Enum SignalProcessingRequest

pub enum SignalProcessingRequest {
    GetElements {
        responder: SignalProcessingGetElementsResponder,
    },
    WatchElementState {
        processing_element_id: u64,
        responder: SignalProcessingWatchElementStateResponder,
    },
    GetTopologies {
        responder: SignalProcessingGetTopologiesResponder,
    },
    WatchTopology {
        responder: SignalProcessingWatchTopologyResponder,
    },
    SetTopology {
        topology_id: u64,
        responder: SignalProcessingSetTopologyResponder,
    },
    SetElementState {
        processing_element_id: u64,
        state: SettableElementState,
        responder: SignalProcessingSetElementStateResponder,
    },
    _UnknownMethod {
        ordinal: u64,
        control_handle: SignalProcessingControlHandle,
        method_type: MethodType,
    },
}

This protocol is required for Composite audio drivers, and unsupported for other audio driver types (Codec, Dai, StreamConfig).

For an overview see [Signal Processing Interface].

Variants

GetElements

Returns a vector of supported processing elements. This vector must include one or more processing elements.

Fields

responder: SignalProcessingGetElementsResponder

WatchElementState

Get the processing element state via a hanging get. For a given processing_element_id, the driver will immediately reply to the first WatchElementState sent by the client. The driver will not respond to subsequent client WatchElementState calls for that processing_element_id until any portion of the ElementState has changed from what was most recently reported for that element.

The driver will close the protocol channel with an error of ZX_ERR_INVALID_ARGS, if processing_element_id does not match an ElementId returned by GetElements.

The driver will close the protocol channel with an error of ZX_ERR_BAD_STATE, if this method is called again while there is already a pending WatchElementState for this client and processing_element_id.

Fields

processing_element_id: u64

responder: SignalProcessingWatchElementStateResponder

GetTopologies

Returns a vector of supported topologies. This vector must include one or more topologies. If more than one topology is returned, then the client may select any topology from the list by calling SetTopology. If only one topology is returned, SetTopology can still be called but causes no change.

Each Element must be included in at least one Topology, but need not be included in every Topology.

Fields

responder: SignalProcessingGetTopologiesResponder

WatchTopology

Get the current topology via a hanging get. The driver will immediately reply to the first WatchTopology sent by each client. The driver will not respond to subsequent WatchTopology calls from that client until the signal processing topology changes; this occurs as a result of a SetTopology call.

The driver will close the protocol channel with an error of ZX_ERR_BAD_STATE, if this method is called again while there is already a pending WatchTopology for this client.

Fields

responder: SignalProcessingWatchTopologyResponder

SetTopology

Sets the currently active topology by specifying a topology_id, which matches to an entry in the vector returned by GetTopologies. The currently active topology is communicated by WatchTopology responses. To change which topology is active, a client uses SetTopology.

If GetTopologies returns only one Topology, SetTopology is optional and has no effect.

This call will fail and return ZX_ERR_INVALID_ARGS if the specified topology_id is not found within thetopologies returned by GetTopologies.

SetTopology may be called before or after non-SignalProcessing protocol calls. If called after non-SignalProcessing protocol calls, then SetTopology may return ZX_ERR_BAD_STATE to indicate that the operation can not proceed without renegotiation of the driver state. See SetElementState for further discussion.

Fields

topology_id: u64

responder: SignalProcessingSetTopologyResponder

SetElementState

Controls the processing element specified by processing_element_id, a unique ElementId returned by GetElements. The state specified in calls to SetElementState is a SettableElementState. This is a subset of ElementState because some fields returned by WatchElementState (e.g. latency or plug_state) can only be observed (not set) by the client.

Returns ZX_ERR_INVALID_ARGS if processing_element_id does not match a known ElementId returned by GetElements, or if state is not valid for the element. This entails any violation of the rules specified in this protocol.

Examples: state specifies that an element should be stopped or bypassed, but the corresponding element does not specify (or explicitly set to false) can_stop or can_bypass. state includes a type_specific entry, but that SettableTypeSpecificElementState does not match the ElementType of the element corresponding to processing_element_id. state changes an EqualizerBandState for an EQUALIZER element (so far so good), but specifies a change to frequency when this element did not set CAN_CONTROL_FREQUENCY in its supported_controls. state specifies a GainElementState for a GAIN element with a gain value that is -infinity, NAN, or outside the Element’s stated [min_gain, max_gain] range.

Callers may intersperse method calls to the SignalProcessing protocol with calls to other driver protocols. Some non-SignalProcessing configuration changes may require a renegotiation of the driver state before certain elements can receive a SetElementState. For example, if a DaiFormat is changed, then SetElementState changing an AGL element’s parameters may not require renegotiation of driver state because changing gain parameters usually does not change the set of supported audio formats. By contrast, following the same DaiFormat change, before SetElementState can be called on a CONNECTION_POINT element, the driver state may need to be reestablished because the format change may invalidate the set of supported formats returned in a previous GetDaiFormats protocol call for another part of the Topology.

It is the driver’s job to determine when renegotiation is required. When this is needed, the related SetElementState call must return ZX_ERR_BAD_STATE and the client must close the protocol channel entirely, such that the protocol negotiations are started over. The client then must re-invoke the SetElementState call that returned ZX_ERR_BAD_STATE before any non-SignalProcessing protocol calls.

Fields

processing_element_id: u64

state: SettableElementState

responder: SignalProcessingSetElementStateResponder

_UnknownMethod

An interaction was received which does not match any known method.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

ordinal: u64

Ordinal of the method that was called.

control_handle: SignalProcessingControlHandle

method_type: MethodType

Implementations

impl SignalProcessingRequest

pub fn into_get_elements(self) -> Option<SignalProcessingGetElementsResponder>

pub fn into_watch_element_state( self, ) -> Option<(u64, SignalProcessingWatchElementStateResponder)>

pub fn into_get_topologies( self, ) -> Option<SignalProcessingGetTopologiesResponder>

pub fn into_watch_topology( self, ) -> Option<SignalProcessingWatchTopologyResponder>

pub fn into_set_topology( self, ) -> Option<(u64, SignalProcessingSetTopologyResponder)>

pub fn into_set_element_state( self, ) -> Option<(u64, SettableElementState, SignalProcessingSetElementStateResponder)>

pub fn method_name(&self) -> &'static str

Name of the method defined in FIDL

Trait Implementations

impl Debug for SignalProcessingRequest

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.