WMI Driver API¶
The WMI driver core supports a more modern bus-based interface for interacting
with WMI devices, and an older GUID-based interface. The latter interface is
considered to be deprecated, so new WMI drivers should generally avoid it since
it has some issues with multiple WMI devices sharing the same GUID.
The modern bus-based interface instead maps each WMI device to a
struct wmi_device, so it supports WMI devices sharing the
same GUID. Drivers can then register a struct wmi_driver
which will be bound to compatible WMI devices by the driver core.
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struct wmi_device¶
WMI device structure
Definition:
struct wmi_device {
struct device dev;
bool setable;
const char *driver_override;
};
Members
devDevice associated with this WMI device
setableTrue for devices implementing the Set Control Method
driver_overrideDriver name to force a match; do not set directly, because core frees it; use
driver_set_override()to set or clear it.
Description
This represents WMI devices discovered by the WMI driver core.
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to_wmi_device¶
to_wmi_device (device)
Helper macro to cast a device to a wmi_device
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struct wmi_driver¶
WMI driver structure
Definition:
struct wmi_driver {
struct device_driver driver;
const struct wmi_device_id *id_table;
bool no_notify_data;
bool no_singleton;
int (*probe)(struct wmi_device *wdev, const void *context);
void (*remove)(struct wmi_device *wdev);
void (*notify)(struct wmi_device *device, union acpi_object *data);
};
Members
driverDriver model structure
id_tableList of WMI GUIDs supported by this driver
no_notify_dataDriver supports WMI events which provide no event data
no_singletonDriver can be instantiated multiple times
probeCallback for device binding
removeCallback for device unbinding
notifyCallback for receiving WMI events
Description
This represents WMI drivers which handle WMI devices.
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wmi_driver_register¶
wmi_driver_register (driver)
Helper macro to register a WMI driver
Parameters
driverwmi_driver struct
Description
Helper macro for registering a WMI driver. It automatically passes THIS_MODULE to the underlying function.
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module_wmi_driver¶
module_wmi_driver (__wmi_driver)
Helper macro to register/unregister a WMI driver
Parameters
__wmi_driverwmi_driver struct
Description
Helper macro for WMI drivers which do not do anything special in module
init/exit. This eliminates a lot of boilerplate. Each module may only
use this macro once, and calling it replaces module_init() and module_exit().
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int wmi_instance_count(const char *guid_string)¶
Get number of WMI object instances
Parameters
const char *guid_string36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
Description
Get the number of WMI object instances.
Return
Number of WMI object instances or negative error code.
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u8 wmidev_instance_count(struct wmi_device *wdev)¶
Get number of WMI object instances
Parameters
struct wmi_device *wdevA wmi bus device from a driver
Description
Get the number of WMI object instances.
Return
Number of WMI object instances.
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acpi_status wmi_evaluate_method(const char *guid_string, u8 instance, u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)¶
Evaluate a WMI method (deprecated)
Parameters
const char *guid_string36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
u8 instanceInstance index
u32 method_idMethod ID to call
const struct acpi_buffer *inMandatory buffer containing input for the method call
struct acpi_buffer *outEmpty buffer to return the method results
Description
Call an ACPI-WMI method, the caller must free out.
Return
acpi_status signaling success or error.
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acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)¶
Evaluate a WMI method
Parameters
struct wmi_device *wdevA wmi bus device from a driver
u8 instanceInstance index
u32 method_idMethod ID to call
const struct acpi_buffer *inMandatory buffer containing input for the method call
struct acpi_buffer *outEmpty buffer to return the method results
Description
Call an ACPI-WMI method, the caller must free out.
Return
acpi_status signaling success or error.
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acpi_status wmi_query_block(const char *guid_string, u8 instance, struct acpi_buffer *out)¶
Return contents of a WMI block (deprecated)
Parameters
const char *guid_string36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
u8 instanceInstance index
struct acpi_buffer *outEmpty buffer to return the contents of the data block to
Description
Query a ACPI-WMI block, the caller must free out.
Return
ACPI object containing the content of the WMI block.
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union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)¶
Return contents of a WMI block
Parameters
struct wmi_device *wdevA wmi bus device from a driver
u8 instanceInstance index
Description
Query an ACPI-WMI block, the caller must free the result.
Return
ACPI object containing the content of the WMI block.
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acpi_status wmi_set_block(const char *guid_string, u8 instance, const struct acpi_buffer *in)¶
Write to a WMI block (deprecated)
Parameters
const char *guid_string36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
u8 instanceInstance index
const struct acpi_buffer *inBuffer containing new values for the data block
Description
Write the contents of the input buffer to an ACPI-WMI data block.
Return
acpi_status signaling success or error.
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acpi_status wmidev_block_set(struct wmi_device *wdev, u8 instance, const struct acpi_buffer *in)¶
Write to a WMI block
Parameters
struct wmi_device *wdevA wmi bus device from a driver
u8 instanceInstance index
const struct acpi_buffer *inBuffer containing new values for the data block
Description
Write contents of the input buffer to an ACPI-WMI data block.
Return
acpi_status signaling success or error.
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acpi_status wmi_install_notify_handler(const char *guid, wmi_notify_handler handler, void *data)¶
Register handler for WMI events (deprecated)
Parameters
const char *guid36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
wmi_notify_handler handlerFunction to handle notifications
void *dataData to be returned to handler when event is fired
Description
Register a handler for events sent to the ACPI-WMI mapper device.
Return
acpi_status signaling success or error.
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acpi_status wmi_remove_notify_handler(const char *guid)¶
Unregister handler for WMI events (deprecated)
Parameters
const char *guid36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
Description
Unregister handler for events sent to the ACPI-WMI mapper device.
Return
acpi_status signaling success or error.
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bool wmi_has_guid(const char *guid_string)¶
Check if a GUID is available
Parameters
const char *guid_string36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
Description
Check if a given GUID is defined by _WDG.
Return
True if GUID is available, false otherwise.
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char *wmi_get_acpi_device_uid(const char *guid_string)¶
Get _UID name of ACPI device that defines GUID (deprecated)
Parameters
const char *guid_string36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
Description
Find the _UID of ACPI device associated with this WMI GUID.
Return
The ACPI _UID field value or NULL if the WMI GUID was not found.
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void wmi_driver_unregister(struct wmi_driver *driver)¶
Unregister a WMI driver
Parameters
struct wmi_driver *driverWMI driver to unregister
Description
Unregisters a WMI driver from the WMI bus.