Subject: Re: kern/13702: kernel hardpps support is not working
To: Andreas Wrede <>
From: Dave Tyson <>
List: current-users
Date: 08/21/2002 10:08:02
On Tue, 20 Aug 2002, Andreas Wrede wrote:

>Could someone please look at the above PR and please commit the
>patches if they are acceptable. I have been running a GPS based
>NTP server with these patches in NetBSD/i386 1.5.[1-3] kernels for
>almost a year now.
>    - aew

This bugs me as well!

I have just modified the 13702 patches locally to work on current
(1.6F). The version of ntp integrated with netbsd really needs to be
pulled up to 4.1.1 as well.

With the existing patches it seems to work OK. I have a Trimble TAIP GPS
connected up and get pretty good stability on an old pentium 200 box. I
haven't managed to get the ATOM PPS loopback to work yet.

ntp_gettime() returns code 0 (OK)
  time c10dd50e.96e9c000  Wed, Aug 21 2002  9:59:58.589, (.589504),
  maximum error 10059 us, estimated error 100 us.
ntp_adjtime() returns code 0 (OK)
  modes 0x0 (),
  offset -55.000 us, frequency 28.879 ppm, interval 64 s,
  maximum error 10059 us, estimated error 100 us,
  time constant 2, precision 1.000 us, tolerance 512 ppm,
  pps frequency -0.006 ppm, stability 0.058 ppm, jitter 0.000 us,
  intervals 299, jitter exceeded 2, stability exceeded 4, errors 2.

I hope to add additional code to implement the PPS API echo feature
as this will allow the kernel pps delays to be measured with a scope,
I'll submit a pr for this once it is working.


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