On Mon, Jan 24, 2011 at 9:25 PM, Gilles Chanteperdrix <
[email protected]> wrote:

> at91_enthus wrote:
> > On Mon, Jan 24, 2011 at 8:41 PM, Gilles Chanteperdrix <
> > [email protected]> wrote:
> >
> >> at91_enthus wrote:
> >>> Hi.
> >>>
> >>> I  was testing Xenomai on my AT91SAM9G20-based board and tried to adapt
> >> the
> >>> code found here:
> >>> http://www.armadeus.com/wiki/index.php?title=Xenomai:Blinking_LEDs .
> >> By the way, this code is ridiculous. It creates a real-time task to
> >> write to some non real-time device, which makes the real-time task
> useless.
> >>
> >>
> > I know.
>
> Yes, but this example is bad in many ways:
> - first it uses xenomai api to create a real-time task, and uses write
> which causes the real-time task to switch to secondary domain;
> - the Makefile does not use xeno-config, which have been the recommended
> way of getting the compiler flags since day 1;
> - it nullifies SIGTERM and SIGINT, which is a dubious decision, and
> could lead people to believe that they should do the same when using
> Xenomai, whereas there is no such requirement.
> - the pointers point to outdated version of the documentation.
> - it uses runinfo/xeno-load, which are kind of outdated too, make things
> uselessly complicated, and in any case, tell you to type Ctrl-C to
> interrupt the program, which is bound to fail if anything goes wrong,
> since SIGINT is neutralized in the program.
>
> >
> > That's why I went to mmap().
>
> That is not really the right solution either. I admit that for driving
> leds, it may be a bit overkill, but anyway, what you should do is write
> an RTDM driver for driving the leds. Keeping the driver separated from
> the application will allow the same program to run on other platforms
> where driving the LEDS is done differently without changing much of the
> application code. In other word, the application/driver separation is a
> sane one.
>
> Anyway, mmap should work.
>
>  (I chose that sample code because, for
> > now, I am only learning to use basic functions)
>
> >> Wrong test here. Should be "if (aic_base == MAP_FAILED)"
> >
> > Indeed, my program fails miserably when I check the mapping of AIC, not
> > PIOB's. And yet, I just can't figure why in the non-Xenomai code, AIC
> > mmap-ing works  fine.
>
> Well errno might give you a clue. Do you have FCSE enabled?
>
> Regards.
>
> --
>                                                                 Gilles.
>

FCSE is enabled. errno returns  22 (invalid argument).

Thanks.
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