linux-kernel - [PATCH v2 5/5] cpufreq/amd-pstate: Call cppc_set_auto

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Message-ID: <20251107074145.2340-6-gautham.shenoy@amd.com>
Date: Fri, 7 Nov 2025 13:11:45 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
	Mario Limonciello <mario.limonciello@....com>, Yunhui Cui
	<cuiyunhui@...edance.com>, Jeremy Linton <jeremy.linton@....com>, "Viresh
 Kumar" <viresh.kumar@...aro.org>, Ionela Voinescu <ionela.voinescu@....com>
CC: <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>, "Christopher
 Harris" <chris.harris79@...il.com>, <linux-pm@...r.kernel.org>, "Gautham R.
 Shenoy" <gautham.shenoy@....com>, "Mario Limonciello (AMD) (kernel.org)"
	<superm1@...nel.org>
Subject: [PATCH v2 5/5] cpufreq/amd-pstate: Call cppc_set_auto_sel() only for online CPUs

amd_pstate_change_mode_without_dvr_change() calls cppc_set_auto_sel()
for all the present CPUs.

However, this callpath eventually calls cppc_set_reg_val() which
accesses the per-cpu cpc_desc_ptr object. This object is initialized
only for online CPUs via acpi_soft_cpu_online() -->
__acpi_processor_start() --> acpi_cppc_processor_probe().

Hence, restrict calling cppc_set_auto_sel() to only the online CPUs.

Fixes: 3ca7bc818d8c ("cpufreq: amd-pstate: Add guided mode control support via sysfs")
Suggested-by: "Mario Limonciello (AMD) (kernel.org)" <superm1@...nel.org>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@....com>
---
 drivers/cpufreq/amd-pstate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index b44f0f7a5ba1..602e4fa81d6c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1282,7 +1282,7 @@ static int amd_pstate_change_mode_without_dvr_change(int mode)
 	if (cpu_feature_enabled(X86_FEATURE_CPPC) || cppc_state == AMD_PSTATE_ACTIVE)
 		return 0;
 
-	for_each_present_cpu(cpu) {
+	for_each_online_cpu(cpu) {
 		cppc_set_auto_sel(cpu, (cppc_state == AMD_PSTATE_PASSIVE) ? 0 : 1);
 	}
 
-- 
2.34.1