OpenLConnect

An open-source Linux replacement for Lian Li L-Connect 3. Control UNI FAN controller fan speeds (manual % and temperature curves) and ARGB (per-LED colors + hardware effects) directly over USB HID — no vendor software, no cloud, no GUI required. The command-line tool is lianctl.

Pure Go, zero external dependencies, no cgo, no libusb. Talks straight to /dev/hidraw*.

Status: fan control works on all UNI FAN controllers. Full per-LED RGB is implemented and verified on real hardware for the UNI FAN SL-Infinity (0cf2:a102). RGB for other models and LCD streaming are framework-ready — see docs/PROTOCOL.md and docs/CAPTURE.md to help decode them.

Not affiliated with or endorsed by Lian Li. "L-Connect" is used only to describe compatibility.

Supported hardware

Controller	Fan	RGB
UNI FAN SL v1 (0cf2:7750, a100)	✅	sync only
UNI FAN AL (a101)	✅	sync only
UNI FAN SL-Infinity (a102)	✅	✅ per-LED + effects
UNI FAN SL v2 (a103, a105)	✅	sync only
UNI FAN AL v2 (a104)	✅	sync only

Install

No toolchain required — the installer downloads a prebuilt binary for your machine (curl or wget is enough). Go is only needed if you want to build from source.

git clone https://github.com/pwnmeow/OpenLconnect
cd OpenLconnect
./scripts/install.sh            # downloads binary, installs it + udev rule
# optional: also install & enable the fan-curve daemon
./scripts/install.sh --service

Prefer to build from the checkout instead of downloading? Install Go 1.25+ and run BUILD_FROM_SOURCE=1 ./scripts/install.sh.

Re-login or replug the controller once so the udev rule grants access. Then:

lianctl list

Cross-compile from another OS

GOOS=linux GOARCH=amd64 go build -o lianctl ./cmd/lianctl   # x86-64
GOOS=linux GOARCH=arm64 go build -o lianctl ./cmd/lianctl   # ARM (e.g. SBCs)

Usage

lianctl list                      # detected controllers
lianctl sensors                   # available temperature sources

# Fans (channels 0-3)
lianctl fan 0 60                  # set channel 0 to 60%
lianctl fan 1 pwm                 # hand channel 1 to motherboard 4-pin PWM
lianctl speed high                # all fans to a preset (low|medium|high|full)

# RGB (SL-Infinity, channels 0-7)
lianctl rgb off                   # all lights off (every channel)
lianctl rgb on                    # all lights on (white, full brightness)
lianctl rgb on '#5a00ff' 80       # all lights on, purple at 80%
lianctl color 0 '#5a00ff' 100     # solid purple on one channel, 100% brightness
lianctl effect 0 rainbow speed=80 # hardware rainbow
lianctl effect 0 breathing color='#00ff88' bri=50
lianctl effects                   # list effect names
lianctl sync on                   # mirror the motherboard 5V ARGB header

# Daemon (temperature-driven fan curves)
lianctl config init               # write a starter config
lianctl daemon                    # run curves in the foreground

Fan curves

lianctl config init writes JSON to ~/.config/lianctl/config.json (or /etc/lianctl/config.json for the system service). Example:

{
  "poll_seconds": 2,
  "fans": [
    {
      "channel": 0,
      "source": "hwmon:k10temp/Tctl",
      "curve": [[30, 30], [50, 45], [65, 70], [80, 100]]
    },
    { "channel": 1, "source": "max", "curve": [[40, 40], [70, 100]] }
  ],
  "rgb": [
    { "channel": 0, "effect": "static", "color": "#5a00ff", "brightness": 100 }
  ]
}

curve points are [tempC, dutyPercent], linearly interpolated and clamped at the ends. Temperature source can be:

• max — hottest hwmon sensor on the system
• hwmon:<chip>/<label> — e.g. hwmon:k10temp/Tctl, hwmon:coretemp/Package id 0
• file:/sys/class/hwmon/hwmon2/temp1_input — a raw sysfs millidegree file
• cmd:<shell command> — any command printing degrees C on stdout

Run lianctl sensors to see what's available on your box.

How it works

Each command is a HID output report (report ID 0xE0) written to the controller's hidraw node. The full byte-level protocol — fan RPM mapping, channel-mode register, and the SL-Infinity RGB packets — is documented in docs/PROTOCOL.md and asserted in internal/device/unihub_test.go.

cmd/lianctl        CLI
internal/device    controller drivers (uniHub) + protocol
internal/hid       /dev/hidraw transport (pure Go, Linux)
internal/sensors   temperature sources
internal/config    JSON config + curve interpolation
internal/daemon    curve evaluation loop

Contributing

Highest-value next steps:

1. Per-LED RGB for SL/AL/v2 hubs — capture L-Connect traffic (docs/CAPTURE.md) and add a driver case.
2. LCD streaming for the TL-LCD / Universal-Screen devices.
3. RPM read-back so the daemon can log/limit by actual fan RPM.

PRs welcome. Add a byte-level test for any new packet.

Credits

Protocol knowledge stands on the shoulders of uni-sync (fan control) and OpenRGB (RGB). This project is an independent clean-room Go implementation for Linux.

License

MIT — see LICENSE. Not affiliated with or endorsed by Lian Li.