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| author |  Xuewen Yan <xuewen.yan@unisoc.com>
| 2024-03-19 16:01:53 +0800 |
|---|---|---|
| committer |  Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| 2024-03-27 16:19:39 +0100 |
| commit | db9ea3b22315b74fd682d0c381a6e2ad09a105e3 (patch) | |
| tree | 75c1e2b836fc6eb1636dd764ff1cf35af4ceea09 /drivers/cpufreq | |
| parent | Linux 6.9-rc1 (diff) | |
| download | linux-db9ea3b22315b74fd682d0c381a6e2ad09a105e3.tar.gz linux-db9ea3b22315b74fd682d0c381a6e2ad09a105e3.tar.bz2 linux-db9ea3b22315b74fd682d0c381a6e2ad09a105e3.zip | |
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 <xuewen.yan@unisoc.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/freq_table.c | 8 |
1 files changed, 4 insertions, 4 deletions
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); } |