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

serial: stm32: fix software flow control transfer

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-linus 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 hopefully also be merged in Linus's tree for the next -rc kernel release.

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

From 037b91ec7729524107982e36ec4b40f9b174f7a2 Mon Sep 17 00:00:00 2001 From: Valentin Caron valentin.caron@foss.st.com Date: Tue, 11 Jan 2022 17:44:41 +0100 Subject: serial: stm32: fix software flow control transfer

x_char is ignored by stm32_usart_start_tx() when xmit buffer is empty.

Fix start_tx condition to allow x_char to be sent.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver") Cc: stable stable@vger.kernel.org Signed-off-by: Erwan Le Ray erwan.leray@foss.st.com Signed-off-by: Valentin Caron valentin.caron@foss.st.com Link: https://lore.kernel.org/r/20220111164441.6178-3-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/stm32-usart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index c1b8828451c8..9570002d07e7 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -742,7 +742,7 @@ static void stm32_usart_start_tx(struct uart_port *port) struct serial_rs485 *rs485conf = &port->rs485; struct circ_buf *xmit = &port->state->xmit;

- if (uart_circ_empty(xmit)) + if (uart_circ_empty(xmit) && !port->x_char) return;

if (rs485conf->flags & SER_RS485_ENABLED) {