4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chen Hu hu1.chen@intel.com
commit dfcab6ba573445c703235ab6c83758eec12d7f28 upstream.
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(-)
--- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -224,7 +224,7 @@ static void dw8250_set_termios(struct ua unsigned int rate; int ret;
- if (IS_ERR(d->clk) || !old) + if (IS_ERR(d->clk)) goto out;
clk_disable_unprepare(d->clk);