Re: [PATCH] drivers:usb:serial:ftdi_sio.c: ftdi_set_termios make nosense some in a situation

From: Alan Cox
Date: Mon Dec 05 2011 - 06:32:36 EST


On Mon, 5 Dec 2011 15:47:30 +0800
wangyanqing <udknight@xxxxxxxxx> wrote:

> b1ffb4c851f185e9051ba837c16d9b84ef688d26 make a improvement to drop no sense reset
> termios. But it miss the situation, when call ftdi_set_termios with the value that
> same with the default settings all the time, then termios will take no effect any way,
> we need usb_control_msg to make effect. This patch try to resolve this question.
>
> Signed-off-by: Wang YanQing <ukdnight@xxxxxxxxx>
> ---
> drivers/usb/serial/ftdi_sio.c | 10 ++++++++--
> 1 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
> index 486769c..61f1be4 100644
> --- a/drivers/usb/serial/ftdi_sio.c
> +++ b/drivers/usb/serial/ftdi_sio.c
> @@ -2056,6 +2056,7 @@ static void ftdi_set_termios(struct tty_struct *tty,
> struct ktermios *termios = tty->termios;
> unsigned int cflag = termios->c_cflag;
> __u16 urb_value; /* will hold the new flags */
> + static int init_once = 1;

NACK

Think about what happens if you have two such ports or remove and re-add
it.

What code path is calling set_termios passing a termios data which has
never been set ?

Alan
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