linux-kernel - Re: [PATCH RESEND 2/5] USB: serial: cp210x: Made sure SERIAL_XOFF

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Message-ID: <20160425101239.GH18866@localhost>
Date:	Mon, 25 Apr 2016 12:12:39 +0200
From:	Johan Hovold <johan@...nel.org>
To:	Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
Cc:	johan@...nel.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND 2/5] USB: serial: cp210x: Made sure
 SERIAL_XOFF_CONTINUE flag is clear.

On Sun, Apr 24, 2016 at 12:09:10PM -0500, Konstantin Shkolnyy wrote:
> The CRTCTS flag code intended to clear the SERIAL_XOFF_CONTINUE flag, but
> did it inconsistently. This change is non-functional for existing chips
> because the driver never set the flag and it's clear by default.
> 
> Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
> ---
>  drivers/usb/serial/cp210x.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> index de1606f..ede5c52 100644
> --- a/drivers/usb/serial/cp210x.c
> +++ b/drivers/usb/serial/cp210x.c
> @@ -955,7 +955,6 @@ static void cp210x_set_termios(struct tty_struct *tty,
>  			modem_ctl[0] &= ~0x7B;
>  			modem_ctl[0] |= 0x09;
>  			modem_ctl[4] = 0x80;
> -			modem_ctl[7] = 0;
>  			dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
>  		} else {
>  			modem_ctl[0] &= ~0x7B;
> @@ -963,6 +962,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
>  			modem_ctl[4] = 0x40;
>  			dev_dbg(dev, "%s - flow control = NONE\n", __func__);
>  		}
> +		modem_ctl[7] = 0;

I'd rather see this done using bit operations and a define (see my
comments on the next patch).

>  
>  		dev_dbg(dev, "%s - write modem controls = %02x .. .. .. %02x .. .. %02x\n",
>  			__func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);

Thanks,
Johan