[LinuxPPS] Found it, problem with current PPS code.

[clemens at dwf.com]

OK, here's the problem Im seeing with ntpd.
Ntpd uses a generic function ntp_refclock to open the serial file, which I
use in the ONCORE driver.

This function does a "tcgetattr" to get the attributes of the tty line, then
proceeds to set or clear those attributes before doing a tcsetattr 
(there is separate code for termio/termios/sysV ttys/BSD ttys, which is
the reason for using this code)

In any case the call to tcgetattr, returns with the error message

    tcgetattr: Invalid arguments

I can follow this thru if necessary, but Ill assume that this is enough
of a clue for you.  My assumption is that he device being pointed at
(/dev/ttyS0) must not appear to be a tty.

Not sure how easy this is going to be to correct.
-- 
                                        Reg.Clemens
                                        reg at dwf.com