Re: [PATCH v10 12/14] arm_mpam: detect and enable MPAM-Fb PCC support

[Sudeep Holla <sudeep.holla@kernel.org>]

On Mon, Sep 21, 2026 at 05:28:27PM +0100, Ben Horgan wrote:
> Hi Andre,
> 
> On 21/09/2026 17:09, Andre Przywara wrote:
>> Hi Ben,
>> 
>> On 9/11/26 17:09, Ben Horgan wrote:
>>> Hi Andre,
>>>

[...]

>>>
>>> This looks like the change earlier in the series to
>>> drivers/acpi/arm64/mpam.c makes no functional effect unless the proposed
>>> spec changes are accepted; the default is msc->id. I'd just move the
>> 
>> Yes, but it reduces churn, and more importantly, is more true to the
>> MPAM-Fb spec, which says:"The MSC identifiers are sequential and start from
>> 0 for each agent which uses this protocol." So this requires that we have
>> per-channel IDs for the MSCs, that's why I think it's justified to
>> introduce this already now, even when it's somewhat redundant as the code
>> stands now, as we always assign the system-wide ID to it.
>> 
>> I can of course move that out (and have that already on top of v9,
>> internally), but wanted to check this with you.
> 
> I don't really mind. If Lorenzo/Sudeep are happy with doing the preparation
> work in drivers/acpi/arm64/mpam.c then I'm ok with it. It's currently a
> non-functional change but does make the expected path forward slightly
> clearer.
> 

Sure, I am okay to have it added here if we plan to use it in the future.
We can always rip it off if the spec changes its direction or gets deemed
as broken 😉.

-- 
Regards,
Sudeep