Re: [PATCH RFC v7 0/9] firmware: arm_scmi: vendors: Qualcomm Generic Vendor Extensions

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

On Fri, Jun 19, 2026 at 06:01:23PM +0530, Pragnesh Papaniya wrote:
> 
> On 16-Jun-26 1:57 PM, Sudeep Holla wrote:
> 
> > Not sure if it was discussed in the previous versions or not, it would be
> > good if you can capture why some of bus scaling doesn't work with the existing
> > SCMI performance protocol and the monitors don't fit the MPAM mode.
> > 
> > Please capture them in 1/9 as a motivation for this vendor protocol. It will
> > then help to understand it better as I am still struggling to. Sorry for that.
> 
> Thanks for the input!
> 
> SCMI perf protocol exports perf domains to kernel where kernel can set
> the frequency but here the scaling governor runs on the SCP while kernel
> just observes frequency changes made by remote governor.

OK if it is sort of read-only w.r.t kernel, why not perf domain notifications
work to consume the change done by the SCMI platform.

And why do you have set operations in the vendor protocol being proposed then.
It all looks like something just cooked up to make things work. I need
detailed reasoning as why the existing perf protocol can't work considering
all the existing notifications in place.

> While MPAM is not enabled/supported on all hardware (Hamoa).

Fair enough but I still don't fully understand to rule that out yet.

-- 
Regards,
Sudeep