Fix TUF keyboard RGB, battery charge limits, and performance mode persistence

[utajum]

Summary

• Add TUF keyboard RGB control via kbd_rgb_mode/kbd_rgb_state sysfs attributes — the primary RGB interface for TUF Gaming keyboards, derived from kernel source and asusctl analysis
• Add systemd-tmpfiles config to fix sysfs permissions lost on reboot when kernel modules are built-in (affects battery charge limit + platform_profile)
• Add readback verification after setting performance mode to detect and recover from kernel coupling between throttle_thermal_policy and platform_profile
• Update udev rules and install script for new sysfs paths

Models affected

• ASUS TUF Gaming A16 FA617NT (and all TUF models with kbd_rgb_mode)
• ASUS ROG Zephyrus G14 GA403UM (performance mode persistence)
• Any ASUS laptop on Fedora 43+ / kernel 6.12+ with built-in asus-wmi

Root cause analysis

Backlight / Aura controls do nothing (TUF)

Windows G-Helper calls DEVS(0x00100056, [0xb4, mode, R, G, B, speed]) directly via ATKACPI driver. Linux kernel exposes the same ACPI call through /sys/class/leds/asus::kbd_backlight/kbd_rgb_mode — but g-helper-linux was only writing to multi_intensity which many TUF models don't have. Now routes TUF models through kbd_rgb_mode with proper protocol (matching asusctl's implementation). Falls back to multi_intensity if kbd_rgb_mode doesn't exist — no risk to other models.

Battery limit ignored after reboot

Windows uses Task Scheduler to re-apply the limit at boot via direct ATKACPI. Linux kernel resets charge limit to 100% on every boot (asus_wmi_battery_add sets RSOC=100), and the sysfs file is created root-only (0644). If asus-wmi is built-in (common on Fedora), udev rules never fire. The new systemd-tmpfiles config ensures the file is writable before G-Helper starts.

Performance mode reverts to Standard after reboot (GA403UM)

Windows calls DEVS(0x00120075, mode) directly — no intermediate layer. Linux has both throttle_thermal_policy and platform_profile which can be coupled in the kernel — writing one may reset the other. Added readback verification with automatic re-apply if the thermal policy was overridden.

Files changed

File	Change
src/Platform/Linux/LinuxAsusWmi.cs	+3 methods: SetKeyboardRgbMode(), SetKeyboardRgbState(), HasKeyboardRgbMode()
src/USB/Aura.cs	Route TUF ApplyAura()/ApplyDirect()/ApplyPower() through kbd_rgb_mode/state
src/Mode/ModeControl.cs	Readback verification after setting thermal policy + platform profile
install/90-ghelper.conf	NEW — systemd-tmpfiles for boot-time sysfs permissions
install/90-ghelper.rules	Add kbd_rgb_mode/kbd_rgb_state udev chmod rules
install/install.sh	Deploy tmpfiles config + chmod new sysfs paths
TODO.md	Remove completed tmpfiles task

[github-actions]

Build Artifacts

Built from commit c6db4d0 — Download from Actions run

Artifact	Description
ghelper	Native AOT binary
native-libs	libSkiaSharp.so + libHarfBuzzSharp.so
appimage	GHelper-x86_64.AppImage (all-in-one)

Quick test:

# Option 1: AppImage (easiest)
chmod +x GHelper-x86_64.AppImage
./GHelper-x86_64.AppImage

# Option 2: Native binary
chmod +x ghelper
./ghelper

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