diff options
Diffstat (limited to 'drivers/cpufreq/amd-pstate.c')
-rw-r--r-- | drivers/cpufreq/amd-pstate.c | 432 |
1 files changed, 354 insertions, 78 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 07f3419954..6af175e6c0 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -36,7 +36,7 @@ #include <linux/delay.h> #include <linux/uaccess.h> #include <linux/static_call.h> -#include <linux/amd-pstate.h> +#include <linux/topology.h> #include <acpi/processor.h> #include <acpi/cppc_acpi.h> @@ -45,10 +45,45 @@ #include <asm/processor.h> #include <asm/cpufeature.h> #include <asm/cpu_device_id.h> + +#include "amd-pstate.h" #include "amd-pstate-trace.h" #define AMD_PSTATE_TRANSITION_LATENCY 20000 #define AMD_PSTATE_TRANSITION_DELAY 1000 +#define CPPC_HIGHEST_PERF_PERFORMANCE 196 +#define CPPC_HIGHEST_PERF_DEFAULT 166 + +#define AMD_CPPC_EPP_PERFORMANCE 0x00 +#define AMD_CPPC_EPP_BALANCE_PERFORMANCE 0x80 +#define AMD_CPPC_EPP_BALANCE_POWERSAVE 0xBF +#define AMD_CPPC_EPP_POWERSAVE 0xFF + +/* + * enum amd_pstate_mode - driver working mode of amd pstate + */ +enum amd_pstate_mode { + AMD_PSTATE_UNDEFINED = 0, + AMD_PSTATE_DISABLE, + AMD_PSTATE_PASSIVE, + AMD_PSTATE_ACTIVE, + AMD_PSTATE_GUIDED, + AMD_PSTATE_MAX, +}; + +static const char * const amd_pstate_mode_string[] = { + [AMD_PSTATE_UNDEFINED] = "undefined", + [AMD_PSTATE_DISABLE] = "disable", + [AMD_PSTATE_PASSIVE] = "passive", + [AMD_PSTATE_ACTIVE] = "active", + [AMD_PSTATE_GUIDED] = "guided", + NULL, +}; + +struct quirk_entry { + u32 nominal_freq; + u32 lowest_freq; +}; /* * TODO: We need more time to fine tune processors with shared memory solution @@ -64,6 +99,8 @@ static struct cpufreq_driver amd_pstate_driver; static struct cpufreq_driver amd_pstate_epp_driver; static int cppc_state = AMD_PSTATE_UNDEFINED; static bool cppc_enabled; +static bool amd_pstate_prefcore = true; +static struct quirk_entry *quirks; /* * AMD Energy Preference Performance (EPP) @@ -108,6 +145,41 @@ static unsigned int epp_values[] = { typedef int (*cppc_mode_transition_fn)(int); +static struct quirk_entry quirk_amd_7k62 = { + .nominal_freq = 2600, + .lowest_freq = 550, +}; + +static int __init dmi_matched_7k62_bios_bug(const struct dmi_system_id *dmi) +{ + /** + * match the broken bios for family 17h processor support CPPC V2 + * broken BIOS lack of nominal_freq and lowest_freq capabilities + * definition in ACPI tables + */ + if (boot_cpu_has(X86_FEATURE_ZEN2)) { + quirks = dmi->driver_data; + pr_info("Overriding nominal and lowest frequencies for %s\n", dmi->ident); + return 1; + } + + return 0; +} + +static const struct dmi_system_id amd_pstate_quirks_table[] __initconst = { + { + .callback = dmi_matched_7k62_bios_bug, + .ident = "AMD EPYC 7K62", + .matches = { + DMI_MATCH(DMI_BIOS_VERSION, "5.14"), + DMI_MATCH(DMI_BIOS_RELEASE, "12/12/2019"), + }, + .driver_data = &quirk_amd_7k62, + }, + {} +}; +MODULE_DEVICE_TABLE(dmi, amd_pstate_quirks_table); + static inline int get_mode_idx_from_str(const char *str, size_t size) { int i; @@ -287,6 +359,21 @@ static inline int amd_pstate_enable(bool enable) return static_call(amd_pstate_enable)(enable); } +static u32 amd_pstate_highest_perf_set(struct amd_cpudata *cpudata) +{ + struct cpuinfo_x86 *c = &cpu_data(0); + + /* + * For AMD CPUs with Family ID 19H and Model ID range 0x70 to 0x7f, + * the highest performance level is set to 196. + * https://bugzilla.kernel.org/show_bug.cgi?id=218759 + */ + if (c->x86 == 0x19 && (c->x86_model >= 0x70 && c->x86_model <= 0x7f)) + return CPPC_HIGHEST_PERF_PERFORMANCE; + + return CPPC_HIGHEST_PERF_DEFAULT; +} + static int pstate_init_perf(struct amd_cpudata *cpudata) { u64 cap1; @@ -297,13 +384,14 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) if (ret) return ret; - /* - * TODO: Introduce AMD specific power feature. - * - * CPPC entry doesn't indicate the highest performance