diff --git a/lichee/linux-4.9/drivers/usb/gadget/function/u_serial.c b/lichee/linux-4.9/drivers/usb/gadget/function/u_serial.c
index 2f151e0aa..57cc7ebfc 100644
--- a/lichee/linux-4.9/drivers/usb/gadget/function/u_serial.c
+++ b/lichee/linux-4.9/drivers/usb/gadget/function/u_serial.c
@@ -140,6 +140,7 @@ static struct portmaster {
 } ports[MAX_U_SERIAL_PORTS];
 
 #define GS_CLOSE_TIMEOUT		15		/* seconds */
+#define HAS_GS_CLOSE_TIMEOUT	400		/* ms */
 
 
 
@@ -882,7 +883,8 @@ static void gs_close(struct tty_struct *tty, struct file *file)
 		spin_unlock_irq(&port->port_lock);
 		wait_event_interruptible_timeout(port->drain_wait,
 					gs_writes_finished(port),
-					GS_CLOSE_TIMEOUT * HZ);
+					msecs_to_jiffies(HAS_GS_CLOSE_TIMEOUT));
+					// GS_CLOSE_TIMEOUT * HZ);
 		spin_lock_irq(&port->port_lock);
 		gser = port->port_usb;
 	}