[Tinyos-devel] Resource arbitration bug in SerialP

[Eric Decker]

Hi Kevin,

What exactly is wrong with the serial code?

Is it simply a matter of making the Serial Stack conform to
SplitControl.start/done?
Or are there other things that need to be mucked?

eric

On Mon, Sep 8, 2008 at 7:57 AM, Kevin Klues <klueska at gmail.com> wrote:

> After glancing briefly at the code, it looks to me like there are more
> things wrong here than the simple fix you propose.  Until now, no one
> has really arbitrated access to the serial stack i.e. it has been a
> dedicated resource on most platforms.  Because of this, it seems like
> it doesn't follow the proper semantics for SplitControl.start() and
> SplitControl.stop() as outlined in TEP115.  A proper fix would be to
> get it in line with these specifications so that putting a resource
> arbiter around it can work properly.
>
> Kevin
>
> On Mon, Sep 8, 2008 at 3:23 AM, Maxime Muller - s h o c k f i s h /
> <maxime at shockfish.com> wrote:
> > Hi there,
> >
> > Francois Ingelrest from LCAV @ epfl noticed a bug in
> > $TOSDIR/lib/serial/SerialP.nc
> >
> > Description:
> > A call to SplitControl.stop() will eventually set txState to
> > TXSTATE_INACTIVE. Then calling SplitControl.start() wont set txState to
> > TXSTATE_IDLE thus locking the resource.
> >
> > Possible fix:
> >
> >   task void startDoneTask() {
> >       if(call SerialControl.start()==SUCCESS) {
> >          if(txState == TXSTATE_INACTIVE)
> >              txInit();
> >          signal SplitControl.startDone(SUCCESS);
> >       } else signal SplitControl.startDone(FAIL);
> >   }
> >
> > imho, the rx part should be ok as void rx_state_machine(...) restores
> > the right state.
> >
> > Kind Regards,
> > maxime
> > _______________________________________________
> > Tinyos-devel mailing list
> > Tinyos-devel at millennium.berkeley.edu
> >
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-devel
> >
>
>
>
> --
> ~Kevin
> _______________________________________________
> Tinyos-devel mailing list
> Tinyos-devel at millennium.berkeley.edu
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-devel
>



-- 
Eric B. Decker
Senior (over 50 :-) Researcher
Autonomous Systems Lab
Jack Baskin School of Engineering
UCSC
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.millennium.berkeley.edu/pipermail/tinyos-devel/attachments/20080909/2ed93166/attachment.htm