nixpkgs/nixos/modules/config/power-management.nix
Maximilian Bosch 8ed3a90cdf
nixos/powerManagement: set cpuFreqGovernor with mkOptionDefault
`nixos-generate-config` detects the `cpuFreqGovernor` suited best for my
machine, e.g. `powerManagement.cpuFreqGovernor = lib.mkDefault "powersave";`.

However the `powerManagement` module sets a sensitive default for
`cpuFreqGovernor` using `mkDefault` to avoid breackage with older
setups. Since 140ac2f1 the `hardware-configuration.nix` sets the
gorvernor with `mkDefault` as well which causes evaluation errors if the
powermanagement module is enabled:

```
error: The unique option `powerManagement.cpuFreqGovernor' is defined multiple times, in `/home/ma27/Projects/nixos-config/hardware-configuration.nix' and `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/nixos/modules/config/power-management.nix'.
```

Using `mkOptionDefault` rather than `mkDefault` in the powermanagement
module fixes this issue as it decreases the priority of the module and
prefers the value set in `hardware-configuration.nix`.

I have confirmed the change using the following VM declaration:

```
{
  cpuFreq = { lib, ... }: {
    powerManagement.cpuFreqGovernor = lib.mkDefault "powersave";
    powerManagement.enable = true;
  };
}
```
2018-01-28 09:38:45 +01:00

110 lines
2.6 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.powerManagement;
in
{
###### interface
options = {
powerManagement = {
enable = mkOption {
type = types.bool;
default = true;
description =
''
Whether to enable power management. This includes support
for suspend-to-RAM and powersave features on laptops.
'';
};
resumeCommands = mkOption {
type = types.lines;
default = "";
description = "Commands executed after the system resumes from suspend-to-RAM.";
};
powerUpCommands = mkOption {
type = types.lines;
default = "";
example = literalExample ''
"''${pkgs.hdparm}/sbin/hdparm -B 255 /dev/sda"
'';
description =
''
Commands executed when the machine powers up. That is,
they're executed both when the system first boots and when
it resumes from suspend or hibernation.
'';
};
powerDownCommands = mkOption {
type = types.lines;
default = "";
example = literalExample ''
"''${pkgs.hdparm}/sbin/hdparm -B 255 /dev/sda"
'';
description =
''
Commands executed when the machine powers down. That is,
they're executed both when the system shuts down and when
it goes to suspend or hibernation.
'';
};
};
};
###### implementation
config = mkIf cfg.enable {
# Leftover for old setups, should be set by nixos-generate-config now
powerManagement.cpuFreqGovernor = mkOptionDefault "ondemand";
systemd.targets.post-resume = {
description = "Post-Resume Actions";
requires = [ "post-resume.service" ];
after = [ "post-resume.service" ];
wantedBy = [ "sleep.target" ];
unitConfig.StopWhenUnneeded = true;
};
# Service executed before suspending/hibernating.
systemd.services."pre-sleep" =
{ description = "Pre-Sleep Actions";
wantedBy = [ "sleep.target" ];
before = [ "sleep.target" ];
script =
''
${cfg.powerDownCommands}
'';
serviceConfig.Type = "oneshot";
};
systemd.services."post-resume" =
{ description = "Post-Resume Actions";
after = [ "suspend.target" "hibernate.target" "hybrid-sleep.target" ];
script =
''
${config.systemd.package}/bin/systemctl try-restart post-resume.target
${cfg.resumeCommands}
${cfg.powerUpCommands}
'';
serviceConfig.Type = "oneshot";
};
};
}