Documentation/hid/hid-transport.rst

79 The terms "asynchronous" and "synchronous" in this document describe the
81 not perform any synchronous operations like waiting for acknowledgements or
84 On the other hand, synchronous channels can be implemented by the transport
105  - Control Channel (ctrl): The ctrl channel is used for synchronous requests and
111    Outgoing reports are usually sent on the ctrl channel via synchronous
142 channel provides synchronous GET/SET_REPORT requests. Plain reports are only
147    requested report ID on the ctrl channel as a synchronous acknowledgement.
168    A device must answer with a synchronous acknowledgement. However, HID core
173    multiple synchronous SET_REPORT requests.
320    be synchronous. A transport driver must not use ->wait() to complete such
353 API. Responses to ->raw_request() are synchronous and must be intercepted by the