ACPI FFH Address Space

configname: CONFIG_ACPI_FFH

Linux Kernel Configuration
└─>Power management and ACPI options
└─>ACPI (Advanced Configuration and Power Interface) Support
└─>ACPI FFH Address Space
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
The FFH(Fixed Function Hardware) Address Space also referred as FFH
Operation Region allows to define platform specific opregion.

Enable this feature if you want to set up and install the FFH Address
Space handler to handle FFH OpRegion in the firmware.

depends
CONFIG_ACPI