diff --git a/drivers/staging/comedi/drivers/comedi_test.c b/drivers/staging/comedi/drivers/comedi_test.c
index 9655dc333e34..a750f84529ff 100644
--- a/drivers/staging/comedi/drivers/comedi_test.c
+++ b/drivers/staging/comedi/drivers/comedi_test.c
@@ -70,7 +70,7 @@ struct waveform_private {
 	unsigned long state_bits;
 	unsigned int ai_scan_period;	/* AI scan period in usec */
 	unsigned int ai_convert_period;	/* AI conversion period in usec */
-	unsigned int ao_loopbacks[N_CHANS];
+	unsigned short ao_loopbacks[N_CHANS];
 };
 
 /* fake analog input ranges */