Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!sco!dionj
From: dionj@sco.COM (Dion L. Johnson)
Newsgroups: comp.unix.i386
Subject: IRQ conflict on SCO Open Desktop
Message-ID: <6119@scorn.sco.COM>
Date: 25 May 90 21:31:27 GMT
Sender: news@sco.COM
Reply-To: wul@sco.com
Organization: The Santa Cruz Operation, Inc.
Lines: 93
In-Reply-To: <97@bohra.cpg.oz>


/--He said...
| I have been installing SCO's Open Desktop Rel 1.0 and am having problems with 
| the device drivers. The machine is a standard 386 AT (Samsung). The devices 
| are a 3com 503 Ethernet board and an Archive VP402 controller for a QIC02 tape
| drive.
| 
| I can get either one of them working fine on IRQ 5. Obviously I want both of
| them at the same time. If I put the Ethernet board on IRQ 2 as recommended it
| does not work. Similarly for the tape controller.
\--

You can't have two different cards jumpered for the same IRQ level, or
you'll get interrupt conflicts.  I don't understand why your 3c503 doesn't
work at IRQ2; we have several 3c503s in use internally and they all work
fine.  Have you tried the diagnostics on the disk that came with the card?

/--
| The mkdev installation script for the Ethernet board sets the kernel's 
| interrupt vector to 9 when I ask for an IRQ of 2. This is consistent with a
| board's IRQ2 line being tied to IRQ9 on the AT bus. HOWEVER the kernel's 
| startup messages report that the Ethernet board's vector is 11 (hwconfig 
| says the same).
\--

This is ok.  The IRQ levels printed out at boot time, and by hwconfig,
is in octal.

/--
| I can install the tape controller on IRQ2, set the kernel's interrupt vector
| to 9 and the tape drive is accessed when the kernel is booted (a Reset
| operation I think). But the tape won't work when accessed as /dev/?ct0.
\--

I haven't tried setting a tape controller to use IRQ2; all of the tape
drives I've configured have been set for IRQ5, or in one case, IRQ7.
I'll have to give this a try sometime...

/--
| I could try setting one of the boards to IRQ4 but this clashes with one of the
| serial devices which I can't disable. Setting N in the sdevice/sio entry as
| recommended does not seem to remove it from the kernel. The 2 devices on IRQ3,
| 4 seem to be hard wired into the kernel.
\--

Yes, the kernel by default enables the sio drivers for both COM1 and
COM2.  You can turn them off, as you know, by editing the sdevice.d/sio
file and changing the Y's to N's.  By the way, IRQ4 is used for COM1
(tty1a), not COM2 (tty2a).

In your case, I would guess the reason you're not able to use IRQ4
because you have a COM1 serial port, either on a card or built into
the motherboard.  This would result in an interrupt conflict, which
PC-class machines don't deal with gracefully.  You may want to try
IRQ3 if you don't have a COM2 serial port, or, if you don't have use
for serial ports, try disabling them altogether.  If you have one of
those generic serial/parallel port cards, you should be able to set
the jumpers and/or switches on the card to do so.

/--
| Neither the tape controller nor (I think) the Ethernet controller can have an
| IRQ greater than 7.
| 
| In summary:
| 
| Is IRQ2 usable with SCO Unix? 
\--

Yes.  The standard configuration for network cards used internally
with TCP/IP (3c501s, 3c503s, WD8003s) is IRQ2.

/--
| Is the kernel and hwconfig report of a vector of 11 when I ask for 9 just a 
| reporting bug or is the vector really wrong inside where it counts?
\--

See above.

/-- 
| How can I use IRQ3 or IRQ4?
\--

By disabling the sio drivers in /etc/conf/sdevice.d/sio, and making sure
that there aren't any serial ports installed in your machine that are set
to use these IRQs.

Hope this helps.

-- 
Wu Liu -- Member, Technical Staff       The Santa Cruz Operation, Inc.
UUCP:      ...!uunet!sco!wul            400 Encinal St.
        or ...!ucbvax!ucscc!sco!wul     Santa Cruz, CA  95061
Internet:  wul@sco.COM