From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: Questions regarding adding a patch in linux/drivers/char/8250.c
Date: Tue, 19 Jun 2012 10:18:27 +0100
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To: Donald <donald@asix.com.tw>
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> +	struct pci_dev *pdev = container_of(port->dev, struct pci_dev, dev);
> +
>  	switch (termios->c_cflag & CSIZE) {
>  	case CS5:
>  		cval = UART_LCR_WLEN5;
> @@ -2351,6 +2354,13 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
>  	if (up->capabilities & UART_CAP_RTOIE)
>  		up->ier |= UART_IER_RTOIE;
>  
> +	if ((termios->c_cflag & PARENB) && (pdev->vendor == 0x9710)) {
> +		fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
> +		up->ier &= ~UART_IER_RLSI;
> +	} else {
> +		up->ier |= UART_IER_RLSI;
> +	}
> +

It's on my TODO list for the 3.6 merge. Your patch doesn't work (in fact
it crashes in some cases) because it blindly assumes an 8250 port is on
the PCI bus.

However it documents everything I need to know to push an actual fix.

Alan