From cf36b3db809da129e2046d4948082d1ed0ac09ec Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 20 Dec 2011 22:44:58 +0000
Subject: [PATCH] =?UTF-8?q?*=20If=20power=20management=20is=20enabled,=20s?=
 =?UTF-8?q?et=20the=20governor=20to=20=E2=80=98ondemand=E2=80=99=20by=20?=
 =?UTF-8?q?=20=20default.=20=20See?=
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    http://www.codon.org.uk/~mjg59/power/good_practices.html

  for the reasoning.  (Basically, the ‘performance’ and ‘powersave’
  governors don't actually provide extra performance or power savings
  in most cases.)

  It used to be that desktop environments like KDE were able to set
  the governor through HAL (e.g. KDE could be configured to switch to
  the powersave governor when the user unplugs his laptop).  However,
  this is no longer the case with upower — it is now expected that
  everybody uses the ondemand governor.  See

    http://old.nabble.com/-PATCH--powerdevil-remove-cpufreq.patch-td27815354.html

* Rename ‘cpuFreqGovernor’ to ‘powerManagement.cpuFreqGovernor’.

* Include cpufreq-utils in the system path if a governor is set, since
  we depend on it anyway.

svn path=/nixos/trunk/; revision=30991
---
 modules/config/power-management.nix |  2 ++
 modules/tasks/cpu-freq.nix          | 16 +++++++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/modules/config/power-management.nix b/modules/config/power-management.nix
index cb7047a2ba80..10aa821964a8 100644
--- a/modules/config/power-management.nix
+++ b/modules/config/power-management.nix
@@ -91,6 +91,8 @@ in
         "p4_clockmod"
       ];
 
+    powerManagement.cpuFreqGovernor = "ondemand";
+
   };
 
 }
diff --git a/modules/tasks/cpu-freq.nix b/modules/tasks/cpu-freq.nix
index 6498b45a6352..b7d9756db1b5 100644
--- a/modules/tasks/cpu-freq.nix
+++ b/modules/tasks/cpu-freq.nix
@@ -6,7 +6,8 @@ with pkgs.lib;
   ###### interface
 
   options = {
-    cpuFreqGovernor = mkOption {
+  
+    powerManagement.cpuFreqGovernor = mkOption {
       default = "";
       example = "ondemand";
       description = ''
@@ -15,13 +16,17 @@ with pkgs.lib;
         "userspace".
       '';
     };
+    
   };
 
 
   ###### implementation
 
-  config = mkIf (config.cpuFreqGovernor != "") ({
-    jobs.cpuFreq =
+  config = mkIf (config.powerManagement.cpuFreqGovernor != "") {
+
+    environment.systemPackages = [ pkgs.cpufrequtils ];
+
+    jobs.cpufreq =
       { description = "Initialize CPU frequency governor";
 
         startOn = "started udev";
@@ -30,10 +35,11 @@ with pkgs.lib;
 
         script = ''
           for i in $(seq 0 $(($(nproc) - 1))); do
-            ${pkgs.cpufrequtils}/bin/cpufreq-set -g ${config.cpuFreqGovernor} -c $i
+            ${pkgs.cpufrequtils}/bin/cpufreq-set -g ${config.powerManagement.cpuFreqGovernor} -c $i
           done
         '';
       };
-  });
+      
+  };
 
 }