*BSD News Article 9650


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Path: sserve!manuel.anu.edu.au!munnari.oz.au!spool.mu.edu!news.nd.edu!mentor.cc.purdue.edu!noose.ecn.purdue.edu!en.ecn.purdue.edu!maraman
From: maraman@en.ecn.purdue.edu (Jason J Maraman)
Subject: Re: Still more XFree86 problems
Message-ID: <1993Jan8.084149.19688@en.ecn.purdue.edu>
Organization: Purdue University Engineering Computer Network
References: <51098@shamash.cdc.com>
Date: Fri, 8 Jan 93 08:41:49 GMT
Lines: 34

In article <51098@shamash.cdc.com> pbd@runyon.cim.cdc.com (Paul Dokas) writes:
>I'm still having problems with XFree86.  When ever I run 'startx'
>or 'xinit' or 'X386 :0' the X server starts up, puts the screen
>into graphics mode (not clear) and just hangs.
>

>BTW, my problems might be due to the com ports that I have in my system.
>Here is a section of my config file:
>
>  device          com1    at isa? port "IO_COM1" tty irq 4 vector comintr
>  device          com2    at isa? port "IO_COM2" tty irq 3 vector comintr
>  device          com3    at isa? port 0x3e8 tty irq 4 vector comintr
>  device          com4    at isa? port 0x2e8 tty irq 3 vector comintr
>
>com1 and com2 are on a multi-io board (ide, fd, 2serial, 1parallel, 1game)
>and com3 and com4 are on a serial io card.  Com3 is a 16450, and com4 is
>a 16550.  They are all found and configured correctly at boot time.  My mouse
>is on com1 and my ascii terminal is on com3.

Because of the way ISA handles interrupts, it is not possible to 
reliably share interrupts among multiple cards.  However, if all the ports 
are on the same card and the card is designed properly, then the ports can 
be shared (this assumes the device driver knows how to deal with this).

If you want to use all your com ports, there is no reason why you can't
use interrupts other than 3 and 4 by cutting the leader to the appropriate
pin and soldering a wire from there to the interrupt line you want to use.
It's really quite simple and I have it working on my machine.  If you
want more information on this then please email.  Also, if you decide
to do this and fry your board then don't blame me.

------------------------------------------------------------------------------
Jason J. Maraman    -   maraman@en.ecn.purdue.edu
Purdue University