diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 4ad4ca4..fada988 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -932,8 +932,6 @@ static int wait_serial_change(struct acm *acm, unsigned long arg)
 	DECLARE_WAITQUEUE(wait, current);
 	struct async_icount old, new;
 
-	if (arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD))
-		return -EINVAL;
 	do {
 		spin_lock_irq(&acm->read_lock);
 		old = acm->oldcount;