From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932608AbcASH5a (ORCPT ); Tue, 19 Jan 2016 02:57:30 -0500 Received: from mail-lb0-f171.google.com ([209.85.217.171]:32924 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757285AbcASH5Y (ORCPT ); Tue, 19 Jan 2016 02:57:24 -0500 Subject: Re: [PATCH V3 20/21] pci, acpi: Match PCI config space accessors against platfrom specific quirks. To: "liudongdong (C)" , Mark Salter , bhelgaas@google.com, arnd@arndb.de, will.deacon@arm.com, catalin.marinas@arm.com, rjw@rjwysocki.net, hanjun.guo@linaro.org, Lorenzo.Pieralisi@arm.com, okaya@codeaurora.org, jiang.liu@linux.intel.com, Stefano.Stabellini@eu.citrix.com References: <1452691267-32240-1-git-send-email-tn@semihalf.com> <1452691267-32240-21-git-send-email-tn@semihalf.com> <1452785776.28109.22.camel@redhat.com> <569CDD8F.807@semihalf.com> <569D9634.3040304@huawei.com> Cc: robert.richter@caviumnetworks.com, mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com, tglx@linutronix.de, wangyijing@huawei.com, Suravee.Suthikulpanit@amd.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, jchandra@broadcom.com, jcm@redhat.com, Zhou Wang , Gabriele Paoloni From: Tomasz Nowicki Message-ID: <569DEBE9.5090909@semihalf.com> Date: Tue, 19 Jan 2016 08:55:21 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <569D9634.3040304@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19.01.2016 02:49, liudongdong (C) wrote: > Hi Tomasz, Mark > > 在 2016/1/18 20:41, Tomasz Nowicki 写道: >> On 14.01.2016 16:36, Mark Salter wrote: >>>> +extern struct pci_mcfg_fixup __start_acpi_mcfg_fixups[]; >>>> >+extern struct pci_mcfg_fixup __end_acpi_mcfg_fixups[]; >>>> >+ >>>> >+static struct pci_ops *pci_mcfg_check_quirks(struct acpi_pci_root >>>> *root) >>>> >+{ >>>> >+ struct pci_mcfg_fixup *f; >>>> >+ int bus_num = root->secondary.start; >>>> >+ int domain = root->segment; >>>> >+ >>>> >+ /* >>>> >+ * First match against PCI topology then use DMI or >>>> >+ * custom match handler. >>>> >+ */ >>>> >+ for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups; >>>> f++) { >>>> >+ if ((f->domain == domain || f->domain == >>>> PCI_MCFG_DOMAIN_ANY) && >>>> >+ (f->bus_num == bus_num || f->bus_num == >>>> PCI_MCFG_BUS_ANY) && >>>> >+ (f->system ? dmi_check_system(f->system) : 0 || >>>> >+ f->match ? f->match(f, root) : 0)) >>>> >+ return f->ops; >>> I think this would be better as: >>> >>> (f->system ? dmi_check_system(f->system) : 1 && >>> f->match ? f->match(f, root) : 1)) >>> return f->ops; >>> >>> Otherwise, one has to call dmi_check_system() from f->match() if >>> access to root is needed. >> > > Non-DMI, we need not to call dmi_check_system() from f->match(), > we can use _HID to decide to hook the pci_ops or not. Sorry, but I dont understand your point. Can you elaborate? With Mark modification, you can use the following cases to identify platform: 1. DMI only 2. f->match() only (_HID can be used there) 3. DMI and f->match() DMI used to be very convenient way to recognise platform, sometimes it is not enough, hence f->match() alternative. Tomasz