Arch GPSD PPS Issues

[Jason R Begley]

I have a bare metal box(dell r720), running Arch, physical serial port (uart:16550A), and a ublox on a 9 pin serial cable with good gps lock to at least 5 satellites. Via USB and windows PC the GPS shows PPS sync. PPS light shows pulses as expected. cgps shows 3d fix. NTPD gets time from GPS. Some time ago (don't know when it stopped working, but probably beyond a year) NTPD would no longer sync with PPS. GPSD would throw the following error "gpsd:INFO: KPPS:/dev/ttyS1 kernel PPS timeout Connection timed out(110)" Upon investigations I found that even with gpsd out of the equation PPS was still not working correctly. disabling gpsd and running ldattach 18 /dev/ttyS1 to get a pps0 dev and ppstest throws time_pps_fetch() error -1 (Connection timed out). I worked with gemiller in the irc channel for a good deal of time, and I think there is some issue with Arch and how its setting up PPS.. just not sure what has changed since it worked properly. pps_ldisc module is also loaded and shown in use with a lsmod. Also testing "modprobe pps-ktimer" gives me a kernel pps device that I can actually connect to with pps tools and get a response back. I though it may be something from this machine in particular, but installing gpsd on another arch box and performing the same tests have the same results.  Below is a log from latest build and test.

