Date: Tue, 30 Nov 1999 22:18:59 +0000 (GMT) From: Doug Rabson <dfr@nlsystems.com> To: Warner Losh <imp@village.org> Cc: new-bus@freebsd.org Subject: Re: Interrupt irq activation question Message-ID: <Pine.BSF.4.10.9911290954500.324-100000@salmon.nlsystems.com> In-Reply-To: <199911290721.AAA90820@harmony.village.org>
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On Mon, 29 Nov 1999, Warner Losh wrote: > > In my pccard_nbk I turned on interrupts when the IRQ resource was > activated. In my newconfig pccard code, I'd like to do the same > thing. I notice that the NetBSD code base turns them on/off in its > intr_establish/intr_disestablish routines, which basically map to our > bus_intr_setup and bus_intr_teardown methods. It got me thinking. Do > I want to do them in the activate phase, or later in the establish > phase. > > The advantage of doing them in the activate phase is that devices like > sio that try to probe for the interrupt used can activate the > interrupt w/o registering an actual interrupt handler for the device > and somehow check to see if that interrupt is responding. > > The advantage for doing them in the setup/teardown methods is that I > suppose this violates POLA less and might result in fewer stray > interrupts. > > Any opinions on the matter? I seem to recall that Doug Rabson once > told me activate/deactivate was the architecturally pure way to do > this. I cannot find his email that told me this, so I thought I'd ask > here in an archived forum. I think that doing this in activate/deactivate was Garrett's intention. Practically, its difficult to activate the irq without a handler in all cases. For pci, its really bad to trigger an interrupt without a handler... -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-new-bus" in the body of the message
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