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Date: Mon, 3 Mar 1997 05:10:33 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199703021810.FAA27377@godzilla.zeta.org.au>
To: ejs@bfd.com, freebsd-hackers@FreeBSD.ORG
Subject: Re: sio projects
Sender: owner-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
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>Before I embark on my first FreeBSD kernel hacking project, does anyone
>know if someone is already working on 16650/16750 UART support?  My plans
>are for the following
>
>1) Autodetect the UARTS, and use their deeper fifos.

There is already some support for this (for 16550s) in sio.c.  It is
disabled because it doesn't quite work.  I think auto-detection works.

>3) Throw in a flag to use the UART-driven hardware flow control methods.

The hardware flow control on at least the original 16550's is reported
to be worse that useless because it is invoked at the wrong time - at
the same time that a fifo-trigger-level-reached interrupt is generated
or something like that - it breaks streaming.

Bruce