From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Subject: RE: [PATCH 0/2] PCI/AER: Consistently use _OSC to determine who owns AER Date: Fri, 16 Nov 2018 12:37:00 +0000 Message-ID: References: <20181115231605.24352-1-mr.nuke.me@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <20181115231605.24352-1-mr.nuke.me@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: 'Alexandru Gagniuc' Cc: "austin_bolen@dell.com" , "alex_gagniuc@dellteam.com" , "keith.busch@intel.com" , "Shyam_Iyer@Dell.com" , "lukas@wunner.de" , Bjorn Helgaas , "Rafael J. Wysocki" , Len Brown , Russell Currey , Sam Bobroff , Oliver O'Halloran , "linux-pci@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" List-Id: linux-acpi@vger.kernel.org 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. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)