[ECOS] Problems with internal timer in XScale platform

[Cristiano Ligieri Pereira <cpereira at ics dot uci dot edu>]

Hi all,

I'm doing some programming on a XScale board running eCos and I'm having a
nasty problem that is bugging me for quite a while.

I have an external interruption coming into the processor's IRQ pin and
this external interruption is the tick of the system. In addition to that,
I'm also using the internal performance counter as a second timer that
triggers in a frequency higher than the tick and in fact takes care of
some other timing things (it is just a more precise timer that gives me
fraction of ticks).

When I have only one thread running in the system, everything seems to be
working fine but when I have two or more threads the internal
interruption (coming from the performance counter) stops triggering. I
honestly have no clue of why this is happening. It looks like the
interruption is getting disabled for some reason? Would it be the context
switch? 

Any help or suggestion is very welcome,

Thanks a lot,
Cristiano.

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Cristiano Ligieri Pereira - http://www.ics.uci.edu/~cpereira