The Composite interface is a FIDL protocol exposed by audio drivers. The Composite interface
is generic and allows the configuration of various audio hardware types including those supported
by the StreamConfig, Dai and Codec FIDL interfaces. The Composite interface is more
generic and provides more flexible routing within audio subsystems.
In this protocol, ring buffers, DAI interconnects, and packet streams are configured based on
the topology exposed via the Audio Signal Processing APIs. In particular,
these elements represent the hardware that is abstracted, specifically the number of ring buffers,
DAI interconnects, and packet streams. Audio hardware that can be represented by other audio driver
types (StreamConfig, Dai, Codec) can instead be represented with a Composite driver. For
example, a Composite driver can represent a Codec with a topology that has zero ring buffers
and one DAI interconnect.
When an audio driver provides the Composite interface, its client is responsible for configuring
the hardware, including data topology. Driver responsibilities include using the
SignalProcessing protocol to enumerate the topologies and capabilities supported by the hardware
it abstracts.
The Composite FIDL protocol is defined at
composite.fidl.