Re: [PATCH v7 02/26] PM / Domains: Deal with multiple states but no governor in genpd

[Lina Iyer]

On Thu, Apr 12 2018 at 05:14 -0600, Ulf Hansson wrote:
> A caller of pm_genpd_init() that provides some states for the genpd via the
> ->states pointer in the struct generic_pm_domain, should also provide a
> governor. This because it's the job of the governor to pick a state that
> satisfies the constraints.
>
> Therefore, let's print a warning to inform the user about such bogus
> configuration and avoid to bail out, by instead picking the shallowest
> state before genpd invokes the ->power_off() callback.
>
> Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>

Reviewed-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>

> ---
> drivers/base/power/domain.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index c2ef944..9aff79d 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -466,6 +466,10 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
> 			return -EAGAIN;
> 	}
>
> +	/* Default to shallowest state. */
> +	if (!genpd->gov)
> +		genpd->state_idx = 0;
> +
> 	if (genpd->power_off) {
> 		int ret;
>
> @@ -1694,6 +1698,8 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
> 		ret = genpd_set_default_power_state(genpd);
> 		if (ret)
> 			return ret;
> +	} else if (!gov) {
> +		pr_warn("%s : no governor for states\n", genpd->name);
> 	}
>
> 	mutex_lock(&gpd_list_lock);
> --
> 2.7.4