[ntp:questions] linux pps ntp help

Jim Kusznir jkusznir at gmail.com
Tue Mar 26 21:14:47 UTC 2013

Hi all:

I have a CentOS-based system currently working happily with the shm PPS
driver and SEL 2407 clock.  (homebrew cable currently connecting the BNC
PPS output to the pin on the DB9 serial connector).  However, I've thought
that the in-kernel PPS support and the ntp PPS driver would be a "better"
driver (and also a half-step toward implementing the new PARSE mode 24 SEL
driver w/ PPS).

I've installed kernel-ml to get me up to 3.8.4 with pps and pps_ldisc
support.  I've loaded the module and run the ldattach command, and presto,
I get /dev/pps0.  All looks good.  When I cat the assert in
/sys/class/pps/pps0/, I see it incrementing a little.  the desert looks
more normal.

When I run ppstest /dev/pps0, I get "time_pps_fetch() error -1 (connection
timed out).

I can't seem to find a lot of info on specifically how to get the linux pps
stuff working/set up.  Can anyone here give me some insight on how to make
this work?


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