diff --git a/sound/pci/asihpi/hpios.h b/sound/pci/asihpi/hpios.h
index 03273e7..2f605e3 100644
--- a/sound/pci/asihpi/hpios.h
+++ b/sound/pci/asihpi/hpios.h
@@ -38,6 +38,7 @@
 #include <linux/firmware.h>
 #include <linux/interrupt.h>
 #include <linux/pci.h>
+#include <linux/mutex.h>
 
 #define HPI_NO_OS_FILE_OPS