Hi everyone,
I want to share a Linux userspace project for restoring and extending the front Light Bar functionality on the ASUS ExpertBook B9400CBA/B9450CBA.
The project was developed and physically tested on:
- Fedora Linux 44 KDE Plasma Desktop Edition
- Kernel: 7.1.9-200.fc44.x86_64
- KDE Plasma: 6.7.4
- Wayland
- Laptop: ASUS EXPERTBOOK B9400CBA_B9450CBA
- Light Bar controller: ALED0217
- HID VID:PID: 0B05:0124
- HID-over-I2C
- 5 RGB zones
- Report ID: 0x20
This is a userspace Light Bar controller, not a kernel driver.
There are now two releases. Both are kept because they serve slightly different goals.
v1.0.0 — Windows-parity baseline
v1.0.0 is the conservative version.
Its goal is to restore the basic Light Bar behavior expected from the laptop without adding extra Linux-specific effects.
Behavior
| Laptop state | Light Bar behavior |
|---|---|
| AC disconnected | Off |
| AC connected + charging below 100% | Dim red |
| Battery reaches 100% while connected to AC | Dim green |
| Entering Performance profile | Blue/cyan for 3 seconds |
| After Performance indication | Previous state is restored |
It also includes:
- Automatic ALED0217 HID discovery
- Controller/report-descriptor validation
- Five-zone controller handshake
- Automatic reconnect handling
- systemd integration
- Safe shutdown behavior
v1.0.0 release
I would recommend v1.0.0 to users who only want the missing ASUS Light Bar functionality restored with a minimal implementation.
v2.0.0 — Linux-enhanced edition
v2.0.0 keeps the validated automatic behavior from v1, but adds Linux-specific functionality and configurable charging effects.
The selected charging pattern is persistent and survives reboot/shutdown until the user changes it again.
Terminal control
The charging pattern can be selected directly from the terminal:
lightbarctl 1
lightbarctl 2
lightbarctl 3
lightbarctl 4
lightbarctl 5
To check the current configuration:
lightbarctl status
To list the available patterns:
lightbarctl list
Available charging patterns
| Pattern | Effect |
|---|---|
| 1 | Liquid Rainbow v0.2 |
| 2 | Center Bloom |
| 3 | Hard-edge Constant-Luminance Flow |
| 4 | ASUS hardware Effect 14 |
| 5 | Original v1 Static Red |
Additional v2 features
- Persistent pattern selection across reboot/shutdown
- Terminal-based pattern control
- KDE/Freedesktop notification integration
- Very dim yellow Light Bar indication for 1 second when a desktop notification is received
- Automatic restoration of the selected charging pattern after a notification
- Original green indication at 100% battery
- Original blue/cyan Performance-profile indication
- Automatic restoration of the selected charging pattern after overlays
- Support for ASUS hardware Effect 14
- Validated ALED0217 reset handling when leaving Effect 14
The Effect 14 path required special handling because the controller can remain in its internal hardware-animation state after switching back to direct RGB.
The final implementation uses a tested i2c_hid_acpi unbind/rebind reset sequence with a stabilization delay before direct RGB is restored.
v2.0.0 release
For users who want the full feature set, I recommend v2.0.0.
v1 vs v2 summary
| Feature | v1.0.0 | v2.0.0 |
|---|---|---|
| AC disconnected → Off | Yes | Yes |
| Charging → Red | Yes | Yes / selectable pattern |
| Battery 100% → Green | Yes | Yes |
| Performance → Blue/Cyan for 3s | Yes | Yes |
| Multiple charging patterns | No | Yes |
| Persistent pattern selection | No | Yes |
| Terminal control | No | Yes |
| KDE notification Light Bar indication | No | Yes |
| ASUS hardware Effect 14 | No | Yes |
| Intended philosophy | Windows-parity baseline | Linux-enhanced edition |
Hardware compatibility warning
Please do not install this blindly on another ASUS RGB device.
The tested hardware is specifically:
ASUS EXPERTBOOK B9400CBA_B9450CBA
ALED0217
0B05:0124
Other ExpertBook or ASUS models may use a different HID controller, report format, ACPI implementation, or RGB protocol.
The project performs hardware validation before controlling the Light Bar, but reports from other B9400/B9450 variants would still be very useful.
Project repository
The repository contains the source code, installer, systemd units, protocol/reverse-engineering notes, release notes, rollback information, and both v1 and v2 releases.
Feedback from Fedora users with the same or closely related ExpertBook hardware is welcome.
Development, diagnostics, protocol analysis, integration, and documentation were assisted by OpenAI ChatGPT (GPT-5.6 Sol).
All hardware behavior described in the project was physically tested and validated on the actual ASUS ExpertBook laptop.