Re: [chrony-users] Configuring chrony debian service - BBB

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It's looking like I will need to recompile gpsd with pps=off as Lichvar suggested. I disabled the BeagleBone overlay for the GPIO pin that I was using for PPS and connected the PPS line to the CTS pin for UART4. That caused only one PPS source to be created for /dev/ttyS4

[    1.537951] pps_core: LinuxPPS API ver. 1 registered
[    1.537960] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@xxxxxxxx>
[   17.542045] pps_ldisc: PPS line discipline registered
[   17.543815] pps pps0: new PPS source serial4
[   17.543896] pps pps0: source "/dev/ttyS4" added

However chrony doesn't appear to be getting that PPS based on what I see using chrony sources

debian@beaglebone:~$ chronyc sources
210 Number of sources = 2
MS Name/IP address         Stratum Poll Reach LastRx Last sample
#? NMEA                          0   4   377    14   -9382h[ -9382h] +/-  107ms
#? PPS                           0   4     0     -     +0ns[   +0ns] +/-    0ns

Also, ppstest /dev/pps0 outputs errors

debian@beaglebone:~$ sudo ppstest /dev/pps0
trying PPS source "/dev/pps0"
found PPS source "/dev/pps0"
ok, found 1 source(s), now start fetching data...
time_pps_fetch() error -1 (Connection timed out)
time_pps_fetch() error -1 (Connection timed out)
time_pps_fetch() error -1 (Connection timed out)

On Wed, Nov 29, 2017 at 9:39 AM, Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:
On Wed, Nov 29, 2017 at 08:51:33AM -0500, Joe Smith wrote:
> However, if gpsd is really what's giving me my problems then I'll ditch it
> and configure chrony to read the NMEA serial port directly. I'll just need
> to consult the documentation to figure out how to properly update
> chrony.conf for that.

chrony doesn't have an NMEA driver. If gpsd attaching the ldisc is
causing problems and there is no way to tell it to not do that, you
could recompile gpsd with pps=off. That should disable the PPS
support completely.

Miroslav Lichvar

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