gpsd:INFO: launching (Version 3.23.2~dev, revision release-3.23.1-260-g42b1e1e00)
gpsd:INFO: starting uid 0, gid 0
gpsd:INFO: Command line: ./gpsd -n -D 4 -N /dev/ttyS1 
gpsd:INFO: listening on port gpsd
gpsd:PROG: NTP:SHM: shmat(0,0,0) succeeded, unit 0
gpsd:PROG: NTP:SHM: shmat(1,0,0) succeeded, unit 1
gpsd:PROG: NTP:SHM: shmat(2,0,0) succeeded, unit 2
gpsd:PROG: NTP:SHM: shmat(3,0,0) succeeded, unit 3
gpsd:PROG: NTP:SHM: shmat(4,0,0) succeeded, unit 4
gpsd:PROG: NTP:SHM: shmat(5,0,0) succeeded, unit 5
gpsd:PROG: NTP:SHM: shmat(6,0,0) succeeded, unit 6
gpsd:PROG: NTP:SHM: shmat(7,0,0) succeeded, unit 7
gpsd:PROG: successfully connected to the DBUS system bus
gpsd:PROG: SHM: shmget(0x47505344, 26712, 0666) for SHM export succeeded
gpsd:PROG: SHM: shmat() for SHM export succeeded, segment 8
gpsd:INFO: stashing device /dev/ttyS1 at slot 0
gpsd:PROG: CORE: open_device(/dev/ttyS1) fd -1
gpsd:PROG: CORE: gpsd_activate(/dev/ttyS1, 2) fd -1
gpsd:PROG: CORE: no /etc/gpsd/device-hook present, skipped running ACTIVATE hook. No such file or directory(2)
gpsd:PROG: CORE: gpsd_open(/dev/ttyS1) fd -1
gpsd:PROG: SER: gpsd_serial_open(/dev/ttyS1) sourcetype 2 fd -1
gpsd:INFO: SER: opening GPS data source type 2 at '/dev/ttyS1'
gpsd:INFO: SER: fd 7 current speed 9600, 8N1
gpsd:PROG: GREIS: Writing command '%dm%dm', checksum: 51
gpsd:PROG: GREIS: Writing command '%vendor%print,/par/rcv/vendor', checksum: 0A
gpsd:PROG: writing oncore control type Cj
gpsd:PROG: CORE: Probing "Garmin USB binary" driver...
gpsd:PROG: CORE: Probe not found "Garmin USB binary" driver...
gpsd:PROG: CORE: Probing "GeoStar" driver...
gpsd:PROG: Sent GeoStar packet id 0xc1
gpsd:PROG: CORE: Probe not found "GeoStar" driver...
gpsd:PROG: CORE: Probing "Trimble TSIP" driver...
gpsd:INFO: SER: fd 7 current speed 9600, 8O1
gpsd:PROG: GREIS: Writing command '%dm%dm', checksum: 51
gpsd:PROG: GREIS: Writing command '%vendor%print,/par/rcv/vendor', checksum: 0A
gpsd:PROG: writing oncore control type Cj
gpsd:INFO: SER: fd 7 current speed 9600, 8N1
gpsd:PROG: GREIS: Writing command '%dm%dm', checksum: 51
gpsd:PROG: GREIS: Writing command '%vendor%print,/par/rcv/vendor', checksum: 0A
gpsd:PROG: writing oncore control type Cj
gpsd:PROG: CORE: Probe not found "Trimble TSIP" driver...
gpsd:PROG: CORE: Probing "iSync" driver...
gpsd:INFO: SER: fd 7 current speed 9600, 8N1
gpsd:PROG: GREIS: Writing command '%dm%dm', checksum: 51
gpsd:PROG: GREIS: Writing command '%vendor%print,/par/rcv/vendor', checksum: 0A
gpsd:PROG: writing oncore control type Cj
gpsd:INFO: SER: fd 7 current speed 9600, 8N1
gpsd:PROG: GREIS: Writing command '%dm%dm', checksum: 51
gpsd:PROG: GREIS: Writing command '%vendor%print,/par/rcv/vendor', checksum: 0A
gpsd:PROG: writing oncore control type Cj
gpsd:PROG: CORE: Probe not found "iSync" driver...
gpsd:PROG: CORE: no probe matched...
gpsd:PROG: CORE: activate fd 7 done
gpsd:PROG: NTP:SHM: ntpshm_link_activate(/dev/ttyS1), sourcetype 2 fd 7
gpsd:PROG: NTP:SHM: ntpshm_alloc(/dev/ttyS1), sourcetype 2 shm_clock using SHM(0)
gpsd:PROG: NTP:SHM: ntpshm_alloc(/dev/ttyS1), sourcetype 2 shm_pps using SHM(1)
gpsd:PROG: NTP:/dev/ttyS1 chrony socket /run/chrony.ttyS1.sock doesn't exist
gpsd:PROG: KPPS:/dev/ttyS1 checking /sys/devices/virtual/pps/pps0/path, /dev/ttyS1
gpsd:INFO: KPPS:/dev/ttyS1 RFC2783 path:/dev/pps0, fd 8
gpsd:INFO: KPPS:/dev/ttyS1 pps_caps 0x1133
gpsd:INFO: KPPS:/dev/ttyS1 have PPS_CANWAIT
gpsd:INFO: KPPS:/dev/ttyS1 kernel PPS will be used
gpsd:PROG: PPS:/dev/ttyS1 thread launched
gpsd:INFO: SHM: ntpshm_link_activate(/dev/ttyS1): NTP NTP activated 7
gpsd:INFO: KPPS:/dev/ttyS1 kernel PPS timeout Interrupted system call(4)
gpsd:INFO: KPPS:/dev/ttyS1 kernel PPS timeout Interrupted system call(4)
gpsd:INFO: running with effective group ID 0
gpsd:INFO: running with effective user ID 99
gpsd:INFO: startup at 2022-01-04T18:40:01.000Z (1641321601)
gpsd:PROG: CORE: switching to match packet type 11: b56201063400206a4e0eea24fcff8f0803dd0d383e0239b045e274298317d4070000d9ffffffffffffff0e00000055000000bd0003076e190100ccf9
gpsd:PROG: CORE: switch_driver(u-blox) called...
gpsd:PROG: CORE: selecting u-blox driver...
gpsd:INFO: CORE: /dev/ttyS1 identified as type u-blox, 1 sec
gpsd:INFO: CORE: /dev/ttyS1 9600bps
gpsd:PROG: => GPS: UBX class: 0a, id: 04, len: 0, crc: 0e34
gpsd:PROG: UBX identified
gpsd:PROG: => GPS: UBX class: 06, id: 00, len: 20, crc: e275
gpsd:PROG: UBX ubx_cfg_prt mode 1 port 1 PROTVER 0

**also when testing without doing "gpsd ldattach 18 /dev/ttyS1" I still get from ppscheck "PPS ioctl(TIOCMIWAIT) failed: 25"..., 64PPS ioctl(TIOCMIWAIT) failed: 25 Inappropriate ioctl for device"