nixos/lact: init

On AMD GPU, you should enable overdrive mode by using `hardware.amdgpu.overdrive.enable = true;` in your configuration.

Co-authored-by: PopeRigby <poperigby@mailbox.org>
Signed-off-by: John Titor <50095635+JohnRTitor@users.noreply.github.com>

nixos/doc/manual/release-notes/rl-2511.section.md

@@ -14,6 +14,9 @@
 
 - [FileBrowser](https://filebrowser.org/), a web application for managing and sharing files. Available as [services.filebrowser](#opt-services.filebrowser.enable).
 
+- [LACT](https://github.com/ilya-zlobintsev/LACT), a GPU monitoring and configuration tool, can now be enabled through [services.lact.enable](#opt-services.lact.enable).
+  Note that for LACT to work properly on AMD GPU systems, you need to enable [hardware.amdgpu.overdrive.enable](#opt-hardware.amdgpu.overdrive.enable).
+
 - [SuiteNumérique Docs](https://github.com/suitenumerique/docs), a collaborative note taking, wiki and documentation web platform and alternative to Notion or Outline. Available as [services.lasuite-docs](#opt-services.lasuite-docs.enable).
 
 ## Backward Incompatibilities {#sec-release-25.11-incompatibilities}

nixos/modules/module-list.nix

@@ -646,6 +646,7 @@
   ./services/hardware/kanata.nix
   ./services/hardware/keyd.nix
   ./services/hardware/kmonad.nix
+  ./services/hardware/lact.nix
   ./services/hardware/lcd.nix
   ./services/hardware/libinput.nix
   ./services/hardware/lirc.nix

nixos/modules/services/hardware/lact.nix

@@ -0,0 +1,39 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  cfg = config.services.lact;
+in
+{
+  meta.maintainers = [ lib.maintainers.johnrtitor ];
+
+  options.services.lact = {
+    enable = lib.mkEnableOption null // {
+      description = ''
+        Whether to enable LACT, a tool for monitoring, configuring and overclocking GPUs.
+
+        ::: {.note}
+        If you are on an AMD GPU, it is recommended to enable overdrive mode by using
+        `hardware.amdgpu.overdrive.enable = true;` in your configuration.
+        See [LACT wiki](https://github.com/ilya-zlobintsev/LACT/wiki/Overclocking-(AMD)) for more information.
+        :::
+      '';
+    };
+
+    package = lib.mkPackageOption pkgs "lact" { };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [ cfg.package ];
+    systemd.packages = [ cfg.package ];
+
+    systemd.services.lactd = {
+      description = "LACT GPU Control Daemon";
+      wantedBy = [ "multi-user.target" ];
+    };
+  };
+}