Acpi Wstadef 2&daba3ff&0 _verified_ May 2026

ACPI Power States

ACPI defines several power states for devices and the system as a whole. These power states help in managing power consumption and are critical for modern operating systems and hardware.

  • S0 (Working): The system is fully powered and operational. This is the state when the computer is on and in use.

  • S1 (Power On Standby): Although the system appears to be off, it can quickly wake up. This state is often used in desktops and laptops when the user wants to temporarily turn off the system without shutting down.

    • S1i1: CPU is off, but some system context is saved. Wakeup latency is short.
    • S1i2: More power savings than S1i1. Wakeup latency is longer.
    • S1i3: The deepest of S1 states with the longest wakeup latency.

  • S3 (Sleep or Standby): The system appears to be off. The system context is saved in RAM, and the system can wake up quickly. This state is commonly used for laptops and desktops when they are put to sleep.

  • S4 (Hibernation or Suspend to Disk): The system context is saved to disk before shutting down. When the system boots, it restores the context from the disk. This state uses no power.

  • S5 (Soft Off): The system is off, and no context is saved. The next boot will start from a cold boot state.

ACPI also defines states for devices (D0 to D3), which indicate the power state of a device: acpi wstadef 2&daba3ff&0

  • D0: Fully on.
  • D1 and D2: Intermediate power saving states, where some functionality is disabled.
  • D3: Powered off.

The string "acpi wstadef 2&daba3ff&0" appears to be a Windows ACPI (Advanced Configuration and Power Interface) hardware identifier, specifically for a Wake Source Timer Device (likely a wake-capable timer or ACPI time source).

If you want to develop a feature based on this identifier, here’s a structured approach:

What is it?

The hardware ID WSTADEF typically refers to a WMI (Windows Management Instrumentation) Sensor or a Battery/Motherboard Sensor.

  • Commonly associated with: Lenovo, Dell, or ASUS laptops.
  • Function: It is often related to "Smart Battery" data, thermal sensors, or power state monitoring. It tells the motherboard basic status information.
  • Why the error? The device is working, but Windows lacks the "string" (text driver) to give it a friendly name like "Lenovo Power Management," so it displays the cryptic code WSTADEF instead.

Step 3 – Update BIOS/UEFI Firmware

OEMs often patch ACPI table bugs via BIOS updates. The wstadef methods are stored in the DSDT (Differentiated System Description Table).

  • For Dell: Run Dell Command Update.
  • For Lenovo: Use Lenovo Vantage.
  • For HP: Use HP Support Assistant.
  • For others: Check your motherboard/laptop support page for a BIOS update labeled "improves system stability" or "ACPI fixes".

⚠️ Warning: Only download BIOS updates from the official OEM website.

Common user scenarios:

  • You found it in Device Manager → likely as a hidden/system device.
  • You saw it in registry (e.g., HKLM\SYSTEM\CurrentControlSet\Enum\ACPI).
  • It appears in a driver or hardware troubleshooting log (like setupapi.dev.log).

Conclusion

ACPI\WSTADEF_2&DABA3FF&0 is an obscure, OEM-defined ACPI device identifier for a motherboard-specific component, likely from a legacy or embedded system. Without proprietary drivers, Windows treats it as unknown hardware. For normal consumer PCs, it can often be ignored or disabled; for industrial systems, the correct driver must be obtained from the board vendor. ACPI Power States ACPI defines several power states

Recommendation: If this ID appears on a generic desktop or laptop and no functionality seems broken, disable the device in Device Manager. If on a special-purpose or older machine, search the exact HWID on the OEM’s support site.

The identifier ACPI\WSTADEF\2&DABA3FF&0 is a Hardware ID or Device Instance Path used by the Windows operating system to identify a specific hardware component connected via the Advanced Configuration and Power Interface (ACPI). Technical Breakdown

ACPI: Indicates the device is managed by the Advanced Configuration and Power Interface, which handles hardware discovery and power management.

WSTADEF: This is the Hardware ID portion. While specific to certain firmware implementations, identifiers starting with "WSTA" are often associated with Microsoft Windows Surface devices or specific system-level drivers like the System Aggregator Module (SAM).

2&DABA3FF&0: This is the Instance ID. It is a unique string generated by the operating system to distinguish between multiple identical devices or to mark a specific physical path on the motherboard. Common Contexts

You will typically encounter this string in the following areas of a PC: S0 (Working): The system is fully powered and operational

Device Manager: Under the "Details" tab of a device's properties (listed as Device Instance Path).

Windows Registry: Found under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\.

System Information (msinfo32): Listed under components with "Problem Devices" if a driver is missing. If you are seeing this as an "Unknown Device"

If this ID is appearing with a yellow exclamation mark in your Device Manager, it usually means a chipset or system driver is missing. For Surface or modern laptop users, this is typically resolved by installing the latest Firmware and Driver Pack from the manufacturer's official support site.

This string, ACPI WSTADEF 2&daba3ff&0, is a technical identifier found within the Windows Device Manager. It typically appears when a hardware component does not have a dedicated driver installed, causing it to display as an "Unknown Device."

Here is a content breakdown explaining what this string means, why it appears, and how to resolve it.

3. Where It Appears

  • Device Manager → Properties of a “Unknown Device”, “System Device”, or “Other Device”.
  • Registry path:
    HKLM\SYSTEM\CurrentControlSet\Enum\ACPI\WSTADEF_2&DABA3FF&0
  • Power management logs or ACPI dump tools (e.g., acpidump.exe, RWEverything).

C. High CPU usage from ACPI.sys

  • A malfunctioning _WST method can cause the ACPI driver to poll repeatedly, leading to 5-15% constant CPU usage on a single core.

What does "WSTA" stand for?

The string WSTA is less common. In Microsoft’s ACPI source language (ASL) and Windows ACPI driver naming conventions, "WSTA" typically refers to a Windows System Trigger Alert or, more likely, a custom Device Naming node created by an OEM (Original Equipment Manufacturer). Specifically:

  • WST could abbreviate "Wake Source Timer" or "Wireless Status".
  • A often stands for "Alert" or "Adapter".
  • DEF at the end strongly suggests "Default" or "Definition".

In many observed cases, Wstadef is a virtual device defined in the BIOS’s ACPI tables to support a specific OEM feature—most commonly related to Modern Standby (S0 Low Power Idle), ambient light sensors, or lid switch state monitoring.