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Date:      Wed, 16 Aug 2023 18:14:36 -0400
From:      Dennis Clarke <dclarke@blastwave.org>
To:        freebsd-current@freebsd.org
Subject:   Re: Defaulting serial communication to 115200 bps for FreeBSD 14
Message-ID:  <22dd3552-480b-05da-76d7-dfbe2cb03110@blastwave.org>
In-Reply-To: <20230816161057.f8c6a3b4ebe9c672d920811e@dec.sakura.ne.jp>
References:  <CAPyFy2DFVp1BfwwY0czHU7XRZhOLYyF1tAr7MvbmXZ6ALSD==w@mail.gmail.com> <20230816040257.A397366@slippy.cwsent.com> <20230816161057.f8c6a3b4ebe9c672d920811e@dec.sakura.ne.jp>

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On 8/16/23 03:10, Tomoaki AOKI wrote:
> On Tue, 15 Aug 2023 21:02:57 -0700
> Cy Schubert <Cy.Schubert@cschubert.com> wrote:
> 
>> Cheers,
>> Cy Schubert <Cy.Schubert@cschubert.com>
>> FreeBSD UNIX:  <cy@FreeBSD.org>   Web:  https://FreeBSD.org
>> NTP:           <cy@nwtime.org>    Web:  https://nwtime.org
>>
>> 			e^(i*pi)+1=0
>>
>>     message dated "Tue, 15 Aug 2023 17:18:37 -0400."
>> Mime-Version: 1.0
>> Content-Type: text/plain; charset=us-ascii
>> --------
>> In message <CAPyFy2DFVp1BfwwY0czHU7XRZhOLYyF1tAr7MvbmXZ6ALSD==w@mail.gmail.c
>> om>
>> , Ed Maste writes:
>>> FreeBSD currently uses 9600 bps as the default for serial
>>> communication -- in the boot loader, kernel serial console, /etc/ttys,
>>> and so on. This was consistent with most equipment in the 90s, when
>>> these defaults were established. Today 115200 bps seems to be much
>>> more common, and I'm proposing that we make it the default for FreeBSD
>>> 14.0.
>>>
>>> I have a review open: https://reviews.freebsd.org/D36295. There are a
>>> few minor nits in the review to be addressed still but assuming
>>> there's general agreement I'll iterate on those and commit this in a
>>> few logical chunks.
>>>
>>
>> There should probably be an UPDATING entry for those who use boot0 to
>> revert back to 9600 in that case.
> 
> Not read the diff though, if the baud rate is re-initialized in boot1
> or later (including btx, loader, kernel and userland) and handshake
> again, most of the boot process and later would run at 115200 bps.
> 

The default serial communications config on most telecom equipment that
I have seen ( in the last forty years ) defaults to 9600 8n1. If people
want something faster from FreeBSD then do the trivial :

     set comconsole_speed="115200"
     set console="comconsole"

Is that not trivial enough?

Also, merely a funny observation, if one tries a baud rate lower than
9600 then FreeBSD will panic. Jut a funny thing I have seen over and
over.



--
Dennis Clarke
RISC-V/SPARC/PPC/ARM/CISC
UNIX and Linux spoken
GreyBeard and suspenders optional




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