Acpi Processor Aggregator Error 45jpfasr

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  1. Acpi Processor Aggregator
  2. Acpi Processor Aggregator Driver

0.275334 ACPI: Added OSI(Processor Aggregator Device) 0.308417 ACPI: Dynamic OEM Table Load: 0.308438 ACPI: SSDT 0xFFFFA037B5EE6 (v01 PmRef Cpu0Ist 00003000 INTL 20120913). Dec 01 06:27:07 dell-7577 kernel: ACPI Error: SB.PCI0.XHC.RHUB.HS11 Namespace lookup failure, AENOTFOUND (20170831/dswload-210) Dec 01 06:27:07 dell-7577 kernel: ACPI Exception: AENOTFOUND, During name lookup/catalog (20170831/psobject-252) Dec 01 06:27:07 dell-7577 kernel: ACPI Exception: AENOTFOUND, (SSDT:xhOEMBD) while loading. The original acpi.sys is an important part of Windows and rarely causes problems. Acpi.sys is located in the C: Windows System32 drivers folder. Note: Some malware disguises itself as acpi.sys, particularly when not located in the C: Windows System32 drivers folder. Therefore, you should check the acpi.sys process on your PC to see if it is a.

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 ACPI BIOS, the HAL causes Acpi.sys to be loaded during system startup at the base of the device tree. 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 ACPI Namespace Hierarchy.

Acpi processor aggregator driver

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). 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 Device Stacks for an ACPI Device.

A device for which Acpi.sys creates a device object is called an ACPI device. 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. Synopsis, art, and a phone!. 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. For more information, see Operation of an ACPI Device Function Driver.

An ACPI device is specified by a definition block in the system description tables in the ACPI BIOS. A device's definition block specifies, among other things, an operation region, which is a contiguous block of device memory that is used to access device data. Only Acpi.sys modifies the data in an operation region. The device's function driver can read the data in an operation region but must not modify the data. When called, an operation region handler transfers bytes in the operation region to and from the data buffer in Acpi.sys. The combined operation of the function driver and Acpi.sys is device-specific and is defined in the ACPI BIOS by the hardware vendor. In general, the function driver and Acpi.sys access particular areas in an operation region to perform device-specific operations and retrieve information. For more information, see Supporting an Operation Region.

ACPI control methods

ACPI control methods are software objects that declare and define simple operations to query and configure ACPI devices. Control methods are stored in the ACPI BIOS and are encoded in a byte-code format called ACPI Machine Language (AML). The control methods for a device are loaded from the system firmware into the device's ACPI namespace in memory, and interpreted by the Windows ACPI driver, Acpi.sys.

To invoke a control method, the kernel-mode driver for an ACPI device initiates an IRP_MJ_DEVICE_CONTROL request, which is handled by Acpi.sys. For drivers loaded on ACPI-enumerated devices, Acpi.sys always implements the physical device object (PDO) in the driver stack. For more information, see Evaluating ACPI Control Methods.

ACPI specification

The Advanced Configuration and Power Interface Specification (ACPI 5.0 specification) is available from the Unified Extensible Firmware Interface Forum website.

Revision 5.0 of the ACPI specification introduces a set of features to support low-power, mobile PCs that are based on System on a Chip (SoC) integrated circuits and that implement the connected standby power model. Starting with Windows 8 and later versions, the Windows ACPI driver, Acpi.sys, supports the new features in the ACPI 5.0 specification. For more information, see Windows ACPI design guide for SoC platforms.

ACPI debugging

System integrators and ACPI device driver developers can use the Microsoft AMLI debugger to debug AML code. Because AML is an interpreted language, AML debugging requires special software tools.

For more information about the AMLI debugger, see ACPI Debugging.

Microsoft ACPI source language (ASL) compiler

For information about compiling ACPI Source Language (ASL) into AML, see Microsoft ASL Compiler.

Version 5.0 of the Microsoft ASL compiler supports features in the ACPI 5.0 specification.

The ASL compiler is distributed with the Windows Driver Kit (WDK).

The ASL compiler (asl.exe) is located in the ToolsarmACPIVerify, Toolsarm64ACPIVerify, Toolsx86ACPIVerify, and Toolsx64ACPIVerify directories of the installed WDK, for example, C:Program Files (x86)Windows Kits10Toolsx86ACPIVerify.


ACPI Processor Aggregator Driver (acpipagr) Service Defaults in Windows 10

ACPI Processor Aggregator Device Driver by Microsoft Corporation.

Default Settings

Startup type:Manual
Display name:ACPI Processor Aggregator Driver
Service name:acpipagr
Service type:kernel
Error control:normal
Registry key:HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesacpipagr

Default Behavior

ACPI Processor Aggregator Driver is a kernel device driver. In Windows 10 it is starting only if the user, an application or another service starts it. If ACPI Processor Aggregator Driver fails to start, the failure details are being recorded into Event Log. Then Windows 10 will start up and notify the user that the acpipagr service has failed to start due to the error.

Restore Default Startup Configuration for ACPI Processor Aggregator Driver


Acpi Processor Aggregator


Acpi Processor Aggregator Driver

1. Run the Command Prompt as an administrator.

2. Copy the command below, paste it into the command window and press ENTER:

Acpi Processor Aggregator Error 45jpfasr

sc config acpipagr start= demand

3. Close the command window and restart the computer.

The acpipagr service is using the acpipagr.sys file that is located in the %WinDir%System32drivers folder. If the file is changed, damaged or deleted, you can restore its original version from Windows 10 installation media.