---
name: "acpi_wmi"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/acpi_wmi"
---

# acpi\_wmi(4)

ACPI to WMI mapping driver

## NAME

**acpi\_wmi** – ACPI to WMI mapping driver

## SYNOPSIS

To compile this driver into the kernel, place the following line in your kernel configuration file:

```
device acpi_wmi
```

Alternatively, to load the driver as a module at boot time, place the following line in [loader.conf(5)](/loader.conf/5.md):

```
acpi_wmi_load="YES"
```

## DESCRIPTION

The **acpi\_wmi** driver provides an interface for vendor specific WMI implementations (e.g. HP and Acer laptops). It creates */dev/wmistat%d*, which can be read to get information about GUIDs found in the system.

## FILES

- */dev/wmistat%d*

  WMI status devices.

## SYSCTLS

The following sysctl node is currently implemented:

- *dev.acpi\_wmi.%d.bmof*

  binary Managed Object Format (MOF) buffer

## EXAMPLES

Read GUIDs from the first WMI interface found in the system:

```
# cat /dev/wmistat0
GUID                                  INST EXPE METH STR EVENT OID
{5FB7F034-2C63-45E9-BE91-3D44E2C707E4}   1 NO   WMAA NO  NO    AA
{95F24279-4D7B-4334-9387-ACCDC67EF61C}   1 NO   NO   NO  0x80+ -
{2B814318-4BE8-4707-9D84-A190A859B5D0}   1 NO   NO   NO  0xA0  -
{05901221-D566-11D1-B2F0-00A0C9062910}   1 NO   NO   NO  NO    AB
{1F4C91EB-DC5C-460B-951D-C7CB9B4B8D5E}   1 NO   WMBA NO  NO    BA
{2D114B49-2DFB-4130-B8FE-4A3C09E75133}  57 NO   NO   NO  NO    BC
{988D08E3-68F4-4C35-AF3E-6A1B8106F83C}  20 NO   NO   NO  NO    BD
{14EA9746-CE1F-4098-A0E0-7045CB4DA745}   1 NO   NO   NO  NO    BE
{322F2028-0F84-4901-988E-015176049E2D}   2 NO   NO   NO  NO    BF
{8232DE3D-663D-4327-A8F4-E293ADB9BF05}   0 NO   NO   NO  NO    BG
{8F1F6436-9F42-42C8-BADC-0E9424F20C9A}   0 NO   NO   NO  NO    BH
{8F1F6435-9F42-42C8-BADC-0E9424F20C9A}   0 NO   NO   NO  NO    BI
```

Read first WMI interface description with **bmf2mof** from *ports/converters/bmfdec*:

```
# sysctl -b dev.acpi_wmi.0.bmof | bmf2mof
[abstract]
class Lenovo_BIOSElement {
};
[WMI, Dynamic, Provider("WMIProv"), WmiExpense(1), Description("Bios Setting"),
GUID("{51F5230E-9677-46cd-A1CF-C0B23EE34DB7}"), Locale("MS\0x409")]
class Lenovo_BiosSetting : Lenovo_BiosElement {
  [key, read] String InstanceName;
    [read] Boolean Active;
      [WmiDataId(1), Description("BIOS setting")] String CurrentSetting;
      };
   ...
```

## SEE ALSO

[acpi(4)](/acpi/4.md)

## STANDARDS

*Windows Instrumentation: WMI and ACPI*, Microsoft Corporation, https://github.com/microsoft/Windows-driver-samples/tree/main/wmi/wmiacpi.

## HISTORY

The **acpi\_wmi** device driver first appeared in FreeBSD 8.0.

## AUTHORS

The **acpi\_wmi** driver was written by Michael Gmelin ⟨*freebsd@grem.de*⟩.

Work inspired by the Linux **acpi-wmi** driver written by Carlos Corbacho.

MOF handling inspired by the Linux **wmi-bmof** driver written by Andy Lutomirski.

This manual page was written by Michael Gmelin ⟨*freebsd@grem.de*⟩.