diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 0453f0eb1178..74d0a91e8427 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -926,10 +926,10 @@ static int get_serial_info(struct acm *acm, struct serial_struct __user *info)
 	memset(&tmp, 0, sizeof(tmp));
 	tmp.xmit_fifo_size = acm->writesize;
 	tmp.baud_base = le32_to_cpu(acm->line.dwDTERate);
-	tmp.close_delay	= acm->port.close_delay / 10;
+	tmp.close_delay	= jiffies_to_msecs(acm->port.close_delay) / 10;
 	tmp.closing_wait = acm->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 				ASYNC_CLOSING_WAIT_NONE :
-				acm->port.closing_wait / 10;
+				jiffies_to_msecs(acm->port.closing_wait) / 10;
 
 	if (copy_to_user(info, &tmp, sizeof(tmp)))
 		return -EFAULT;
@@ -947,9 +947,10 @@ static int set_serial_info(struct acm *acm,
 	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
 		return -EFAULT;
 
-	close_delay = new_serial.close_delay * 10;
+	close_delay = msecs_to_jiffies(new_serial.close_delay * 10);
 	closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
-			ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
+			ASYNC_CLOSING_WAIT_NONE :
+			msecs_to_jiffies(new_serial.closing_wait * 10);
 
 	mutex_lock(&acm->port.mutex);