ACPI

The Advanced Configuration and Power Interface is the standard through which Windows and system firmware coordinate sleep, wake, battery status, thermal controls, and device power states. Device Manager lists several ACPI-related system devices, but their behavior depends heavily on the firmware tables supplied by the PC maker. Problems such as failed wake, inaccurate battery reporting, or an integrated device disappearing after sleep can require a BIOS or UEFI update rather than a separate downloadable ACPI package. Install current chipset support first, compare the system maker's firmware notes, and test with default power settings. Use firmware made for the exact model and keep the machine connected to reliable power throughout any update.