Re: [PATCH V4 4/5] soc: qcom: Introduce SCMI based Memlat (Memory Latency) governor

[Sibi Sankar <quic_sibis@quicinc.com>]

On 11/15/24 06:08, MyungJoo Ham wrote:
>>
>> Hey Dmitry,
>>
>> Thanks for taking time to review the series.
>>
>> + Devfreq maintainers to comment (I thought you already added
>> them by name)
>>
>>
>> Hey MyungJoo/Kyungmin/Chanwoo,
>>
>> Can you weigh in here? Does it make sense to add a new
>> class of devfreq devices that don't have governors
>> associated with them just for them to export a few
>> essential data to userspace? In this scenario the
>> scaling algorithm is in a SCP and we just start
>> them from the kernel. We do have ways to get the
>> current frequency of various buses but does this
>> warrant adding a new class of governor less devices?
>>
>> -Sibi
> 
> If voltage/frequency is controlled by SCP
> (it's an SoC's internal hardware IP, right?),
> it's good to have a userspace governer
> with the driver not accepting updates from userspace.
> 
> E.g., Let "target" callback not update the frequency value,
>   or let "target" callback always return an error with
>   a dev_err message that you don't accept frequency changes
>   from userspace.

Thanks for the input. Will implement something similar to
what you suggested for the next re-spin.

-Sibi

> 
> Cheers,
> MyungJoo.