Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751965AbbHTJP5 (ORCPT ); Thu, 20 Aug 2015 05:15:57 -0400 Received: from www.linutronix.de ([62.245.132.108]:35675 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751544AbbHTJPy (ORCPT ); Thu, 20 Aug 2015 05:15:54 -0400 Date: Thu, 20 Aug 2015 11:15:18 +0200 (CEST) From: Thomas Gleixner To: Jiang Liu cc: "Rafael J. Wysocki" , "Rafael J . Wysocki" , Nick Meier , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, ACPI Devel Maling List , Linux Kernel Mailing List , "linux-pm@vger.kernel.org" Subject: Re: [Patch v2] x86, ACPI, irq: Add a quirk to override SCI polarity for HyperV In-Reply-To: <55D57160.40108@linux.intel.com> Message-ID: References: <1439963634-12006-1-git-send-email-jiang.liu@linux.intel.com> <55D42185.1000709@linux.intel.com> <55D427D3.7040103@linux.intel.com> <55D57160.40108@linux.intel.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2250 Lines: 54 On Thu, 20 Aug 2015, Jiang Liu wrote: > On 2015/8/19 16:40, Thomas Gleixner wrote: > > On Wed, 19 Aug 2015, Thomas Gleixner wrote: > >> On Wed, 19 Aug 2015, Jiang Liu wrote: > >>> On 2015/8/19 14:45, Rafael J. Wysocki wrote: > >>>> Well, the regression at hand has just shown that the assertion in the > >>>> changelog of that commit ("no need for for special treatment for GSI > >>>> used by ACPI SCI") does not really hold. So, if the only motivation > >>>> for it was to get rid of one extra check in mp_unregister_gsi() > >>>> (mp_register_gsi() still needs to check if it is dealing with the SCI > >>>> anyway), I'd vote for reverting it. > >>> Hi Rafael, > >>> The motivation is to treat SCI as normal IOAPIC interrupt so > >>> we could enforce stricter pin attribute checking. Now it does reveal > >>> flaws in ACPI BIOS implementations, but we ran into trouble about how to > >>> handle those flaws:( > >> > >> The intent of this change is entirely correct, though it seems that > >> reality of ACPI is just different. > >> > >> To be on the safe side of things, I agree with Rafael that we should > >> revert that patch instead of introducing a single platform quirk. > > > > Jiang, > > > > can you please prepare a revert patch for this? > Hi Rafael and Thomas, > I have tried to revert commit cd68f6bd53cf, but found > it's not an easy task now. That's what I feared > When converting to hierarchical irqdomain, the IOAPIC > internal and interfaces have changed much, and seems no easy > way to revert cd68f6bd53cf. There may be three possible solutions > here: > 1) use quirk to correct SCI polarity, as the patch does. > 2) change IOAPIC interfaces to provide a special way to > handle SCI interrupt. > 3) change drivers/acpi/pci_link.c to penalize SCI IRQ so it > won't be used for PCI IRQ if SCI polarity conflicts with > PCI IRQ polarity. Stupid question. Is the SCI polarity ever the opposite of PCI polarity? I.e. is such a ACPI override valid at all? Thanks, tglx -- 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/