linux-kernel - Re: [PATCH] Revert "serial: 8250: Fix max baud limit in generic 8250 port"

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Message-ID: <20200701043001.73qhxyyjx6bayn2m@wunner.de>
Date:   Wed, 1 Jul 2020 06:30:01 +0200
From:   Lukas Wunner <lukas@...ner.de>
To:     Daniel Winkler <danielwinkler@...gle.com>,
        Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>
Cc:     linux-serial@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        chromeos-bluetooth-upstreaming 
        <chromeos-bluetooth-upstreaming@...omium.org>,
        Aaron Sierra <asierra@...-inc.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert "serial: 8250: Fix max baud limit in generic 8250
 port"

On Tue, Jun 30, 2020 at 04:42:11PM -0700, Daniel Winkler wrote:
> This reverts commit 0eeaf62981ecc79e8395ca8caa1570eaf3a12257.

That is not an upstream commit.  You probably mean:

    commit 7b668c064ec33f3d687c3a413d05e355172e6c92
    Author: Serge Semin <Sergey.Semin@...kalelectronics.ru>
    Date:   Thu May 7 02:31:32 2020 +0300

    serial: 8250: Fix max baud limit in generic 8250 port

And you didn't cc the commit author (hereby fixed).

Thanks,

Lukas

> 
> The change regresses the QCA6174A-3 bluetooth chip, preventing
> firmware from being properly loaded. We have verified that without
> this patch, the chip works as intended.
> 
> Signed-off-by: Daniel Winkler <danielwinkler@...gle.com>
> ---
> 
>  drivers/tty/serial/8250/8250_port.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index 1632f7d25acca..e057c65ac1580 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -2618,8 +2618,6 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port,
>  					     struct ktermios *termios,
>  					     struct ktermios *old)
>  {
> -	unsigned int tolerance = port->uartclk / 100;
> -
>  	/*
>  	 * Ask the core to calculate the divisor for us.
>  	 * Allow 1% tolerance at the upper limit so uart clks marginally
> @@ -2628,7 +2626,7 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port,
>  	 */
>  	return uart_get_baud_rate(port, termios, old,
>  				  port->uartclk / 16 / UART_DIV_MAX,
> -				  (port->uartclk + tolerance) / 16);
> +				  port->uartclk);
>  }
>  
>  void
> -- 
> 2.27.0.212.ge8ba1cc988-goog