diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 68fa0e43b78107fd7b02bac3d6ede9049edcbf01..8c075b2416bb6237402326dcd92d9d00dc454b7c 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -912,6 +912,7 @@ static void sierra_release(struct usb_serial *serial)
 	}
 }
 
+#ifdef CONFIG_PM
 static void stop_read_write_urbs(struct usb_serial *serial)
 {
 	int i, j;
@@ -988,6 +989,10 @@ static int sierra_resume(struct usb_serial *serial)
 
 	return ec ? -EIO : 0;
 }
+#else
+#define sierra_suspend NULL
+#define sierra_resume NULL
+#endif
 
 static struct usb_serial_driver sierra_device = {
 	.driver = {