linux-kernel - Re: [PATCH v1] PM: domains: Improve runtime PM performance state handling

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Date:   Tue, 24 Aug 2021 09:49:47 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Kevin Hilman <khilman@...nel.org>,
        Viresh Kumar <vireshk@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>, Nishanth Menon <nm@...com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-tegra <linux-tegra@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>
Subject: Re: [PATCH v1] PM: domains: Improve runtime PM performance state handling

On Mon, 23 Aug 2021 at 22:25, Dmitry Osipenko <digetx@...il.com> wrote:
>
> GENPD core doesn't support handling performance state changes while
> consumer device is runtime-suspended or when runtime PM is disabled.
> GENPD core may override performance state that was configured by device
> driver while RPM of the device was disabled or device was RPM-suspended.
> Let's close that gap by allowing drivers to control performance state
> while RPM of a consumer device is disabled and to set up performance
> state of RPM-suspended device that will be applied by GENPD core on
> RPM-resume of the device.
>
> Fixes: 5937c3ce2122 ("PM: domains: Drop/restore performance state votes for devices at runtime PM")
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>

Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

Rafael, if not too late, can you please queue this as a fix for v5.14?
I haven't heard about any regression, but the error is there.

Kind regards
Uffe

> ---
>  drivers/base/power/domain.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index e1c8994ae225..3a13a942d012 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -435,7 +435,7 @@ static void genpd_restore_performance_state(struct device *dev,
>  int dev_pm_genpd_set_performance_state(struct device *dev, unsigned int state)
>  {
>         struct generic_pm_domain *genpd;
> -       int ret;
> +       int ret = 0;
>
>         genpd = dev_to_genpd_safe(dev);
>         if (!genpd)
> @@ -446,7 +446,13 @@ int dev_pm_genpd_set_performance_state(struct device *dev, unsigned int state)
>                 return -EINVAL;
>
>         genpd_lock(genpd);
> -       ret = genpd_set_performance_state(dev, state);
> +       if (pm_runtime_suspended(dev)) {
> +               dev_gpd_data(dev)->rpm_pstate = state;
> +       } else {
> +               ret = genpd_set_performance_state(dev, state);
> +               if (!ret)
> +                       dev_gpd_data(dev)->rpm_pstate = 0;
> +       }
>         genpd_unlock(genpd);
>
>         return ret;
> --
> 2.32.0
>