Index: share/man/man9/efirt.9
===================================================================
--- share/man/man9/efirt.9
+++ share/man/man9/efirt.9
@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd August 12, 2018
+.Dd December 11, 2018
 .Dt EFIRT 9
 .Os
 .Sh NAME
@@ -54,7 +54,7 @@
 .Ft int
 .Fn efi_get_time_capabilities "struct efi_tmcap *tmcap"
 .Ft int
-.Fn efi_reset_system "void"
+.Fn efi_reset_system "enum efi_reset type"
 .Ft int
 .Fn efi_set_time "struct efi_tm *tm"
 .Ft int
@@ -123,7 +123,20 @@
 .Pp
 The
 .Fn efi_reset_system
-function requests a warm reset and reboot of the system.
+function requests a reset of the system.
+The
+.Fa type
+argument may be one of the
+.Vt enum efi_reset
+values:
+.Bl -tag -width ".Dv EFI_RESET_SHUTDOWN"
+.It Dv EFI_RESET_COLD
+Perform a cold reset of the system, and reboot.
+.It Dv EFI_RESET_WARM
+Perform a warm reset of the system, and reboot.
+.It Dv EFI_RESET_SHUTDOWN
+Power off the system.
+.El
 .Pp
 The
 .Fn efi_set_time
@@ -239,7 +252,7 @@
 .It Dv EROFS
 The variable in question is read-only or may not be deleted.
 .It Dv EDOOFUS
-The varialbe could not be set due to an authentication failure.
+The variable could not be set due to an authentication failure.
 .It Dv ENOENT
 The variable trying to be updated or deleted was not found.
 .El
Index: sys/dev/efidev/efirt.c
===================================================================
--- sys/dev/efidev/efirt.c
+++ sys/dev/efidev/efirt.c
@@ -34,6 +34,7 @@
 
 #include <sys/param.h>
 #include <sys/efi.h>
+#include <sys/eventhandler.h>
 #include <sys/kernel.h>
 #include <sys/linker.h>
 #include <sys/lock.h>
@@ -41,6 +42,7 @@
 #include <sys/mutex.h>
 #include <sys/clock.h>
 #include <sys/proc.h>
+#include <sys/reboot.h>
 #include <sys/rwlock.h>
 #include <sys/sched.h>
 #include <sys/sysctl.h>
@@ -106,6 +108,10 @@
 }
 
 static struct mtx efi_lock;
+static SYSCTL_NODE(_hw, OID_AUTO, efi, CTLFLAG_RWTUN, NULL, "EFI");
+static bool efi_poweroff = true;
+SYSCTL_BOOL(_hw_efi, OID_AUTO, poweroff, CTLFLAG_RWTUN, &efi_poweroff, 0,
+    "If true, use EFI runtime services to power off in preference to ACPI");
 
 static bool
 efi_is_in_map(struct efi_md *map, int ndesc, int descsz, vm_offset_t addr)
@@ -126,6 +132,19 @@
 	return (false);
 }
 
+static void
+efi_shutdown_final(void *dummy __unused, int howto)
+{
+
+	/*
+	 * On some systems, ACPI S5 is missing or does not function properly.
+	 * When present, shutdown via EFI Runtime Services instead, unless
+	 * disabled.
+	 */
+	if ((howto & RB_POWEROFF) != 0 && efi_poweroff)
+		(void)efi_reset_system(EFI_RESET_SHUTDOWN);
+}
+
 static int
 efi_init(void)
 {
@@ -214,6 +233,12 @@
 	}
 #endif
 
+	/*
+	 * We use SHUTDOWN_PRI_LAST - 1 to trigger after IPMI, but before ACPI.
+	 */
+	EVENTHANDLER_REGISTER(shutdown_final, efi_shutdown_final, NULL,
+	    SHUTDOWN_PRI_LAST - 1);
+
 	return (0);
 }
 
@@ -411,16 +436,24 @@
 }
 
 int
-efi_reset_system(void)
+efi_reset_system(enum efi_reset type)
 {
 	struct efirt_callinfo ec;
 
+	switch (type) {
+	case EFI_RESET_COLD:
+	case EFI_RESET_WARM:
+	case EFI_RESET_SHUTDOWN:
+		break;
+	default:
+		return (EINVAL);
+	}
 	if (efi_runtime == NULL)
 		return (ENXIO);
 	bzero(&ec, sizeof(ec));
 	ec.ec_name = "rt_reset";
 	ec.ec_argcnt = 4;
-	ec.ec_arg1 = (uintptr_t)EFI_RESET_WARM;
+	ec.ec_arg1 = (uintptr_t)type;
 	ec.ec_arg2 = (uintptr_t)0;
 	ec.ec_arg3 = (uintptr_t)0;
 	ec.ec_arg4 = (uintptr_t)NULL;
Index: sys/dev/ipmi/ipmi.c
===================================================================
--- sys/dev/ipmi/ipmi.c
+++ sys/dev/ipmi/ipmi.c
@@ -938,14 +938,14 @@
 	} else if (!on)
 		(void)ipmi_set_watchdog(sc, 0);
 	/*
-	 * Power cycle the system off using IPMI. We use last - 1 since we don't
+	 * Power cycle the system off using IPMI. We use last - 2 since we don't
 	 * handle all the other kinds of reboots. We'll let others handle them.
 	 * We only try to do this if the BMC supports the Chassis device.
 	 */
 	if (sc->ipmi_dev_support & IPMI_ADS_CHASSIS) {
 		device_printf(dev, "Establishing power cycle handler\n");
 		sc->ipmi_power_cycle_tag = EVENTHANDLER_REGISTER(shutdown_final,
-		    ipmi_power_cycle, sc, SHUTDOWN_PRI_LAST - 1);
+		    ipmi_power_cycle, sc, SHUTDOWN_PRI_LAST - 2);
 	}
 }
 
Index: sys/sys/efi.h
===================================================================
--- sys/sys/efi.h
+++ sys/sys/efi.h
@@ -42,8 +42,9 @@
 	{0xeb9d2d32,0x2d88,0x11d3,0x9a,0x16,{0x00,0x90,0x27,0x3f,0xc1,0x4d}}
 
 enum efi_reset {
-	EFI_RESET_COLD,
-	EFI_RESET_WARM
+	EFI_RESET_COLD = 0,
+	EFI_RESET_WARM = 1,
+	EFI_RESET_SHUTDOWN = 2,
 };
 
 typedef uint16_t	efi_char;
@@ -184,7 +185,7 @@
 int efi_get_table(struct uuid *uuid, void **ptr);
 int efi_get_time(struct efi_tm *tm);
 int efi_get_time_capabilities(struct efi_tmcap *tmcap);
-int efi_reset_system(void);
+int efi_reset_system(enum efi_reset type);
 int efi_set_time(struct efi_tm *tm);
 int efi_var_get(uint16_t *name, struct uuid *vendor, uint32_t *attrib,
     size_t *datasize, void *data);