ACPI
So what the heck is that character soup ACPI?
ACPI stands for Advanced Configuration and Power Interface
Okay, but what is ACPI?
ACPI can first be understood as an architecture-independent power management and configuration framework that forms a subsystem within the host OS. This framework establishes a hardware register set to define power states (sleep, hibernate, wake, etc). The hardware register set can accommodate operations on dedicated hardware and general purpose hardware.1
Simpler...
To put it very simply, it's the subsystem that handles your computer's power management. If you've ever wondered how LEDs, fans, and other devices/controllers know when to turn on/off, return their status, and a host of other functions, that's ACPI for you. It lets you, well not you; the operating system, and you by association, more or less interface with the motherboard
Interface with the motherboard, you say?
Yes. This brings us to this much needed
Now that we got the formalities out of the way, let's dive in