Tiny Power Button Driver

modulename: tiny-power-button.ko

configname: CONFIG_ACPI_TINY_POWER_BUTTON

Linux Kernel Configuration
└─>Power management and ACPI options
└─>ACPI (Advanced Configuration and Power Interface) Support
└─>Tiny Power Button Driver
In linux kernel since version 5.1 (release Date: 2019-05-05)  
This driver provides a tiny alternative to the ACPI Button driver.
The tiny power button driver only handles the power button. Rather
than notifying userspace via the input layer or a netlink event, this
driver directly signals the init process to shut down.

This driver is particularly suitable for cloud and VM environments,
which use a simulated power button to initiate a controlled poweroff,
but which may not want to run a separate userspace daemon to process
input events.

source code: