Re: [RFC PATCH v3 03/10] PM: Introduce an Energy Model management framework
From: Quentin Perret
Date: Wed Jun 06 2018 - 12:59:59 EST
On Wednesday 06 Jun 2018 at 18:47:34 (+0200), Juri Lelli wrote:
> Hi Quentin,
>
> On 21/05/18 15:24, Quentin Perret wrote:
>
> [...]
>
> > +#ifdef CONFIG_ENERGY_MODEL
>
> [...]
>
> > +struct em_data_callback {
> > + /**
> > + * active_power() - Provide power at the next capacity state of a CPU
> > + * @power : Active power at the capacity state (modified)
> > + * @freq : Frequency at the capacity state (modified)
> > + * @cpu : CPU for which we do this operation
> > + *
> > + * active_power() must find the lowest capacity state of 'cpu' above
> > + * 'freq' and update 'power' and 'freq' to the matching active power
> > + * and frequency.
> > + *
> > + * Return 0 on success.
> > + */
> > + int (*active_power) (unsigned long *power, unsigned long *freq, int cpu);
> > +};
>
> [...]
>
> > +#else
> > +struct em_freq_domain;
> > +struct em_data_callback;
>
> This doesn't compile for CONFIG_ENERGY_MODEL=n:
>
> drivers/cpufreq/cpufreq-dt.c:164:9: error: variable 'em_cb' has initializer but incomplete type
> struct em_data_callback em_cb = { &dev_pm_opp_of_estimate_power };
> ^~~~~~~~~~~~~~~~
Ah, this is an issue with a patch which isn't part of this patch-set ...
But yeah, that's a valid point :-)
> Guess you need some sort of macro to init the struct (w/o introducing
> ifdeffery into drivers code)?
Yes, the EM framework should provide a generic way of doing this
initialization with nice stubs for CONFIG_ENERGY_MODEL=n, otherwise we
risk wild fixes in the drivers I suppose. I'll fix that in v4.
Thanks for pointing that out !
Quentin