[PATCH v2 2/2] cpufreq: fix schedutil not returning to non-boost freq when boost is disabled

[Ananthu C V]

Commit 538b0188da46 ("cpufreq: ACPI: Set cpuinfo.max_freq directly if
max boost is known") introduced a guard for cpuinfo max updates to only
increase, to preserve driver-set values above the freq table maximum,
causing cpuinfo max to be stuck at boost frequency even when boost is
disabled.

Unconditionally track the highest non-boost frequency (max_base_freq)
in the freq table. When a freq table is available, use max_table_freq/
max_base_freq instead of cpuinfo->max_freq to control boost values, so
the value can decrease again when boost is disabled.

Fixes: 538b0188da46 ("cpufreq: ACPI: Set cpuinfo.max_freq directly if max boost is known")
Signed-off-by: Ananthu C V <ananthu.cv@xxxxxxxxxxxxxxxx>
---
 drivers/cpufreq/cpufreq.c    | 14 +++++++++++++-
 drivers/cpufreq/freq_table.c |  5 +++++
 include/linux/cpufreq.h      |  1 +
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0d0df986fa3d..a13e72711597 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -574,6 +574,7 @@ static ssize_t show_local_boost(struct cpufreq_policy *policy, char *buf)
 
 static int policy_set_boost(struct cpufreq_policy *policy, bool enable)
 {
+	unsigned int max_freq;
 	int ret;
 
 	if (policy->boost_enabled == enable)
@@ -587,7 +588,18 @@ static int policy_set_boost(struct cpufreq_policy *policy, bool enable)
 		return ret;
 	}
 
-	ret = freq_qos_update_request(&policy->boost_freq_req, policy->cpuinfo.max_freq);
+	if (policy->freq_table) {
+		max_freq = enable ? policy->cpuinfo.max_table_freq :
+				    policy->cpuinfo.max_base_freq;
+
+		if (!max_freq)
+			/* when the freq table contains only boost frequencies */
+			max_freq = policy->cpuinfo.max_table_freq;
+	} else {
+		max_freq = policy->cpuinfo.max_freq;
+	}
+
+	ret = freq_qos_update_request(&policy->boost_freq_req, max_freq);
 	if (ret < 0) {
 		policy->boost_enabled = !policy->boost_enabled;
 		cpufreq_driver->set_boost(policy, policy->boost_enabled);
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 4984142dc08a..7e183e16162d 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -34,6 +34,7 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
 	unsigned int min_freq = ~0;
 	unsigned int max_freq = 0;
 	unsigned int max_table_freq = 0;
+	unsigned int max_base_freq = 0;
 	unsigned int freq, i;
 
 	cpufreq_for_each_valid_entry_idx(pos, table, i) {
@@ -42,6 +43,9 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
 		if (freq > max_table_freq)
 			max_table_freq = freq;
 
+		if (!(pos->flags & CPUFREQ_BOOST_FREQ) && freq > max_base_freq)
+			max_base_freq = freq;
+
 		if ((!cpufreq_boost_enabled() || !policy->boost_enabled)
 		    && (pos->flags & CPUFREQ_BOOST_FREQ))
 			continue;
@@ -62,6 +66,7 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
 		policy->cpuinfo.max_freq = max_freq;
 
 	policy->cpuinfo.max_table_freq = max_table_freq;
+	policy->cpuinfo.max_base_freq = max_base_freq;
 
 	if (min_freq == ~0)
 		return -EINVAL;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 3f3b1380251a..419c71ccff7c 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -46,6 +46,7 @@ struct cpufreq_cpuinfo {
 	unsigned int		max_freq;
 	unsigned int		min_freq;
 	unsigned int		max_table_freq; /* Highest valid frequency in the table */
+	unsigned int		max_base_freq; /* Highest non-boost frequency in the table */
 
 	/* in 10^(-9) s = nanoseconds */
 	unsigned int		transition_latency;

-- 
2.43.0