in some ASICs. + /* For platforms that do not support the preferred core feature, the + * highest_pef may be configured with 166 or 255, to avoid max frequency + * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as + * the default max perf. */ - highest_perf = amd_get_highest_perf(); - if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1)) + if (cpudata->hw_prefcore) + highest_perf = amd_pstate_highest_perf_set(cpudata); + else highest_perf = AMD_CPPC_HIGHEST_PERF(cap1); WRITE_ONCE(cpudata->highest_perf, highest_perf); @@ -311,6 +399,7 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1)); WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1)); WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1)); + WRITE_ONCE(cpudata->prefcore_ranking, AMD_CPPC_HIGHEST_PERF(cap1)); WRITE_ONCE(cpudata->min_limit_perf, AMD_CPPC_LOWEST_PERF(cap1)); return 0; } @@ -324,8 +413,9 @@ static int cppc_init_perf(struct amd_cpudata *cpudata) if (ret) return ret; - highest_perf = amd_get_highest_perf(); - if (highest_perf > cppc_perf.highest_perf) + if (cpudata->hw_prefcore) + highest_perf = amd_pstate_highest_perf_set(cpudata); + else highest_perf = cppc_perf.highest_perf; WRITE_ONCE(cpudata->highest_perf, highest_perf); @@ -334,6 +424,7 @@ static int cppc_init_perf(struct amd_cpudata *cpudata) WRITE_ONCE(cpudata->lowest_nonlinear_perf, cppc_perf.lowest_nonlinear_perf); WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf); + WRITE_ONCE(cpudata->prefcore_ranking, cppc_perf.highest_perf); WRITE_ONCE(cpudata->min_limit_perf, cppc_perf.lowest_perf); if (cppc_state == AMD_PSTATE_ACTIVE) @@ -477,12 +568,19 @@ static int amd_pstate_verify(struct cpufreq_policy_data *policy) static int amd_pstate_update_min_max_limit(struct cpufreq_policy *policy) { - u32 max_limit_perf, min_limit_perf; + u32 max_limit_perf, min_limit_perf, lowest_perf; struct amd_cpudata *cpudata = policy->driver_data; max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq); min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq); + lowest_perf = READ_ONCE(cpudata->lowest_perf); + if (min_limit_perf < lowest_perf) + min_limit_perf = lowest_perf; + + if (max_limit_perf < min_limit_perf) + max_limit_perf = min_limit_perf; + WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf); WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf); WRITE_ONCE(cpudata->max_limit_freq, policy->max); @@ -592,74 +690,22 @@ static void amd_pstate_adjust_perf(unsigned int cpu, static int amd_get_min_freq(struct amd_cpudata *cpudata) { - struct cppc_perf_caps cppc_perf; - - int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); - if (ret) - return ret; - - /* Switch to khz */ - return cppc_perf.lowest_freq * 1000; + return READ_ONCE(cpudata->min_freq); } static int amd_get_max_freq(struct amd_cpudata *cpudata) { - struct cppc_perf_caps cppc_perf; - u32 max_perf, max_freq, nominal_freq, nominal_perf; - u64 boost_ratio; - - int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); - if (ret) - return ret; - - nominal_freq = cppc_perf.nominal_freq; - nominal_perf = READ_ONCE(cpudata->nominal_perf); - max_perf = READ_ONCE(cpudata->highest_perf); - - boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT, - nominal_perf); - - max_freq = nominal_freq * boost_ratio >> SCHED_CAPACITY_SHIFT; - - /* Switch to khz */ - return max_freq * 1000; + return READ_ONCE(cpudata->max_freq); } static int amd_get_nominal_freq(struct amd_cpudata *cpudata) { - struct cppc_perf_caps cppc_perf; - - int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); - if (ret) - return ret; - - /* Switch to khz */ - return cppc_perf.nominal_freq * 1000; + return READ_ONCE(cpudata->nominal_freq); } static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata) { - struct cppc_perf_caps cppc_perf; - u32 lowest_nonlinear_freq, lowest_nonlinear_perf, - nominal_freq, nominal_perf; - u64 