From owner-freebsd-current  Fri Dec  3  9:38:47 1999
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To: Mike Heffner <spock@techfour.net>
Cc: Doug Rabson <dfr@nlsystems.com>,
	FreeBSD-current <FreeBSD-current@freebsd.org>
Subject: Re: incorrect irqs with pci devices 
In-Reply-To: Message from Mike Heffner <spock@techfour.net> 
   of "Fri, 03 Dec 1999 09:55:43 EST." <XFMail.991203095543.spock@techfour.net> 
Date: Sat, 04 Dec 1999 01:37:52 +0800
From: Peter Wemm <peter@netplex.com.au>
Message-Id: <19991203173752.F0B3E1CC8@overcee.netplex.com.au>
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Mike Heffner wrote:
> 
> On 03-Dec-99 Doug Rabson said:
>   | On Fri, 3 Dec 1999, Mike Heffner wrote:
>   | 
>   |> Hi,
>   |> 
>   |> I have recently noticed that the irqs for my PCI devices are being screw
    ed
>   |> up
>   |> somehow. It is easily noticeable with dmesg, the correct one's are in
>   |> paren.:
>   | 
>   | Is this an SMP box by any chance? Does the kernel work with the irqs whic
    h
>   | it chose?
>   | 
> 
> Yes, it is a SMP box, and yes, the devices work fine. I just thought it was o
    dd
> that the kernel would report incorrect ones.

It isn't "incorrect"..  SMP motherboards have a seperate interrupt
controller (APIC - Advanced programmable interupt controller) that is used
for message passing as well as distributing interrupts per cpu. It also
generally has 24 interrupt pins, and there can be more than one APIC in a
system.  When a system boots, it's in "legacy" mode until the switch is
thrown and it's running in SMP mode.  At that time, the alternative IRQ
assignments are activated.

fxp0: <Intel EtherExpress Pro 10/100B Ethernet> irq 18 at device 6.0 on pci0
ahc0: <Adaptec aic7880 Ultra SCSI adapter> irq 17 at device 9.0 on pci0

etc.  Run the mptable(1) program to see your motherboard config.

Cheers,
-Peter



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