feat(predator): add PHN16-72 back logo/lightbar support

[0PeterAdel]

Summary

Adds back-lid logo/lightbar RGB support for Acer Predator PHN16-72.

This exposes a new sysfs group:

/sys/module/linuwu_sense/drivers/platform:acer-wmi/acer-wmi/back_logo/color

Format:

RRGGBB,brightness,enable

Example:

echo 'FFFFFF,100,1' | sudo tee /sys/module/linuwu_sense/drivers/platform:acer-wmi/acer-wmi/back_logo/color
cat /sys/module/linuwu_sense/drivers/platform:acer-wmi/acer-wmi/back_logo/color

Example output:

ffffff,100,1

Tested on

Model: Acer Predator PHN16-72
BIOS: V1.16
Board: EQE_RTX
OS: Fedora 44
Kernel: 7.0.14-201.fc44.x86_64

Test result

• Build succeeds.
• No misleading-indentation warning.
• The new back_logo/color sysfs path appears.
• Writing 00FFCC,100,1 successfully updates the rear logo/lightbar.
• Reading the sysfs node returns:

00ffcc,100,1

DAMX daemon detects the feature:

{
  "success": true,
  "data": {
    "available_features": [
      "lcd_override",
      "battery_calibration",
      "battery_limiter",
      "per_zone_mode",
      "boot_animation_sound",
      "four_zone_mode",
      "back_logo",
      "usb_charging",
      "fan_speed",
      "thermal_profile",
      "backlight_timeout"
    ],
    "laptop_type": "PREDATOR",
    "has_four_zone_kb": true
  }
}

Notes

The feature is gated behind the PHN16-72 quirk via ACER_CAP_BACK_LOGO, so it should not affect other models.

This is intended to enable future DAMX GUI support for rear logo/lightbar color control when the driver exposes back_logo/color.