Date: Fri, 04 Jul 2008 06:35:40 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: xcllnt@mac.com Cc: arch@freebsd.org, sam@freebsd.org, freebsd-current@freebsd.org, ed@80386.nl Subject: Re: MPSAFE TTY schedule [uart vs sio] Message-ID: <20080704.063540.1210476607.imp@bsdimp.com> In-Reply-To: <993E865A-A426-4036-9E09-A87D7474DE80@mac.com> References: <20080703205220.GW14567@hoeg.nl> <486D4006.2050303@freebsd.org> <993E865A-A426-4036-9E09-A87D7474DE80@mac.com>
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In message: <993E865A-A426-4036-9E09-A87D7474DE80@mac.com>
Marcel Moolenaar <xcllnt@mac.com> writes:
:
: On Jul 3, 2008, at 2:09 PM, Sam Leffler wrote:
:
: >> But I just got told sio(4) is required for pc98, because uart(4) is
: >> not
: >> supported there. This means I'll seriously consider porting sio(4)
: >> one
: >> of these days. It's no biggie, even though I think someone could
: >> better
: >> take the effort to extend uart(4).
: >>
: >
: > I would suggest first investigating how difficult it is to port uart
: > to pc98. Given that we're broadening our platform support having a
: > single serial driver seems preferable.
:
: I looked into it in 2003 but since I don't have any hardware,
: I wasn't the one able to do it. I think the fundamental problem
: is that the BRG is not part of the UART itself and needs a
: separate handle or even (tag, handle) pair to access. That's as
: far as I know the only big thing about the work.
:
: For me not having access to the hardware is a showstopper for
: looking into it myself.
Do you need physical access? I have a pc98 machine I can put back on
the network. It has the 8251 chip in it. It also has a 16550 part as
well since it is a later model which had both...
I believe that uart works for the 16550 part, but haven't tried it
lately...
Warner
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