IOCTL_BTHHFP_DEVICE_GET_VOLUMEPROPERTYVALUES IOCTL

Description

The IOCTL_BTHHFP_DEVICE_GET_VOLUMEPROPERTYVALUES IOCTL returns KSPROPERTY_VALUES data for the KSPROPERTY_AUDIO_VOLUMELEVEL property.

Parameters

Major code

Input buffer

None.

Input buffer length

None.

Output buffer

A buffer containing a KSPROPERTY_VALUES structure followed by any other data referenced by this structure.

Output buffer length

The size of a KSPROPERTY_VALUES structure and referenced data.

Input/output buffer

Input/output buffer length

Status block

N/A

Remarks

The audio driver’s KS filter topology includes a KS node of type KSNODETYPE_VOLUME for both input and output if the BTHHFP_DESCRIPTOR descriptor indicates volume support. The audio driver’s KSNODE_DESCRIPTOR structure for this node includes a PKSPROPERTY_ITEM for the KSPROPERTY_AUDIO_VOLUMELEVEL property. The audio driver sets the PKSPROPERTY_ITEM.Values member to the KSPROPERTY_VALUES structured returned by this request.

This allows the Handsfree profile (HFP) driver to almost entirely handle the problem of mapping KSPROPERTY_AUDIO_VOLUMELEVEL property values to the Bluetooth Handsfree profile. The audio driver’s property Get and Set handlers for this property simply call the HFP driver.

See also

Bluetooth HFP DDI IOCTLs

KSNODETYPE_VOLUME

KSNODE_DESCRIPTOR

KSPROPERTY_VALUES