DisplayControl (dispctl)

A dynamic, TUI-based display control tool that allows you to manage monitor settings via DDC/CI commands. Built in Go with Bubbletea for an interactive terminal interface.

Features

• 🎯 Dynamic Configuration: Auto-generate configs from your monitor's capabilities
• 📋 Interactive TUI: Navigate settings with an intuitive menu interface
• 🔍 Dry-run Mode: Preview commands before executing
• 🎨 Breadcrumb Navigation: Track your location in nested menus
• ⚡ Single Binary: No runtime dependencies except ddcutil
• ✅ Error Handling: Clear feedback on command success/failure

Prerequisites

• Linux system with I2C support
• ddcutil installed and configured
• Go 1.23+ (for building from source)

Installing ddcutil

# Debian/Ubuntu
sudo apt install ddcutil

# Fedora
sudo dnf install ddcutil

# Arch
sudo pacman -S ddcutil

Setting up I2C permissions

Add your user to the i2c group:

sudo usermod -aG i2c $USER

Load the i2c-dev module:

sudo modprobe i2c-dev
echo "i2c-dev" | sudo tee /etc/modules-load.d/i2c-dev.conf

Installation

Building from Source

git clone https://github.com/clobrano/DisplayControl
cd DisplayControl
make build
sudo make install

Usage

Generate Configuration

Generate a configuration file from your monitor's capabilities:

dispctl --generate

This creates a configuration file at ~/.config/display-control/config.yaml.

For multi-monitor setups, specify the display:

dispctl --generate --display 1

Run the Interactive Menu

dispctl

Use a custom configuration file:

dispctl --file /path/to/config.yaml

Dry-run Mode

Preview commands without executing them:

dispctl --dry-run

Other Options

dispctl --version          # Show version
dispctl --help             # Show help

Configuration File Format

The configuration file is generated from ddcutil capabilities output and follows this structure:

brightness:
  _code: "0x10"
  _description: "Brightness"
  values:
    "0": "0x00"
    "50": "0x32"
    "100": "0x64"

input_source:
  _code: "0x60"
  _description: "Input Source"
  values:
    HDMI-1: "0x11"
    DisplayPort-1: "0x0f"

• _code: VCP feature code in hex format
• _description: Human-readable feature description
• values: Map of setting names to hex values

See examples/sample-config.yaml for a complete example.

TUI Navigation

• ↑/↓ or j/k: Navigate menu items
• Enter: Select item / Execute command
• b or Esc: Go back one level
• r: Return to root menu
• q or Ctrl+C: Quit

Command-Line Flags

Flag	Short	Description
--generate	-g	Generate config from ddcutil capabilities
--file PATH	-f	Specify custom config file path
--dry-run	-d	Preview commands without executing
--display ID		Specify display ID for ddcutil
--version	-v	Show version information
--help	-h	Show help message

Troubleshooting

Permission Denied

If you get permission errors:

1. Ensure you're in the i2c group:

   groups $USER

2. Load the i2c-dev module:

   sudo modprobe i2c-dev

3. Log out and back in for group changes to take effect

ddcutil Not Found

Install ddcutil for your distribution (see Prerequisites section).

No Features in Configuration

Your monitor may not support DDC/CI or the feature list is empty. Check with:

ddcutil capabilities

I2C Device Access

If you see "Cannot open I2C device":

1. Check that /dev/i2c-* devices exist
2. Verify i2c-dev module is loaded: lsmod | grep i2c_dev
3. Check permissions: ls -l /dev/i2c-*

Development

Running Tests

make test

Building

make build

Cleaning

make clean

Project Structure

DisplayControl/
├── cmd/
│   └── dispctl/
│       └── main.go              # CLI entry point
├── internal/
│   ├── config/
│   │   ├── config.go            # YAML configuration parsing
│   │   └── config_test.go
│   ├── parser/
│   │   ├── capabilities.go      # ddcutil capabilities parser
│   │   └── capabilities_test.go
│   ├── generator/
│   │   ├── generator.go         # Configuration generator
│   │   └── generator_test.go
│   ├── ddcutil/
│   │   ├── executor.go          # DDC/CI command executor
│   │   └── executor_test.go
│   ├── ui/
│   │   ├── menu.go              # Bubbletea TUI
│   │   └── menu_test.go
│   └── version/
│       └── version.go           # Version information
├── examples/
│   └── sample-config.yaml       # Example configuration
├── Makefile
└── README.md

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Acknowledgments

• Built with Bubbletea for the TUI
• Uses ddcutil for DDC/CI communication
• Inspired by the need for better monitor control on Linux