Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756020AbZANPz7 (ORCPT ); Wed, 14 Jan 2009 10:55:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757789AbZANPze (ORCPT ); Wed, 14 Jan 2009 10:55:34 -0500 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 Date: Wed, 14 Jan 2009 16:55:29 +0100 From: Olaf Dabrunz 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 Subject: Re: PCI, ACPI, IRQ, IOAPIC: reroute PCI interrupt to legacy boot interrupt equivalent Message-ID: <20090114155529.GP25512@suse.de> Mail-Followup-To: Bjorn Helgaas , Stefan Assmann , Shaohua Li , Len Brown , Ingo Molnar , Jesse Barnes , Thomas Gleixner , Steven Rostedt , Linux Kernel Mailing List , "linux-acpi@vger.kernel.org" , Sven Dietrich 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-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <200901140848.08531.bjorn.helgaas@hp.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1405 Lines: 33 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? > > > > This would not solve the problem of asserting 2 different interrupt > > lines, in the masked interrupt handling case, for 1 interrupt request. > > 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. > > 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. > > 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, -- Olaf Dabrunz (od/odabrunz), SUSE Linux Products GmbH, Nürnberg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/