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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
 Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Subject:
 [PATCH v1 6/6] cpufreq: intel_pstate: Update the maximum CPU frequency
 consistently
Date: Mon, 25 Mar 2024 18:06:09 +0100
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

There are 3 places at which the maximum CPU frequency may change,
store_no_turbo(), intel_pstate_update_limits() (when called by the
cpufreq core) and intel_pstate_notify_work() (when handling a HWP
change notification).  Currently, cpuinfo.max_freq is only updated by
store_no_turbo(), although it principle it may be necessary to update
it at the other 2 places too.

Make all of them mutually consistent.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/intel_pstate.c |   23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1153,18 +1153,32 @@ static void intel_pstate_update_policies
 static void __intel_pstate_update_max_freq(struct cpudata *cpudata,
 					   struct cpufreq_policy *policy)
 {
+	intel_pstate_get_hwp_cap(cpudata);
+
 	policy->cpuinfo.max_freq = READ_ONCE(global.no_turbo) ?
 			cpudata->pstate.max_freq : cpudata->pstate.turbo_freq;
+
 	refresh_frequency_limits(policy);
 }
 
 static void intel_pstate_update_limits(unsigned int cpu)
 {
-	mutex_lock(&intel_pstate_driver_lock);
+	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
 
-	cpufreq_update_policy(cpu);
+	if (!policy)
+		return;
 
-	mutex_unlock(&intel_pstate_driver_lock);
+	__intel_pstate_update_max_freq(all_cpu_data[cpu], policy);
+
+	cpufreq_cpu_release(policy);
+}
+
+static void intel_pstate_update_limits_for_all(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		intel_pstate_update_limits(cpu);
 }
 
 /************************** sysfs begin ************************/
@@ -1311,7 +1325,7 @@ static ssize_t store_no_turbo(struct kob
 
 	mutex_unlock(&intel_pstate_limits_lock);
 
-	intel_pstate_update_policies();
+	intel_pstate_update_limits_for_all();
 	arch_set_max_freq_ratio(no_turbo);
 
 unlock_driver:
@@ -1595,7 +1609,6 @@ static void intel_pstate_notify_work(str
 	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpudata->cpu);
 
 	if (policy) {
-		intel_pstate_get_hwp_cap(cpudata);
 		__intel_pstate_update_max_freq(cpudata, policy);
 
 		cpufreq_cpu_release(policy);