[PATCH V2 22/23] pci, acpi: Match PCI config space accessors against platfrom specific quirks.
gabriele.paoloni at huawei.com
Tue Dec 22 01:29:02 PST 2015
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
> Computer Architect | Sent from my 64-bit #ARM Powered phone
> > On Dec 21, 2015, at 09:11, Arnd Bergmann <arnd at arndb.de> wrote:
> > On Monday 21 December 2015, Gabriele Paoloni wrote:
> >>> -----Original Message-----
> >>> From: linux-kernel-owner at vger.kernel.org [mailto:linux-kernel-
> >>> owner at vger.kernel.org] 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
> >>> 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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