linux-kernel - [PATCH v2 2/4] PM: domains: Return early if perf state is already set for the device

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Date:   Thu,  3 Jun 2021 11:34:36 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        linux-pm@...r.kernel.org
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        Dmitry Osipenko <digetx@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Stephan Gerhold <stephan@...hold.net>,
        Roja Rani Yarubandi <rojay@...eaurora.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/4] PM: domains: Return early if perf state is already set for the device

When dev_pm_genpd_set_performance_state() gets called to set a new
performance state for the device, let's take a quicker path by doing an
early return, if it turns out that the new state is already set for the
device.

Suggested-by: Viresh Kumar <viresh.kumar@...aro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---

Changes in v2:
	- New patch.

---
 drivers/base/power/domain.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 5c476ed1c6c9..ef25a5b18587 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -387,6 +387,9 @@ static int genpd_set_performance_state(struct device *dev, unsigned int state)
 	int ret;
 
 	prev_state = gpd_data->performance_state;
+	if (prev_state == state)
+		return 0;
+
 	gpd_data->performance_state = state;
 	state = _genpd_reeval_performance_state(genpd, state);
 
-- 
2.25.1