From owner-freebsd-hackers Wed Aug 14 05:30:22 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id FAA26606 for hackers-outgoing; Wed, 14 Aug 1996 05:30:22 -0700 (PDT) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id FAA26600; Wed, 14 Aug 1996 05:30:19 -0700 (PDT) Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.12/8.6.9) id WAA02817; Wed, 14 Aug 1996 22:17:43 +0930 From: Michael Smith Message-Id: <199608141247.WAA02817@genesis.atrad.adelaide.edu.au> Subject: Re: Recap of sio weirdness, where to go from here... To: ponds!rivers@dg-rtp.dg.com (Thomas David Rivers) Date: Wed, 14 Aug 1996 22:17:42 +0930 (CST) Cc: freebsd-hackers@freefall.freebsd.org, lakes!rivers@freefall.freebsd.org In-Reply-To: <199608141146.HAA04041@lakes> from "Thomas David Rivers" at Aug 14, 96 07:46:55 am MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Thomas David Rivers stands accused of saying: > > Mike Smith has made several good points - notably that most "modern" > 16550s, are, in fact, not 16550s - but some clone chip. That could > be the situation in my P75 laptop (actually, kinda likely since it > is a laptop...) However, the 386 and 486 I have which demonstrate > the problem have *actual* 16550s in them. I know because I replaced > the 8250s in the serial cards myself... Unless these parts are marked "PC16550DN" they are _not_ *actual* 16550's. They may be a clone produced by another manufacturer, but as has also been discussed here at great length (Where's Frank D. these days?), this is _no_ guarantee that the part doesn't do something funny. Have you tried using 'lptest' and a loopback cable to ascertain whether these FIFO overflows are real or imaginary? > [My point being that while it's certainly possible I have faulty hardware > on one machine; the likelyhood of that decreases when you consider that > I can reproduce this symptom on two other, disparit, machines...] If you installed the same part in these machines, then the problem may well still be hardware-related. Please note that I am not trying to suggest that the fix to your solution cannot possibly lie with a change to the sio driver, merely that there are a plethora of systems out there using the sio driver that do _not_ exhibit the problem that you are seeing. > - Dave Rivers - -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[