[LinuxPPS] PPS kernel discipline

[Thorsten Mühlfelder]

Hi
I can't get the PPS kernel discipline to work:
# ntpdc -c kern
pll offset:           -2.3554e-05 s
pll frequency:        76.939 ppm
maximum error:        0.00352 s
estimated error:      1.5e-05 s
status:               2001  pll nano
pll time constant:    4
precision:            1e-09 s
frequency tolerance:  500 ppm

As you can see the status is "pll nano" but it should be something like
"pll ppsfreq ppstime ppssignal nano". I've found a similiar problem on the mailing list without solution:
http://ml.enneenne.com/pipermail/linuxpps/2008-November/002490.html

Of yourse I've already tried the relevant ntp.conf option (flag3 1). According to the description in timex.h there is no PPS signal detected by the kernel at all (status 2_0_01):
#define STA_PPSSIGNAL   0x0100  /* PPS signal present (ro) */
#define STA_PPSJITTER   0x0200  /* PPS signal jitter exceeded (ro) */
#define STA_PPSWANDER   0x0400  /* PPS signal wander exceeded (ro) */
#define STA_PPSERROR    0x0800  /* PPS signal calibration error (ro) */

This is the thread that brought this to my attention:
http://groups.google.com/group/comp.protocols.time.ntp/t/1f2a90c9e4456169?hl=en

More info about the kernel discipline could be found here:
http://www.cis.udel.edu/~mills/ntp/html/kern.html
http://www.cis.udel.edu/~mills/ntp/html/pps.html
http://www.ntp.org/ntpfaq/NTP-s-algo-kernel.htm#AEN2368
http://www.cis.udel.edu/~mills/ntp/html/drivers/driver22.html