6915719b36
When the cpufreq driver starts up at boot time, it calls into the default governor which might not be initialised yet. This hurts when the governor's worker function relies on memory that is not yet set up by its init function. This migrates all governors from module_init() to fs_initcall() when being the default, as was already done in cpufreq_performance when it was the only possible choice. The performance governor is always initialized early because it might be used as fallback even when not being the default. Fixes at least one actual oops where ondemand is the default governor and cpufreq_governor_dbs() uses the uninitialised kondemand_wq work-queue during boot-time. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
240 lines
6.2 KiB
C
240 lines
6.2 KiB
C
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/*
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* linux/drivers/cpufreq/cpufreq_userspace.c
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*
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* Copyright (C) 2001 Russell King
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* (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/cpufreq.h>
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#include <linux/cpu.h>
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#include <linux/types.h>
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#include <linux/fs.h>
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#include <linux/sysfs.h>
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#include <linux/mutex.h>
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#include <asm/uaccess.h>
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/**
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* A few values needed by the userspace governor
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*/
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static unsigned int cpu_max_freq[NR_CPUS];
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static unsigned int cpu_min_freq[NR_CPUS];
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static unsigned int cpu_cur_freq[NR_CPUS]; /* current CPU freq */
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static unsigned int cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
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static unsigned int cpu_is_managed[NR_CPUS];
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static DEFINE_MUTEX (userspace_mutex);
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static int cpus_using_userspace_governor;
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#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
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/* keep track of frequency transitions */
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static int
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userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
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void *data)
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{
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struct cpufreq_freqs *freq = data;
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if (!cpu_is_managed[freq->cpu])
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return 0;
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dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n",
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freq->cpu, freq->new);
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cpu_cur_freq[freq->cpu] = freq->new;
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return 0;
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}
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static struct notifier_block userspace_cpufreq_notifier_block = {
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.notifier_call = userspace_cpufreq_notifier
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};
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/**
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* cpufreq_set - set the CPU frequency
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* @freq: target frequency in kHz
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* @cpu: CPU for which the frequency is to be set
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*
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* Sets the CPU frequency to freq.
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*/
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static int cpufreq_set(unsigned int freq, struct cpufreq_policy *policy)
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{
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int ret = -EINVAL;
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dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
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mutex_lock(&userspace_mutex);
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if (!cpu_is_managed[policy->cpu])
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goto err;
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cpu_set_freq[policy->cpu] = freq;
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if (freq < cpu_min_freq[policy->cpu])
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freq = cpu_min_freq[policy->cpu];
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if (freq > cpu_max_freq[policy->cpu])
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freq = cpu_max_freq[policy->cpu];
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/*
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* We're safe from concurrent calls to ->target() here
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* as we hold the userspace_mutex lock. If we were calling
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* cpufreq_driver_target, a deadlock situation might occur:
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* A: cpufreq_set (lock userspace_mutex) -> cpufreq_driver_target(lock policy->lock)
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* B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_mutex)
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*/
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ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
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err:
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mutex_unlock(&userspace_mutex);
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return ret;
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}
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/************************** sysfs interface ************************/
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static ssize_t show_speed (struct cpufreq_policy *policy, char *buf)
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{
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return sprintf (buf, "%u\n", cpu_cur_freq[policy->cpu]);
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}
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static ssize_t
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store_speed (struct cpufreq_policy *policy, const char *buf, size_t count)
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{
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unsigned int freq = 0;
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unsigned int ret;
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ret = sscanf (buf, "%u", &freq);
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if (ret != 1)
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return -EINVAL;
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cpufreq_set(freq, policy);
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return count;
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}
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static struct freq_attr freq_attr_scaling_setspeed =
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{
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.attr = { .name = "scaling_setspeed", .mode = 0644 },
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.show = show_speed,
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.store = store_speed,
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};
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static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
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unsigned int event)
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{
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unsigned int cpu = policy->cpu;
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int rc = 0;
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switch (event) {
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case CPUFREQ_GOV_START:
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if (!cpu_online(cpu))
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return -EINVAL;
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BUG_ON(!policy->cur);
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mutex_lock(&userspace_mutex);
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rc = sysfs_create_file (&policy->kobj,
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&freq_attr_scaling_setspeed.attr);
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if (rc)
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goto start_out;
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if (cpus_using_userspace_governor == 0) {
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cpufreq_register_notifier(
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&userspace_cpufreq_notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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}
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cpus_using_userspace_governor++;
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cpu_is_managed[cpu] = 1;
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cpu_min_freq[cpu] = policy->min;
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cpu_max_freq[cpu] = policy->max;
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cpu_cur_freq[cpu] = policy->cur;
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cpu_set_freq[cpu] = policy->cur;
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dprintk("managing cpu %u started (%u - %u kHz, currently %u kHz)\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu]);
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start_out:
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mutex_unlock(&userspace_mutex);
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break;
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case CPUFREQ_GOV_STOP:
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mutex_lock(&userspace_mutex);
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cpus_using_userspace_governor--;
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if (cpus_using_userspace_governor == 0) {
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cpufreq_unregister_notifier(
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&userspace_cpufreq_notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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}
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cpu_is_managed[cpu] = 0;
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cpu_min_freq[cpu] = 0;
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cpu_max_freq[cpu] = 0;
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cpu_set_freq[cpu] = 0;
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sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
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dprintk("managing cpu %u stopped\n", cpu);
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mutex_unlock(&userspace_mutex);
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break;
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case CPUFREQ_GOV_LIMITS:
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mutex_lock(&userspace_mutex);
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dprintk("limit event for cpu %u: %u - %u kHz,"
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"currently %u kHz, last set to %u kHz\n",
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cpu, policy->min, policy->max,
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cpu_cur_freq[cpu], cpu_set_freq[cpu]);
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if (policy->max < cpu_set_freq[cpu]) {
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__cpufreq_driver_target(policy, policy->max,
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CPUFREQ_RELATION_H);
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}
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else if (policy->min > cpu_set_freq[cpu]) {
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__cpufreq_driver_target(policy, policy->min,
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CPUFREQ_RELATION_L);
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}
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else {
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__cpufreq_driver_target(policy, cpu_set_freq[cpu],
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CPUFREQ_RELATION_L);
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}
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cpu_min_freq[cpu] = policy->min;
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cpu_max_freq[cpu] = policy->max;
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cpu_cur_freq[cpu] = policy->cur;
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mutex_unlock(&userspace_mutex);
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break;
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}
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return rc;
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}
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struct cpufreq_governor cpufreq_gov_userspace = {
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.name = "userspace",
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.governor = cpufreq_governor_userspace,
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.owner = THIS_MODULE,
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};
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EXPORT_SYMBOL(cpufreq_gov_userspace);
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static int __init cpufreq_gov_userspace_init(void)
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{
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return cpufreq_register_governor(&cpufreq_gov_userspace);
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}
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static void __exit cpufreq_gov_userspace_exit(void)
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{
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cpufreq_unregister_governor(&cpufreq_gov_userspace);
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}
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MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");
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MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");
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MODULE_LICENSE ("GPL");
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#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
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fs_initcall(cpufreq_gov_userspace_init);
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#else
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module_init(cpufreq_gov_userspace_init);
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#endif
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module_exit(cpufreq_gov_userspace_exit);
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