From: Zucheng Zheng zhengzucheng@huawei.com
On some specific platforms, the cpufreq driver does not define cpufreq_driver.get() routine (eg:x86 intel_pstate driver), as a result, the cpufreq_get() can't get the correct CPU frequency.
Modern x86 processors include the hardware needed to accurately calculate frequency over an interval -- APERF, MPERF and the TSC. Here we use arch_freq_get_on_cpu() in preference to any driver driver-specific cpufreq_driver.get() routine to get CPU frequency.
Fixes: f8475cef9008 ("x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF") Signed-off-by: Zucheng Zheng zhengzucheng@huawei.com --- drivers/cpufreq/cpufreq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 80f535cc8a75..d777257b4454 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1806,10 +1806,14 @@ unsigned int cpufreq_get(unsigned int cpu) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); unsigned int ret_freq = 0; + unsigned int freq;
if (policy) { down_read(&policy->rwsem); - if (cpufreq_driver->get) + freq = arch_freq_get_on_cpu(policy->cpu); + if (freq) + ret_freq = freq; + else if (cpufreq_driver->get) ret_freq = __cpufreq_get(policy); up_read(&policy->rwsem);