cpufreq: intel_pstate: Reflect current no_turbo state correctly

Some BIOSes modify the state of MSR_IA32_MISC_ENABLE_TURBO_DISABLE
based on the current power source for the system battery AC vs
battery. Reflect the correct current state and ability to modify the
no_turbo sysfs file based on current state of
MSR_IA32_MISC_ENABLE_TURBO_DISABLE.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=83151
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 36 insertions, 12 deletions

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 7547ab559a97..5f5f5ed11691 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -138,6 +138,7 @@ struct perf_limits {
 
 static struct perf_limits limits = {
         .no_turbo = 0,
+        .turbo_disabled = 0,
         .max_perf_pct = 100,
         .max_perf = int_tofp(1),
         .min_perf_pct = 0,
@@ -218,6 +219,18 @@ static inline void intel_pstate_reset_all_pid(void)
         }
 }
 
+static inline void update_turbo_state(void)
+{
+        u64 misc_en;
+        struct cpudata *cpu;
+
+        cpu = all_cpu_data[0];
+        rdmsrl(MSR_IA32_MISC_ENABLE, misc_en);
+        limits.turbo_disabled =
+                (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE ||
+                 cpu->pstate.max_pstate == cpu->pstate.turbo_pstate);
+}
+
 /************************** debugfs begin ************************/
 static int pid_param_set(void *data, u64 val)
 {
@@ -274,6 +287,20 @@ static void __init intel_pstate_debug_expose_params(void)
                 return sprintf(buf, "%u\n", limits.object);             \
         }
 
+static ssize_t show_no_turbo(struct kobject *kobj,
+                             struct attribute *attr, char *buf)
+{
+        ssize_t ret;
+
+        update_turbo_state();
+        if (limits.turbo_disabled)
+                ret = sprintf(buf, "%u\n", limits.turbo_disabled);
+        else
+                ret = sprintf(buf, "%u\n", limits.no_turbo);
+
+        return ret;
+}
+
 static ssize_t store_no_turbo(struct kobject *a, struct attribute *b,
                               const char *buf, size_t count)
 {
@@ -283,11 +310,14 @@ static ssize_t store_no_turbo(struct kobject *a, struct attribute *b,
         ret = sscanf(buf, "%u", &input);
         if (ret != 1)
                 return -EINVAL;
-        limits.no_turbo = clamp_t(int, input, 0 , 1);
+
+        update_turbo_state();
         if (limits.turbo_disabled) {
                 pr_warn("Turbo disabled by BIOS or unavailable on processor\n");
-                limits.no_turbo = limits.turbo_disabled;
+                return -EPERM;
         }
+        limits.no_turbo = clamp_t(int, input, 0, 1);
+
         return count;
 }
 
@@ -323,7 +353,6 @@ static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
         return count;
 }
 
-show_one(no_turbo, no_turbo);
 show_one(max_perf_pct, max_perf_pct);
 show_one(min_perf_pct, min_perf_pct);
 
@@ -501,7 +530,7 @@ static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
         int max_perf_adj;
         int min_perf;
 
-        if (limits.no_turbo)
+        if (limits.no_turbo || limits.turbo_disabled)
                 max_perf = cpu->pstate.max_pstate;
 
         max_perf_adj = fp_toint(mul_fp(int_tofp(max_perf), limits.max_perf));
@@ -516,6 +545,8 @@ static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
 {
         int max_perf, min_perf;
 
+        update_turbo_state();
+
         intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
 
         pstate = clamp_t(int, pstate, min_perf, max_perf);
@@ -717,7 +748,7 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy)
                 limits.max_policy_pct = 100;
                 limits.max_perf_pct = 100;
                 limits.max_perf = int_tofp(1);
-                limits.no_turbo = limits.turbo_disabled;
+                limits.no_turbo = 0;
                 return 0;
         }
         limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
@@ -760,7 +791,6 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
 {
         struct cpudata *cpu;
         int rc;
-        u64 misc_en;
 
         rc = intel_pstate_init_cpu(policy->cpu);
         if (rc)
@@ -768,12 +798,6 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
 
         cpu = all_cpu_data[policy->cpu];
 
-        rdmsrl(MSR_IA32_MISC_ENABLE, misc_en);
-        if (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE ||
-            cpu->pstate.max_pstate == cpu->pstate.turbo_pstate) {
-                limits.turbo_disabled = 1;
-                limits.no_turbo = 1;
-        }
         if (limits.min_perf_pct == 100 && limits.max_perf_pct == 100)
                 policy->policy = CPUFREQ_POLICY_PERFORMANCE;
         else