[1/4] USB: serial: ftdi_sio: fix IXON/IXOFF mixup

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, May 18, 2018 at 03:25:47PM +0200, Johan Hovold wrote:
> Since forever this driver has had IXON and IXOFF mixed up, and has used
> the latter rather than the former to enable hardware-assisted software
> flow control on output.
> 
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
>  drivers/usb/serial/ftdi_sio.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
> index 7ea221d42dba..62c99871863c 100644
> --- a/drivers/usb/serial/ftdi_sio.c
> +++ b/drivers/usb/serial/ftdi_sio.c
> @@ -2342,12 +2342,8 @@ static void ftdi_set_termios(struct tty_struct *tty,
>  	} else {
>  		/*
>  		 * Xon/Xoff code
> -		 *
> -		 * Check the IXOFF status in the iflag component of the
> -		 * termios structure. If IXOFF is not set, the pre-xon/xoff
> -		 * code is executed.
>  		 */
> -		if (iflag & IXOFF) {
> +		if (iflag & IXON) {
>  			dev_dbg(ddev, "%s  request to enable xonxoff iflag=%04x\n",
>  				__func__, iflag);
>  			/* Try to enable the XON/XOFF on the ftdi_sio
> @@ -2372,7 +2368,7 @@ static void ftdi_set_termios(struct tty_struct *tty,
>  			}
>  		} else {
>  			/* else clause to only run if cflag ! CRTSCTS and iflag
> -			 * ! XOFF. CHECKME Assuming XON/XOFF handled by tty
> +			 * ! XON. CHECKME Assuming XON/XOFF handled by tty
>  			 * stack - not by device */
>  			dev_dbg(ddev, "%s Turning off hardware flow control\n", __func__);
>  			if (usb_control_msg(dev,

Ugh, that's a huge sign that no one actually uses IXON/IXOFF anymore :(

Anyway, thanks for fixing this up, should also probably be backported to
the stable kernels.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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