This is a note to let you know that I've just added the patch titled serial: 8250_mtk: Fix uart_get_baud_rate warning to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: serial-8250_mtk-fix-uart_get_baud_rate-warning.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 912ab37c798770f21b182d656937072b58553378 Mon Sep 17 00:00:00 2001 From: Claire Chang <tientzu@xxxxxxxxxxxx> Date: Mon, 2 Nov 2020 20:07:49 +0800 Subject: serial: 8250_mtk: Fix uart_get_baud_rate warning From: Claire Chang <tientzu@xxxxxxxxxxxx> 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@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20201102120749.374458-1-tientzu@xxxxxxxxxxxx Cc: stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -47,7 +47,7 @@ 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); Patches currently in stable-queue which might be from tientzu@xxxxxxxxxxxx are queue-4.19/serial-8250_mtk-fix-uart_get_baud_rate-warning.patch