diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index ff4a174fa5de..a1a9062954c4 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -420,7 +420,7 @@ static void pl2303_set_termios(struct tty_struct *tty,
 	control = priv->line_control;
 	if ((cflag & CBAUD) == B0)
 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
-	else
+	else if ((old_termios->c_cflag & CBAUD) == B0)
 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
 	if (control != priv->line_control) {
 		control = priv->line_control;