{ config, lib, pkgs, ... }:
let
  cfg = config.sane.hal.x86_64;
in
{
  options = {
    sane.hal.x86_64.enable = (lib.mkEnableOption "x86_64-specific hardware support") // {
      default = pkgs.system == "x86_64-linux";
    };
  };
  config = lib.mkIf cfg.enable {
    boot.initrd.availableKernelModules = [
      "xhci_pci" "ahci" "sd_mod" "sdhci_pci"  # nixos-generate-config defaults
      "usb_storage"   # rpi needed this to boot from usb storage, i think.
      "nvme"  # to boot from nvme devices
      # efi_pstore evivars

      # added (speculatively) 2024/05/21; these were implicitly being added by nixos/modules/system/boot/kernel.nix
      # i've copied not all of them, but most
      "mmc_block"
      "dm_mod"
      # USB keyboards
      "uhci_hcd" "ehci_hcd" "ehci_pci" "ohci_hcd" "ohci_pci" "xhci_hcd" "xhci_pci" "usbhid" "hid_generic" "hid_lenovo" "hid_apple" "hid_roccat" "hid_logitech_hidpp" "hid_logitech_dj" "hid_microsoft" "hid_cherry" "hid_corsair"
      # x86 keyboard stuff
      "pcips2" "atkbd" "i8042"
      # stage-2 init needs rtc?
      "rtc_cmos"
    ];

    hardware.cpu.amd.updateMicrocode = true;    # desktop
    hardware.cpu.intel.updateMicrocode = true;  # laptop
  };
}