cardwire

A GPU manager for Linux using eBPF LSM hooks to block GPUs

Creator and Main maintainer: @luytan

Disclaimer

• This project is in early development. Expect bugs and incomplete functionality

Getting Started

Head to the docs to see how to install Cardwire on your system

Usage

The cardwire CLI lets you manage GPU states and system modes

Modes

• Integrated: Blocks the discrete GPU
• Hybrid: Unblocks the discrete GPU
• Manual: Default mode for safety, allows individual GPU blocking/unblocking
• Smart: Like integrated mode but uses eBPF to analyze applications at launch and selectively allow GPU access

Note: Integrated/Hybrid/Smart modes only work on systems with exactly two GPUs

# Set system mode
cardwire set integrated / hybrid / manual / smart

# Get current mode status
cardwire get

# List all detected GPUs and their status
cardwire list

# Manually block/unblock a specific GPU by ID
cardwire gpu 1 --block
cardwire gpu 1 --unblock

Configuration

The daemon reads its configuration from /etc/cardwire/cardwire.toml.

# /etc/cardwire/cardwire.toml
auto_apply_gpu_state = true
experimental_nvidia_block = false
battery_auto_switch = false
battery_auto_switch_mode = "hybrid"

experimental_nvidia_block is an experimental feature that blocks specific NVIDIA files, must be used with caution.

battery_auto_switch_mode controls which mode cardwire switches to on AC power when battery_auto_switch is enabled. Can be set to integrated, hybrid, manual, or smart.

Community projects:

for issues related to these projects, please report to their respective repo

GNOME extension (by Moxuz): https://extensions.gnome.org/extension/9919/cardwire-gpu-toggle/

Cardwire-tray (by SeawolfTony): https://github.com/JuanDelPueblo/cardwire-tray

How it works

Cardwire uses eBPF with LSM hooks to intercept file operations on GPU device nodes, such as /dev/dri/renderDX, /dev/dri/cardX, sysfs config and nvidiaX

When a GPU is "blocked," the eBPF program returns -ENOENT for any syscall targeting that device. This provides several key benefits:

• Instant App Startup: Prevents applications (like Electron apps or GTK apps) from attempting to initialize the GPU, this eliminates the 3–4 second "hang" typically caused by waiting for a sleeping GPU to power up
• Power Efficiency: By blocking access at the syscall level, the GPU is never woken from its lowest power state (D3cold), extending battery life on laptops
• Non-Invasive: Unlike traditional methods that might require driver unloading, risky unbind or complex Wayland setups, this approach is transparent to the rest of the system and easy to toggle

Note: X11 is not supported. Cardwire requires Wayland.

• Also works with games

Notes

• I'm still learning Rust, if some parts of the code are bad or unoptimized, feel free to open a PR

Credits

• Asus-linux Discord for helping me find the ebpf method

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.