[ntp:questions] Linux 2.6 + PPS + ntpd?
armenb at ll.mit.edu
Fri Dec 30 00:10:29 UTC 2005
I have a Garmin GPS 25LP that I have connected to a serial port on my
linux 2.6 laptop, and I need to get my system's clock synchronized with
the PPS signal from the GPS.
I've verified that my GPS is indeed outputting the PPS signal
(100ms-long pulse, once a second) with an oscilloscope and gpsd (which
will output messages relating to getting or losing carrier detect on the
My problems comes in the kernel/ntp area. After trying with RedHat
Enterprise Linux's kernel (2.6.9-22.0.1.EL), vanilla 2.6.13 and vanilla
22.214.171.124, I've had unsuccessful results, ranging from kernel panics to
test programs and ntp not producing correct output.
I've tried using both PPSkit and LinuxPPS - do you (collectively) had
more luck with one over the other? Has anyone had a post-2.6.9/pps/ntp
configuration working somewhat recently? I'd be interested to hear
about specific software/hardware configurations to mimic a known-good
MIT Lincoln Laboratory
armenb at ll.mit.edu . 781-981-1796
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