linux-kernel - [PATCH v3 3/6] pmdomain: Respect the CPU system wakeup QoS limit for cpuidle

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Message-ID: <20251121100315.316300-4-ulf.hansson@linaro.org>
Date: Fri, 21 Nov 2025 11:03:09 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: "Rafael J . Wysocki" <rafael@...nel.org>,
	linux-pm@...r.kernel.org
Cc: Vincent Guittot <vincent.guittot@...aro.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Kevin Hilman <khilman@...libre.com>,
	Pavel Machek <pavel@...nel.org>,
	Len Brown <len.brown@...el.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Maulik Shah <quic_mkshah@...cinc.com>,
	Prasad Sodagudi <psodagud@...cinc.com>,
	Dhruva Gole <d-gole@...com>,
	Deepti Jaggi <quic_djaggi@...cinc.com>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH v3 3/6] pmdomain: Respect the CPU system wakeup QoS limit for cpuidle

The CPU system wakeup QoS limit must be respected for the regular cpuidle
state selection. Therefore, let's extend the genpd governor for CPUs to
take the constraint into account when it selects a domain idle state for
the corresponding PM domain.

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

Changes in v3:
	- New patch.

---
 drivers/pmdomain/governor.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pmdomain/governor.c b/drivers/pmdomain/governor.c
index bd1b9d66d4a5..05e68680f34b 100644
--- a/drivers/pmdomain/governor.c
+++ b/drivers/pmdomain/governor.c
@@ -351,7 +351,7 @@ static bool cpu_power_down_ok(struct dev_pm_domain *pd)
 	ktime_t domain_wakeup, next_hrtimer;
 	ktime_t now = ktime_get();
 	struct device *cpu_dev;
-	s64 cpu_constraint, global_constraint;
+	s64 cpu_constraint, global_constraint, wakeup_constraint;
 	s64 idle_duration_ns;
 	int cpu, i;
 
@@ -362,7 +362,11 @@ static bool cpu_power_down_ok(struct dev_pm_domain *pd)
 	if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))
 		return true;
 
+	wakeup_constraint = cpu_wakeup_latency_qos_limit();
 	global_constraint = cpu_latency_qos_limit();
+	if (global_constraint > wakeup_constraint)
+		global_constraint = wakeup_constraint;
+
 	/*
 	 * Find the next wakeup for any of the online CPUs within the PM domain
 	 * and its subdomains. Note, we only need the genpd->cpus, as it already
-- 
2.43.0