Jovian NixOS Documentation

Jovian NixOS organizes its configuration options into several distinct namespaces. When extending or interacting with the system, you should identify which namespace your configuration belongs to:

• devices/: Contains options specific to individual devices. New devices must prefix their namespace (both folder and options) with the vendor name.
• hardware/: Contains hardware-specific options intended for a broad scope of devices. These options are typically gated behind hardware.has.* options.
• steam/: Contains options that control the "steam deck mode" Steam interface.
• steamos/: Contains opinionated configurations that mirror generic SteamOS settings but are not tied to a specific device.
• jovian/: Contains miscellaneous and mostly internal options required for the Jovian NixOS system to function.

Jovian NixOS includes specific configurations for gaming hardware.

• Steam Deck: The Valve Steam Deck is a known supported device.
• Other Hardware: While other computers work with standard NixOS, portable gaming devices may require specific Jovian NixOS modules.
• AMD vs NVIDIA: The Steam Deck experience is developed on AMD hardware. Using other hardware, particularly NVIDIA hardware, may result in issues.

Jovian-NixOS extends standard NixOS configurations by providing a set of extra options. To use these options in your NixOS configuration files, you must use the jovian prefix (e.g., jovian.<option_name>).

Most of these options are implementation details and typically do not require modification. For the specific options relevant to users, refer to the Getting Started and Configuration documentation.

If you encounter issues or have questions regarding Jovian NixOS, you can reach out through the following channels:

• Technical Issues: File an issue on GitHub.
• Questions and Discussions: Use the Discussions page.
• Community Chat: Join the Matrix room at #Jovian-Experiments:matrix.org.

To use Jovian NixOS, you must first install NixOS. The project currently only supports the unstable channel.

Requirements & Tips:

• Channel: Use the unstable channel only.
• Input Methods: Ensure you have a way to type commands (e.g., a keyboard) during setup.
• Boot Media: You can use an SD card to boot installation media to save USB ports.
• Encryption: If using Full-Disk Encryption (FDE), be aware that the lack of a physical keyboard on some devices might complicate entering decryption keys.

Firmware updates for the BIOS and controller are provided via the steamdeck-firmware package. These updates are not handled automatically and must be run manually using sudo.

# Update BIOS
sudo jupiter-biosupdate

# Update Controller
sudo jupiter-controller-update

To enable Decky Loader, add the jovian.decky-loader option to your Nix configuration and set enable = true;.

{
  jovian.decky-loader = {
    enable = true;
  };
}

You can manually enter Gaming Mode (the Steam Deck UI) using one of two methods:

1. From the Display Manager: Select "Gaming Mode" from the session selection menu.
2. From a Virtual Terminal (VT): Run the start-gamescope-session command.
3. From an existing desktop session: Launch gamescope-session. Note that running this within an existing session executes gamescope in nested mode, which may result in higher latency.

To enable Steam Deck-specific hardware configurations, import the ./modules directory from the jovian-nixos repository into your NixOS configuration and set the jovian.devices.steamdeck.enable option to true.

# Import modules from the repository
{ ... }: import ./modules

{ config, pkgs, ... }: {
  # Enable Steam Deck hardware configurations
  jovian.devices.steamdeck.enable = true;
}