diff --git a/sound/hda/ext/hdac_ext_bus.c b/sound/hda/ext/hdac_ext_bus.c
index 4449d1a990893..2433f7c814728 100644
--- a/sound/hda/ext/hdac_ext_bus.c
+++ b/sound/hda/ext/hdac_ext_bus.c
@@ -19,6 +19,7 @@
 
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/io.h>
 #include <sound/hdaudio_ext.h>
 
 MODULE_DESCRIPTION("HDA extended core");