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From: | Chris Kuethe |
Subject: | Re: [gpsd-dev] gpsd processor load |
Date: | Wed, 30 Oct 2013 17:21:47 -0700 |
Yo Chris!
I baffled how they can manage without TIOCMIWAIT. How can you write any
On Wed, 30 Oct 2013 16:16:24 -0700
Chris Kuethe <address@hidden> wrote:
> > TIOCMIWAIT is what sleeps and wakes up the thread. It would need
> > to be replaced with some sort of usleep() and then KPPS would need
> > to actually work on BSD. Doable, but a lot of work, and only a BSD
> > person could do it.
> I don't think any of the BSDs seem to have TIOCMIWAIT.
sort of low level serial client without it? BSD has to have some way to
wake on control changes...
Thn the PPS thread would wake up on every character as well. Not good.
> I think select() will return a ready fd with no data bytes from
> read() when a control line changes.
Maybe, but it all needs KPPS to work to get any sort of time. And if
> Could we fake it on that?
KPPS is working we just need to wake up the thread a few times a second
and check if KPPS has anything for us.
Looking at RFC 2783, there is a way to have time_pps_fecth() block until
the next edge. Linux does not need that and has no documentation if it
would work. That might be the answer if you can figure it out.
RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701
address@hidden Tel:+1(541)382-8588
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