Re: [RESEND][PATCH v2 4/4] soc: samsung: exynos-asv: Update Energy Model after adjusting voltage

[Lukasz Luba]

Hi Dietmar,

On 3/26/24 11:20, Dietmar Eggemann wrote:
> On 22/03/2024 12:08, Lukasz Luba wrote:
>
> [...]
>
> > @@ -97,9 +98,17 @@ static int exynos_asv_update_opps(struct exynos_asv *asv)
> >   			last_opp_table = opp_table;
> >   
> >   			ret = exynos_asv_update_cpu_opps(asv, cpu);
> > -			if (ret < 0)
> > +			if (!ret) {
> > +				/*
> > +				 * When the voltage for OPPs successfully
> > +				 * changed, update the EM power values to
> > +				 * reflect the reality and not use stale data
>
> At this point, can we really say that the voltage has changed?
>
>    exynos_asv_update_cpu_opps()
>
>      ...
>      ret = dev_pm_opp_adjust_voltage()
>      if (!ret)
>        em_dev_update_chip_binning()
>      ...
>
> dev_pm_opp_adjust_voltage() also returns 0 when the voltage value stays
> the same?
>
> [...]

The comment for the dev_pm_opp_adjust_voltage() says that it
returns 0 if no modification was done or modification was
successful. So I cannot distinguish in that driver code, but
also there is no additional need to do it IMO (even framework
doesn't do this).

Regards,
Lukasz

[1] 
https://elixir.bootlin.com/linux/v6.9-rc1/source/drivers/opp/core.c#L2950