Re:

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Wed May 09 2001 - 09:10:31 EST


> while(!!time_before(jiffies, timer))
> {
> if(!!(*event & mask))
> {
> stat = 0;
> break;
> }
> schedule();

You want to yield as well otherwise you may just spin anyway

> Both of these procedures schedule() while waiting for something to
> happen. The wait can be very long (1 second) so I don't want to
> just spin eating CPU cycles. I have to give the CPU to somebody.

So use a timer

void tick_tick_boom(unsigned long l)
{
        struct my_device *d = (struct my_device *)l;

        if(its_still_busy(d))
        {
                d->timer_count--;
                if(d->timer_count)
                {
                        /* Try again until timer_count hits zero */
                        add_timer(&t->timer, jiffies+1);
                        return;
                }
                else
                {
                        /* Lose some .. */
                        d->event_status = TIMEOUT;
                }
        }
        else
        {
                /* Win some .. */
                d->event_status = OK;
        }
        /* Wake up the invoker */
        wake_up(&d->timer_wait);
}

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