Re: [PATCH] tty/serial: Lay the foundations for the next set of reworks

[Jiri Slaby <jirislaby@gmail.com>]

On 04/08/2008 05:58 PM, Alan Cox wrote:
> - Remove private put_char method that does a write call for one char - we
> have that anyway

> diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.25-rc8-mm1/drivers/char/nozomi.c linux-2.6.25-rc8-mm1/drivers/char/nozomi.c
> --- linux.vanilla-2.6.25-rc8-mm1/drivers/char/nozomi.c	2008-04-08 11:34:51.000000000 +0100
> +++ linux-2.6.25-rc8-mm1/drivers/char/nozomi.c	2008-04-08 11:44:09.000000000 +0100
> @@ -1724,6 +1724,8 @@
>  	const struct ctrl_dl *ctrl_dl = &port->ctrl_dl;
>  	const struct ctrl_ul *ctrl_ul = &port->ctrl_ul;
>  
> +	/* Note: these could change under us but it is not clear this
> +	   matters if so */
>  	return	(ctrl_ul->RTS ? TIOCM_RTS : 0) |
>  		(ctrl_ul->DTR ? TIOCM_DTR : 0) |
>  		(ctrl_dl->DCD ? TIOCM_CAR : 0) |
> @@ -1849,16 +1851,6 @@
>  	spin_unlock_irqrestore(&dc->spin_mutex, flags);
>  }
>  
> -/* just to discard single character writes */
> -static void ntty_put_char(struct tty_struct *tty, unsigned char c)
> -{
> -	/*
> -	 * card does not react correct when we write single chars
> -	 * to the card, so we discard them
> -	 */
> -	DBG2("PUT CHAR Function: %c", c);
> -}
> -
>  /* Returns number of chars in buffer, called by tty layer */
>  static s32 ntty_chars_in_buffer(struct tty_struct *tty)
>  {
> @@ -1892,7 +1884,6 @@
>  	.unthrottle = ntty_unthrottle,
>  	.throttle = ntty_throttle,
>  	.chars_in_buffer = ntty_chars_in_buffer,
> -	.put_char = ntty_put_char,
>  	.tiocmget = ntty_tiocmget,
>  	.tiocmset = ntty_tiocmset,
>  };

Well, how exactly the card behaves on 1 byte write? And how did the .write 
protect against it?