[LinuxPPS] Linux hardpps, RFC 1589 issue

[Udo van den Heuvel]

Hello,

When starting ntpsec's ntpd with flag3 set, I get:

REFCLOCK: refclock_params: kernel PLL (hardpps, RFC 1589) not implemented
REFCLOCK: NMEA(0) set PPSAPI params fails


So what is missing from my kernel?
What should I check, correct?

Of course the kernel has PPS support, what else is needed?

Kind regards,
Udo