lowest_nonlinear_ratio; - - int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); - if (ret) - return ret; - - nominal_freq = cppc_perf.nominal_freq; - nominal_perf = READ_ONCE(cpudata->nominal_perf); - - lowest_nonlinear_perf = cppc_perf.lowest_nonlinear_perf; - - lowest_nonlinear_ratio = div_u64(lowest_nonlinear_perf << SCHED_CAPACITY_SHIFT, - nominal_perf); - - lowest_nonlinear_freq = nominal_freq * lowest_nonlinear_ratio >> SCHED_CAPACITY_SHIFT; - - /* Switch to khz */ - return lowest_nonlinear_freq * 1000; + return READ_ONCE(cpudata->lowest_nonlinear_freq); } static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state) @@ -675,7 +721,7 @@ static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state) if (state) policy->cpuinfo.max_freq = cpudata->max_freq; else - policy->cpuinfo.max_freq = cpudata->nominal_freq; + policy->cpuinfo.max_freq = cpudata->nominal_freq * 1000; policy->max = policy->cpuinfo.max_freq; @@ -706,6 +752,169 @@ static void amd_perf_ctl_reset(unsigned int cpu) wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0); } +/* + * Set amd-pstate preferred core enable can't be done directly from cpufreq callbacks + * due to locking, so queue the work for later. + */ +static void amd_pstste_sched_prefcore_workfn(struct work_struct *work) +{ + sched_set_itmt_support(); +} +static DECLARE_WORK(sched_prefcore_work, amd_pstste_sched_prefcore_workfn); + +/* + * Get the highest performance register value. + * @cpu: CPU from which to get highest performance. + * @highest_perf: Return address. + * + * Return: 0 for success, -EIO otherwise. + */ +static int amd_pstate_get_highest_perf(int cpu, u32 *highest_perf) +{ + int ret; + + if (boot_cpu_has(X86_FEATURE_CPPC)) { + u64 cap1; + + ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1); + if (ret) + return ret; + WRITE_ONCE(*highest_perf, AMD_CPPC_HIGHEST_PERF(cap1)); + } else { + u64 cppc_highest_perf; + + ret = cppc_get_highest_perf(cpu, &cppc_highest_perf); + if (ret) + return ret; + WRITE_ONCE(*highest_perf, cppc_highest_perf); + } + + return (ret); +} + +#define CPPC_MAX_PERF U8_MAX + +static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata) +{ + int ret, prio; + u32 highest_perf; + + ret = amd_pstate_get_highest_perf(cpudata->cpu, &highest_perf); + if (ret) + return; + + cpudata->hw_prefcore = true; + /* check if CPPC preferred core feature is enabled*/ + if (highest_perf < CPPC_MAX_PERF) + prio = (int)highest_perf; + else { + pr_debug("AMD CPPC preferred core is unsupported!\n"); + cpudata->hw_prefcore = false; + return; + } + + if (!amd_pstate_prefcore) + return; + + /* + * The priorities can be set regardless of whether or not + * sched_set_itmt_support(true) has been called and it is valid to + * update them at any time after it has been called. + */ + sched_set_itmt_core_prio(prio, cpudata->cpu); + + schedule_work(&sched_prefcore_work); +} + +static void amd_pstate_update_limits(unsigned int cpu) +{ + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + struct amd_cpudata *cpudata = policy->driver_data; + u32 prev_high = 0, cur_high = 0; + int ret; + bool highest_perf_changed = false; + + mutex_lock(&amd_pstate_driver_lock); + if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore)) + goto free_cpufreq_put; + + ret = amd_pstate_get_highest_perf(cpu, &cur_high); + if (ret) + goto free_cpufreq_put; + + prev_high = READ_ONCE(cpudata->prefcore_ranking); + if (prev_high != cur_high) { + highest_perf_changed = true; + WRITE_ONCE(cpudata->prefcore_ranking, cur_high); + + if (cur_high < CPPC_MAX_PERF) + sched_set_itmt_core_prio((int)cur_high, cpu); + } + +free_cpufreq_put: + cpufreq_cpu_put(policy); + + if (!highest_perf_changed) + cpufreq_update_policy(cpu); + + mutex_unlock(&amd_pstate_driver_lock); +} + +/** + * amd_pstate_init_freq: Initialize the max_freq, min_freq, + * nominal_freq