[PATCH] serial: core: stop passing NULL in uart_resume_port

[Chen Hu <hu1.chen@intel.com>]

We found the baud rate is changed after S3 on some Intel Broxton
platforms. The baud rate should be restored during resume. However, some
set_termios() callback such as dw8250_set_termios() for DesignWare 8250
will skip setting if old termios is NULL. We address this issue via
passing a dummy.

Signed-off-by: Chen Hu <hu1.chen@intel.com>
---
 drivers/tty/serial/serial_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index f02965936f2e..8b815f1539e8 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2217,6 +2217,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
 	struct device *tty_dev;
 	struct uart_match match = {uport, drv};
 	struct ktermios termios;
+	static struct ktermios dummy;
 
 	mutex_lock(&port->mutex);
 
@@ -2277,7 +2278,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
 			pm_runtime_put_autosuspend(uport->dev);
 			if (ret == 0) {
 				if (tty)
-					uart_change_speed(tty, state, NULL);
+					uart_change_speed(tty, state, &dummy);
 				pm_runtime_get_sync(uport->dev);
 				spin_lock_irq(&uport->lock);
 				ops->set_mctrl(uport, uport->mctrl);
-- 
2.13.0