[LinuxPPS] Linuxpps on 2.6.28 vs. ntpd 4.2.4p6

[Hal V. Engel]

On Wednesday 14 January 2009 13:24:21 Thorsten Mühlfelder wrote:
> Hi Heiko
>
> I've used kernel 2.6.28rc6 with ntp 4.2.4p5 for about 3 weeks without
> problems on my test machines. Today I've done an upgrade to kernel
> 2.6.28 and ntp 4.2.4p6. With this combination the ntpd doesn't use the
> PPS signal. I've checked ntpd syslog entries but there was nothing
> special. So I've decided to play with the different versions and these
> are my results:
>
> 2.6.28rc6 + 4.2.4p5 = working
> 2.6.28rc6 + 4.2.5p6 = not working
> 2.6.28 + 4.2.4p5 = working
> 2.6.28 + 4.2.5p6 = not working
>
> ppstest works in every case and restarting ppsldisc and ntp doesn't
> change anything.
> So the problem must be the ntpd 4.2.5p6.
>
> Greetings
> Thorsten
>
> PS: I'm usin Meinberg DCF and GPS cards as time and PPS source in
> different servers, too. But as PPS just uses the atom driver I don't
> think it's a Meinberg related problem.

Above you wrote ntp 4.2.5p6 but I think you intended to write 4.2.4p6.  I am 
using kernel 2.6.26 with ntp 4.2.4p6 and everything is working OK.  I am using 
the Oncore driver.  Maybe there is a problem with the way 4.2.4p6 is built?

Hal

>
> On Wed, 14 Jan 2009 12:42:54 +0100
>
> Heiko Gerstung <heiko.gerstung at meinberg.de> wrote:
> > Hi everybody!
> >
> > I am trying to prepare a new kernel for our series of NTP time server
> > appliances called LANTIME (see our website if you are interested) but I
> > have problems getting ntp-4.2.4p6 to work with my 2.6.28 kernel and the
> > rc6 linuxpps patch.
> >
> > What already works is that if I start ppsldisc /dev/ttyS0 on a console,
> > I can see that assert and clear events are correctly recognized in
> > /sys/class/pps/pps/assert and clear and they represent the 200ms pulse
> > width we are using on our GPS receivers.
> >
> > But for some it does not work when I start ppsldisc as a background
> > process during startup. I can see that there are a number of events
> > recorded because the assert file for example shows a timestamp and the
> > event count, which can be #32 for example or #43 but does not recognize
> > any further events until I "killall ppsldisc" and run ppsldisc on my
> > console (in the foreground).
> >
> > Additionally, when I start ntpd, it cannot initialize the Atom driver
> >
> > and the parse driver also cannot setup PPS usage:
> > > Jan 14 09:17:19 LantimeV5 ntpd[13940]: PARSE receiver #0: parse_start:
> > > could not set up PPS: Invalid argument
> > > Jan 14 09:17:19 LantimeV5 ntpd[13940]: PARSE receiver #0:
> > > parse_ppsapi: time_pps_getcap failed: Bad file descriptor
> > > Jan 14 09:17:19 LantimeV5 ntpd[13940]: refclock_atom: time_pps_create
> > > failed: Inappropriate ioctl for device
> >
> > I am not running udev on my machine and therefore have to create the
> > /dev/pps0 device node manually. I can see from /sys/class/pps/pps0/dev
> > that this should be c254:0 and therefore run "mknod /dev/pps0 c 254 0"
> > before doing anything else at startup.
> >
> > What am I missing? First and foremost I would like to get ntpd to use
> > the PPS stuff, but if someone has any hints on why ppsldisc does not
> > work when it is sent into the background, I would be grateful for any
> > hints.
> >
> > Best Regards,
> >   Heiko
> >
> >
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