diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 8e7a88b185d2..cafc80bb1fa7 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1701,3 +1701,5 @@ outb(u_int port, u_char data)
 }
 
 #endif /* DDB */
+
+MODULE_VERSION(acpi, 100);