and lowest_nonlinear_freq for + * the @cpudata object. + * + * Requires: highest_perf, lowest_perf, nominal_perf and + * lowest_nonlinear_perf members of @cpudata to be + * initialized. + * + * Returns 0 on success, non-zero value on failure. + */ +static int amd_pstate_init_freq(struct amd_cpudata *cpudata) +{ + int ret; + u32 min_freq; + u32 highest_perf, max_freq; + u32 nominal_perf, nominal_freq; + u32 lowest_nonlinear_perf, lowest_nonlinear_freq; + u32 boost_ratio, lowest_nonlinear_ratio; + struct cppc_perf_caps cppc_perf; + + + ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); + if (ret) + return ret; + + if (quirks && quirks->lowest_freq) + min_freq = quirks->lowest_freq * 1000; + else + min_freq = cppc_perf.lowest_freq * 1000; + + if (quirks && quirks->nominal_freq) + nominal_freq = quirks->nominal_freq ; + else + nominal_freq = cppc_perf.nominal_freq; + + nominal_perf = READ_ONCE(cpudata->nominal_perf); + + highest_perf = READ_ONCE(cpudata->highest_perf); + boost_ratio = div_u64(highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf); + max_freq = (nominal_freq * boost_ratio >> SCHED_CAPACITY_SHIFT) * 1000; + + lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf); + lowest_nonlinear_ratio = div_u64(lowest_nonlinear_perf << SCHED_CAPACITY_SHIFT, + nominal_perf); + lowest_nonlinear_freq = (nominal_freq * lowest_nonlinear_ratio >> SCHED_CAPACITY_SHIFT) * 1000; + + WRITE_ONCE(cpudata->min_freq, min_freq); + WRITE_ONCE(cpudata->lowest_nonlinear_freq, lowest_nonlinear_freq); + WRITE_ONCE(cpudata->nominal_freq, nominal_freq); + WRITE_ONCE(cpudata->max_freq, max_freq); + + return 0; +} + static int amd_pstate_cpu_init(struct cpufreq_policy *policy) { int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret; @@ -727,10 +936,16 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy) cpudata->cpu = policy->cpu; + amd_pstate_init_prefcore(cpudata); + ret = amd_pstate_init_perf(cpudata); if (ret) goto free_cpudata1; + ret = amd_pstate_init_freq(cpudata); + if (ret) + goto free_cpudata1; + min_freq = amd_get_min_freq(cpudata); max_freq = amd_get_max_freq(cpudata); nominal_freq = amd_get_nominal_freq(cpudata); @@ -772,13 +987,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy) goto free_cpudata2; } - /* Initial processor data capability frequencies */ - cpudata->max_freq = max_freq; - cpudata->min_freq = min_freq; cpudata->max_limit_freq = max_freq; cpudata->min_limit_freq = min_freq; - cpudata->nominal_freq = nominal_freq; - cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq; policy->driver_data = cpudata; @@ -877,6 +1087,28 @@ static ssize_t show_amd_pstate_highest_perf(struct cpufreq_policy *policy, return sysfs_emit(buf, "%u\n", perf); } +static ssize_t show_amd_pstate_prefcore_ranking(struct cpufreq_policy *policy, + char *buf) +{ + u32 perf; + struct amd_cpudata *cpudata = policy->driver_data; + + perf = READ_ONCE(cpudata->prefcore_ranking); + + return sysfs_emit(buf, "%u\n", perf); +} + +static ssize_t show_amd_pstate_hw_prefcore(struct cpufreq_policy *policy, + char *buf) +{ + bool hw_prefcore; + struct amd_cpudata *cpudata = policy->driver_data; + + hw_prefcore = READ_ONCE(cpudata->hw_prefcore); + + return sysfs_emit(buf, "%s\n", str_enabled_disabled(hw_prefcore)); +} + static ssize_t show_energy_performance_available_preferences( struct cpufreq_policy *policy, char *buf) { @@ -1074,18 +1306,29 @@ static ssize_t status_store(struct device *a, struct device_attribute *b, return ret < 0 ? ret : count; } +static ssize_t prefcore_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%s\n", str_enabled_disabled(amd_pstate_prefcore)); +} + cpufreq_freq_attr_ro(amd_pstate_max_freq); cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq); cpufreq_freq_attr_ro(amd_pstate_highest_perf); +cpufreq_freq_attr_ro(amd_pstate_prefcore_ranking); +cpufreq_freq_attr_ro(amd_pstate_hw_prefcore); cpufreq_freq_attr_rw(energy_performance_preference); cpufreq_freq_attr_ro(energy_performance_available_preferences); static