From: z00314508 <zhengzucheng@huawei.com>
To: <rafael@kernel.org>, <viresh.kumar@linaro.org>,
<tglx@linutronix.de>, <len.brown@intel.com>
Cc: <zhengzucheng@huawei.com>, <linux-pm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>
Subject: [PATCH] cpufreq: fix cpufreq_get() can't get correct CPU frequency
Date: Fri, 11 Mar 2022 16:11:11 +0800 [thread overview]
Message-ID: <20220311081111.159639-1-zhengzucheng@huawei.com> (raw)
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);
--
2.18.0.huawei.25
next reply other threads:[~2022-03-11 8:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-11 8:11 z00314508 [this message]
2022-03-11 8:33 ` [PATCH] cpufreq: fix cpufreq_get() can't get correct CPU frequency Greg KH
2022-03-11 15:52 ` Rafael J. Wysocki
2022-03-15 2:30 ` zhengzucheng
2022-03-15 10:47 ` Rafael J. Wysocki
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