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SubjectRe: [PATCH] tty: serial: 8250_mtk: Fix quot calculation
From
Hi Greg,

2014-10-10 10:10 GMT+02:00 Matthias Brugger <matthias.bgg@gmail.com>:
> 2014-10-09 23:52 GMT+02:00 Greg KH <gregkh@linuxfoundation.org>:
>> On Thu, Oct 09, 2014 at 06:23:31PM +0200, Matthias Brugger wrote:
>>> The calculation of value quot for highspeed register set to three
>>> was wrong. This patch fixes the calculation so that the serial port
>>> for baudrates bigger then 576000 baud is working correctly.
>>>
>>> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
>>> ---
>>> drivers/tty/serial/8250/8250_mtk.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
>>> index 1c4b4bf..4376c48 100644
>>> --- a/drivers/tty/serial/8250/8250_mtk.c
>>> +++ b/drivers/tty/serial/8250/8250_mtk.c
>>> @@ -81,7 +81,7 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
>>> /* Set to highest baudrate supported */
>>> if (baud >= 1152000)
>>> baud = 921600;
>>> - quot = DIV_ROUND_CLOSEST(port->uartclk, 256 * baud);
>>> + quot = (port->uartclk / (256 * baud)) + 1;
>>> }
>>>
>>> /*
>>
>> Has this always been incorrect, or was it caused by a specific patch?
>
> It has always been incorrect :o
>
>> Should it go to the stable kernels? If so, how far back?
>
> No need to go to the stable kernels. The driver is only in linux-next.

Any comments on that?

Thanks,
Matthias

>
> Cheers,
> Matthias Brugger
>
>>
>> thanks,
>>
>> greg k-h
>
>
>
> --
> motzblog.wordpress.com



--
motzblog.wordpress.com


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