[Tinyos-devel] problem of using FTSP and CTP

[Miklos Maroti]

On Mon, Mar 23, 2009 at 6:38 PM, Philip Levis <pal at cs.stanford.edu> wrote:
>
> On Mar 23, 2009, at 10:34 AM, Miklos Maroti wrote:
>
>> There is a separate issue: do we want to allow the EBUSY return code
>> from the MAC layer? I always assumed that we should because there
>> could be several conditions where sending is not possible temporarily
>> (see my previous post). If we decide that it is NOT possible, then we
>> need to audit/rework the radio drivers (at least the RF230 I guess).
>
> I think returning EBUSY due to an internal condition is problematic: the
> caller won't know when to retry the call.
>
> The radio stack should buffer the send instead. Otherwise we'll get into a
> situation where a sender needs to wire to every possible (and possibly
> hardware-dependent) split-phase interface, in order to retry on getting the
> corresponding completion event.

I would always use a task to retry it later. Or if we decide to
deprecate EBUSY, then either a buffer could be used in the driver, or
by signaling the EBUSY with the sendDone event.

Miklos