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

[dirk.brandewie@gmail.com]

From: Dirk Brandewie <dirk.j.brandewie@intel.com>

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.
   https://bugzilla.kernel.org/show_bug.cgi?id=59481

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+

Reported-by: arjan@linux.intel.com
Reported-by: dsmythies@telus.net
Tested-by: arjan@linux.intel.com
Tested-by: dsmythies@telus.net

CC: stable@vger.kernel.org
CC: dsmythies@telus.net
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
---
 drivers/cpufreq/intel_pstate.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 07f2840..6d6a0b4 100644
--- 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);
 }
-- 
1.8.3.1