{self, ...}: {
  # Hybrid Intel + NVIDIA (PRIME) for laptops like the T480 (Intel UHD 620 +
  # NVIDIA MX150). Uses "offload" mode: the dGPU stays powered down by default
  # (minimal extra battery drain) and is only used for apps launched with
  # `nvidia-offload <cmd>`. It also pulls in the Intel GPU stack (gpuIntel).
  #
  # Bus IDs below are specific to the T480 (from `lspci`):
  #   Intel  00:02.0 -> PCI:0:2:0
  #   NVIDIA 01:00.0 -> PCI:1:0:0
  # Adjust for other machines.
  flake.nixosModules.gpuNvidiaPrime = {
    config,
    pkgs,
    ...
  }: {
    imports = [self.nixosModules.gpuIntel];

    services.xserver.videoDrivers = ["nvidia"];

    hardware.nvidia = {
      modesetting.enable = true;
      # MX150 is Pascal (pre-Turing); the proprietary modules are the safe choice.
      open = false;
      nvidiaSettings = true;
      powerManagement.enable = true;

      prime = {
        # Offload keeps the NVIDIA GPU asleep until explicitly used. This gives
        # the `nvidia-offload` helper wrapper. Swap to sync mode if you want the
        # dGPU always driving the display (higher power draw).
        offload = {
          enable = true;
          enableOffloadCmd = true; # provides `nvidia-offload` wrapper
        };

        intelBusId = "PCI:0:2:0";
        nvidiaBusId = "PCI:1:0:0";
      };
    };
  };
}