FAILED: patch "[PATCH] cpufreq: intel_pstate: Sync policy->cur during CPU offline" failed to apply to 5.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x bcbdaa1086c25a8a5d48e04e1b82fdfb0682b681
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071452-shimmer-reformer-0bc4@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bcbdaa1086c25a8a5d48e04e1b82fdfb0682b681 Mon Sep 17 00:00:00 2001
From: Fushuai Wang <wangfushuai@baidu.com>
Date: Wed, 20 May 2026 11:21:19 +0800
Subject: [PATCH] cpufreq: intel_pstate: Sync policy->cur during CPU offline

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: bb18008f8086 ("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>

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 1f093e346430..0fbbdbd5765c 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -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);