Re: [PATCH 1/2] ACPI: CPPC: Add support for CPPC v4

Sumit Gupta
2026-04-28T12:54:00Z

On 27/04/26 21:03, Mario Limonciello wrote:
> External email: Use caution opening links or attachments
>
>
> On 4/27/26 03:04, Sumit Gupta wrote:
>>
>> On 27/04/26 12:36, zhenglifeng (A) wrote:
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> It seems that mario has sent a similar patch:
>>>
>>> https://lore.kernel.org/all/20260427035520.1427080-3-superm1@kernel.org/
>>>
>>
>>
>> Thank you for sharing.
>> Yes, both look similar with below two change.
>> 1. REG_OPTIONAL needs the 0x1FC7D0 -> 0x7FC7D0 update to mark
>>     the two new registers optional. This is present in my [PATCH 1/2].
>> 2. For Resource Priority, pkg_data added to cpc_entry.
>>      This is present in Mario's [PATCH 2/6].
>>
>>
>> Hi Mario,
>> How would you like to proceed? A few options:
>>    (a) Let both CPPCv4 patches from this series go separately.
>>    (b) Fold the REG_OPTIONAL update from my patch 1/2 into your
>>        patch, and pull my patch 2/2 into your series.
>>    (c) Anything else you'd prefer.
>> Either way works for me.
>>
>> Thank you,
>> Sumit Gupta
>>
>
>
> Reviewing yours points out that I totally missed updating REG_OPTIONAL
> with the two new ACPI 6.7 fields being optional too.
>
> In my series I only add in CPPv4 so I can build on top of the changes
> for CPPCv5.
>
> So - I would say we should let your patches merge for v4 and I'll drop
> the relevant ones from my series and rebase mine on top of your work.
>

Thanks Mario.
I will proceed with this series and add your Reviewed-by to this patch
in v2.

Thank you,
Sumit Gupta

>
>>
>>>
>>> On 4/27/2026 1:18 PM, Sumit Gupta wrote:
>>>> CPPC v4 (ACPI 6.6, Section 8.4.6) adds two optional entries to the
>>>> _CPC package:
>>>>
>>>> 1. OSPM Nominal Performance (8.4.6.1.2.6): A write-only register that
>>>>     lets OSPM inform the platform what it considers nominal
>>>> performance.
>>>>     The platform classifies performance above this level as boost and
>>>>     below as throttle for its power/thermal decisions.
>>>>
>>>> 2. Resource Priority (8.4.6.1.2.7): A Package of Resource Priority
>>>>     Register Descriptor sub-packages that allow OSPM to set relative
>>>>     priority among processors for shared resources (boost, throttle,
>>>>     L2/L3 cache, memory bandwidth). Parsing the full structure is not
>>>>     yet supported; such entries are marked as unsupported.
>>>>
>>>> Add v4 _CPC table parsing (25 entries) and update REG_OPTIONAL to
>>>> mark the two new registers as optional.
>>>>
>>>> Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
>>>> ---

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