diff --git a/sys/arch/i386/i386/mainbus.c b/sys/arch/i386/i386/mainbus.c
index 130c1f42c7e0..e4a687a9bc31 100644
--- a/sys/arch/i386/i386/mainbus.c
+++ b/sys/arch/i386/i386/mainbus.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: mainbus.c,v 1.32 2001/04/01 23:14:02 jdolecek Exp $	*/
+/*	$NetBSD: mainbus.c,v 1.33 2001/09/28 03:56:21 thorpej Exp $	*/
 
 /*
  * Copyright (c) 1996 Christopher G. Demetriou.  All rights reserved.
@@ -48,6 +48,7 @@
 #include "mca.h"
 #include "apm.h"
 #include "pnpbios.h"
+#include "acpi.h"
 
 #if NAPM > 0
 #include <machine/bioscall.h>
@@ -58,6 +59,10 @@
 #include <arch/i386/pnpbios/pnpbiosvar.h>
 #endif
 
+#if NACPI > 0
+#include <dev/acpi/acpivar.h>
+#endif
+
 #if NMCA > 0
 #include <dev/mca/mcavar.h>
 #endif
@@ -85,6 +90,9 @@ union mainbus_attach_args {
 #if NPNPBIOS > 0
 	struct pnpbios_attach_args mba_paa;
 #endif
+#if NACPI > 0
+	struct acpibus_attach_args mba_acpi;
+#endif
 };
 
 /*
@@ -132,7 +140,31 @@ mainbus_attach(parent, self, aux)
 
 	printf("\n");
 
+#if NACPI > 0
+	if (acpi_probe()) {
+		mba.mba_acpi.aa_busname = "acpi";
+		mba.mba_acpi.aa_iot = I386_BUS_SPACE_IO;
+		mba.mba_acpi.aa_memt = I386_BUS_SPACE_MEM;
+		mba.mba_acpi.aa_pc = NULL;
+		mba.mba_acpi.aa_pciflags =
+		    PCI_FLAGS_IO_ENABLED | PCI_FLAGS_MEM_ENABLED;
+		config_found(self, &mba.mba_acpi, mainbus_print);
+#if 0 /* XXXJRT not yet */
+		if (acpi_active) {
+			/*
+			 * ACPI already did all the work for us, there
+			 * is nothing more for us to do.
+			 */
+			return;
+		}
+#endif
+	}
+#endif
+
 #if NPNPBIOS > 0
+#if NACPI > 0
+	if (acpi_active == 0)
+#endif
 	if (pnpbios_probe()) {
 		mba.mba_paa.paa_busname = "pnpbios";
 		mba.mba_paa.paa_ic = &i386_isa_chipset;
@@ -189,6 +221,9 @@ mainbus_attach(parent, self, aux)
 #endif
 
 #if NAPM > 0
+#if NACPI > 0
+	if (acpi_active == 0)
+#endif
 	if (apm_busprobe()) {
 		mba.mba_aaa.aaa_busname = "apm";
 		config_found(self, &mba.mba_aaa, mainbus_print);