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Message-ID: <fdabd92b-1e5f-e66a-a8ec-0f763b74de99@codeaurora.org>
Date: Thu, 3 Nov 2016 13:06:28 -0400
From: Sinan Kaya <okaya@...eaurora.org>
To: Bjorn Helgaas <helgaas@...nel.org>
Cc: cov@...eaurora.org, Tomasz Nowicki <tn@...ihalf.com>,
will.deacon@....com, catalin.marinas@....com, rafael@...nel.org,
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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, jcm@...hat.com,
andrea.gallo@...aro.org, jeremy.linton@....com,
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jhugo@...eaurora.org, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2] PCI: QDF2432 32 bit config space accessors
On 11/3/2016 12:58 PM, Sinan Kaya wrote:
>> > This is the crucial point I have failed to communicate clearly: the
>> > PNP0C02 resource is *always* required, even if the MCFG is correct.
>> >
> Interesting...
>
> It looks like there is a lot of lessons learnt here from history.
>
> I think this requirement is only true if your system DDR space and PCIe
> space overlaps in the memory map. I understand that Intel systems allow
> sharing of these two memory ranges. An OS could potentially reclaim this
> address range.
>
> If there is no overlap and PCI is not enabled, there can't be any SW entity
> to reclaim this space.
>
> Did I miss something?
>
For protection, it makes sense to reserve this range. I'm trying to understand
who would claim this range.
--
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
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