From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Dabrunz Subject: Re: PCI, ACPI, IRQ, IOAPIC: reroute PCI interrupt to legacy boot interrupt equivalent Date: Wed, 14 Jan 2009 16:55:29 +0100 Message-ID: <20090114155529.GP25512@suse.de> References: <20090113082513.GA18449@sli10-desk.sh.intel.com> <496DB702.40302@suse.de> <200901140848.08531.bjorn.helgaas@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:59406 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755378AbZANPzc (ORCPT ); Wed, 14 Jan 2009 10:55:32 -0500 Content-Disposition: inline In-Reply-To: <200901140848.08531.bjorn.helgaas@hp.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Bjorn Helgaas Cc: Stefan Assmann , Shaohua Li , Len Brown , Ingo Molnar , Jesse Barnes , Olaf Dabrunz , Thomas Gleixner , Steven Rostedt , Linux Kernel Mailing List , "linux-acpi@vger.kernel.org" , Sven Dietrich On 14-Jan-09, Bjorn Helgaas wrote: > On Wednesday 14 January 2009 02:57:22 am Stefan Assmann wrote: > > Shaohua Li wrote: > > > So a device can generate interrupt from two irqs. And we can get = the irq > > > number for the routing table. Can we extend the irq mechanism and > > > automatically register the interrupt handler for the two irqs? > >=20 > > This would not solve the problem of asserting 2 different interrupt > > lines, in the masked interrupt handling case, for 1 interrupt reque= st. > > The result would be that the ISR is called twice and at the second = call > > you can't be sure that the device hasn't already been serviced. >=20 > Calling the ISR twice isn't a problem, is it? We're talking about > PCI interrupts, which are shareable, so ISRs have to handle being > called extra times. >=20 > There's still the problem that the core will disable an IRQ if we > take it too many times without any ISR that cares about it. But that= 's > a core issue, not an ISR issue. It is not solvable in the core. How do you find out that the "nobody cared" spurious IRQ is benign? Regards, --=20 Olaf Dabrunz (od/odabrunz), SUSE Linux Products GmbH, N=C3=BCrnberg -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html