From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Subject: Re: [PATCHv2] PCI: QDF2432 32 bit config space accessors To: Bjorn Helgaas , Sinan Kaya References: <20160921173129.GA20006@localhost> <20160921223805.21652-1-cov@codeaurora.org> <20161031214833.GB14603@bhelgaas-glaptop.roam.corp.google.com> <20161102160820.GA6568@bhelgaas-glaptop.roam.corp.google.com> <3fd26a0d-a5c2-c385-866e-b957dffb7dda@codeaurora.org> <20161103140058.GA31142@bhelgaas-glaptop.roam.corp.google.com> Cc: cov@codeaurora.org, Tomasz Nowicki , will.deacon@arm.com, catalin.marinas@arm.com, rafael@kernel.org, Lorenzo.Pieralisi@arm.com, arnd@arndb.de, hanjun.guo@linaro.org, jchandra@broadcom.com, dhdang@apm.com, ard.biesheuvel@linaro.org, robert.richter@caviumnetworks.com, mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com, wangyijing@huawei.com, msalter@redhat.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-acpi@lists.linaro.org, andrea.gallo@linaro.org, jeremy.linton@arm.com, liudongdong3@huawei.com, gabriele.paoloni@huawei.com, jhugo@codeaurora.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org From: Jon Masters Message-ID: <3a386ce0-33df-fb88-33df-88b9ca8816c7@redhat.com> Date: Thu, 1 Dec 2016 23:58:52 -0500 MIME-Version: 1.0 In-Reply-To: <20161103140058.GA31142@bhelgaas-glaptop.roam.corp.google.com> Content-Type: text/plain; charset=windows-1252 List-ID: On 11/03/2016 10:00 AM, Bjorn Helgaas wrote: > It turns out that we can't use the _CRS of host bridges because of the > Producer/Consumer bit screwup [1]. So the fallback is to include the > ECAM space in the _CRS of a PNP0C02 device. This is what the PCI > Firmware spec r3.0, Table 4-2, footnote 2 is talking about. > > Bjorn > > [1] The original ACPI spec intent was that Consumer resources would be > space like ECAM that is consumed directly by the bridge, and Producer > resources would be the windows forwarded down to PCI. But BIOSes > didn't use the Producer/Consumer bit consistently, so we have to > assume that all resources in host bridge _CRS are windows, which > leaves us no way to describe the Consumer resources. Aside - and now I realize you'd called this out as recently as last month. Alas the HPE m400 I reference on the other thread about the APM quirks doesn't have the motherboard resource entry so we're stuck with exactly the situation you describe above there. Jon. -- Computer Architect | Sent from my Fedora powered laptop