[LinuxPPS] ntp 'bugs'

[Udo van den Heuvel]

Rodolfo Giometti wrote:
>         /* First we check if current device is a PPS valid PPS one...
>          */
>         ret = ioctl(source, PPS_CHECK);
>         if (ret == 0) {
> 		/* Got it! Since in LinuxPPS there are no differences
> 		 * between a "PPS source" and a "PPS handle", we
> 		 * simply return the same value.
> 		 */
> 		*handle = source;
> 
> 		return 0;
> 	}
> 
> 	/* Before exiting an error we have to verify if we can
> 	 * change the line discipline for the current device in
> 	 * case it's a serial one.
> 	 */
> 	ldisc = N_PPS;
> 	(void) ioctl(pp->io.fd, TIOCSETD, &ldisc);
> 
> 	/* The we return error, so caller should try the alternate
> 	 * device.
> 	 */
>         errno = EOPNOTSUPP;
>         return -1;
> }

Hmm. I had to look at the code in refclock_nmea...
Does the ldisc change work on the pps device so that it effects the
`connected` serial line?
This because the first time_pps_create in refclock_nmea is on the pps
device. Only when that fails we do a time_pps_create on the serial line
itself as a fallback.

Please enlighten us on the flow of the change in time_pps_create and the
correlation with e.g. the code in refclock_nmea.

Thanks,
Udo