| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.10 025/100] serial: stm32: fix software flow control transfer | Date | Mon, 31 Jan 2022 11:55:46 +0100 |
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From: Valentin Caron <valentin.caron@foss.st.com>
commit 037b91ec7729524107982e36ec4b40f9b174f7a2 upstream.
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(-)
--- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -574,7 +574,7 @@ static void stm32_usart_start_tx(struct 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) {
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