[PATCH 02/16] cpufreq: intel_pstate: Drop pointless initialization of PID parameters

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From	"Rafael J. Wysocki" <rjw@rjwysocki.net>
Newsgroups	linux.kernel
Subject	[PATCH 02/16] cpufreq: intel_pstate: Drop pointless initialization of PID parameters
Date	Tue, 28 Mar 2017 00:50:02 +0200
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The P-state selection algorithm used by intel_pstate for Atom
processors is not based on the PID controller and the initialization
of PID parametrs for those processors is pointless and confusing, so
drop it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/intel_pstate.c |   28 ++--------------------------
 1 file changed, 2 insertions(+), 26 deletions(-)

Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1540,14 +1540,6 @@ static struct cpu_defaults core_params =
 };
 
 static const struct cpu_defaults silvermont_params = {
-	.pid_policy = {
-		.sample_rate_ms = 10,
-		.deadband = 0,
-		.setpoint = 60,
-		.p_gain_pct = 14,
-		.d_gain_pct = 0,
-		.i_gain_pct = 4,
-	},
 	.funcs = {
 		.get_max = atom_get_max_pstate,
 		.get_max_physical = atom_get_max_pstate,
@@ -1561,14 +1553,6 @@ static const struct cpu_defaults silverm
 };
 
 static const struct cpu_defaults airmont_params = {
-	.pid_policy = {
-		.sample_rate_ms = 10,
-		.deadband = 0,
-		.setpoint = 60,
-		.p_gain_pct = 14,
-		.d_gain_pct = 0,
-		.i_gain_pct = 4,
-	},
 	.funcs = {
 		.get_max = atom_get_max_pstate,
 		.get_max_physical = atom_get_max_pstate,
@@ -1602,14 +1586,6 @@ static const struct cpu_defaults knl_par
 };
 
 static const struct cpu_defaults bxt_params = {
-	.pid_policy = {
-		.sample_rate_ms = 10,
-		.deadband = 0,
-		.setpoint = 60,
-		.p_gain_pct = 14,
-		.d_gain_pct = 0,
-		.i_gain_pct = 4,
-	},
 	.funcs = {
 		.get_max = core_get_max_pstate,
 		.get_max_physical = core_get_max_pstate_physical,
@@ -2637,9 +2613,9 @@ static int __init intel_pstate_init(void
 			return -ENODEV;
 
 		cpu_def = (struct cpu_defaults *)id->driver_data;
-
-		copy_pid_params(&cpu_def->pid_policy);
 		copy_cpu_funcs(&cpu_def->funcs);
+		if (pstate_funcs.get_target_pstate == get_target_pstate_use_performance)
+			copy_pid_params(&cpu_def->pid_policy);
 	}
 
 	if (intel_pstate_msrs_not_valid())

Thread

[PATCH 00/16] cpufreq: intel_pstate: Cleanups and optimizations "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 02/16] cpufreq: intel_pstate: Drop pointless initialization of PID parameters "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 13/16] cpufreq: intel_pstate: Drop struct cpu_defaults "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 10/16] cpufreq: intel_pstate: Use different utilization update callbacks "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 14/16] cpufreq: intel_pstate: Introduce pid_in_use() "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 08/16] cpufreq: intel_pstate: Drop driver_registered variable "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 03/16] cpufreq: intel_pstate: Initialize pid_params statically "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 06/16] cpufreq: intel_pstate: Set HWP sampling interval once "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 05/16] cpufreq: intel_pstate: Clean up intel_pstate_busy_pid_reset() "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 11/16] cpufreq: intel_pstate: Add update_util callback to pstate_funcs "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 09/16] cpufreq: intel_pstate: Modify check in intel_pstate_update_status() "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200
  [PATCH 01/16] cpufreq: intel_pstate: Eliminate struct perf_limits "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-03-28 00:50 +0200

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