Add a config for Asus Zephyrus GA402X* (2023) series

- Disable power-saving for the keyboard on the Asus Zephyrus GA402X series (2023)
- Add more-aggressive roaming rules for Asus Mediatek cards when using IWD
  - Add note about potentially needing more-aggressive roaming rules for Asus Mediatek cards when using WPA-Supplicant
  - Make enabling the higher scanning optional
- Split-up the AMD-GPU and Nvidia configs
- Add switch for AMD-GPU recovery mode
- Add switch for AMD-GPU sg_display (Scatter/Gather) mode
- Add switch for AMD-GPU PSR support

asus/zephyrus/ga402x/nvidia/default.nix

@@ -0,0 +1,55 @@
+{ lib,
+  pkgs,
+  ...
+}:
+
+let
+  inherit (lib) mkDefault;
+
+in {
+  imports = [
+    ../shared.nix
+    ## "prime.nix" loads this, aleady:
+    # ../../../common/gpu/nvidia
+    ../../../../common/gpu/nvidia/prime.nix
+  ];
+
+  # NVIDIA GeForce RTX 4060 Mobile
+
+  boot = {
+    blacklistedKernelModules = [ "nouveau" ];
+  };
+
+  # Also in nvidia/default.nix
+  services.xserver.videoDrivers = mkDefault [ "nvidia" ];
+
+  hardware = {
+    ## Enable the Nvidia card, as well as Prime and Offload:
+    amdgpu.loadInInitrd = true;
+    opengl.extraPackages = with pkgs; [
+      # Also in nvidia/default.nix
+      vaapiVdpau
+      libvdpau-va-gl
+    ];
+
+    nvidia = {
+      modesetting.enable = true;
+      nvidiaSettings = true;
+
+      prime = {
+        offload = {
+          enable = true;
+          enableOffloadCmd = true;
+        };
+        amdgpuBusId = "PCI:101:0:0";
+        nvidiaBusId = "PCI:1:0:0";
+      };
+
+      powerManagement = {
+        # This is unreliable on the 4060;  works a few times, then hangs:
+        # enable = true;
+        # finegrained = true
+      };
+    };
+  };
+}