Hardware Compatibility¶

Overview¶

Hara Hachi Bu works with any laptop that exposes battery charge control via the standard Linux sysfs interface. No vendor-specific drivers or kernel patches required.

Minimum Requirements¶

Device Detection¶

The extension automatically enumerates batteries in /sys/class/power_supply/. If enumeration fails, it falls back to checking BAT0, BAT1, BAT2, BAT3 in order. The first battery with charge_control_end_threshold is used as the primary control device.

Multi-battery systems (BAT0 through BAT3) are fully supported with synchronized thresholds.

Known Compatible Hardware¶

Full Support (start + end threshold)¶

• ThinkPad — via thinkpad_acpi kernel module (all modern models)
• Framework — via standard kernel interfaces
• Some Dell models — depends on kernel version and model

End-Only Support¶

• ASUS — many models expose only charge_control_end_threshold; end-only devices are fully supported including battery mode auto-detection based on the end threshold value

End-only devices display a simplified view in Preferences → Thresholds (no start threshold slider).

Checking Your Hardware¶

# Check for threshold support
ls /sys/class/power_supply/BAT0/charge_control_*

# Typical output on ThinkPad / Framework:
# /sys/class/power_supply/BAT0/charge_control_end_threshold
# /sys/class/power_supply/BAT0/charge_control_start_threshold

# ASUS (end-only):
# /sys/class/power_supply/BAT0/charge_control_end_threshold

# Check force discharge support
ls /sys/class/power_supply/BAT0/charge_behaviour

AC Adapter Detection¶

The extension automatically detects the AC adapter by checking these known names in order: AC, ACAD, ADP0, ADP1. The first available adapter is used for power source detection.

Power Profiles¶

Power profile switching requires power-profiles-daemon. Check if it's installed and running:

systemctl status power-profiles-daemon
powerprofilesctl list

If not installed:

# Debian/Ubuntu
sudo apt install power-profiles-daemon

# Fedora
sudo dnf install power-profiles-daemon

Adding Support for New Hardware¶

The extension uses a modular device backend architecture. If your device uses a completely different mechanism (not standard sysfs paths), you can add a new backend.

When You Don't Need a New Backend¶

If your device exposes /sys/class/power_supply/BAT0/charge_control_end_threshold, it is already supported by the built-in GenericSysfsDevice implementation.

Creating a New Backend¶

1. Create a new file in lib/device/ (e.g., MyLaptopDevice.js)
2. Inherit from BaseDevice and implement the required methods:

import {BaseDevice} from './BaseDevice.js';

export const MyLaptopDevice = GObject.registerClass(
    {
        GTypeName: 'HHBMyLaptopDevice',
    },
    class MyLaptopDevice extends BaseDevice {
        async initialize() {
            // Check for specific files or DMI strings
            // Return true if compatible
        }

        static isSupported() {
            // Synchronous check — return true if this is a MyLaptop
            return false;
        }

        async setThresholds(start, end) {
            // Write to sysfs
            // Use hhb-power-ctl if root permissions are required
        }
    }
);

1. Register your device in lib/device/DeviceManager.js before the GenericSysfsDevice catch-all.

Extending the Helper Script¶

If root privileges are needed, extend resources/hhb-power-ctl:

1. Add a new command case for your hardware
2. Security note: Hardcode the sysfs paths in the script — do not pass arbitrary paths as arguments

See Contributing for how to submit the new backend.

Mock Mode (Testing Without Hardware)¶

To test the UI without real battery hardware:

mkdir -p ~/.config/hara-hachi-bu
touch ~/.config/hara-hachi-bu/use_mock

Reload the extension. All threshold changes will be simulated in-memory and logged to the journal. Remove the file to return to real hardware.