Date: Thu, 23 Nov 1995 11:03:43 +0000 () From: Michael Smith <msmith@atrad.adelaide.edu.au> To: pol@leissner.se (Peter Olsson) Cc: msmith@atrad.adelaide.edu.au, questions@freebsd.org Subject: Re: FreeBSD-boot crashes ICL-machines, anyone else had this? Message-ID: <199511231103.LAA28700@genesis.atrad.adelaide.edu.au> In-Reply-To: <9511231105.aa08203@lda.leissner.se> from "Peter Olsson" at Nov 23, 95 11:57:22 am
next in thread | previous in thread | raw e-mail | index | archive | help
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." [[
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199511231103.LAA28700>