[LinuxPPS] Linuxpps on 2.6.28 vs. ntpd 4.2.4p6

[Heiko Gerstung]

I got this to work fine by using Folkert's ppsldisc patch, great stuff!

It turned out that I always have to start ppsldisc right before ntpd and 
it seems that I have to kill and restart ppsldisc every time I connect 
to the serial port again.

So, at least it works for now, but I have a new problem :-) More on that 
in a separate mail ...

Regards,
Heiko


Heiko Gerstung schrieb:
> 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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