From mboxrd@z Thu Jan 1 00:00:00 1970 From: jcm@redhat.com (Jon Masters) Date: Thu, 1 Dec 2016 23:58:52 -0500 Subject: [PATCHv2] PCI: QDF2432 32 bit config space accessors In-Reply-To: <20161103140058.GA31142@bhelgaas-glaptop.roam.corp.google.com> 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> Message-ID: <3a386ce0-33df-fb88-33df-88b9ca8816c7@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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