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To: freebsd-hackers@freebsd.org
Subject: ISA device irq/mem auto-configuration
Date: Wed, 21 Feb 1996 12:48:53 +0530
From: A JOSEPH KOSHY <koshy@india.hp.com>
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This is a basic question about how we handle boards whose IRQ, I/O and
memory ranges can be autodetected at boot time.  

Consider a network card : If the kernel has been configured for say, 
IRQ 5 but the actual board was detected at IRQ 11, whats the right thing to 
do? We could :

(a) Ignore the board : this can be pretty frustrating to the user.

(b) Print out some informative message : stating something like 
    "board setup for IRQ XX but kernel was configured for YY" and leave
    it at that.  

(c) Take in the new IRQ setting somehow and do the right thing.

Option (C) seems to me to be the right thing from the users point of
view; I don't know enough of the FreeBSD kernel to tell if it is feasible.

I have seen in some places "-1" being used as a kind of "wildcard" address
in some drivers.  Is this a convention?

Can anyone point me to further reading?   Have I missed something?

Koshy