Re: Interrupts not being raised.

Stephen Williams (steve@icarus.com)
Fri, 12 Feb 1999 08:38:06 -0800


mlord@pobox.com said:
> Perhaps the BIOS has not set up the motherboard interrupt steering
> for this card. If you have a BIOS "non PnP operating system" option
> in the BIOS setup, try toggling it.

David.Woodhouse@mvhi.com said:
> It was on. Now it's off. It doesn't appear to make any difference.

Careful. Turning "PnP O/S" on will cause some bioses to turn of all the
BARS and IRQ lines for PCI devices off. I think the Phoenix BIOS works
this way. Caused me no end of trouble under *NT*.

Neither NT nor Linux are PnP systems, and the BIOS should be configured
accordingly. (Although I think that as of 2.2.x, Linux can be coaxed
into doing all the PCI mapping itself.)

As for the original poster's lack of interrupts, I would check the INTA#
line at the PCI card. If the card is generating an IRQ and the driver is
not being called, the machine will hang in an interrupt loop. If the
signal is active but the O/S is not hung, the motherboard is preventing the
delivery of the interrupt.

Try shuffling boards. I've seen this mysteriously work under both Linux
and NT.

-- 
Steve Williams                "The woods are lovely, dark and deep.
steve@icarus.com              But I have promises to keep,
steve@picturel.com            and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."

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