From 6a1a82df91fa0eb1cc76069a9efe5714d087eccd Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Thu, 3 Jun 2010 13:55:02 +0200 Subject: [PATCH] USB: ftdi_sio: fix DTR/RTS line modes Call set_mctrl() and clear_mctrl() according to the flow control mode selected. This makes serial communication for FT232 connected devices work when CRTSCTS is not set. This fixes a regression introduced by 4175f3e31 ("tty_port: If we are opened non blocking we still need to raise the carrier"). This patch calls the low-level driver's dtr_rts() function which consequently sets TIOCM_DTR | TIOCM_RTS. A later call to set_termios() without CRTSCTS in cflags, however, does not reset these bits, and so data is not actually sent out on the serial wire. Signed-off-by: Daniel Mack Cc: Johan Hovold Cc: Alan Cox Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ftdi_sio.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 050211afc07e..79dd1ae195e5 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -2005,6 +2005,8 @@ static void ftdi_set_termios(struct tty_struct *tty, "urb failed to set to rts/cts flow control\n"); } + /* raise DTR/RTS */ + set_mctrl(port, TIOCM_DTR | TIOCM_RTS); } else { /* * Xon/Xoff code @@ -2052,6 +2054,8 @@ static void ftdi_set_termios(struct tty_struct *tty, } } + /* lower DTR/RTS */ + clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); } return; } -- 2.20.1