Don't let receiver hardware automatically control RTS output if it was requested to be inactive. To ensure this, set_termios() shouldn't set UCR2_CTSC bit if UCR2_CTS (=TIOCM_RTS) is cleared. Added corresponding check in imx_uart_rts_auto() to fix this. Acked-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> Reviewed-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> Tested-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> Signed-off-by: Sergey Organov <sorganov@xxxxxxxxx> --- drivers/tty/serial/imx.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 57d6e6b..32f36d8 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -405,7 +405,12 @@ static void imx_uart_rts_inactive(struct imx_port *sport, u32 *ucr2) /* called with port.lock taken and irqs caller dependent */ static void imx_uart_rts_auto(struct imx_port *sport, u32 *ucr2) { - *ucr2 |= UCR2_CTSC; + /* + * Only let receiver control RTS output if we were not requested to have + * RTS inactive (which then should take precedence). + */ + if (*ucr2 & UCR2_CTS) + *ucr2 |= UCR2_CTSC; } /* called with port.lock taken and irqs off */ -- 2.10.0.1.g57b01a3