Re: [PATCH v4 0/6] arm-mpam: Add basic device tree support for resctrl

[Yin Li]

On 11/4/2026 4:13 PM, Ping Li wrote:
> Hi Yin, Rob,
>
> > Changes in v4:
> >    - Drop memory controller MSC patch (no concrete platform user).
>
> We do have a concrete platform user for that patch.
>
> On our SoC we have implemented an MPAM 1.1 compliant MSC on the DDR
> egress path, which provides system-wide bandwidth QoS. The MSC is
> described in the device tree with the "arm,mpam-memory-controller-msc"
> and "arm,mpam-msc" compatibles, and this patch is what classifies it
> as MPAM_CLASS_MEMORY so that it can be used through resctrl.
>
> We have verified this on hardware with v3 of this series (patches
> 1-6) on top of a v7.4-rc1 based tree: the memory controller MSC
> probes correctly from DT, resctrl exposes the MB resource backed by
> it, and both bandwidth allocation (MPAMCFG_MBW_MAX) and the MBWU-based
> mbm_total_bytes monitoring work for it.
>
> So this patch is genuinely useful for us, and we would like to ask
> you to reconsider dropping it. We are happy to help with testing, or
> to provide more details of our DT description if that is useful.

Hi Ping,

Thank you for the feedback — it is great to hear that the memory
controller MSC support has a concrete user and has been verified on
hardware.

Could you share your DT description? That would help us understand
your use case and ensure the binding covers it correctly before we
decide on the next steps.

Thanks,
Yin

> Thanks,
> Ping Li

--
Thx and BRs,
Yin