From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.19.201]:54282 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751663AbaEWL4a (ORCPT ); Fri, 23 May 2014 07:56:30 -0400 Date: Fri, 23 May 2014 13:56:22 +0200 From: Robert Richter To: Bjorn Helgaas Cc: Suravee Suthikulanit , Borislav Petkov , Daniel J Blueman , Andreas Herrmann , "linux-kernel@vger.kernel.org" , Aravind Gopalakrishnan , "linux-pci@vger.kernel.org" , Borislav Petkov , Myron Stowe Subject: Re: [PATCH V5 3/4] x86/PCI: Stop enabling ECS for AMD CPUs after Fam16h Message-ID: <20140523115622.GU27560@rric.localhost> References: <20140521231615.26447.38060.stgit@bhelgaas-glaptop.roam.corp.google.com> <20140521231817.26447.55150.stgit@bhelgaas-glaptop.roam.corp.google.com> <20140521233802.GA21575@pd.tnic> <20140522191746.GL4383@pd.tnic> <537E8ACF.6000103@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-pci-owner@vger.kernel.org List-ID: On 22.05.14 20:54:54, Bjorn Helgaas wrote: > I'm going to go out on a limb and guess that Windows does not enable > ECS, so it probably uses ECAM. Therefore, I suspect Linux's parsing > of MCFG is broken in some way, and we probably *could* use ECAM in all > these cases I'm seeing. Even if ECS is not enabled the system should be fine anyway, as ECS is only used to enable certain features. For family 10h this was originally the IBS EILVT (extended interrupt local vector table, needed for hw profiling) setup which need to be set by the OS which the BIOS didn't right. This should be fixed now and properly set by the BIOS on 15h+ systems. I don't remember what was added to 16h where ECS was needed, I think there was one (Suravee?). Not sure if this is essential. So using MCFG should be fine, since if in the rare case when it is broken, the system should work properly anyway without it and only some special features, if any, do not work anymore (e.g. IBS should work fine). -Robert