linux-kernel - [PATCH v4 11/11] cpufreq: amd-pstate: enable shared memory type CPPC by default

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Date: Mon, 17 Jun 2024 14:59:13 +0800
From: Perry Yuan <perry.yuan@....com>
To: <rafael.j.wysocki@...el.com>, <Mario.Limonciello@....com>,
	<viresh.kumar@...aro.org>, <Ray.Huang@....com>, <gautham.shenoy@....com>,
	<Borislav.Petkov@....com>
CC: <Alexander.Deucher@....com>, <Xinmei.Huang@....com>,
	<Xiaojian.Du@....com>, <Li.Meng@....com>, <linux-pm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH v4 11/11] cpufreq: amd-pstate: enable shared memory type CPPC by default

The amd-pstate-epp driver has been implemented and resolves the
performance drop issue seen in passive mode. Users who enable the
active mode driver will not experience a performance drop compared
to the passive mode driver. Therefore, the EPP driver should be
loaded by default at system boot.

Signed-off-by: Perry Yuan <perry.yuan@....com>
---
 drivers/cpufreq/amd-pstate.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index b48fd60cbc6d..eca2f7dcf7ce 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -96,15 +96,6 @@ enum amd_core_type {
 	CPU_CORE_TYPE_UNDEFINED = 2,
 };
 
-/*
- * TODO: We need more time to fine tune processors with shared memory solution
- * with community together.
- *
- * There are some performance drops on the CPU benchmarks which reports from
- * Suse. We are co-working with them to fine tune the shared memory solution. So
- * we disable it by default to go acpi-cpufreq on these processors and add a
- * module parameter to be able to enable it manually for debugging.
- */
 static struct cpufreq_driver *current_pstate_driver;
 static struct cpufreq_driver amd_pstate_driver;
 static struct cpufreq_driver amd_pstate_epp_driver;
@@ -1867,11 +1858,9 @@ static int __init amd_pstate_init(void)
 		/* Disable on the following configs by default:
 		 * 1. Undefined platforms
 		 * 2. Server platforms
-		 * 3. Shared memory designs
 		 */
 		if (amd_pstate_acpi_pm_profile_undefined() ||
-		    amd_pstate_acpi_pm_profile_server() ||
-		    !cpu_feature_enabled(X86_FEATURE_CPPC)) {
+		    amd_pstate_acpi_pm_profile_server()) {
 			pr_info("driver load is disabled, boot with specific mode to enable this\n");
 			return -ENODEV;
 		}
-- 
2.34.1