Re: [PATCH 1/1] LinuxPPS: Pulse per Second support for Linux

From: Rodolfo Giometti
Date: Thu Feb 22 2007 - 04:00:25 EST

On Thu, Feb 22, 2007 at 12:51:48AM +0100, Roman Zippel wrote:
> Hi,
> On Wednesday 21 February 2007 13:04, Rodolfo Giometti wrote:
> > RFC simply doesn't consider the fact that you can have a PPS source
> > __without__ a filedes connected with, and a single filedes is
> > considered __always__ connected with a single PPS source.
> That's not entirely true. It doesn't say that pps_handle_t must be a file
> descriptor and it leaves the option for the argument to time_pps_create() not
> to be a file descriptor as well.

Yes. In fact that's my solution!

The problem is that "pps_handle_t" is forced by the RFC to be a scalar
and _not_ a generic (and opaque) type. I suppose that since right now
such handler was simply the filedes of the serial/parallel port
connected with the GPS antenna. But this is not always the case. As
already told the GPS antenna can be connected with the serial line
while the PPS signal is not, so NTPD should always open the serial
port to read GPS data but it must not use such filedes for the

My support try to resolve this problem with minor changes in both RFC
and NTPD code.




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