A Rust port of the original switcheroo-control daemon and CLI tool by Bastien Nocera.

From a switcheroo-control man page:

switcherooctl is the command-line interface for switcheroo-control, a daemon that manages hybrid graphics on Linux laptops with multiple GPUs. It provides a simple way to list available graphics adapters and launch applications on a specific GPU.

On hybrid graphics systems with both integrated (power-efficient) and discrete (high-performance) GPUs, applications default to the integrated GPU. Using switcherooctl, you can run specific applications on the discrete GPU for better graphics performance.

This port uses the udev crate for GPU monitoring, combined with the nix crate for low-level ioctl driver queries (amdgpu, i915, nouveau, and xe drivers) to determine whether a card is discrete or integrated.

It reimplements the standard net.hadess.SwitcherooControl interface using the zbus crate.

switcherooctl provides a user-friendly CLI via the clap crate, including implicit subcommands which are also present in the original project. The daemon likewise uses clap for its own --replace flag.

Also, just like the original project, it includes a regex-based cleanup module to prettify GPU information before it is published over D-Bus

Workspace Members

Architecture

flowchart TB
    User((User))

    subgraph Userspace [Userspace Context]
        CLI(switcherooctl)
        Daemon(switcheroo-daemon)
        DBus{{D-Bus System Bus}}
        TargetApp[[Target Application]]
    end

    subgraph OS_Kernel [OS & Kernel Interface]
        subgraph UdevSub [udev Subsystem]
            Udev[udev crate]
            LibUdev[libudev C FFI]
        end

        subgraph IOCTL_Sub [DRM Subsystem]
            DRM_Nodes[(/dev/dri/render*)]
            Drivers[\amdgpu, i915, xe, nouveau, nvidia/]
        end
    end

    User -->|Runs| CLI
    
    CLI -->|Queries GPUs| DBus
    DBus <-->|net.hadess.SwitcherooControl| Daemon
    DBus -->|GPU info & env| CLI
    
    CLI -.->|Spawns with env vars| TargetApp
    
    Daemon -->|Queries GPUs & watch events| Udev
    Udev -->|GPUs info & events| Daemon
    
    Daemon -->|switcheroo-discrete-gpu tag check| LibUdev
    LibUdev -->|is_discrete| Daemon
    
    Daemon -->|IOCTL probe| DRM_Nodes
    DRM_Nodes -->|VRAM / LMEM status| Daemon
    
    DRM_Nodes --- Drivers
    TargetApp -.->|Render offload| Drivers

Usage

Ensure you have the libudev library installed where it can be found by pkg-config.

Example:

sudo apt-get install libudev-dev    # Debian-based Linux distributions
sudo zypper install systemd-devel   # openSUSE/SLE

Compile a release build using Cargo:

To test the daemon locally, stop the existing system service first to avoid D-Bus conflicts:

sudo systemctl stop switcheroo-control
sudo ./target/release/switcheroo-daemon

You can now use the CLI tool:

./target/release/switcherooctl help

Usage: switcherooctl [OPTIONS] [COMMAND]

Commands:
  list    List the known GPUs
  launch  Launch a command on a specific GPU
  help    Print this message or the help of the given subcommand(s)

Options:
  -g, --gpu <GPU>
  -h, --help       Print help

Example

Launch the glmark2's refract benchmark on a discrete GPU:

./target/release/switcherooctl launch --gpu 1 glmark2 -b refract

For simplicity, you can also omit subcommands:

./target/release/switcherooctl            # "switcherooctl list"
./target/release/switcherooctl <program>  # "switcherooctl launch <program>" 

License

The project is licensed under GPL-3.0-or-later to match upstream.