From db9ea3b22315b74fd682d0c381a6e2ad09a105e3 Mon Sep 17 00:00:00 2001 From: Xuewen Yan Date: Tue, 19 Mar 2024 16:01:53 +0800 Subject: cpufreq: Use a smaller freq for the policy->max when verify When driver use the cpufreq_frequency_table_verify() as the cpufreq_driver->verify's callback. It may cause the policy->max bigger than the freq_qos's max freq. Just as follow: unisoc:/sys/devices/system/cpu/cpufreq/policy0 # cat scaling_available_frequencies 614400 768000 988000 1228800 1469000 1586000 1690000 1833000 2002000 2093000 unisoc:/sys/devices/system/cpu/cpufreq/policy0 # echo 1900000 > scaling_max_freq unisoc:/sys/devices/system/cpu/cpufreq/policy0 # echo 1900000 > scaling_min_freq unisoc:/sys/devices/system/cpu/cpufreq/policy0 # cat scaling_max_freq 2002000 unisoc:/sys/devices/system/cpu/cpufreq/policy0 # cat scaling_min_freq 2002000 When user set the qos_min and qos_max as the same value, and the value is not in the freq-table, the above scenario will occur. This is because in cpufreq_frequency_table_verify() func, when it can not find the freq in table, it will change the policy->max to be a bigger freq, as above, because there is no 1.9G in the freq-table, the policy->max would be set to 2.002G. As a result, the cpufreq_policy->max is bigger than the user's qos_max. This is unreasonable. So use a smaller freq when can not find the freq in fre-table, to prevent the policy->max exceed the qos's max freq. Signed-off-by: Xuewen Yan Acked-by: Viresh Kumar Reviewed-by: Dhruva Gole Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/freq_table.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/cpufreq') diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index c17dc51a5a02..40e146942f3e 100644 --- a/drivers/cpufreq/freq_table.c +++ b/drivers/cpufreq/freq_table.c @@ -70,7 +70,7 @@ int cpufreq_frequency_table_verify(struct cpufreq_policy_data *policy, struct cpufreq_frequency_table *table) { struct cpufreq_frequency_table *pos; - unsigned int freq, next_larger = ~0; + unsigned int freq, prev_smaller = 0; bool found = false; pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n", @@ -86,12 +86,12 @@ int cpufreq_frequency_table_verify(struct cpufreq_policy_data *policy, break; } - if ((next_larger > freq) && (freq > policy->max)) - next_larger = freq; + if ((prev_smaller < freq) && (freq <= policy->max)) + prev_smaller = freq; } if (!found) { - policy->max = next_larger; + policy->max = prev_smaller; cpufreq_verify_within_cpu_limits(policy); } -- cgit v1.2.3