Re: [ECOS] asynchronous break stability on i386

[Jonathan Larmour <jlarmour at redhat dot co dot uk>]

Daan Huybrechs wrote:
[ breaks sometimes fail ]

I had a quick check with our latest sources here, and I can confirm that
the normal PC HAL appears to have the same symptoms. I reduced the delays
in twothreads down to about 5 ticks on average. When I ran it, as you
report, it sometimes ignored Ctrl-Cs. It also started randomly outputting
"Interrupt: 39" messages occasionally as well after a while. Except it
wasn't that random - it started when I pressed Ctrl-C so it is related.

So the good news is that it's not something you've done; the bad news of
course being that you still have the problem :-). Obviously if you do track
it down and fix it, please tell us! At this time, we don't have anyone
working on development of the PC HAL.

> I would like to know if this is a bug in my port, or in the i386-pc target,
> so I have some questions:
> - Has anyone seen this behaviour when using the regular i386-pc target?
> - ..and possibly solved it?
> - At first the breaks seemed to fail in code paths that include an interrupt
> call. Is it at all possible to break into an interrupt handler (with the
> current code or with ecos in general)?  I recently had the same problem in
> rand() though, which uses no interrupt whatsoever.

You can't interrupt an ISR - but any interrupt should be handled as soon as
any running ISRs are processed - so in this case the serial interrupt
indicating the Ctrl-C should be deferred for a very small period of time.
 
Jifl
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