In previous sections, we saw how to manage an interrupt directly in its handler or by deferring the interrupt activities by using tasklets, workqueues, and so on. Also, we saw how to do periodic operations or how to delay an action forward in time; however, a device driver may need to wait for a specific event, such as waiting for some data, waiting for a buffer to become full, or a for a variable to reach a desired value.
Please don't confuse events managed by the notifiers, we saw before, which are kernel related, with generic events for a specific driver.
When there is no data to be read from a peripheral, the reading process must be put on sleep and then awakened when the "data ready" event arrives. Another example is when we start a complex job and we wish to be signaled when it's finished; in this case, we start the job and then we...
