linux-kernel - Re: [PATCH] PM: domains: log failures to register always-on domains

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Date:   Thu, 29 Sep 2022 16:57:05 -0700
From:   Kevin Hilman <khilman@...nel.org>
To:     Johan Hovold <johan+linaro@...nel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Matthias Kaehlcke <mka@...omium.org>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Johan Hovold <johan+linaro@...nel.org>
Subject: Re: [PATCH] PM: domains: log failures to register always-on domains

Johan Hovold <johan+linaro@...nel.org> writes:

> Always-on PM domains must be on during initialisation or the domain is
> currently silently rejected.
>
> Print an error message in case an always-on domain is not on to make it
> easier to debug drivers getting this wrong (e.g. by setting an always-on
> genpd flag without making sure that the state matches).
>
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>

Reviewed-by: Kevin Hilman <khilman@...libre.com>

> ---
>  drivers/base/power/domain.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
>
> Both myself and Matthias have hit this with the Qualcomm GCC drivers
> when updating static genpd flags directly instead of using/adding driver
> specific flags to propagate the setting.
>
> Johan
>
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index bbfbf05b3446..7200e307effb 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2087,8 +2087,10 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
>  
>  	/* Always-on domains must be powered on at initialization. */
>  	if ((genpd_is_always_on(genpd) || genpd_is_rpm_always_on(genpd)) &&
> -			!genpd_status_on(genpd))
> +			!genpd_status_on(genpd)) {
> +		pr_err("always-on PM domain %s is not on\n", genpd->name);
>  		return -EINVAL;
> +	}
>  
>  	/* Multiple states but no governor doesn't make sense. */
>  	if (!gov && genpd->state_count > 1)
> -- 
> 2.35.1