serial: Test for no tx data on tx restart

[mirror_ubuntu-artful-kernel.git] / drivers / tty / serial / sunzilog.c

diff --git a/drivers/tty/serial/sunzilog.c b/drivers/tty/serial/sunzilog.c
index a85db8b8715639d01193c3ce394de1a058783314..02df3940b95e4e14d5db2c4b35eb8a0ebe70be71 100644 (file)
--- a/drivers/tty/serial/sunzilog.c
+++ b/drivers/tty/serial/sunzilog.c
@@ -703,6 +703,8 @@ static void sunzilog_start_tx(struct uart_port *port)
        } else {
                struct circ_buf *xmit = &port->state->xmit;
 
+               if (uart_circ_empty(xmit))
+                       return;
                writeb(xmit->buf[xmit->tail], &channel->data);
                ZSDELAY();
                ZS_WSYNC(channel);