Re: wait_event_interruptible

[Roland Dreier <roland@topspin.com>]

    Hendrik> Hello, I created a kernel thread inside of my driver by
    Hendrik> calling the function kernel_thread with a function
    Hendrik> pointer. Now this thread calls daemonize and allow_signal
    Hendrik> and then it runs a forever loop until it is terminated by
    Hendrik> the kernel (unloading the driver etc). And because it is
    Hendrik> written in the documentation I put the thread asleep by
    Hendrik> calling wait_event_interruptible with a wait queue called
    Hendrik> "dpn_wq_run" inside the forever loop. Now is it right
    Hendrik> that a wake_up_interruptible in the ISR has to wake up
    Hendrik> the thread so it continues its work? If yes... why isn't
    Hendrik> that working for me? I called wait_event_interruptible
    Hendrik> with that dpn_wq_run inside the kernel thread and do a
    Hendrik> wake_up_interruptible inside the ISR with the same
    Hendrik> dpn_wq_run. But my kernel thread won't wake up. Is there
    Hendrik> anything else I have to do to the wait queue, but calling
    Hendrik> init_wait_queue on it?

wait_event_interruptible() will sleep until your ISR wakes it up, but
for your thread to run, you also need to make sure that the condition
being tested by wait_event_interruptible() is true (otherwise it will
go back to sleep).  For example, if your thread does:

	wait_event_interruptible(&my_wait, work != 0);

then your ISR needs to do

	work = 1;
	wake_up_interruptible(&my_wait);

If you don't set work, the wake_up will have no effect.

 - R.