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Message-ID: <3a386ce0-33df-fb88-33df-88b9ca8816c7@redhat.com>
Date: Thu, 1 Dec 2016 23:58:52 -0500
From: Jon Masters <jcm@...hat.com>
To: Bjorn Helgaas <helgaas@...nel.org>,
Sinan Kaya <okaya@...eaurora.org>
Cc: cov@...eaurora.org, Tomasz Nowicki <tn@...ihalf.com>,
will.deacon@....com, catalin.marinas@....com, rafael@...nel.org,
Lorenzo.Pieralisi@....com, arnd@...db.de, hanjun.guo@...aro.org,
jchandra@...adcom.com, dhdang@....com, ard.biesheuvel@...aro.org,
robert.richter@...iumnetworks.com, mw@...ihalf.com,
Liviu.Dudau@....com, ddaney@...iumnetworks.com,
wangyijing@...wei.com, msalter@...hat.com,
linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linaro-acpi@...ts.linaro.org, andrea.gallo@...aro.org,
jeremy.linton@....com, liudongdong3@...wei.com,
gabriele.paoloni@...wei.com, jhugo@...eaurora.org,
linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2] PCI: QDF2432 32 bit config space accessors
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
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