diff --git a/sys/amd64/include/param.h b/sys/amd64/include/param.h
--- a/sys/amd64/include/param.h
+++ b/sys/amd64/include/param.h
@@ -47,8 +47,6 @@
  * Machine dependent constants for AMD64.
  */
 
-#define __HAVE_ACPI
-
 #ifndef MACHINE
 #define	MACHINE		"amd64"
 #endif
diff --git a/sys/i386/include/param.h b/sys/i386/include/param.h
--- a/sys/i386/include/param.h
+++ b/sys/i386/include/param.h
@@ -41,7 +41,6 @@
  * Machine dependent constants for Intel 386.
  */
 
-#define __HAVE_ACPI
 #define	__HAVE_PIR
 
 #ifndef MACHINE