diff --git a/chipset_enable.c b/chipset_enable.c
index 04b1a1c..9356b1e 100644
--- a/chipset_enable.c
+++ b/chipset_enable.c
@@ -27,6 +27,7 @@
 
 #define _LARGEFILE64_SOURCE
 
+#include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>