[LinuxPPS] LinuxPPS 5.0.0-rc1

[clemens at dwf.com]

> On Thu, Aug 09, 2007 at 06:21:02PM +0200, Udo van den Heuvel wrote:
> 
> > > If you supply one device it tries to read both GPS and PPS data from
> > > it, but if you supply 2 devices it tries to read GPS data from
> > > /dev/refclock-u while PPS data from /dev/refclockpps-u.
> > 
> > So I make two links pointing to the same /dev/ttySx for my current
> > Garmin GPS18?
> 
> No. In LinuxPPS a device can __not__ be in the same time a serial line
> __and__ a PPS source, they must be considered as __two__ separate
> devices.
> 

This seems like another arbitrary change to the interface.
As it has stood up to now, linking both the GPS data and the PPS data to
the same device was just fine.

It is quite common with ntp (and the oncore driver) to put the following
in the dev file

ln -s /dev/oncore.serial.0 /dev/ttyS0
ln -s /dev/oncore.pps,0    /dev/ttyS0

linking BOTH the serial and the pps  devices used by the code to the 
same device.  This could equally well read

ln -s /dev/oncore.serial.0 /dev/ttyS0
ln -s /dev/oncore.pps.0    /dev/lp0

if the parallel interface were being used for the PPS signal,
the code expects it will be able to open these two devices.

For a standard GPS unit, with the PPS on the DCD line what am I 
supposed to do with this new interface?
    (a) open it once, and use it for both GPS and PPS data?
    (b) open it twice and use one each for GPS and PPS data?  (as I do currently)

I guess I just dont understand your words/example, but it appears to be
a significant change from what we have had in the past and have in
the previous linuxPPS.

-- 
                                        Reg.Clemens
                                        reg at dwf.com