From: Daniel Mack Date: Thu, 3 Jun 2010 11:55:02 +0000 (+0200) Subject: USB: ftdi_sio: fix DTR/RTS line modes X-Git-Tag: firefly_0821_release~10186^2~1477 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e067c7a9f9441cf9c3e2e81e22a01fa54f2f3434;p=firefly-linux-kernel-4.4.55.git USB: ftdi_sio: fix DTR/RTS line modes commit 6a1a82df91fa0eb1cc76069a9efe5714d087eccd upstream. 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 9cf46526a967..bf56be19d7b2 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -2306,6 +2306,8 @@ 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 @@ -2353,6 +2355,8 @@ static void ftdi_set_termios(struct tty_struct *tty, } } + /* lower DTR/RTS */ + clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); } return; }