Ken,
Which version of RTLinux do you use?
Michael.
Ken Teh ([EMAIL PROTECTED]) wrote:
> I apologize if this sounds confused; it's because I am.
>
> I'm trying to understand how thread dispatching works. Using the sound
> example, I wrote an IRQ handler that does the following:
>
> irq_handler()
> {
> clear_hardware_irq();
> pulse_output();
> rtl_hard_enable_irq(x);
> }
>
> Everything works fine. I look on my scope and can measure the time between
> the input pulse that causes the interrupt and the output pulse from
> pulse_output().
>
> >From the same sound example, I then tried a variation where a thread is
> dispatched from the handler, ie.
>
> irq_handler()
> {
> pthread_wakeup_np(thread);
> clear_hardware_irq();
> rtl_hard_enable_irq(x);
> }
>
> and my thread looks like
>
> void *my_thread(void *param)
> {
> rtl_stop_interrupts();
> while (1) {
> pthread_suspend_np(pthread_self());
> pulse_output();
> }
> }
>
> When I look on the scope I see 2 output pulses about 10usec apart, instead
> of the expected 1 which I saw with the previous version. Since I don't have
> a capture scope where I can freeze, I cannot say for certain there were
> actually 2 pulses. But it sure looks this way. Only way for this to happen
> is if the thread ran twice. Not possible, is it?
>
> As a afternote, the system cannot be interrupted twice because the input
> that generated the interrupt is vetoed until I do pulse_output() which
> removes the veto. In any case the input rate is too slow.
>
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