diff -uprN -X dontdiff 2.6-mm-clean/drivers/char/hpet.c 2.6-mm/drivers/char/hpet.c
--- 2.6-mm-clean/drivers/char/hpet.c	2004-05-17 09:38:03.000000000 -0300
+++ 2.6-mm/drivers/char/hpet.c	2004-05-17 09:23:04.000000000 -0300
@@ -976,6 +976,7 @@ hpet_alloc (struct hpet_data *hdp)
 	return 0;
 }
 
+#ifdef ACPI
 static acpi_status __init
 hpet_resources (struct acpi_resource *res, void *data)
 {
@@ -1056,7 +1057,10 @@ static struct acpi_driver hpet_acpi_driv
 		.remove	=	hpet_acpi_remove,
 	},
 };
-
+#else	/* ACPI */
+#define acpi_bus_register_driver(x) do {} while(0) 
+#define acpi_bus_unregister_driver(x) do {} while(0)
+#endif	/* ACPI */
 
 
 static int __init
@@ -1067,7 +1071,7 @@ hpet_init (void)
 	if (hpets)
 		hpet_post_platform();
 
-	(void) acpi_bus_register_driver(&hpet_acpi_driver);
+	acpi_bus_register_driver(&hpet_acpi_driver);
 
 	if (hpets) {
 		entry = create_proc_entry("driver/hpet", 0, 0);