Questions about Using PPS+GPS on AGX Orin

Hello,
My HW env: a custom carrier board and Jetson AGX Orin module
My SW env: JP5.1.2
I an using PPS signal and GPS NMEA info to make a timing source, but it failed now. I compile pps_ldisc and pps_gpio into modules.
dmesg:

[   23.125716] pps pps0: PPS_FETCH
[   23.125729] pps pps0: timeout 0.000000000
[   23.743433] pps pps0: PPS event at 4173.433560052
[   23.743445] pps pps0: capture assert seq #8
[   23.753324] pps_ldisc: PPS line discipline registered
[   24.126901] pps pps0: PPS_FETCH
[   24.126934] pps pps0: timeout 0.000000000
[   24.188422] fuse: init (API version 7.32)
[   24.193230] nvidia-modeset: Loading NVIDIA UNIX Open Kernel Mode Setting Driver for aarch64  35.4.1  Release Build  (buildbrain@mobile-u64-6422-d7000)  Tue Aug  1 12:45:42 PDT 2023
[   24.743450] pps pps0: PPS event at 4174.433577857
[   24.743473] pps pps0: capture assert seq #9
[   25.128043] pps pps0: PPS_FETCH
[   25.128057] pps pps0: timeout 0.000000000
[   25.743397] pps pps0: PPS event at 4175.433560238
[   25.743408] pps pps0: capture assert seq #10
[   26.129163] pps pps0: PPS_FETCH
[   26.129185] pps pps0: timeout 0.000000000
[   26.743381] pps pps0: PPS event at 4176.433559515
[   26.743393] pps pps0: capture assert seq #11
[   27.130536] pps pps0: PPS_FETCH
[   27.130553] pps pps0: timeout 0.000000000
[   27.743366] pps pps0: PPS event at 4177.433558599
[   27.743377] pps pps0: capture assert seq #12
[   28.131660] pps pps0: PPS_FETCH
[   28.131679] pps pps0: timeout 0.000000000
[   28.743361] pps pps0: PPS event at 4178.433563476
[   28.743372] pps pps0: capture assert seq #13
[   29.132781] pps pps0: PPS_FETCH
[   29.132803] pps pps0: timeout 0.000000000
[   29.743340] pps pps0: PPS event at 4179.433557857
[   29.743355] pps pps0: capture assert seq #14
[   30.134158] pps pps0: PPS_FETCH
[   30.134176] pps pps0: timeout 0.000000000
[   30.743326] pps pps0: PPS event at 4180.433558382
[   30.743342] pps pps0: capture assert seq #15
[   31.135271] pps pps0: PPS_FETCH
[   31.135291] pps pps0: timeout 0.000000000
[   31.743528] pps pps0: PPS event at 4181.433780958
[   31.743540] pps pps0: capture assert seq #16
[   32.136375] pps pps0: PPS_FETCH
[   32.136390] pps pps0: timeout 0.000000000
[   32.743519] pps pps0: PPS event at 4182.433778123
[   32.743534] pps pps0: capture assert seq #17
[   33.137711] pps pps0: PPS_FETCH
[   33.137725] pps pps0: timeout 0.000000000
[   33.743492] pps pps0: PPS event at 4183.433776184
[   33.743502] pps pps0: capture assert seq #18
[   34.139025] pps pps0: PPS_FETCH
[   34.139038] pps pps0: timeout 0.000000000
[   34.743476] pps pps0: PPS event at 4184.433772708
[   34.743487] pps pps0: capture assert seq #19
[   35.140365] pps pps0: PPS_FETCH
[   35.140385] pps pps0: timeout 0.000000000
[   35.743472] pps pps0: PPS event at 4185.433779697
[   35.743484] pps pps0: capture assert seq #20
[   36.141473] pps pps0: PPS_FETCH
[   36.141489] pps pps0: timeout 0.000000000
[   36.743233] pps pps0: PPS event at 4186.433556411
[   36.743244] pps pps0: capture assert seq #21
[   37.142795] pps pps0: PPS_FETCH
[   37.142807] pps pps0: timeout 0.000000000
[   37.743225] pps pps0: PPS event at 4187.433555688
[   37.743242] pps pps0: capture assert seq #22
[   38.143449] pps pps0: PPS_FETCH
[   38.143462] pps pps0: timeout 0.000000000
[   38.743411] pps pps0: PPS event at 4188.433765912
[   38.743422] pps pps0: capture assert seq #23
[   39.144780] pps pps0: PPS_FETCH
[   39.144796] pps pps0: timeout 0.000000000
[   39.743419] pps pps0: PPS event at 4189.433776901
[   39.743434] pps pps0: capture assert seq #24
[   40.145893] pps pps0: PPS_FETCH
[   40.145911] pps pps0: timeout 0.000000000
[   40.743399] pps pps0: PPS event at 4190.433771793
[   40.743416] pps pps0: capture assert seq #25
[   41.147257] pps pps0: PPS_FETCH
[   41.147272] pps pps0: timeout 0.000000000
