diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 701f49d6d2402e..204e39006dda8f 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -59,12 +59,8 @@ * 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 bool shared_mem = false; -module_param(shared_mem, bool, 0444); -MODULE_PARM_DESC(shared_mem, - "enable amd-pstate on processors with shared memory solution (false = disabled (default), true = enabled)"); - static struct cpufreq_driver amd_pstate_driver; +static int cppc_load __initdata; static inline int pstate_enable(bool enable) { @@ -626,6 +622,15 @@ static int __init amd_pstate_init(void) if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) return -ENODEV; + /* + * by default the pstate driver is disabled to load + * enable the amd_pstate passive mode driver explicitly + * with amd_pstate=passive in kernel command line + */ + if (!cppc_load) { + pr_debug("driver load is disabled, boot with amd_pstate=passive to enable this\n"); + return -ENODEV; + } if (!acpi_cpc_valid()) { pr_warn_once("the _CPC object is not present in SBIOS or ACPI disabled\n"); @@ -640,13 +645,11 @@ static int __init amd_pstate_init(void) if (boot_cpu_has(X86_FEATURE_CPPC)) { pr_debug("AMD CPPC MSR based functionality is supported\n"); amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf; - } else if (shared_mem) { + } else { + pr_debug("AMD CPPC shared memory based functionality is supported\n"); static_call_update(amd_pstate_enable, cppc_enable); static_call_update(amd_pstate_init_perf, cppc_init_perf); static_call_update(amd_pstate_update_perf, cppc_update_perf); - } else { - pr_info("This processor supports shared memory solution, you can enable it with amd_pstate.shared_mem=1\n"); - return -ENODEV; } /* enable amd pstate feature */ @@ -665,6 +668,21 @@ static int __init amd_pstate_init(void) } device_initcall(amd_pstate_init); +static int __init amd_pstate_param(char *str) +{ + if (!str) + return -EINVAL; + + if (!strcmp(str, "disable")) { + cppc_load = 0; + pr_info("driver is explicitly disabled\n"); + } else if (!strcmp(str, "passive")) + cppc_load = 1; + + return 0; +} +early_param("amd_pstate", amd_pstate_param); + MODULE_AUTHOR("Huang Rui "); MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver"); MODULE_LICENSE("GPL");