Re: [PATCH] arm_mpam: Only program MATCH_PMG when the monitor supports it

[Ben Horgan]

Hi Ping,

On 03/11/2026 09:55, Ping Li wrote:
> Hi Ben,
> 
> Sharing the outcome of our discussions with the hardware team and Arm
> support, to close this thread:
> 
> Although the MPAM specification allows up to 8 bits of PMG, our
> hardware team found that the DSU120AE and the Cortex-A520 only
> propagate 1 bit of PMG. Assuming 1 bit was as good as none, and
> without consulting the software team, they considered the 2 monitor
> groups it would allow dispensable. So the MSC they designed
> implements MSMON but no PMG support, and the bus carries PARTID only,
> without the PMG bit.

Thanks for sharing this information. 1 bit of PMG is common because
until recently CHI didn't allow more.

Ben

> 
> Sorry for the noise again on this one, and thanks for the pointers.
> 
> Ping