1 files changed, 20 insertions, 12 deletions

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index a092b13ffb..67c4a6a0ef 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -304,10 +304,8 @@ static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
 	int epp = -EINVAL;
 	int ret;
 
-	if (!pref_index) {
-		pr_debug("EPP pref_index is invalid\n");
-		return -EINVAL;
-	}
+	if (!pref_index)
+		epp = cpudata->epp_default;
 
 	if (epp == -EINVAL)
 		epp = epp_values[pref_index];
@@ -1439,7 +1437,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 
 	policy->driver_data = cpudata;
 
-	cpudata->epp_cached = amd_pstate_get_epp(cpudata, 0);
+	cpudata->epp_cached = cpudata->epp_default = amd_pstate_get_epp(cpudata, 0);
 
 	policy->min = policy->cpuinfo.min_freq;
 	policy->max = policy->cpuinfo.max_freq;
@@ -1766,8 +1764,13 @@ static int __init amd_pstate_init(void)
 	/* check if this machine need CPPC quirks */
 	dmi_check_system(amd_pstate_quirks_table);
 
-	switch (cppc_state) {
-	case AMD_PSTATE_UNDEFINED:
+	/*
+	* determine the driver mode from the command line or kernel config.
+	* If no command line input is provided, cppc_state will be AMD_PSTATE_UNDEFINED.
+	* command line options will override the kernel config settings.
+	*/
+
+	if (cppc_state == AMD_PSTATE_UNDEFINED) {
 		/* Disable on the following configs by default:
 		 * 1. Undefined platforms
 		 * 2. Server platforms
@@ -1779,15 +1782,20 @@ static int __init amd_pstate_init(void)
 			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;
+		/* get driver mode from kernel config option [1:4] */
+		cppc_state = CONFIG_X86_AMD_PSTATE_DEFAULT_MODE;
+	}
+
+	switch (cppc_state) {
 	case AMD_PSTATE_DISABLE:
+		pr_info("driver load is disabled, boot with specific mode to enable this\n");
 		return -ENODEV;
 	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;
@@ -1808,7 +1816,7 @@ 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)\n", cppc_state);
 		return ret;
 	}