RE: [PATCH V2 22/23] pci, acpi: Match PCI config space accessors against platfrom specific quirks.

[Gabriele Paoloni]

Hi Jon, thanks for replying

> -----Original Message-----
> From: Jon Masters [mailto:jcm@xxxxxxxxxx]
> Sent: 21 December 2015 23:11
> To: Arnd Bergmann
> Cc: Gabriele Paoloni; Tomasz Nowicki; bhelgaas@xxxxxxxxxx;
> will.deacon@xxxxxxx; catalin.marinas@xxxxxxx; rjw@xxxxxxxxxxxxx;
> hanjun.guo@xxxxxxxxxx; Lorenzo.Pieralisi@xxxxxxx; okaya@xxxxxxxxxxxxxx;
> jiang.liu@xxxxxxxxxxxxxxx; Stefano.Stabellini@xxxxxxxxxxxxx;
> robert.richter@xxxxxxxxxxxxxxxxxx; mw@xxxxxxxxxxxx; Liviu.Dudau@xxxxxxx;
> ddaney@xxxxxxxxxxxxxxxxxx; tglx@xxxxxxxxxxxxx; Wangyijing;
> Suravee.Suthikulpanit@xxxxxxx; msalter@xxxxxxxxxx; linux-
> pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
> acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linaro-
> acpi@xxxxxxxxxxxxxxxx; jchandra@xxxxxxxxxxxx
> 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
> 
> > On Dec 21, 2015, at 09:11, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> >
> > On Monday 21 December 2015, Gabriele Paoloni wrote:
> >>> -----Original Message-----
> >>> From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel-
> >>> owner@xxxxxxxxxxxxxxx] On Behalf Of Tomasz Nowicki
> >
> >>> 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
> >>> 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.
> >
> >    Arnd
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