Re: [PATCH] tty/8250_early: Prevent rounding error in uartclk tobaud ratio

From: Alan Cox
Date: Fri Sep 28 2012 - 09:01:53 EST


On Fri, 28 Sep 2012 16:19:08 +0400
Alexey Brodkin <Alexey.Brodkin@xxxxxxxxxxxx> wrote:

> Modify divisor to select the nearest baud rate divider rather than the
> lowest. It minimizes baud rate errors especially on low UART clock
> frequencies.
>
> For example, if uartclk is 33000000 and baud is 115200 the ratio is
> about 17.9 The current code selects 17 (5% error) but should select 18
> (0.5% error).
>
> On the same lines as following:
> http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.9-rc3/2.6.9-rc3-mm2/broken-out/serial-pick-nearest-baud-rate-divider.patch
>
> Signed-off-by: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>

Seems sensible to me.

Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
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