DEVICE_ATTR_RW(status); +static DEVICE_ATTR_RO(prefcore); static struct freq_attr *amd_pstate_attr[] = { &amd_pstate_max_freq, &amd_pstate_lowest_nonlinear_freq, &amd_pstate_highest_perf, + &amd_pstate_prefcore_ranking, + &amd_pstate_hw_prefcore, NULL, }; @@ -1093,6 +1336,8 @@ static struct freq_attr *amd_pstate_epp_attr[] = { &amd_pstate_max_freq, &amd_pstate_lowest_nonlinear_freq, &amd_pstate_highest_perf, + &amd_pstate_prefcore_ranking, + &amd_pstate_hw_prefcore, &energy_performance_preference, &energy_performance_available_preferences, NULL, @@ -1100,6 +1345,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = { static struct attribute *pstate_global_attributes[] = { &dev_attr_status.attr, + &dev_attr_prefcore.attr, NULL }; @@ -1151,10 +1397,16 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) cpudata->cpu = policy->cpu; cpudata->epp_policy = 0; + amd_pstate_init_prefcore(cpudata); + ret = amd_pstate_init_perf(cpudata); if (ret) goto free_cpudata1; + ret = amd_pstate_init_freq(cpudata); + if (ret) + goto free_cpudata1; + min_freq = amd_get_min_freq(cpudata); max_freq = amd_get_max_freq(cpudata); nominal_freq = amd_get_nominal_freq(cpudata); @@ -1171,12 +1423,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) /* It will be updated by governor */ policy->cur = policy->cpuinfo.min_freq; - /* Initial processor data capability frequencies */ - cpudata->max_freq = max_freq; - cpudata->min_freq = min_freq; - cpudata->nominal_freq = nominal_freq; - cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq; - policy->driver_data = cpudata; cpudata->epp_cached = amd_pstate_get_epp(cpudata, 0); @@ -1216,6 +1462,13 @@ free_cpudata1: static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy) { + struct amd_cpudata *cpudata = policy->driver_data; + + if (cpudata) { + kfree(cpudata); + policy->driver_data = NULL; + } + pr_debug("CPU %d exiting\n", policy->cpu); return 0; } @@ -1232,6 +1485,12 @@ static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy) max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq); min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq); + if (min_limit_perf < min_perf) + min_limit_perf = min_perf; + + if (max_limit_perf < min_limit_perf) + max_limit_perf = min_limit_perf; + WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf); WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf); @@ -1432,6 +1691,7 @@ static struct cpufreq_driver amd_pstate_driver = { .suspend = amd_pstate_cpu_suspend, .resume = amd_pstate_cpu_resume, .set_boost = amd_pstate_set_boost, + .update_limits = amd_pstate_update_limits, .name = "amd-pstate", .attr = amd_pstate_attr, }; @@ -1446,6 +1706,7 @@ static struct cpufreq_driver amd_pstate_epp_driver = { .online = amd_pstate_epp_cpu_online, .suspend = amd_pstate_epp_suspend, .resume = amd_pstate_epp_resume, + .update_limits = amd_pstate_update_limits, .name = "amd-pstate-epp", .attr = amd_pstate_epp_attr, }; @@ -1486,6 +1747,11 @@ static int __init amd_pstate_init(void) if (cpufreq_get_current_driver()) return -EEXIST; + quirks = NULL; + + /* check if this machine need CPPC quirks */ + dmi_check_system(amd_pstate_quirks_table); + switch (cppc_state) { case AMD_PSTATE_UNDEFINED: /* Disable on the following configs by default: @@ -1567,7 +1833,17 @@ static int __init amd_pstate_param(char *str) return amd_pstate_set_driver(mode_idx); } + +static int __init amd_prefcore_param(char *str) +{ + if (!strcmp(str, "disable")) + amd_pstate_prefcore = false; + + return 0; +} + early_param("amd_pstate", amd_pstate_param); +early_param("amd_prefcore", amd_prefcore_param); MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>"); MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver"); |