[   41.743372] pps pps0: PPS event at 4191.433766270
[   41.743383] pps pps0: capture assert seq #26
[   42.148592] pps pps0: PPS_FETCH
[   42.148607] pps pps0: timeout 0.000000000
[   42.743361] pps pps0: PPS event at 4192.433770315
[   42.743372] pps pps0: capture assert seq #27
[   43.149921] pps pps0: PPS_FETCH
[   43.149934] pps pps0: timeout 0.000000000
[   43.743351] pps pps0: PPS event at 4193.433773304
[   43.743361] pps pps0: capture assert seq #28
[   44.151244] pps pps0: PPS_FETCH
[   44.151259] pps pps0: timeout 0.000000000
[   44.417224] vdd-12v-sys: disabling
[   44.417243] vdd-3v3-ftdi: disabling
[   44.743330] pps pps0: PPS event at 4194.433767973
[   44.743340] pps pps0: capture assert seq #29
[   45.152570] pps pps0: PPS_FETCH
[   45.152584] pps pps0: timeout 0.000000000
[   45.743318] pps pps0: PPS event at 4195.433770034
[   45.743329] pps pps0: capture assert seq #30
[   46.153893] pps pps0: PPS_FETCH
[   46.153908] pps pps0: timeout 0.000000000
[   46.743303] pps pps0: PPS event at 4196.433769823
[   46.743314] pps pps0: capture assert seq #31
[   47.155218] pps pps0: PPS_FETCH
[   47.155231] pps pps0: timeout 0.000000000
[   47.743310] pps pps0: PPS event at 4197.433773355
[   47.743326] pps pps0: capture assert seq #32
[   48.156328] pps pps0: PPS_FETCH
[   48.156344] pps pps0: timeout 0.000000000
[   48.833339] pps pps0: PPS event at 4198.523831158
[   48.833354] pps pps0: capture assert seq #33
[   49.157427] pps pps0: PPS_FETCH
[   49.157445] pps pps0: timeout 0.000000000
[   49.743265] pps pps0: PPS event at 4199.433764869
[   49.743281] pps pps0: capture assert seq #34
[   50.157541] pps pps0: PPS_FETCH
[   50.157558] pps pps0: timeout 0.000000000
[   50.743249] pps pps0: PPS event at 4200.433766770
[   50.743264] pps pps0: capture assert seq #35
[   51.158643] pps pps0: PPS_FETCH
[   51.158661] pps pps0: timeout 0.000000000
[   51.743017] pps pps0: PPS event at 4201.433549244
[   51.743032] pps pps0: capture assert seq #36
[   52.159768] pps pps0: PPS_FETCH
[   52.159787] pps pps0: timeout 0.000000000
[   52.830378] pps pps0: PPS event at 4202.520930080
[   52.830389] pps pps0: capture assert seq #37
[   53.160915] pps pps0: PPS_FETCH
[   53.160938] pps pps0: timeout 0.000000000
[   53.743203] pps pps0: PPS event at 4203.433767064
[   53.743216] pps pps0: capture assert seq #38
[   54.161090] pps pps0: PPS_FETCH
[   54.161107] pps pps0: timeout 0.000000000
[   54.743187] pps pps0: PPS event at 4204.433764997
[   54.743197] pps pps0: capture assert seq #39
[   55.162417] pps pps0: PPS_FETCH
[   55.162431] pps pps0: timeout 0.000000000
[   55.743179] pps pps0: PPS event at 4205.433763186
[   55.743194] pps pps0: capture assert seq #40
[   56.162524] pps pps0: PPS_FETCH
[   56.162543] pps pps0: timeout 0.000000000
[   56.742939] pps pps0: PPS event at 4206.433547228
[   56.742950] pps pps0: capture assert seq #41
[   57.162822] pps pps0: PPS_FETCH
[   57.162835] pps pps0: timeout 0.000000000
[   57.743140] pps pps0: PPS event at 4207.433759724
[   57.743152] pps pps0: capture assert seq #42
[   58.162962] pps pps0: PPS_FETCH
[   58.162977] pps pps0: timeout 0.000000000
[   58.742903] pps pps0: PPS event at 4208.433541301
[   58.742914] pps pps0: capture assert seq #43
[   59.163531] pps pps0: PPS_FETCH
[   59.163549] pps pps0: timeout 0.000000000
[   59.743113] pps pps0: PPS event at 4209.433759429
[   59.743126] pps pps0: capture assert seq #44
[   60.163637] pps pps0: PPS_FETCH
[   60.163652] pps pps0: timeout 0.000000000
[   60.742886] pps pps0: PPS event at 4210.433544559
[   60.742901] pps pps0: capture assert seq #45
[   61.163745] pps pps0: PPS_FETCH
[   61.163761] pps pps0: timeout 0.000000000
[   61.742864] pps pps0: PPS event at 4211.433542268
[   61.742874] pps pps0: capture assert seq #46
[   62.163848] pps pps0: PPS_FETCH
[   62.163859] pps pps0: timeout 0.000000000
[   62.742844] pps pps0: PPS event at 4212.433538473
