1 files changed, 48 insertions, 26 deletions

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 6f45b1658a67..338f428a15b7 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -21,6 +21,7 @@
 #include <linux/hrtimer.h>
 #include <linux/tick.h>
 #include <linux/ktime.h>
+#include <linux/sched.h>
 
 /*
  * dbs is used in this file as a shortform for demandbased switching
@@ -51,8 +52,20 @@ static unsigned int def_sampling_rate;
                         (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
 #define MIN_SAMPLING_RATE                       \
                         (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
+/* Above MIN_SAMPLING_RATE will vanish with its sysfs file soon
+ * Define the minimal settable sampling rate to the greater of:
+ *   - "HW transition latency" * 100 (same as default sampling / 10)
+ *   - MIN_STAT_SAMPLING_RATE
+ * To avoid that userspace shoots itself.
+*/
+static unsigned int minimum_sampling_rate(void)
+{
+        return max(def_sampling_rate / 10, MIN_STAT_SAMPLING_RATE);
+}
+
+/* This will also vanish soon with removing sampling_rate_max */
 #define MAX_SAMPLING_RATE                       (500 * def_sampling_rate)
-#define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER    (1000)
+#define LATENCY_MULTIPLIER                      (1000)
 #define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
 
 static void do_dbs_timer(struct work_struct *work);
@@ -65,14 +78,14 @@ struct cpu_dbs_info_s {
         cputime64_t prev_cpu_wall;
         cputime64_t prev_cpu_nice;
         struct cpufreq_policy *cur_policy;
-        struct delayed_work work;
+        struct delayed_work work;
         struct cpufreq_frequency_table *freq_table;
         unsigned int freq_lo;
         unsigned int freq_lo_jiffies;
         unsigned int freq_hi_jiffies;
         int cpu;
         unsigned int enable:1,
-                     sample_type:1;
+                sample_type:1;
 };
 static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
 
@@ -203,12 +216,28 @@ static void ondemand_powersave_bias_init(void)
 /************************** sysfs interface ************************/
 static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
 {
-        return sprintf (buf, "%u\n", MAX_SAMPLING_RATE);
+        static int print_once;
+
+        if (!print_once) {
+                printk(KERN_INFO "CPUFREQ: ondemand sampling_rate_max "
+                       "sysfs file is deprecated - used by: %s\n",
+                       current->comm);
+                print_once = 1;
+        }
+        return sprintf(buf, "%u\n", MAX_SAMPLING_RATE);
 }
 
 static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
 {
-        return sprintf (buf, "%u\n", MIN_SAMPLING_RATE);
+        static int print_once;
+
+        if (!print_once) {
+                printk(KERN_INFO "CPUFREQ: ondemand sampling_rate_min "
+                       "sysfs file is deprecated - used by: %s\n",
+                       current->comm);
+                print_once = 1;
+        }
+        return sprintf(buf, "%u\n", MIN_SAMPLING_RATE);
 }
 
 #define define_one_ro(_name)            \
@@ -238,13 +267,11 @@ static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
         ret = sscanf(buf, "%u", &input);
 
         mutex_lock(&dbs_mutex);
-        if (ret != 1 || input > MAX_SAMPLING_RATE
-                     || input < MIN_SAMPLING_RATE) {
+        if (ret != 1) {
                 mutex_unlock(&dbs_mutex);
                 return -EINVAL;
         }
-
-        dbs_tuners_ins.sampling_rate = input;
+        dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate());
         mutex_unlock(&dbs_mutex);
 
         return count;
@@ -279,14 +306,14 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
         unsigned int j;
 
         ret = sscanf(buf, "%u", &input);
-        if ( ret != 1 )
+        if (ret != 1)
                 return -EINVAL;
 
-        if ( input > 1 )
+        if (input > 1)
                 input = 1;
 
         mutex_lock(&dbs_mutex);
-        if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */
+        if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
                 mutex_unlock(&dbs_mutex);
                 return count;
         }
@@ -337,7 +364,7 @@ define_one_rw(up_threshold);
 define_one_rw(ignore_nice_load);
 define_one_rw(powersave_bias);
 
-static struct attribute * dbs_attributes[] = {
+static struct attribute *dbs_attributes[] = {
         &sampling_rate_max.attr,
         &sampling_rate_min.attr,
         &sampling_rate.attr,
@@ -512,8 +539,7 @@ static void do_dbs_timer(struct work_struct *work)
                 }
         } else {
                 __cpufreq_driver_target(dbs_info->cur_policy,
-                                        dbs_info->freq_lo,
-                                        CPUFREQ_RELATION_H);
+                        dbs_info->freq_lo, CPUFREQ_RELATION_H);
         }
         queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
         unlock_policy_rwsem_write(cpu);
@@ -530,7 +556,7 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
         dbs_info->sample_type = DBS_NORMAL_SAMPLE;
         INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
         queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work,
-                              delay);
+                delay);
 }
 
 static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
@@ -591,11 +617,9 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                         if (latency == 0)
                                 latency = 1;
 
-                        def_sampling_rate = latency *
-                                        DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
-
-                        if (def_sampling_rate < MIN_STAT_SAMPLING_RATE)
-                                def_sampling_rate = MIN_STAT_SAMPLING_RATE;
+                        def_sampling_rate =
+                                max(latency * LATENCY_MULTIPLIER,
+                                    MIN_STAT_SAMPLING_RATE);
 
                         dbs_tuners_ins.sampling_rate = def_sampling_rate;
                 }
@@ -617,12 +641,10 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                 mutex_lock(&dbs_mutex);
                 if (policy->max < this_dbs_info->cur_policy->cur)
                         __cpufreq_driver_target(this_dbs_info->cur_policy,
-                                                policy->max,
-                                                CPUFREQ_RELATION_H);
+                                policy->max, CPUFREQ_RELATION_H);
                 else if (policy->min > this_dbs_info->cur_policy->cur)
                         __cpufreq_driver_target(this_dbs_info->cur_policy,
-                                                policy->min,
-                                                CPUFREQ_RELATION_L);
+                                policy->min, CPUFREQ_RELATION_L);
                 mutex_unlock(&dbs_mutex);
                 break;
         }
@@ -677,7 +699,7 @@ static void __exit cpufreq_gov_dbs_exit(void)
 MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
 MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
 MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
-                   "Low Latency Frequency Transition capable processors");
+        "Low Latency Frequency Transition capable processors");
 MODULE_LICENSE("GPL");
 
 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND