From: Viresh Kumar <viresh.kumar@linaro.org>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
linux-pm@vger.kernel.org, Dmitry Osipenko <digetx@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Thierry Reding <thierry.reding@gmail.com>,
Rajendra Nayak <rnayak@codeaurora.org>,
Stephan Gerhold <stephan@gerhold.net>,
Roja Rani Yarubandi <rojay@codeaurora.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Stephen Boyd <sboyd@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/4] PM: domains: Drop/restore performance state votes for devices at runtime PM
Date: Thu, 3 Jun 2021 15:25:38 +0530 [thread overview]
Message-ID: <20210603095538.b2t3cq25tq7v7kih@vireshk-i7> (raw)
In-Reply-To: <20210603093438.138705-4-ulf.hansson@linaro.org>
On 03-06-21, 11:34, Ulf Hansson wrote:
> A subsystem/driver that need to manage OPPs for its device, should
> typically drop its vote for the OPP when the device becomes runtime
> suspended. In this way, the corresponding aggregation of the performance
> state votes that is managed in genpd for the attached PM domain, may find
> that the aggregated vote can be decreased. Hence, it may allow genpd to set
> the lower performance state for the PM domain, thus avoiding to waste
> energy.
>
> To accomplish this, typically a subsystem/driver would need to call
> dev_pm_opp_set_rate|opp() for its device from its ->runtime_suspend()
> callback, to drop the vote for the OPP. Accordingly, it needs another call
> to dev_pm_opp_set_rate|opp() to restore the vote for the OPP from its
> ->runtime_resume() callback.
>
> To avoid boilerplate code in subsystems/driver to deal with these things,
> let's instead manage this internally in genpd.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>
> Changes in v2:
> - Rebased.
> - A few minor cosmetic changes.
> - Deal with the error path in genpd_runtime_resume().
>
> ---
> drivers/base/power/domain.c | 27 +++++++++++++++++++++++++--
> include/linux/pm_domain.h | 1 +
> 2 files changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index ef25a5b18587..e5d97174c254 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -400,6 +400,23 @@ static int genpd_set_performance_state(struct device *dev, unsigned int state)
> return ret;
> }
>
> +static int genpd_drop_performance_state(struct device *dev)
What about passing the state pointer here? that will simplify the
callers to just a call.
> +{
> + unsigned int prev_state = dev_gpd_data(dev)->performance_state;
> +
> + if (!genpd_set_performance_state(dev, 0))
> + return prev_state;
> +
> + return 0;
> +}
> +
> +static void genpd_restore_performance_state(struct device *dev,
> + unsigned int state)
> +{
> + if (state)
I will skip this check, as we are checking it in
genpd_set_performance_state() anyway ?
> + genpd_set_performance_state(dev, state);
> +}
> +
> /**
> * dev_pm_genpd_set_performance_state- Set performance state of device's power
> * domain.
> @@ -842,7 +859,8 @@ static int genpd_runtime_suspend(struct device *dev)
> {
> struct generic_pm_domain *genpd;
> bool (*suspend_ok)(struct device *__dev);
> - struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
> + struct generic_pm_domain_data *gpd_data = dev_gpd_data(dev);
> + struct gpd_timing_data *td = &gpd_data->td;
> bool runtime_pm = pm_runtime_enabled(dev);
> ktime_t time_start;
> s64 elapsed_ns;
> @@ -899,6 +917,7 @@ static int genpd_runtime_suspend(struct device *dev)
> return 0;
>
> genpd_lock(genpd);
> + gpd_data->rpm_pstate = genpd_drop_performance_state(dev);
So this will become:
genpd_drop_performance_state(dev, &gpd_data->rpm_pstate);
and it can have return type of void.
--
viresh
next prev parent reply other threads:[~2021-06-03 9:56 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 9:34 [PATCH v2 0/4] PM: domains: Avoid boilerplate code for DVFS in subsystem/drivers Ulf Hansson
2021-06-03 9:34 ` [PATCH v2 1/4] PM: domains: Split code in dev_pm_genpd_set_performance_state() Ulf Hansson
2021-06-03 9:34 ` [PATCH v2 2/4] PM: domains: Return early if perf state is already set for the device Ulf Hansson
2021-06-03 9:34 ` [PATCH v2 3/4] PM: domains: Drop/restore performance state votes for devices at runtime PM Ulf Hansson
2021-06-03 9:55 ` Viresh Kumar [this message]
2021-06-03 10:31 ` Ulf Hansson
2021-06-03 11:17 ` Ulf Hansson
2021-06-04 3:53 ` Viresh Kumar
2021-06-04 7:45 ` Ulf Hansson
2021-06-07 4:47 ` Viresh Kumar
2021-06-09 12:25 ` Ulf Hansson
2021-06-03 19:02 ` Dmitry Osipenko
2021-06-03 19:08 ` Dmitry Osipenko
2021-06-04 7:20 ` Ulf Hansson
2021-06-03 9:34 ` [PATCH v2 4/4] PM: domains: Drop/restore performance state votes for devices at system PM Ulf Hansson
2021-06-03 10:20 ` Ulf Hansson
2021-06-03 11:15 ` Mark Brown
2021-06-03 13:48 ` Ulf Hansson
2021-06-08 12:53 ` Stephan Gerhold
2021-06-08 14:08 ` Ulf Hansson
2021-06-08 14:20 ` Mark Brown
2021-06-08 14:39 ` Ulf Hansson
2021-06-08 15:37 ` Stephan Gerhold
2021-06-03 11:12 ` [PATCH v2 0/4] PM: domains: Avoid boilerplate code for DVFS in subsystem/drivers Stephan Gerhold
2021-06-03 15:27 ` Ulf Hansson
2021-06-03 17:14 ` Stephan Gerhold
2021-06-04 7:18 ` Ulf Hansson
2021-06-04 8:23 ` Stephan Gerhold
2021-06-04 10:57 ` Ulf Hansson
2021-06-04 11:50 ` Stephan Gerhold
2021-06-11 16:42 ` Rafael J. Wysocki
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