From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754803AbbI3Wwr (ORCPT ); Wed, 30 Sep 2015 18:52:47 -0400 Received: from mga01.intel.com ([192.55.52.88]:55847 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753580AbbI3Wwp (ORCPT ); Wed, 30 Sep 2015 18:52:45 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,614,1437462000"; d="scan'208";a="571671907" Date: Wed, 30 Sep 2015 15:50:11 -0700 From: "Sean O. Stalley" To: David Daney Cc: David Daney , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Bjorn Helgaas , "Michael S. Tsirkin" , =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , linux-api@vger.kernel.org, yinghai@kernel.org, rajatxjain@gmail.com, gong.chen@linux.intel.com, David Daney Subject: Re: [PATCH v3 2/2] PCI: Add support for Enhanced Allocation devices Message-ID: <20150930225011.GA4244@sean.stalley.intel.com> References: <1443485439-12081-1-git-send-email-ddaney.cavm@gmail.com> <1443485439-12081-3-git-send-email-ddaney.cavm@gmail.com> <20150929192737.GA2517@sean.stalley.intel.com> <560AF3D7.80908@gmail.com> <20150929224727.GB2517@sean.stalley.intel.com> <560B2470.9080100@caviumnetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <560B2470.9080100@caviumnetworks.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 29, 2015 at 04:53:20PM -0700, David Daney wrote: > On 09/29/2015 03:47 PM, Sean O. Stalley wrote: > [...] > >>>>diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > >>>>index 6a9a111..7c60b16 100644 > >>>>--- a/drivers/pci/pci.c > >>>>+++ b/drivers/pci/pci.c > >>>>@@ -2148,6 +2148,284 @@ void pci_pm_init(struct pci_dev *dev) > >>>> } > >>>> } > >>>> > >>>>+static unsigned long pci_ea_set_flags(struct pci_dev *dev, u8 prop) > >>>>+{ > >>>>+ unsigned long flags = IORESOURCE_PCI_FIXED | IORESOURCE_SIZEALIGN; > >>> > >>>Why did you add the IORESOURCE_SIZEALIGN flag? EA allows for unaligned resources. > >> > >>pci_bus_assign_resources() fails causing the devices to be unusable > >>if resource_alignment() returns zero. The easiest fix for this was > >>to specify IORESOURCE_SIZEALIGN. > >> > >>An alternative would be to change the code in setup-bus.c so that > >>for IORESOURCE_PCI_FIXED resources, it didn't barf. > > > >I would do this alternative, but with a IORESOURCE_PCI_EA flag. > > > > I don't think we need IORESOURCE_PCI_EA. If a resource is tagged as > IORESOURCE_PCI_FIXED that means that it cannot be changed, we > shouldn't care why it is fixed (due to an EA capability for > example). We just need to gracefully handle IORESOURCE_PCI_FIXED in > the places where things currently go wrong. > > David Daney > I agree that we need to make sure fixed things stay fixed, regardless of if they are fixed by EA or something else. The question is: do we want to allow all fixed resources to be non-aligned, or just EA? -Sean