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cpufreq: intel_pstate: Sync policy->cur during CPU offline

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When a CPU goes offline with HWP disabled, intel_pstate_set_min_pstate()
sets the MSR_IA32_PERF_CTL to minimum frequency to prevent SMT siblings
from being restricted. However, the policy->cur value was not updated,
leaving it at the previous value.

When the CPU comes back online, governor->limits() checks if target_freq
equals policy->cur and skips the frequency adjustment if they match. Since
policy->cur still holds the previous value, the governor does not call
cpufreq_driver->target to update MSR_IA32_PERF_CTL.

Fix this by synchronizing policy->cur with the hardware state when setting
minimum pstate during CPU offline.

Fixes: bb18008f80 ("intel_pstate: Set core to min P state during core offline")
Cc: stable@vger.kernel.org # 3.15+
Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
[ rjw: Subject refinement ]
Link: https://patch.msgid.link/20260520032119.30615-1-fushuai.wang@linux.dev
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Fushuai Wang 2026-05-20 11:21:19 +08:00 committed by Rafael J. Wysocki
parent 85524e651d
commit bcbdaa1086
1 changed files with 4 additions and 2 deletions
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6
drivers/cpufreq/intel_pstate.c
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@ -2984,10 +2984,12 @@ static int intel_cpufreq_cpu_offline(struct cpufreq_policy *policy)
* from getting to lower performance levels, so force the minimum
* performance on CPU offline to prevent that from happening.
*/
if (hwp_active)
if (hwp_active) {
intel_pstate_hwp_offline(cpu);
else
} else {
intel_pstate_set_min_pstate(cpu);
policy->cur = cpu->pstate.min_freq;
}
intel_pstate_exit_perf_limits(policy);