Ubuntu 20.04.5 LTS下Fn键失效且无hid_apple目录的解决求助

Hey there, sorry to hear you're stuck with the unresponsive Fn key on Ubuntu 20.04.5 LTS! It’s super frustrating when the common fixes don’t apply because the hid_apple directory is missing. Let’s walk through some alternative approaches to get this sorted:

1. 先尝试加载hid_apple模块（可能只是没自动加载） #

First off, let’s check if the hid_apple module exists in your system but isn’t loaded yet:

• Run this command to list loaded modules:

  lsmod | grep hid_apple
  

• If you get no output, try manually loading the module with:

  sudo modprobe hid_apple
  

• Now recheck with lsmod | grep hid_apple — if it shows up, you can use the standard fix:
  • Temporary fix (until reboot): Set the Fn key behavior (replace 2 with 1 or 0 if needed; 2 reverses the default Fn key function):

    echo 2 | sudo tee /sys/module/hid_apple/parameters/fnmode
    

  • Permanent fix: Create a config file to keep the setting after reboot:

    sudo nano /etc/modprobe.d/hid_apple.conf
    

    Add this line inside the file:

    options hid_apple fnmode=2
    

    Save and exit, then update initramfs:

    sudo update-initramfs -u
    

    Reboot your system and test the Fn key.

2. 用ACPI内核参数调整（如果hid_apple模块不存在） #

If modprobe hid_apple fails (meaning your kernel doesn’t include this module), try adjusting ACPI settings, which often works for non-Apple laptops:

• Edit the GRUB configuration file:

  sudo nano /etc/default/grub
  

• Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT and modify it to include ACPI parameters. For example:

  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
  

  Note: If this doesn’t work, you can try alternative parameters like acpi_osi="!Windows 2012" or acpi_osi=, depending on your laptop brand.
• Save the file and update GRUB:

  sudo update-grub
  

• Reboot your system and check if the Fn key works.

3. 尝试品牌特定的工具/模块 #

Many laptop manufacturers have dedicated Linux modules or tools to handle keyboard functions:

• For Lenovo/ThinkPad: Install thinkpad-acpi or check for lenovo-settings in the software center.
• For Dell: Try the dell-smbios tool to adjust keyboard settings.
• For Asus: Look for modules like asus-wmi or asus-nb-wmi (you might need to load them with sudo modprobe).
• Search online for your specific laptop model + "Ubuntu Fn key fix" to find brand-specific tweaks.

4. 检查系统键盘设置 #

Don’t overlook the built-in system settings! Open your desktop environment’s keyboard settings (e.g., GNOME Settings > Keyboard) and look for options related to "Fn key behavior" or "Function row lock" — some desktops have a toggle here that might resolve the issue without command-line tweaks.

Hope one of these methods gets your Fn key working again! Let me know if you need further clarification on any step.

备注：内容来源于stack exchange，提问作者jinsoo Park