From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:42291 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753204AbcA2XZl (ORCPT ); Fri, 29 Jan 2016 18:25:41 -0500 Date: Fri, 29 Jan 2016 17:25:38 -0600 From: Bjorn Helgaas To: Lorenzo Pieralisi Cc: Sinan Kaya , linux-pci@vger.kernel.org, Zhou Wang , Phil Edworthy , Bjorn Helgaas Subject: Re: [RFC] ARM/ARM64 PCI_PROBE_ONLY platforms Message-ID: <20160129232538.GH12965@localhost> References: <20160120160427.GD13437@red-moon> <569FB210.9090605@codeaurora.org> <20160120181003.GF13437@red-moon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160120181003.GF13437@red-moon> Sender: linux-pci-owner@vger.kernel.org List-ID: On Wed, Jan 20, 2016 at 06:10:03PM +0000, Lorenzo Pieralisi wrote: > To do that, we must claim resources on PCI_PROBE_ONLY systems, but > I know for certain Bjorn does not like the idea (I let you trawl > the archives - at least he does not accept the idea of claiming > resources ONLY on PCI_PROBE_ONLY systems, he thinks we should > always claim resources regardless of that flag and fall-back to > reassigning them in case claiming fails. That's perfectly reasonable, > at least on systems with FW initializing PCI). The problem is dealing > with legacy, so switching to resources claiming by default is a tad > complicated, at least for testing (code is easy to implement). I'd like to think of PCI_PROBE_ONLY basically as "setting IORESOURCE_PCI_FIXED for every BAR", i.e., we can do everything we normally do *except* write to the BAR (of course we have to write to it to size the BAR during enumeration, but we have to restore the original value). I don't think PCI_PROBE_ONLY should have anything to do with the iomem_resource and ioport_resource trees. /proc/iomem and /proc/ioports should still contain every resource we know about, regardless of whether PCI_PROBE_ONLY is set or not. Bjorn