Index: sys/amd64/acpica/acpi_machdep.c
===================================================================
--- sys/amd64/acpica/acpi_machdep.c
+++ sys/amd64/acpica/acpi_machdep.c
@@ -359,8 +359,6 @@
 		panic("failed to add acpi0 device");
 
 	error = bus_generic_attach(dev);
-	if (error == 0)
-		acpi_install_wakeup_handler(device_get_softc(acpi_dev));
 
 	return (error);
 }
Index: sys/dev/acpica/acpi.c
===================================================================
--- sys/dev/acpica/acpi.c
+++ sys/dev/acpica/acpi.c
@@ -692,6 +692,10 @@
     callout_reset(&acpi_sleep_timer, hz * ACPI_MINIMUM_AWAKETIME,
 	acpi_sleep_enable, sc);
 
+#ifdef __amd64__
+    acpi_install_wakeup_handler(sc);
+#endif
+
     error = 0;
 
  out: