The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e0bf2d4982fe7d9ddaf550dd023803ea286f47fc Mon Sep 17 00:00:00 2001 From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Date: Sun, 26 Aug 2018 19:49:32 +0200 Subject: [PATCH] serial: mvebu-uart: Fix reporting of effective CSIZE to userspace Apparently, this driver (or the hardware) does not support character length settings. It's apparently running in 8-bit mode, but it makes userspace believe it's in 5-bit mode. That makes tcsetattr with CS8 incorrectly fail, breaking e.g. getty from busybox, thus the login shell on ttyMVx. Fix by hard-wiring CS8 into c_cflag. Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") Cc: stable <stable@xxxxxxxxxxxxxxx> # 4.6+ Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index d04b5eeea3c6..170e446a2f62 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -511,6 +511,7 @@ static void mvebu_uart_set_termios(struct uart_port *port, termios->c_iflag |= old->c_iflag & ~(INPCK | IGNPAR); termios->c_cflag &= CREAD | CBAUD; termios->c_cflag |= old->c_cflag & ~(CREAD | CBAUD); + termios->c_cflag |= CS8; } spin_unlock_irqrestore(&port->lock, flags);