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

[Jon Masters]

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.

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> 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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