On Wed, May 5, 2010 at 2:12 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >> >> Oh, like tell the modem that user mode has handled the ring event and >> its ok to un-block? > > No, that's not how it works. It would go like this: > > The modem IRQ handler queues its event to the input subsystem. > As it does so the input subsystem enables a suspend blocker, > causing the system to stay awake after the IRQ is done. > > The user program enables its own suspend blocker before reading > the input queue. When the queue is empty, the input subsystem > releases its suspend blocker. > > When the user program finishes processing the event, it > releases its suspend blocker. Now the system can go back to > sleep. > > At no point does the user program have to communicate anything to the > modem driver, and at no point does it have to do anything out of the > ordinary except to enable and disable a suspend blocker. Exactly -- and you can use the same style of overlapping suspend blockers with other drivers than input, if the input interface is not suitable for the particular interaction. Brian -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
