Re: [chrony-users] chrony (or I210) loses PHC refclock PPS signal?

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Well, probably the easiest way is to get rid of the fluorescent light and
replace it with an incandescent or  LED. The second is to shield the
input/cable (fluorescents tend to be very radio noisy.) That noise should not
affect the Intel card, but it might well affect the unshielded GPS receiver.
Ie, put the receiver into a metal box, and make sure that all the cables
(antenna and connection to the computer) are well shielded.


William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1 ____|____ and Gravity ______|_ www.theory.physics.ubc.ca/

On Sat, 26 Mar 2022, Fabian wrote:

[CAUTION: Non-UBC Email]

The interface is always up.

I think I might have found the problem, but unsure on how to fix that.
In the room there is a fluorescent lamp, whenever someone switches on the light, there is a chance the PPS input on the card will stop.



Am 26.03.2022 um 18:46 schrieb Christopher Hoover:
    So when this happens I execute "ifdown eth0 && ifup eth0" and restart
    chrony. The refclock is now working again


i'm using i211 with ublox neo 8T and it works well.

is there any chance that something is downing the interface?   The PHC will not work if the interface is not up.

It may be worth checking to be sure the interface is still up (ip link or ifconfig) next time the problem occurs.

-ch



On Fri, Mar 25, 2022 at 4:37 AM Fabian <fabian.schoergi@xxxxxxxxx <mailto:fabian.schoergi@xxxxxxxxx>> wrote:

    I have the following setup:

    Intel I210 with SDP0 as PPS input from a Ublox M8Q-MAX device.
    The Ublox device is set to 1 Hz with 50% pulse width.
    chrony 4.2, Debian 11 with Kernel 5.15, i5-8500T

    I have configured the refclock:

    refclock PHC /dev/ptp0:extpps:nocrossts:pin=0 width 0.5 poll 0
    precision
    1e-9 pps refid GPS prefer trust

    I have attached the whole chrony config down below.

    After some time (which seems to be random, 1 - 24 hours) the PHC no
    longer produces a PPS interrupt (my guess), leading chrony to no longer
    chosing the PHC refclock. LastRx goes up, no longer recovering.
    The Ublox module still outputs a 1 Hz pulse as measured by a logic
    analyzer (also the LED still blinks).

    So when this happens I execute "ifdown eth0 && ifup eth0" and restart
    chrony. The refclock is now working again, until the next failure.
    Nothing shows up in dmesg regarding this event.

    What could be the issue here? I am not sure if this mailing list is the
    correct one, as this might also be a kernel issue, or hopefully not a
    hardware issue with the Intel NIC.
    I have tried some things: different powersupply for the GPS device
    aswell as the PC. Different CPU settings (powersafe, performance).
    Different Kernels: 5.10, 5.16.

    I disconnected the serial output from the GPS. Tried with only PPS and
    GND connected, as I thought maybe the serial port was somehow
    interfering. Disabled EEE, which probably had no effect anyway as the
    switch does not support EEE.

    I also tried disconnecting PPS output and reconnecting it again to see
    if the pulse would be picked up again, it did.


    I'll try to get a chrony debug log when this happens.

    Not sure what else I can try. Any hints?

    best regards
    Fabian

    Some additional info:

    Time stamping parameters for eth0:
    Capabilities:
              hardware-transmit
              software-transmit
              hardware-receive
              software-receive
              software-system-clock
              hardware-raw-clock
    PTP Hardware Clock: 0
    Hardware Transmit Timestamp Modes:
              off
              on
    Hardware Receive Filter Modes:
              none
              all

    01:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network
    Connection (rev 03)

    Settings for eth0:
              Supported ports: [ TP ]
              Supported link modes:   10baseT/Half 10baseT/Full
                                      100baseT/Half 100baseT/Full
                                      1000baseT/Full
              Supported pause frame use: Symmetric
              Supports auto-negotiation: Yes
              Supported FEC modes: Not reported
              Advertised link modes:  10baseT/Half 10baseT/Full
                                      100baseT/Half 100baseT/Full
                                      1000baseT/Full
              Advertised pause frame use: Symmetric
              Advertised auto-negotiation: Yes
              Advertised FEC modes: Not reported
              Speed: 1000Mb/s
              Duplex: Full
              Auto-negotiation: on
              Port: Twisted Pair
              PHYAD: 1
              Transceiver: internal
              MDI-X: off (auto)
              Supports Wake-on: pumbg
              Wake-on: g
              Current message level: 0x00000007 (7)
                                     drv probe link
              Link detected: yes

    phc_ctl[356709.285]:
    capabilities:
        62499999 maximum frequency adjustment (ppb)
        0 programable alarms
        2 external time stamp channels
        2 programmable periodic signals
        4 configurable input/output pins
        has pulse per second support
        doesn't have cross timestamping support


    chrony.conf:

    confdir /etc/chrony/conf.d
    sourcedir /etc/chrony/sources.d
    keyfile /etc/chrony/chrony.keys
    driftfile /var/lib/chrony/chrony.drift
    ntsdumpdir /var/lib/chrony
    logdir /var/log/chrony
    maxupdateskew 100.0
    rtcsync
    makestep 1 3
    leapsectz right/UTC
    hwtimestamp eth0
    allow 192.168/16
    log refclocks
    peer 192.168.0.5 minpoll 2 maxpoll 6 iburst xleave key 1 extfield F323
    peer 192.168.0.84 minpoll 2 maxpoll 6 iburst xleave key 1 extfield F323
    refclock PHC /dev/ptp0:extpps:nocrossts:pin=0 width 0.5 poll 0
    precision
    1e-9 pps refid GPS prefer trust

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