[graphics] Modularizes graphics config. Applies it to vega.

system/features/graphics.nix

@@ -0,0 +1,50 @@
+{ config, lib, ... }:
+{
+  options =
+    with lib;
+    with types;
+    {
+      graphics = {
+        enable = mkEnableOption "graphics support";
+        driverChannel = mkOption {
+          type = str;
+          # Default to production because I often want new features, but I don't want bleeding edge.
+          default = "production";
+          description = "Driver channel to use (in order of oldest to newest): stable, beta, latest";
+        };
+      };
+    };
+
+  config = lib.mkIf config.graphics.enable {
+    # Graphics settings
+    hardware.graphics = {
+      enable = true;
+      enable32Bit = true;
+    };
+
+    services.xserver.videoDrivers = [ "nvidia" ];
+
+    hardware.nvidia = {
+      package = config.boot.kernelPackages.nvidiaPackages."${config.graphics.driverChannel}";
+
+      modesetting.enable = true;
+
+      # Nvidia power management. Experimental, and can cause sleep/suspend to fail.
+      # Enable this if you have graphical corruption issues or application crashes after waking
+      # up from sleep. This fixes it by saving the entire VRAM memory to /tmp/ instead
+      # of just the bare essentials.
+      powerManagement.enable = true;
+
+      # Fine-grained power management for PRIME. Turns off GPU when not in use.
+      # Experimental and only works on modern Nvidia GPUs (Turing or newer).
+      # Requires offload to be enabled.
+      # powerManagement.finegrained = false;
+
+      # Use the open-source driver?
+      open = false;
+
+      # Enable the nvidia-settings menu?
+      nvidiaSettings = true;
+    };
+  };
+}