From owner-freebsd-questions Thu Nov 23 03:06:29 1995 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id DAA02460 for questions-outgoing; Thu, 23 Nov 1995 03:06:29 -0800 Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id DAA02453 for ; Thu, 23 Nov 1995 03:06:11 -0800 Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.12/8.6.9) id LAA28700; Thu, 23 Nov 1995 11:03:44 GMT From: Michael Smith Message-Id: <199511231103.LAA28700@genesis.atrad.adelaide.edu.au> Subject: Re: FreeBSD-boot crashes ICL-machines, anyone else had this? To: pol@leissner.se (Peter Olsson) Date: Thu, 23 Nov 1995 11:03:43 +0000 () Cc: msmith@atrad.adelaide.edu.au, questions@freebsd.org In-Reply-To: <9511231105.aa08203@lda.leissner.se> from "Peter Olsson" at Nov 23, 95 11:57:22 am MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 1866 Sender: owner-questions@freebsd.org Precedence: bulk Peter Olsson stands accused of saying: > >The problem is that a number of video cards (many S3-based, for starters) > >occupy the same port addresses as the fourth serial port. In order to > >successfully probe the second serial port in a four port system, it is > >necessary to write to the fourth port, which can upset some video adapters, > >possibly causing the system to crash. > > I tried disabling several combinations of serial ports, but it didn't help. > Immediately after I go out of config-mode, the screen goes all black and the > computer hangs completely. > > The only combination that works is to disable all four serial ports. I should have explained it better : if _any_ serial ports are enabled, all four possible "COMx" locateions are written to. This is _arguably_ the wrong thing to do, but many many serial cards share interrupts incorrectly. If you want to build a kernel that doesn't do this, change this line in /sys/i386/isa/sio.c : static Port_t likely_com_ports[] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8, }; If your machine only has two serial ports, remove the last two entries : static Port_t likely_com_ports[] = { 0x3f8, 0x2f8, }; And rebuild your kernel (see the FAQ for details on that). This _should_ solve your problem. Incidentally, if you have a Mach64, it's possible that the computer hasn't hung completely, the '64 is just confused, and everything is black. Same result though 8) > Peter Olsson Email: pol@leissner.se -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 041-122-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] "Who does BSD?" "We do Chucky, we do." [[