From LQWiki
ACPI (Advanced Configuration and Power Interface) is a Power Management interface for computers. It is the successor to APM . The main difference from APM is that ACPI moves the power management rule control to the OS, instead of in the BIOS (like with APM). It also adds many more features and possibilities.
Stuff ACPI can do:
- Power/sleep button handling
- CPU power/sleep states
- Individual device power/sleep states
- Fan control/monitoring
- Temperature monitoring (using Thermal Zone)*[1]
- etc.
It requires support in the hardware (mainboard,CPU and devices) and the software (OS).
[1] -- also lm-sensors can be used to monitor temperature, however that's not related to ACPI.
Linux support
For ACPI to work, you need:
- to go into your BIOS and enable ACPI
- your kernel to either have ACPI compiled into it, or else have it built as a module (there are multiple modules for different devices ACPI support, e.g. button, processor, fan, ac, etc.)
- (optional) have an ACPI daemon software package installed (acpid). This daemon reacts to certain events like pressing the power button or disconnecting the power from a laptop.
It is also possible to enable/disable acpi -- when it's compiled in the kernel -- by passing an argument to the kernel. To do this, add "acpi=on" or "acpi=off" to the config file for lilo, GRUB, or whatever boot loader you're using.
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