linux-kernel - [PATCH 11/11] cpufreq: amd-pstate: automatically load pstate driver by default

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Message-ID: <60bdfbeb426512d74faa91597453fd7960ebd7b5.1715065568.git.perry.yuan@amd.com>
Date: Tue, 7 May 2024 15:15:27 +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 11/11] cpufreq: amd-pstate: automatically load pstate driver by default

If the `amd-pstate` driver is not loaded automatically by default,
it is because the kernel command line parameter has not been added.
To resolve this issue, it is necessary to call the `amd_pstate_set_driver()`
function to enable the desired mode (passive/active/guided) before registering
the driver instance.
This ensures that the driver is loaded correctly without relying on the kernel
command line parameter.

[    0.917789] usb usb6: Manufacturer: Linux 6.9.0-rc6-amd-pstate-new-fix-v1 xhci-hcd
[    0.982579] amd_pstate: failed to register with return -22

Reported-by: Andrei Amuraritei <andamu@...teo.net>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218705
Signed-off-by: Perry Yuan <perry.yuan@....com>
---
 drivers/cpufreq/amd-pstate.c | 39 +++++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 3ff381c4edf7..f5368497ee79 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -66,7 +66,7 @@
 static struct cpufreq_driver *current_pstate_driver;
 static struct cpufreq_driver amd_pstate_driver;
 static struct cpufreq_driver amd_pstate_epp_driver;
-static int cppc_state = AMD_PSTATE_UNDEFINED;
+static int cppc_state;
 static bool cppc_enabled;
 static bool amd_pstate_prefcore = true;
 static struct quirk_entry *quirks;
@@ -1762,6 +1762,16 @@ static int __init amd_pstate_init(void)
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
 		return -ENODEV;
 
+	/* Disable on the following configs by default:
+	 * 1. Undefined platforms
+	 * 2. Server platforms
+	 */
+	if (amd_pstate_acpi_pm_profile_undefined() ||
+		amd_pstate_acpi_pm_profile_server()) {
+		pr_info("driver load is disabled for server or undefined platform\n");
+		return -ENODEV;
+	}
+
 	/* show debug message only if CPPC is not supported */
 	if (!amd_cppc_supported())
 		return -EOPNOTSUPP;
@@ -1781,28 +1791,21 @@ static int __init amd_pstate_init(void)
 	/* check if this machine need CPPC quirks */
 	dmi_check_system(amd_pstate_quirks_table);
 
+	/* get default driver mode for loading*/
+	cppc_state = CONFIG_X86_AMD_PSTATE_DEFAULT_MODE;
+	pr_debug("cppc working state set to mode:%d\n", cppc_state);
+
 	switch (cppc_state) {
-	case AMD_PSTATE_UNDEFINED:
-		/* 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)) {
-			pr_info("driver load is disabled, boot with specific mode to enable this\n");
-			return -ENODEV;
-		}
-		ret = amd_pstate_set_driver(CONFIG_X86_AMD_PSTATE_DEFAULT_MODE);
-		if (ret)
-			return ret;
-		break;
 	case AMD_PSTATE_DISABLE:
+		pr_info("driver load is disabled, boot with specific mode to enable this\n");
 		return -ENODEV;
+	case AMD_PSTATE_UNDEFINED:
 	case AMD_PSTATE_PASSIVE:
 	case AMD_PSTATE_ACTIVE:
 	case AMD_PSTATE_GUIDED:
+		ret = amd_pstate_set_driver(cppc_state);
+		if (ret)
+			return ret;
 		break;
 	default:
 		return -EINVAL;
@@ -1823,7 +1826,7 @@ static int __init amd_pstate_init(void)
 	/* enable amd pstate feature */
 	ret = amd_pstate_enable(true);
 	if (ret) {
-		pr_err("failed to enable with return %d\n", ret);
+		pr_err("failed to enable driver mode(%d) with return %d\n", cppc_state, ret);
 		return ret;
 	}
 
-- 
2.34.1