From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 279D6C43441 for ; Fri, 16 Nov 2018 12:40:16 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7CA3C2087C for ; Fri, 16 Nov 2018 12:40:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7CA3C2087C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 42xHrC2HrXzF3hQ for ; Fri, 16 Nov 2018 23:40:11 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ACULAB.COM Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=aculab.com (client-ip=207.82.80.151; helo=eu-smtp-delivery-151.mimecast.com; envelope-from=david.laight@aculab.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ACULAB.COM Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [207.82.80.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42xHmY3DS8zF3mq for ; Fri, 16 Nov 2018 23:36:59 +1100 (AEDT) Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-110-sHBmeO1DNEmY3fg_B1RTqw-1; Fri, 16 Nov 2018 12:36:54 +0000 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b::d117) by AcuMS.aculab.com (fd9f:af1c:a25b::d117) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 16 Nov 2018 12:37:00 +0000 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Fri, 16 Nov 2018 12:37:00 +0000 From: David Laight To: 'Alexandru Gagniuc' , "helgaas@google.com" Subject: RE: [PATCH 0/2] PCI/AER: Consistently use _OSC to determine who owns AER Thread-Topic: [PATCH 0/2] PCI/AER: Consistently use _OSC to determine who owns AER Thread-Index: AQHUfTk7lFmreXBXOEO6S+wDoXDgXaVSVjAw Date: Fri, 16 Nov 2018 12:37:00 +0000 Message-ID: References: <20181115231605.24352-1-mr.nuke.me@gmail.com> In-Reply-To: <20181115231605.24352-1-mr.nuke.me@gmail.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-MC-Unique: sHBmeO1DNEmY3fg_B1RTqw-1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "alex_gagniuc@dellteam.com" , Sam Bobroff , "linux-pci@vger.kernel.org" , "Shyam_Iyer@Dell.com" , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , "keith.busch@intel.com" , "linux-acpi@vger.kernel.org" , "lukas@wunner.de" , Oliver O'Halloran , Bjorn Helgaas , "austin_bolen@dell.com" , "linuxppc-dev@lists.ozlabs.org" , Len Brown Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Alexandru Gagniuc > Sent: 15 November 2018 23:16 ... > I've asked around a few people at Dell and they unanimously agree that > _OSC is the correct way to determine ownership of AER. This is all very well, but we have systems (they might be Dell ones) where failure of a PCIe link (even when all the drivers are removed) causes an NMI - and crashes the kernel. There are other systems which have AER registers available for some of the PCIe devices, but the BIOS ignores them and _OSC doesn't let the kernel take control. In this case the AER registers can contain useful information after a read returns ~0u. It would be useful to be able to get this information without having to grovel through all the PCIe config space. =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)