diff --git a/include/acpi.h b/include/acpi.h
index 2d5fd30..b8e73b3 100644
--- a/include/acpi.h
+++ b/include/acpi.h
@@ -6,6 +6,7 @@
 #ifndef __ACPI_H_
 #define __ACPI_H_
 
+#include <linux/string.h>
 #include <linux/types.h>
 #include <driver.h>