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Prerequisites

Before installing KVantage, ensure you have:
  • A Lenovo laptop (required for ACPI interface compatibility)
  • Java Runtime Environment (JRE) installed on your system
  • The acpi_call kernel module loaded (see System Requirements for details)

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Download KVantage

You can download the latest version of KVantage from: The application is distributed as a single .jar file for portability and ease of installation.

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Install Java Runtime

KVantage requires a Java Runtime Environment to run. Install it using your distribution’s package manager: 
sudo apt update
sudo apt install default-jre
Verify Java is installed: 
java -version

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Installation Process

1

Download the JAR file

Download com.korealm.kvantage-linux-x64-2.1.0-release.jar to your preferred location (e.g., ~/Downloads).
2

Run KVantage for the first time

Navigate to the download location and run:
java -jar com.korealm.kvantage-linux-x64-2.1.0-release.jar
Do not run the application as root or with sudo. The GUI must run as a regular user. Root access is handled internally by the backend service.
3

Complete the embedded installer

On first launch, KVantage will prompt you to install the application:
  • The installer copies the JAR file to ~/.local/bin/
  • Creates a desktop entry at ~/.local/share/applications/kvantage.desktop
  • Extracts the application icon to ~/.local/share/icons/
  • Allows you to launch KVantage from your application menu
If you decline the installation, you can still use KVantage as a portable application by running the JAR file directly. To prevent the installer prompt from appearing again, select “No, and don’t ask me again.”
4

Grant root permissions

When KVantage starts, the backend service (kvand) will prompt for your password using your system’s authentication dialog (e.g., polkit, pkexec, or sudo).Root access is required once per session to interact with /proc/acpi/call for reading and writing ACPI values.
The password prompt is for the backend daemon only. The GUI never runs with elevated privileges for security reasons.
5

Verify installation

After installation, you can launch KVantage:
  • From your application menu (search for “KVantage”)
  • From terminal: java -jar ~/.local/bin/com.korealm.kvantage-linux-x64-2.1.0-release.jar
The main window should appear with your current performance profile and battery settings.

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Portable Usage (No Installation)

If you prefer to use KVantage without installing, you can run it directly: 
java -jar /path/to/com.korealm.kvantage-linux-x64-2.1.0-release.jar
The application will prompt you to install on each launch unless you select “No, and don’t ask me again.”

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Uninstallation

To remove KVantage from your system: 
# Remove the application files
rm ~/.local/bin/com.korealm.kvantage-linux-x64-2.1.0-release.jar
rm ~/.local/share/applications/kvantage.desktop
rm ~/.local/share/icons/favicon.png

# Remove configuration files (optional)
rm -rf ~/.config/KVantage/

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Troubleshooting

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Backend service fails to start

If you see “Failed to initialize the backend service” error:
  1. Verify the acpi_call module is loaded: 
    lsmod | grep acpi_call
  2. Check if /proc/acpi/call exists: 
    ls -l /proc/acpi/call
  3. Ensure you’re not running as root: 
    echo $USER
# Should NOT be "root"

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Application won’t start with “must never be started as root” error

Never run KVantage with sudo or as the root user. Run it as your regular user: 
# Wrong
sudo java -jar kvantage.jar

# Correct
java -jar kvantage.jar

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Java version incompatibility

Ensure you have Java 11 or later installed: 
java -version
If the version is too old, update your Java installation using the commands in the Install Java Runtime section.

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