This is a note to let you know that I've just added the patch titled

serial: 8250_dw: always set baud rate in dw8250_set_termios

to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the tty-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From dfcab6ba573445c703235ab6c83758eec12d7f28 Mon Sep 17 00:00:00 2001

From: Chen Hu hu1.chen@intel.com Date: Fri, 27 Jul 2018 18:32:41 +0800 Subject: serial: 8250_dw: always set baud rate in dw8250_set_termios

dw8250_set_termios() doesn't set baud rate if the arg "old ktermios" is NULL. This happens during resume. Call Trace: ... [ 54.928108] dw8250_set_termios+0x162/0x170 [ 54.928114] serial8250_set_termios+0x17/0x20 [ 54.928117] uart_change_speed+0x64/0x160 [ 54.928119] uart_resume_port ...

So the baud rate is not restored after S3 and breaks the apps who use UART, for example, console and bluetooth etc.

We address this issue by setting the baud rate irrespective of arg "old", just like the drivers for other 8250 IPs. This is tested with Intel Broxton platform.

Signed-off-by: Chen Hu hu1.chen@intel.com Fixes: 4e26b134bd17 ("serial: 8250_dw: clock rate handling for all ACPI platforms") Cc: Heikki Krogerus heikki.krogerus@linux.intel.com Cc: stable stable@vger.kernel.org Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_dw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index b4e6f31936f5..27b7ecc3b59b 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -310,7 +310,7 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, long rate; int ret;

- if (IS_ERR(d->clk) || !old) + if (IS_ERR(d->clk)) goto out;

clk_disable_unprepare(d->clk);