Supporting Bluetooth Event Notifications

When a profile driver opens a connection to a remote device, it should register itself to be notified when the connection is closed, or when any other changes to the connection occur. Additionally, when a profile driver registers itself to accept incoming connections, it must be able to be notified when a remote device attempts to connect to it.

Profile drivers that use Synchronous Connection-Oriented (SCO) connection implement and register a SCO Callback Function. A client profile driver registers the appropriate callback function when it requests a connection to a remote device.

When a SCO profile driver issues a BRB_SCO_OPEN_CHANNEL BRB, it specifies a pointer to its SCO Callback Function in the Callback member of the BRB's corresponding _BRB_SCO_OPEN_CHANNEL structure. If the remote device accepts the SCO connection request, the Bluetooth driver stack can then send notifications to the profile driver through the callback function when a change occurs to the SCO connection .

For more information about creating SCO connections, see Creating a SCO Client Connection to a Remote Device.

Profile drivers that use Logical Link Controller and Adaptation Protocol (L2CAP) connections implement and register an L2CAP Callback Function.

When a L2CAP profile driver issues a BRB_L2CA_OPEN_CHANNEL BRB, it specifies a pointer to its L2CAP Callback Function in the Callback member of the BRB's corresponding _BRB_L2CA_OPEN_CHANNEL structure. If the remote device accepts the L2CAP connection request, the Bluetooth driver stack can then send notifications to the profile driver through the callback function when a change occurs to the L2CAP connection.

For more information about creating L2CAP connections, see Creating a L2CAP Client Connection to a Remote Device.

Similarly, when a profile driver registers itself to accept incoming (L2CAP, SCO) connection requests, it must register a callback function to be notified when a remote device attempts to connect to it.

Profile drivers that use L2CAP specify their L2CAP Callback Function in the IndicationCallback member of the _BRB_L2CA_REGISTER_SERVER structure. The Bluetooth driver stack can then call the callback function to notify the profile driver when a remote device attempts to initiate a L2CAP connection to the profile driver.

Profile drivers that use SCO specify their SCO Callback Function in the IndicationCallback member of the _BRB_SCO_REGISTER_SERVER structure. The Bluetooth driver stack can then call the callback function to notify the profile driver when a remote device attempts to initiate a SCO connection to the profile driver.

After the profile driver registers the appropriate callback function, the Bluetooth driver stack can also notify the profile driver if and when an event occurs across the open connection.

Note  A profile driver can register the same callback function to send it change notifications about an open channel and about remote devices attempting to connect to it.

For L2CAP connections, the L2CAP callback function accepts three parameters:

  • The context that is defined for the L2CAP connection. In the case of BRB_L2CA_REGISTER_SERVER requests, this context is the value passed in the IndicationCallbackContext member of the _BRB_L2CA_REGISTER_SERVER structure passed with the request. In the case of BRB_L2CA_OPEN_CHANNEL or BRB_L2CA_OPEN_CHANNEL_RESPONSE requests, this context is the value passed in the CallbackContext member of the _BRB_L2CA_OPEN_CHANNEL structure passed with the request.

  • A value from the INDICATION_CODE enumeration that indicates the type of the notification event of the incoming L2CAP connection or bonding state change.

  • A pointer to an INDICATION_PARAMETERS structure that contains the parameters associated with the notification event.

The value passed in the L2CAP callback function'sIndication parameter specifies which union member in the Parameters union of the Parameters parameter that the profile driver should use.

If the value of the Indication parameter equals......use the following union member of the Parameters parameter

IndicationRemoteConnect

Connect

IndicationRemoteConfigRequest

ConfigRequest

IndicationRemoteConfigResponse

ConfigResponse

IndicationFreeExtraOptions

FreeExtraOptions

IndicationRemoteDisconnect

Disconnect

IndicationRecvPacket

RecvPacket

 

For SCO connections, the SCO callback function accepts three arguments:

  • The context that is defined for the SCO connection. In the case of BRB_SCO_REGISTER_SERVER requests, this context is the value passed in the IndicationCallbackContext member of the _BRB_SCO_REGISTER_SERVER structure passed with the request. In the case of BRB_SCO_OPEN_CHANNEL or BRB_SCO_OPEN_CHANNEL_RESPONSE requests, this context is the value passed in the CallbackContext member of the _BRB_SCO_OPEN_CHANNEL structure passed with the request.

  • A value from the SCO_INDICATION_CODE enumeration that indicates the type of the notification of the incoming SCO connection or bonding state change.

  • A pointer to a SCO_INDICATION_PARAMETERS structure that contains the parameters associated with the notification event.

The value passed in the SCO callback function'sIndication parameter specifies which union member in the Parameters union of the Parameters parameter that the profile driver should use.

If the value of the Indication parameter equals......use the following union member of the Parameters parameter

ScoIndicationRemoteConnect

Connect

ScoIndicationRemoteDisconnect

Disconnect

 

Handling Plug and Play Removal IRPs

Profile drivers should pass all IRP_MN_SURPRISE_REMOVAL IRPs down the stack immediately to be processed by the Bluetooth driver stack. Do not attempt to close any open channels as part of processing a surprise removal IRP. Do not build and send any further BRBs that send data to the underlying radio after receiving a surprise removal IRP. However, profile drivers can perform other cleanup while processing a surprise removal IRP.

After the Bluetooth driver stack receives the surprise removal IRP, it will pass ScoIndicationRemoteDisconnect to the SCO Callback Function that was specified by the profile driver when the profile driver built and sent a BRB_SCO_OPEN_CHANNEL or BRB_SCO_OPEN_CHANNEL_RESPONSE request, to close any SCO channels that are currently open. Likewise, the Bluetooth driver stack will pass IndicationRemoteDisconnect to the L2CAP Callback Function that was specified by the profile driver when the profile driver built and sent a BRB_L2CA_OPEN_CHANNEL or BRB_L2CA_OPEN_CHANNEL_RESPONSE request, to close any L2CAP channels that are currently open.

Profile drivers should unregister all servers when processing IRP_MN_REMOVE_DEVICE IRPs. To unregister a SCO server, a profile driver should build and send a BRB_SCO_UNREGISTER_SERVER request. To unregister an L2CAP server, a profile driver should build and send a BRB_L2CA_UNREGISTER_SERVER request.

 

 

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