Re: [gpsd-dev] Time to let the code cool down

[Eric S. Raymond]

Gary E. Miller <address@hidden>:
> You changed it, but it does not deal with the delay thing.  You can not just
> add a delay, the code needs to wait for the ACK.  By waiting 4 seconds
> the output from the GPS is overflowing and the GPS resets.

Um, but you were adding a 3-second settle, right? Were you getting overflow?

OK.  I didn't see an overflow during the init sequence.  And shouldn't, as the
way it's coded now it spaces the initialization writes 5 seconds apart while
allowing traffic through.  Are you actually seeing a problem there or is it
getting through those first 10 sends OK?  What sequence of operations
is actually causing overflow/reset?

Note that I'm not unconditionally adding a delay, like you
were. Rather I'm waiting for 4 seconds *since the last send* - often that
will be no delay at all.

We could add a semaphore, I suppose.  Increment on each sirf_write(),
decrement on each ack, return an error if the user tries to trigger a
sirf_write() while the semaphore is nonzero.  That would never block
traffic. Some requests might fail.

What is the actual error pattern you're currently seeing?
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>

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