I see no option for ACPI. I get command not found if I try to run as either my main user or as root. There isn't a man entry for acpi either. Package needing installation perhaps?
EDIT: Intel claims here
that ACPI or at least a portion of its interpretation code is included in Linux as of kernel realease 2.4. I saw another thread in search here that mentioned recompiling the kernel using APM instead of ACPI if your machine supports one but not the other. I don't want have the skill to recompile the kernel or the wish to do so.