[PATCH 3/3] serial: pl011: allow very high baudrates

Linus Walleij linus.walleij at linaro.org
Tue Sep 25 14:48:22 EDT 2012


On Fri, Sep 21, 2012 at 9:56 PM, Alan Cox <alan at lxorguk.ukuu.org.uk> wrote:
> On Fri, 21 Sep 2012 19:52:04 +0200
> Linus Walleij <linus.walleij at linaro.org> wrote:

>> it's the call to
>> tty_termios_encode_baud_rate() that is the problem, not how it
>> gets called. It's that function that fuzzes and "snaps" the baudrate
>> to some rough-fit speed and screws things up for me.
>
> (...)
> The intended behaviour at tty layer is
>
> Caller passes BOTHER and actual bit rate - we return BOTHER and a bit
> rate
>
> Caller does not pass BOTHER (may not be TCGETS2 aware) we snap to the
> nearest Bfoo rate if within 5% otherwise we return BOTHER based rates.

OK sorry for getting this backwards, so I was under the impression that
BOTHER was an internal detail of the TTY layer, not to be or:ed on
and passed in from the outside.

Then everything makes perfect sense, I'll try to patch the caller
instead for this "bug" and see what happens. Probably it JustWorks...

Thanks a lot Alan!
Linus Walleij



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