linux-kernel - [PATCH 1/1] acpi-cpufreq: Honor _PSD table setting in CPU frequency control

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Message-Id: <20201007204412.565881-1-wei.huang2@amd.com>
Date:   Wed,  7 Oct 2020 15:44:12 -0500
From:   Wei Huang <wei.huang2@....com>
To:     linux-kernel@...r.kernel.org
Cc:     rjw@...ysocki.net, viresh.kumar@...aro.org,
        linux-pm@...r.kernel.org, wei.huang2@....com
Subject: [PATCH 1/1] acpi-cpufreq: Honor _PSD table setting in CPU frequency control

acpi-cpufreq has a old quirk that overrides the _PSD table supplied by
BIOS on AMD CPUs. However the _PSD table of new AMD CPUs (Family 19h+)
now accurately reports the P-state dependency of CPU cores. Hence this
quirk needs to be fixed in order to support new CPUs' frequency control.

Fixes: acd316248205 ("acpi-cpufreq: Add quirk to disable _PSD usage on all AMD CPUs")
Signed-off-by: Wei Huang <wei.huang2@....com>
---
 drivers/cpufreq/acpi-cpufreq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index e4ff681faaaa..1e6e2abde428 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -691,7 +691,8 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 		cpumask_copy(policy->cpus, topology_core_cpumask(cpu));
 	}
 
-	if (check_amd_hwpstate_cpu(cpu) && !acpi_pstate_strict) {
+	if (check_amd_hwpstate_cpu(cpu) && (c->x86 < 0x19) &&
+	    !acpi_pstate_strict) {
 		cpumask_clear(policy->cpus);
 		cpumask_set_cpu(cpu, policy->cpus);
 		cpumask_copy(data->freqdomain_cpus,
-- 
2.26.2