Documentation/serial/driver clearly states: If the port does not support CTS, DCD or DSR, the driver should indicate that the signal is permanently active. Hence always set TIOCM_CTS, as we currently don't look at the CTS hardware line state at all. FWIW, this fixes the transmit path when hardware-assisted flow control is enabled, and userspace enables CRTSCTS. The receive path is still broken, as RTS is never asserted. Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Reviewed-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> --- v3: - Add Reviewed-by, v2: - Drop RFC status. --- drivers/tty/serial/sh-sci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 0130feb069aee02f..135f836642ab1c5a 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1835,9 +1835,9 @@ static unsigned int sci_get_mctrl(struct uart_port *port) { /* * CTS/RTS is handled in hardware when supported, while nothing - * else is wired up. Keep it simple and simply assert DSR/CAR. + * else is wired up. Keep it simple and simply assert CTS/DSR/CAR. */ - return TIOCM_DSR | TIOCM_CAR; + return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; } static void sci_break_ctl(struct uart_port *port, int break_state) -- 1.9.1