Hi Jon, thanks for replying

-----Original Message-----
From: Jon Masters [mailto:jcm at redhat.com]
Sent: 21 December 2015 23:11
To: Arnd Bergmann
Cc: Gabriele Paoloni; Tomasz Nowicki; bhelgaas at google.com;
will.deacon at arm.com; catalin.marinas at arm.com; rjw at rjwysocki.net;
hanjun.guo at linaro.org; Lorenzo.Pieralisi at arm.com; okaya at codeaurora.org;
jiang.liu at linux.intel.com; Stefano.Stabellini at eu.citrix.com;
robert.richter at caviumnetworks.com; mw at semihalf.com; Liviu.Dudau at arm.com;
ddaney at caviumnetworks.com; tglx at linutronix.de; Wangyijing;
Suravee.Suthikulpanit at amd.com; msalter at redhat.com; linux-
pci at vger.kernel.org; linux-arm-kernel at lists.infradead.org; linux-
acpi at vger.kernel.org; linux-kernel at vger.kernel.org; linaro-
acpi at lists.linaro.org; jchandra at broadcom.com
Subject: Re: [PATCH V2 22/23] pci, acpi: Match PCI config space
accessors against platfrom specific quirks.

Sorry for top-posting. A quick note that SMBIOS3 is required by SBBR so
it can be presumed that compliant platforms will provide quirks via DMI.

Ok so you completely clarified my question 1). Many Thanks for this

Gab

--
Computer Architect | Sent from my 64-bit #ARM Powered phone

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On Dec 21, 2015, at 09:11, Arnd Bergmann [off-list ref] wrote:

On Monday 21 December 2015, Gabriele Paoloni wrote:

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-----Original Message-----
From: linux-kernel-owner at vger.kernel.org [mailto:linux-kernel-
owner at vger.kernel.org] On Behalf Of Tomasz Nowicki

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Some platforms may not be fully compliant with generic set of PCI
config accessors. For these cases we implement the way to overwrite
accessors set before PCI buses enumeration. Algorithm that

overwrite

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accessors matches against platform ID (DMI), domain and bus number,
hopefully enough for all cases. All quirks can be defined using:
DECLARE_ACPI_MCFG_FIXUP() and keep self contained.

I've got a couple of comments/questions about this patch..

1) So according to this mechanism quirks would be supported only by
  vendors whose BIOS are SMBIOS compliant. Now personally I am ok
  with this but I don't know if this is OK in general as it would
  narrow down the number of platforms that would be able to define
  the quirks...
  Lorenzo, Arnd what is your opinion here?

I'd rather not see the quirks in mainline at all, and only support
SBSA compliant machines, or require the BIOS to work around the
hardware quirks differently (e.g. by trapping config space access
through secure firmware, or going through an AML method to be
defined). I'm certainly ok with making it depend on SMBIOS if we are

going to use something like this.

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   Arnd