linux-kernel - Re: [PATCH 2/3] USB: mxu11x0: clean device control commands

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Date:	Sun, 3 Jan 2016 17:33:13 +0100
From:	Johan Hovold <johan@...nel.org>
To:	Mathieu OTHACEHE <m.othacehe@...il.com>
Cc:	johan@...nel.org, gregkh@...uxfoundation.org,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH 2/3] USB: mxu11x0: clean device control commands

On Sun, Jan 03, 2016 at 03:26:00PM +0100, Mathieu OTHACEHE wrote:
> Sending OPEN and START commands twice is not necessary for this driver.
> Also send STOP command at close.
> 
> Signed-off-by: Mathieu OTHACEHE <m.othacehe@...il.com>
> ---
>  drivers/usb/serial/mxu11x0.c | 31 +++++++------------------------
>  1 file changed, 7 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/usb/serial/mxu11x0.c b/drivers/usb/serial/mxu11x0.c
> index 0fe7eab..354fcb5 100644
> --- a/drivers/usb/serial/mxu11x0.c
> +++ b/drivers/usb/serial/mxu11x0.c
> @@ -823,30 +823,6 @@ static int mxu1_open(struct tty_struct *tty, struct usb_serial_port *port)
>  		goto unlink_int_urb;
>  	}
>  
> -	/*
> -	 * reset the data toggle on the bulk endpoints to work around bug in
> -	 * host controllers where things get out of sync some times
> -	 */
> -	usb_clear_halt(serial->dev, port->write_urb->pipe);
> -	usb_clear_halt(serial->dev, port->read_urb->pipe);

This is an unrelated change. You can remove it, but then do so in a
separate patch.

> -
> -	if (tty)
> -		mxu1_set_termios(tty, port, NULL);

But you should definitely not be removing this.

> -
> -	status = mxu1_send_ctrl_urb(serial, MXU1_OPEN_PORT,
> -				    open_settings, MXU1_UART1_PORT);
> -	if (status) {
> -		dev_err(&port->dev, "cannot send open command: %d\n", status);
> -		goto unlink_int_urb;
> -	}
> -
> -	status = mxu1_send_ctrl_urb(serial, MXU1_START_PORT,
> -				    0, MXU1_UART1_PORT);
> -	if (status) {
> -		dev_err(&port->dev, "cannot send start command: %d\n", status);
> -		goto unlink_int_urb;
> -	}
> -

Also did you not say that your sniffed traffic showed the following
sequence OPEN, CONFIG (e.g. purge, set_termios), START?

Johan
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