp setpoint");
+    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
+        OID_AUTO, "_CR3", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
+	offsetof(struct acpi_tz_softc, tz_zone.cr3), acpi_tz_temp_sysctl, "IK",
+	"too warm temp setpoint (standby now)");
     SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
         OID_AUTO, "_HOT", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, sc,
 	offsetof(struct acpi_tz_softc, tz_zone.hot), acpi_tz_temp_sysctl, "IK",
@@ -421,6 +427,7 @@
     }
     acpi_tz_getparam(sc, "_CRT", &sc->tz_zone.crt);
     acpi_tz_getparam(sc, "_HOT", &sc->tz_zone.hot);
+    acpi_tz_getparam(sc, "_CR3", &sc->tz_zone.cr3);
     sc->tz_zone.psl.Length = ACPI_ALLOCATE_BUFFER;
     sc->tz_zone.psl.Pointer = NULL;
     AcpiEvaluateObject(sc->tz_handle, "_PSL", NULL, &sc->tz_zone.psl);
@@ -438,6 +445,7 @@
      */
     acpi_tz_sanity(sc, &sc->tz_zone.crt, "_CRT");
     acpi_tz_sanity(sc, &sc->tz_zone.hot, "_HOT");
+    acpi_tz_sanity(sc, &sc->tz_zone.cr3, "_CR3");
     acpi_tz_sanity(sc, &sc->tz_zone.psv, "_PSV");
     for (i = 0; i < TZ_NUMLEVELS; i++)
 	acpi_tz_sanity(sc, &sc->tz_zone.ac[i], "_ACx");
@@ -495,6 +503,7 @@
 static void
 acpi_tz_monitor(void *Context)
 {
+    struct acpi_softc	 *acpi_sc;
     struct acpi_tz_softc *sc;
     struct	timespec curtime;
     int		temp;
@@ -545,6 +554,8 @@
     newflags = TZ_THFLAG_NONE;
     if (sc->tz_zone.psv != -1 && temp >= sc->tz_zone.psv)
 	newflags |= TZ_THFLAG_PSV;
+    if (sc->tz_zone.cr3 != -1 && temp >= sc->tz_zone.cr3)
+	newflags |= TZ_THFLAG_CR3;
     if (sc->tz_zone.hot != -1 && temp >= sc->tz_zone.hot)
 	newflags |= TZ_THFLAG_HOT;
     if (sc->tz_zone.crt != -1 && temp >= sc->tz_zone.crt)
@@ -604,13 +615,18 @@
      *
      * If we're almost at that threshold, notify the user through devd(8).
      */
-    if ((newflags & (TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0) {
+    if ((newflags & (TZ_THFLAG_CR3 | TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0) {
 	sc->tz_validchecks++;
 	if (sc->tz_validchecks == TZ_VALIDCHECKS) {
 	    device_printf(sc->tz_dev,
 		"WARNING - current temperature (%d.%dC) exceeds safe limits\n",
 		TZ_KELVTOC(sc->tz_temperature));
-	    shutdown_nice(RB_POWEROFF);
+	    if ((newflags & (TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0)
+		shutdown_nice(RB_POWEROFF);
+	    else {
+		acpi_sc = acpi_device_get_parent_softc(sc->tz_dev);
+		acpi_ReqSleepState(acpi_sc, ACPI_STATE_S3);
+	    }
 	} else if (sc->tz_validchecks == TZ_NOTIFYCOUNT)
 	    acpi_UserNotify("Thermal", sc->tz_handle, TZ_NOTIFY_CRITICAL);
     } else {