Acpi.sys: The Windows ACPI Driver • • 4 minutes to read • Contributors • • In this article The Windows ACPI driver, Acpi.sys, is an inbox component of the Windows operating system. The responsibilities of Acpi.sys include support for power management and Plug and Play (PnP) device enumeration. On hardware platforms that have an, the causes Acpi.sys to be loaded during system startup at the base of the. Acpi.sys acts as the interface between the operating system and the ACPI BIOS. Acpi.sys is transparent to the other drivers in the device tree. Other tasks performed by Acpi.sys on a particular hardware platform might include reprogramming the resources for a COM port or enabling the USB controller for system wake-up. In this topic • • • • ACPI devices The hardware platform vendor specifies a hierarchy of ACPI namespaces in the ACPI BIOS to describe the hardware topology of the platform.

For more information, see. For each device described in the ACPI namespace hierarchy, the Windows ACPI driver, Acpi.sys, creates either a filter device object (filter DO) or a physical device object (PDO). Unbuntu Benchmark. If the device is integrated into the system board, Acpi.sys creates a filter device object, representing an ACPI bus filter, and attaches it to the device stack immediately above the bus driver (PDO). For other devices described in the ACPI namespace but not on the system board, Acpi.sys creates the PDO. Acpi.sys provides power management and PnP features to the device stack by means of these device objects. For more information, see. A device for which Acpi.sys creates a device object is called an.

The set of ACPI devices varies from one hardware platform to the next, and depends on the ACPI BIOS and the configuration of the motherboard. Note that Acpi.sys loads an ACPI bus filter only for a device that is described in the ACPI namespace and is permanently connected to the hardware platform (typically, this device is integrated into the core silicon or soldered to the system board). Not all motherboard devices have an ACPI bus filter. All ACPI functionality is transparent to higher-level drivers. These drivers must make no assumptions about the presence or absence of an ACPI filter in any given device stack. Acpi.sys and the ACPI BIOS support the basic functions of an ACPI device. To enhance the functionality of an ACPI device, the device vendor can supply a WDM function driver.