diff --git a/drivers/char/mxser_new.c b/drivers/char/mxser_new.c
index 0b25457cda051bc18d0b7591f054624b1fe10666..d2dcc546cc7568fc563e4616ba0d1be3a828df1c 100644
--- a/drivers/char/mxser_new.c
+++ b/drivers/char/mxser_new.c
@@ -2153,7 +2153,7 @@ static void mxser_transmit_chars(struct mxser_port *port)
 		return;
 	}
 
-	if (port->xmit_buf == 0)
+	if (port->xmit_buf == NULL)
 		return;
 
 	if ((port->xmit_cnt <= 0) || port->tty->stopped ||