Asynchronous Requests

This document discusses the use of asynchronous requests by device drivers.

An asynchronous request is typically used to start an operation on a device that completes at a later point of time. It returns immediately after starting the operation on the device or making a request to the driver. The user side thread is not blocked and can continue with other operations, including issuing other requests (synchronous or asynchronous).

A driver lists the available asynchronous request types in an enumeration.