anchor.diff:      options snd_hda_intel enable=0,1
     '';
   
  +  boot.cleanTmpDir = true;
     powerManagement.enable = true;
     powerManagement.cpuFreqGovernor = "conservative";
  +
  +  hardware.cpu.intel.updateMicrocode = true;
  +
  +  # Use power key as a suspend key. More useful (and safe) than power
  +  # off, b/c I hit it by accident a lot.
  +  services.logind.extraConfig = ''
  +    HandlePowerKey=suspend
  +    HandleLidSwitch=suspend
  +  '';
   
     # Touchpad configuration.
     services.xserver.synaptics = {
  
positive.code: # Acer C720-specific configuration.
  #
  # Unfortunately things are not working quite yet. Suspend/resume
  # causes some sort of weird USB error to fill up the system logs, and
  # I have to force shut the computer down. I am hopefull I'll get it
  # working eventually, apparently it has been done.
  #
  # The trackpad works, but is -- touchy. If I brush it at all, it
  # clicks or does something silly. I have to build the kernel with a
  # custom flag set for it to work at all.
  #
  # I would like the power button not to immediately shut the computer
  # down without any warning when I am, say, working in emacs and trying
  # to hit the backspace key. (Perhaps this is an xmonad config thing.)
  
  { config, pkgs, ...}:
  
  {
  
    # Asus C720 suspend compat -- doesn't seem to work.
    boot.blacklistedKernelModules = [ "ehci_pci" ];
    boot.kernelParams = [
      "tpm_tis.interrupts=0"
      "i915.enable_ips=0"
    ];
  
    # Get sound working.
    # (disable the first intel sound card, enable the second.)
  
negative.code: 
    # set CHROME_PLATFORMS flag; needed for touchpad.
    # note: this means nix will need to build linux. fun!
    # nixpkgs.config = {
    #   packageOverrides = super: let self = super.pkgs; in rec {
    #     stdenv = super.stdenv // {
    #       platform = super.stdenv.platform // {
    #         kernelExtraConfig = ''
    #           CHROME_PLATFORMS y
    #         '';
    #       };
    #     };
    #   };
    # };
  
    # maybe this is needed?
    services.xserver.vaapiDrivers = [ pkgs.vaapiIntel ];
  