From: Claire Chang tientzu@chromium.org
commit 912ab37c798770f21b182d656937072b58553378 upstream.
Mediatek 8250 port supports speed higher than uartclk / 16. If the baud rates in both the new and the old termios setting are higher than uartclk / 16, the WARN_ON in uart_get_baud_rate() will be triggered. Passing NULL as the old termios so uart_get_baud_rate() will use uartclk / 16 - 1 as the new baud rate which will be replaced by the original baud rate later by tty_termios_encode_baud_rate() in mtk8250_set_termios().
Fixes: 551e553f0d4a ("serial: 8250_mtk: Fix high-speed baud rates clamping") Signed-off-by: Claire Chang tientzu@chromium.org Link: https://lore.kernel.org/r/20201102120749.374458-1-tientzu@chromium.org Cc: stable stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/tty/serial/8250/8250_mtk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -317,7 +317,7 @@ mtk8250_set_termios(struct uart_port *po */ baud = tty_termios_baud_rate(termios);
- serial8250_do_set_termios(port, termios, old); + serial8250_do_set_termios(port, termios, NULL);
tty_termios_encode_baud_rate(termios, baud, baud);