cpufreq / intel_pstate: Change to scale off of max P-state

Change to using max P-state instead of max turbo P-state.  This
change resolves two issues.

On a quiet system intel_pstate can fail to respond to a load change.

On CPU SKUs that have a limited number of P-states and no turbo range
intel_pstate fails to select the highest available P-state.

This change is suitable for stable v3.9+

References: https://bugzilla.kernel.org/show_bug.cgi?id=59481
Reported-and-tested-by: Arjan van de Ven <arjan@linux.intel.com>
Reported-and-tested-by: dsmythies@telus.net
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 3.9+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index b012d7600e1a6c4d29038ba0df98940774cf6b3e..7cde885011ed3d1b15809f6d25c1a7f3ddc3adf1 100644 (file)
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -103,10 +103,10 @@ struct pstate_adjust_policy {
 static struct pstate_adjust_policy default_policy = {
        .sample_rate_ms = 10,
        .deadband = 0,
-       .setpoint = 109,
-       .p_gain_pct = 17,
+       .setpoint = 97,
+       .p_gain_pct = 20,
        .d_gain_pct = 0,
-       .i_gain_pct = 4,
+       .i_gain_pct = 0,
 };
 
 struct perf_limits {
@@ -468,12 +468,12 @@ static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
 static inline int intel_pstate_get_scaled_busy(struct cpudata *cpu)
 {
        int32_t busy_scaled;
-       int32_t core_busy, turbo_pstate, current_pstate;
+       int32_t core_busy, max_pstate, current_pstate;
 
        core_busy = int_tofp(cpu->samples[cpu->sample_ptr].core_pct_busy);
-       turbo_pstate = int_tofp(cpu->pstate.turbo_pstate);
+       max_pstate = int_tofp(cpu->pstate.max_pstate);
        current_pstate = int_tofp(cpu->pstate.current_pstate);
-       busy_scaled = mul_fp(core_busy, div_fp(turbo_pstate, current_pstate));
+       busy_scaled = mul_fp(core_busy, div_fp(max_pstate, current_pstate));
 
        return fp_toint(busy_scaled);
 }