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Message-ID: <20260126101826.94030-6-pierre.gondois@arm.com>
Date: Mon, 26 Jan 2026 11:18:14 +0100
From: Pierre Gondois <pierre.gondois@....com>
To: linux-kernel@...r.kernel.org
Cc: Jie Zhan <zhanjie9@...ilicon.com>,
zhenglifeng1@...wei.com,
Ionela Voinescu <ionela.voinescu@....com>,
Christian Loehle <christian.loehle@....com>,
sumitg@...dia.com,
Pierre Gondois <pierre.gondois@....com>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Viresh Kumar <viresh.kumar@...aro.org>,
Huang Rui <ray.huang@....com>,
"Gautham R. Shenoy" <gautham.shenoy@....com>,
Mario Limonciello <mario.limonciello@....com>,
Perry Yuan <perry.yuan@....com>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Len Brown <lenb@...nel.org>,
Saravana Kannan <saravanak@...nel.org>,
linux-pm@...r.kernel.org
Subject: [PATCH 5/6] cpufreq: Set policy->min and max as real QoS constraints
cpufreq_set_policy() will ultimately override the policy min/max
values written in the .init() callback through:
cpufreq_policy_online()
\-cpufreq_init_policy()
\-cpufreq_set_policy()
\-/* Set policy->min/max */
Thus the policy min/max values provided are only temporary.
There is an exception if CPUFREQ_NEED_INITIAL_FREQ_CHECK is set and:
cpufreq_policy_online()
\-cpufreq_init_policy()
\-__cpufreq_driver_target()
\-cpufreq_driver->target()
is called. In this case, some drivers use the policy min/max
values in their .target() callback before they are overridden.
Check cpufreq drivers:
- if their .target() callback doesn't use policy->min or max,
remove the initialization
- assuming policy->min or max values were populated as constraints,
set them as QoS real constraints in cpufreq_policy_online()
Signed-off-by: Pierre Gondois <pierre.gondois@....com>
---
drivers/cpufreq/amd-pstate.c | 24 ++++++++++++------------
drivers/cpufreq/cpufreq-nforce2.c | 4 ++--
drivers/cpufreq/cpufreq.c | 16 ++++++++++++++--
drivers/cpufreq/gx-suspmod.c | 9 ++++-----
drivers/cpufreq/intel_pstate.c | 3 ---
drivers/cpufreq/pcc-cpufreq.c | 8 ++++----
drivers/cpufreq/pxa3xx-cpufreq.c | 4 ++--
drivers/cpufreq/virtual-cpufreq.c | 6 +++---
8 files changed, 41 insertions(+), 33 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 310d5938cbdf6..aaafbe9b26cae 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1003,12 +1003,12 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
perf = READ_ONCE(cpudata->perf);
- policy->cpuinfo.min_freq = policy->min = perf_to_freq(perf,
- cpudata->nominal_freq,
- perf.lowest_perf);
- policy->cpuinfo.max_freq = policy->max = perf_to_freq(perf,
- cpudata->nominal_freq,
- perf.highest_perf);
+ policy->cpuinfo.min_freq = perf_to_freq(perf,
+ cpudata->nominal_freq,
+ perf.lowest_perf);
+ policy->cpuinfo.max_freq = perf_to_freq(perf,
+ cpudata->nominal_freq,
+ perf.highest_perf);
ret = amd_pstate_cppc_enable(policy);
if (ret)
@@ -1485,12 +1485,12 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
perf = READ_ONCE(cpudata->perf);
- policy->cpuinfo.min_freq = policy->min = perf_to_freq(perf,
- cpudata->nominal_freq,
- perf.lowest_perf);
- policy->cpuinfo.max_freq = policy->max = perf_to_freq(perf,
- cpudata->nominal_freq,
- perf.highest_perf);
+ policy->cpuinfo.min_freq = perf_to_freq(perf,
+ cpudata->nominal_freq,
+ perf.lowest_perf);
+ policy->cpuinfo.max_freq = perf_to_freq(perf,
+ cpudata->nominal_freq,
+ perf.highest_perf);
policy->driver_data = cpudata;
ret = amd_pstate_cppc_enable(policy);
diff --git a/drivers/cpufreq/cpufreq-nforce2.c b/drivers/cpufreq/cpufreq-nforce2.c
index fbbbe501cf2dc..831102522ad64 100644
--- a/drivers/cpufreq/cpufreq-nforce2.c
+++ b/drivers/cpufreq/cpufreq-nforce2.c
@@ -355,8 +355,8 @@ static int nforce2_cpu_init(struct cpufreq_policy *policy)
min_fsb = NFORCE2_MIN_FSB;
/* cpuinfo and default policy values */
- policy->min = policy->cpuinfo.min_freq = min_fsb * fid * 100;
- policy->max = policy->cpuinfo.max_freq = max_fsb * fid * 100;
+ policy->cpuinfo.min_freq = min_fsb * fid * 100;
+ policy->cpuinfo.max_freq = max_fsb * fid * 100;
return 0;
}
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 43bf6aed90e49..209e2673ca50b 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1455,6 +1455,18 @@ static int cpufreq_policy_online(struct cpufreq_policy *policy,
cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
if (new_policy) {
+ unsigned int min, max;
+
+ /*
+ * If the driver has set policy->min or max,
+ * use the value as a QoS request.
