Documentation/wmi/devices/dell-wmi-ddv.rst

Source file repositories/reference/linux-study-clean/Documentation/wmi/devices/dell-wmi-ddv.rst

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Linux kernel
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Documentation/wmi/devices/dell-wmi-ddv.rst
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.rst
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13202 bytes
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320
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
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atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

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Annotated Snippet

.. SPDX-License-Identifier: GPL-2.0-or-later

============================================
Dell DDV WMI interface driver (dell-wmi-ddv)
============================================

Introduction
============

Many Dell notebooks made after ~2020 support a WMI-based interface for
retrieving various system data like battery temperature, ePPID, diagnostic data
and fan/thermal sensor data.

This interface is likely used by the `Dell Data Vault` software on Windows,
so it was called `DDV`. Currently the ``dell-wmi-ddv`` driver supports
version 2 and 3 of the interface, with support for new interface versions
easily added.

.. warning:: The interface is regarded as internal by Dell, so no vendor
             documentation is available. All knowledge was thus obtained by
             trial-and-error, please keep that in mind.

Dell ePPID (electronic Piece Part Identification)
=================================================

The Dell ePPID is used to uniquely identify components in Dell machines,
including batteries. It has a form similar to `CC-PPPPPP-MMMMM-YMD-SSSS-FFF`
and contains the following information:

* Country code of origin (CC).
* Part number with the first character being a filling number (PPPPPP).
* Manufacture Identification (MMMMM).
* Manufacturing Year/Month/Date (YMD) in base 36, with Y being the last digit
  of the year.
* Manufacture Sequence Number (SSSS).
* Optional Firmware Version/Revision (FFF).

The `eppidtool <https://pypi.org/project/eppidtool>`_ python utility can be used
to decode and display this information.

All information regarding the Dell ePPID was gathered using Dell support
documentation and `this website <https://telcontar.net/KBK/Dell/date_codes>`_.

WMI interface description
=========================

The WMI interface description can be decoded from the embedded binary MOF (bmof)
data using the `bmfdec <https://github.com/pali/bmfdec>`_ utility:

::

 [WMI, Dynamic, Provider("WmiProv"), Locale("MS\\0x409"), Description("WMI Function"), guid("{8A42EA14-4F2A-FD45-6422-0087F7A7E608}")]
 class DDVWmiMethodFunction {
   [key, read] string InstanceName;
   [read] boolean Active;

   [WmiMethodId(1), Implemented, read, write, Description("Return Battery Design Capacity.")] void BatteryDesignCapacity([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(2), Implemented, read, write, Description("Return Battery Full Charge Capacity.")] void BatteryFullChargeCapacity([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(3), Implemented, read, write, Description("Return Battery Manufacture Name.")] void BatteryManufactureName([in] uint32 arg2, [out] string argr);
   [WmiMethodId(4), Implemented, read, write, Description("Return Battery Manufacture Date.")] void BatteryManufactureDate([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(5), Implemented, read, write, Description("Return Battery Serial Number.")] void BatterySerialNumber([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(6), Implemented, read, write, Description("Return Battery Chemistry Value.")] void BatteryChemistryValue([in] uint32 arg2, [out] string argr);
   [WmiMethodId(7), Implemented, read, write, Description("Return Battery Temperature.")] void BatteryTemperature([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(8), Implemented, read, write, Description("Return Battery Current.")] void BatteryCurrent([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(9), Implemented, read, write, Description("Return Battery Voltage.")] void BatteryVoltage([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(10), Implemented, read, write, Description("Return Battery Manufacture Access(MA code).")] void BatteryManufactureAceess([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(11), Implemented, read, write, Description("Return Battery Relative State-Of-Charge.")] void BatteryRelativeStateOfCharge([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(12), Implemented, read, write, Description("Return Battery Cycle Count")] void BatteryCycleCount([in] uint32 arg2, [out] uint32 argr);
   [WmiMethodId(13), Implemented, read, write, Description("Return Battery ePPID")] void BatteryePPID([in] uint32 arg2, [out] string argr);
   [WmiMethodId(14), Implemented, read, write, Description("Return Battery Raw Analytics Start")] void BatteryeRawAnalyticsStart([in] uint32 arg2, [out] uint32 argr);

Annotation

Implementation Notes