[En-Nut-Discussion] timer problem

[Erik L]

PragmaLab wrote:
> 
> Hello Hansel,
> 
>> so i see that after the "crash" the timerlist is destroyed and an 
>> endloss loop inside of  "NutTimerInsert" is working. Only one timer 
>> exists, instead of my intended three timers, which really 
>> exists before 
>> (LED-Output).
>> 
>> timer1->next = timer1; timer1->prev=timer1;
>> timer2->next = timer3; timer2->prev= NULL;
>> timer3->next = timer2; timer3->prev= NULL;
>> 
>> had anyone a problem with timers in nut-os???
> 
> 
> I'm not sure if the timer problem we worked around some half year ago is
> related to yours. I just wanted to mention that we indeed had problems
> with
> the timerroutines. What happened was:
> 
> 1) we resuested a one-shot timer in thread A
> 2) used another timer in thread B (implicit by calling NutSleep(xxx))
> 3) manually killed the first one-shot timer while thread A was suspened
> 4) Noticed that when thread A woke up, it still assumed that the first
> one-shot timer was there,
>    killed it when it expired, but in fact was killing the wrong timer (of
> thread B)
> 5) so the second timer of thread B never expired anymore, so thread B
> never
> woke up, so the watchdog was not kicked, so.....
> 
> We even purchased an ICE50 to trace down this problem. The problem was
> 100%
> reproducable and clearly we could see it happen in the tracebuffer (a
> feature which is not available with a MKII -debugger). I've posted this
> issue in this list but never got any reply.
> 
> First we used NutOS 3.9.6 which did not suffer from this problem because
> timercallbacks run in interrupt context. We noticed the bug when we
> started
> using 4.2.1 (to shorten interrupt latencies, callback functions no longer
> run in interrupt-context).
> 
> Our workaround was (and still is) to use our own timeradministration.
> 
> Hope this helps?
> 
> Best regards,
> 
> Rob van Lieshout
> 
> _______________________________________________
> http://lists.egnite.de/mailman/listinfo/en-nut-discussion
> 
> 

Hi.
I experienced the exact same problem as you and did wrote my own
administration.

And it looks like its working, but perhaps you solved it in a much smarter
way?

this is how i did with some simple wraper functions.
---
HANDLE NutTimerStartWithCheck(u_long ms, void (*callback) (HANDLE, void *),
void *arg, u_char flags, HANDLE timerHandle)
{
	u_char * a;
	
	a = arg;
	if(*a != TIMERSTARTED)
	{
		*a = TIMERSTARTED;
		return NutTimerStartTicks(NutTimerMillisToTicks(ms), callback, arg,
flags);		
	}
	else return timerHandle; // Return old handle when trying to start already
started timer.	
}

void NutTimerStopWithCheck(HANDLE tn_handle)
{
	u_char *arg;
	NUTTIMERINFO *tn;
	tn = tn_handle;
	arg = tn->tn_arg;
	if(*arg == TIMERSTARTED)
	{
		*arg = TIMERSTOPPED;
		NutTimerStop(tn_handle);
	}
}

void timer_callback_pressure_adjust_fine_tune(HANDLE tn, void *a)
{
	u_char * arg;
	arg = a;
	*arg = TIMERSTOPPED;
....

}


HANDLE timer_pressure_adjust;
u_char timer_pressure_adjust_status;

timer_pressure_adjust = NutTimerStartWithCheck(PCU_PRESSURE_ADJUST_TIMER,
timer_callback_pressure_adjust_fine_tune,  &timer_pressure_adjust_status,
TM_ONESHOT, timer_pressure_adjust);

NutTimerStopWithCheck(timer_pressure_adjust);

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