+ */
+ min = max(FREQ_QOS_MIN_DEFAULT_VALUE, policy->min);
+ if (policy->max)
+ max = min(FREQ_QOS_MAX_DEFAULT_VALUE, policy->max);
+ else
+ max = FREQ_QOS_MAX_DEFAULT_VALUE;
+
for_each_cpu(j, policy->related_cpus) {
per_cpu(cpufreq_cpu_data, j) = policy;
add_cpu_dev_symlink(policy, j, get_cpu_device(j));
@@ -1469,7 +1481,7 @@ static int cpufreq_policy_online(struct cpufreq_policy *policy,
ret = freq_qos_add_request(&policy->constraints,
policy->min_freq_req, FREQ_QOS_MIN,
- FREQ_QOS_MIN_DEFAULT_VALUE);
+ min);
if (ret < 0) {
/*
* So we don't call freq_qos_remove_request() for an
@@ -1489,7 +1501,7 @@ static int cpufreq_policy_online(struct cpufreq_policy *policy,
ret = freq_qos_add_request(&policy->constraints,
policy->max_freq_req, FREQ_QOS_MAX,
- FREQ_QOS_MAX_DEFAULT_VALUE);
+ max);
if (ret < 0) {
policy->max_freq_req = NULL;
goto out_destroy_policy;
diff --git a/drivers/cpufreq/gx-suspmod.c b/drivers/cpufreq/gx-suspmod.c
index 75b3ef7ec6796..57999b8d51fa2 100644
--- a/drivers/cpufreq/gx-suspmod.c
+++ b/drivers/cpufreq/gx-suspmod.c
@@ -397,7 +397,7 @@ static int cpufreq_gx_target(struct cpufreq_policy *policy,
static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
{
- unsigned int maxfreq;
+ unsigned int minfreq, maxfreq;
if (!policy || policy->cpu != 0)
return -ENODEV;
@@ -418,11 +418,10 @@ static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
policy->cpu = 0;
if (max_duration < POLICY_MIN_DIV)
- policy->min = maxfreq / max_duration;
+ minfreq = maxfreq / max_duration;
else
- policy->min = maxfreq / POLICY_MIN_DIV;
- policy->max = maxfreq;
- policy->cpuinfo.min_freq = maxfreq / max_duration;
+ minfreq = maxfreq / POLICY_MIN_DIV;
+ policy->cpuinfo.min_freq = minfreq;
policy->cpuinfo.max_freq = maxfreq;
return 0;
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index ec4abe3745736..bf2f7524d04a9 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -3047,9 +3047,6 @@ static int __intel_pstate_cpu_init(struct cpufreq_policy *policy)
policy->cpuinfo.max_freq = READ_ONCE(global.no_turbo) ?
cpu->pstate.max_freq : cpu->pstate.turbo_freq;
- policy->min = policy->cpuinfo.min_freq;
- policy->max = policy->cpuinfo.max_freq;
-
intel_pstate_init_acpi_perf_limits(policy);
policy->fast_switch_possible = true;
diff --git a/drivers/cpufreq/pcc-cpufreq.c b/drivers/cpufreq/pcc-cpufreq.c
index ac2e90a65f0c4..231edfe8cabaa 100644
--- a/drivers/cpufreq/pcc-cpufreq.c
+++ b/drivers/cpufreq/pcc-cpufreq.c
@@ -551,13 +551,13 @@ static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
goto out;
}
- policy->max = policy->cpuinfo.max_freq =
+ policy->cpuinfo.max_freq =
ioread32(&pcch_hdr->nominal) * 1000;
- policy->min = policy->cpuinfo.min_freq =
+ policy->cpuinfo.min_freq =
ioread32(&pcch_hdr->minimum_frequency) * 1000;
- pr_debug("init: policy->max is %d, policy->min is %d\n",
- policy->max, policy->min);
+ pr_debug("init: max_freq is %d, min_freq is %d\n",
+ policy->cpuinfo.max_freq, policy->cpuinfo.min_freq);
out:
return result;
}
diff --git a/drivers/cpufreq/pxa3xx-cpufreq.c b/drivers/cpufreq/pxa3xx-cpufreq.c
index 4afa48d172dbe..f53b9d7edc76a 100644
--- a/drivers/cpufreq/pxa3xx-cpufreq.c
+++ b/drivers/cpufreq/pxa3xx-cpufreq.c
@@ -185,8 +185,8 @@ static int pxa3xx_cpufreq_init(struct cpufreq_policy *policy)
int ret = -EINVAL;
/* set default policy and cpuinfo */
- policy->min = policy->cpuinfo.min_freq = 104000;
- policy->max = policy->cpuinfo.max_freq =
+ policy->cpuinfo.min_freq = 104000;
+ policy->cpuinfo.max_freq =
(cpu_is_pxa320()) ? 806000 : 624000;
policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
diff --git a/drivers/cpufreq/virtual-cpufreq.c b/drivers/cpufreq/virtual-cpufreq.c
index 6ffa16d239b2b..6f7dbef7fda96 100644
--- a/drivers/cpufreq/virtual-cpufreq.c
+++ b/drivers/cpufreq/virtual-cpufreq.c
@@ -164,10 +164,10 @@ static int virt_cpufreq_get_freq_info(struct cpufreq_policy *policy)
policy->cpuinfo.min_freq = 1;
policy->cpuinfo.max_freq = virt_cpufreq_get_perftbl_entry(policy->cpu, 0);
- policy->min = policy->cpuinfo.min_freq;
- policy->max = policy->cpuinfo.max_freq;
+ policy->cpuinfo.min_freq;
+ policy->cpuinfo.max_freq;
- policy->cur = policy->max;
+ policy->cur = policy->cpuinfo.max_freq;
return 0;
}
--
2.43.0
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