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Date: Wed, 8 Jan 1997 13:02:19 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199701080202.NAA13412@godzilla.zeta.org.au>
To: current@freebsd.org, nate@mt.sri.com
Subject: Re: Kernel driver advice
Sender: owner-current@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

>Is there a better/different way of registering the need for an interrupt
>and *NOT* being an ISA device?  How do the PCI devices grab an
>interrupt?

No.  The PCI devices just grab an interrupt.  They are initialized
before ISA devices, so this sort of works.  However, the ISA conflict
checking doesn't know about resources grabbed by PCI devices.  If an
ISA probe succeeds, then isa.c attempts to grab the interrupt.  If the
interrupt is already allocated, then the allocation isn't changed and
the error code is ignored, leaving the ISA driver unattached from the
interrupt.

>Finally, is there a way to request the list of used/unused IRQ's in the
>system at a point in time?  I'd like to be able to check if a particular

Attempt to allocate all IRQs and put back the ones that you get but don't
want.

Bruce