struct audio_stream_cmd_get_unique_id_req

AUDIO_STREAM_CMD_GET_UNIQUE_ID

Fetch a globally unique, but persistent ID for the stream.

Drivers should make every effort to return as unique an identifier as

possible for each stream that they publish. This ID must not change between

boots. When available, using a globally unique device serial number is

strongly encouraged. Other possible sources of unique-ness include a

driver's physical connection path, driver binding information, manufacturer

calibration data, and so on.

Note: a small number of hardcoded unique ID has been provided for built-in

devices. Platform drivers for systems with hardwired audio devices may use

these unique IDs as appropriate to signal which audio streams represent the

built-in devices for the system. Drivers for hot-pluggable audio devices

should *never* use these identifiers.

Even given this, higher level code should *not* depend on these identifiers

being perfectly unique, and should be prepared to take steps to de-dupe

identifiers when needed.