linux-kernel - [PATCH 2/4] cpufreq: amd-pstate: Set a fallback policy based on preferred

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Date:   Mon, 5 Jun 2023 10:11:31 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     Huang Rui <ray.huang@....com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
CC:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Robert Moore <robert.moore@...el.com>,
        <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-pm@...r.kernel.org>, <devel@...ica.org>,
        Gautham Ranjal Shenoy <gautham.shenoy@....com>,
        "Wyes Karny" <Wyes.Karny@....com>, Perry Yuan <perry.yuan@....com>,
        "Mario Limonciello" <mario.limonciello@....com>
Subject: [PATCH 2/4] cpufreq: amd-pstate: Set a fallback policy based on preferred_profile

If a user's configuration doesn't explicitly specify the cpufreq
scaling governor then the code currently explicitly falls back to
'powersave'. This default is fine for notebooks and desktops, but
servers and undefined machines should default to 'performance'.

Look at the 'preferred_profile' field from the FADT to set this
policy accordingly.

Link: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#fixed-acpi-description-table-fadt
Suggested-by: Wyes Karny <Wyes.Karny@....com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/cpufreq/amd-pstate.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index ddd346a239e0..c9d296ebf81e 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1102,10 +1102,13 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 	policy->max = policy->cpuinfo.max_freq;
 
 	/*
-	 * Set the policy to powersave to provide a valid fallback value in case
+	 * Set the policy to provide a valid fallback value in case
 	 * the default cpufreq governor is neither powersave nor performance.
 	 */
-	policy->policy = CPUFREQ_POLICY_POWERSAVE;
+	if (acpi_pm_profile_server() || acpi_pm_profile_undefined())
+		policy->policy = CPUFREQ_POLICY_PERFORMANCE;
+	else
+		policy->policy = CPUFREQ_POLICY_POWERSAVE;
 
 	if (boot_cpu_has(X86_FEATURE_CPPC)) {
 		ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
-- 
2.34.1