diff --git a/sys/i386/isa/sound/os.h b/sys/i386/isa/sound/os.h
index 1589ca8a573c..6866017976c5 100644
--- a/sys/i386/isa/sound/os.h
+++ b/sys/i386/isa/sound/os.h
@@ -24,6 +24,7 @@
 #include <sys/proc.h>
 #include <sys/conf.h>
 #include <sys/file.h>
+#include <sys/filio.h>
 #include <sys/uio.h>
 #include <sys/kernel.h>
 #include <sys/syslog.h>