[   62.742855] pps pps0: capture assert seq #47
[   63.163939] pps pps0: PPS_FETCH
[   63.163950] pps pps0: timeout 0.000000000
[   63.743049] pps pps0: PPS event at 4213.433757369
[   63.743060] pps pps0: capture assert seq #48
[   64.164049] pps pps0: PPS_FETCH
[   64.164060] pps pps0: timeout 0.000000000
[   64.742829] pps pps0: PPS event at 1741006491.002407733
[   64.742844] pps pps0: capture assert seq #49
[   65.164522] pps pps0: PPS_FETCH
[   65.164540] pps pps0: timeout 0.000000000
[   65.742820] pps pps0: PPS event at 1741006492.002448929
[   65.742834] pps pps0: capture assert seq #50
[   66.164606] pps pps0: PPS_FETCH
[   66.164634] pps pps0: timeout 0.000000000
[   66.742799] pps pps0: PPS event at 1741006493.002867206
[   66.742813] pps pps0: capture assert seq #51
[   67.164582] pps pps0: PPS_FETCH
[   67.164617] pps pps0: timeout 0.000000000
[   67.742788] pps pps0: PPS event at 1741006494.003288620
[   67.742803] pps pps0: capture assert seq #52
[   68.164390] pps pps0: PPS_FETCH
[   68.164400] pps pps0: timeout 0.000000000
[   68.742748] pps pps0: PPS event at 1741006495.003671733
[   68.742756] pps pps0: capture assert seq #53
[   69.164551] pps pps0: PPS_FETCH
[   69.164561] pps pps0: timeout 0.000000000
[   69.742736] pps pps0: PPS event at 1741006496.003670306
[   69.742743] pps pps0: capture assert seq #54
[   70.164694] pps pps0: PPS_FETCH
[   70.164703] pps pps0: timeout 0.000000000
[   70.742716] pps pps0: PPS event at 1741006497.003669262
[   70.742724] pps pps0: capture assert seq #55
[   71.165062] pps pps0: PPS_FETCH
[   71.165073] pps pps0: timeout 0.000000000
[   71.742706] pps pps0: PPS event at 1741006498.003670331
[   71.742714] pps pps0: capture assert seq #56
[   72.165203] pps pps0: PPS_FETCH
[   72.165213] pps pps0: timeout 0.000000000
[   72.742688] pps pps0: PPS event at 1741006499.003668552
[   72.742696] pps pps0: capture assert seq #57
[   73.165556] pps pps0: PPS_FETCH
[   73.165570] pps pps0: timeout 0.000000000
[   73.773985] pps pps0: PPS event at 1741006500.034976497
[   73.773993] pps pps0: capture assert seq #58
[   74.165711] pps pps0: PPS_FETCH
[   74.165731] pps pps0: timeout 0.000000000
[   74.742686] pps pps0: PPS event at 1741006501.003676034
[   74.742697] pps pps0: capture assert seq #59
[   75.166067] pps pps0: PPS_FETCH
[   75.166086] pps pps0: timeout 0.000000000
[   75.742668] pps pps0: PPS event at 1741006502.003676367
[   75.742683] pps pps0: capture assert seq #60
[   76.166196] pps pps0: PPS_FETCH
[   76.166212] pps pps0: timeout 0.000000000
[   76.742637] pps pps0: PPS event at 1741006503.003672508
[   76.742645] pps pps0: capture assert seq #61
[   77.166531] pps pps0: PPS_FETCH
[   77.166547] pps pps0: timeout 0.000000000
[   77.771073] pps pps0: PPS event at 1741006504.032120604
[   77.771082] pps pps0: capture assert seq #62
[   78.167658] pps pps0: PPS_FETCH
[   78.167676] pps pps0: timeout 0.000000000
[   78.742616] pps pps0: PPS event at 1741006505.003675253
[   78.742627] pps pps0: capture assert seq #63
[   79.168756] pps pps0: PPS_FETCH
[   79.168770] pps pps0: timeout 0.000000000
[   79.742806] pps pps0: PPS event at 1741006506.003883237
[   79.742814] pps pps0: capture assert seq #64
[   80.169822] pps pps0: PPS_FETCH
[   80.169838] pps pps0: timeout 0.000000000
[   80.742574] pps pps0: PPS event at 1741006507.003667471
[   80.742582] pps pps0: capture assert seq #65
[   81.170882] pps pps0: PPS_FETCH
[   81.170895] pps pps0: timeout 0.000000000
[   81.742781] pps pps0: PPS event at 1741006508.003886239
[   81.742790] pps pps0: capture assert seq #66
[   82.171940] pps pps0: PPS_FETCH
[   82.171954] pps pps0: timeout 0.000000000
[   82.742556] pps pps0: PPS event at 1741006509.003673865
[   82.742569] pps pps0: capture assert seq #67
[   83.173006] pps pps0: PPS_FETCH
[   83.173017] pps pps0: timeout 0.000000000
[   83.742751] pps pps0: PPS event at 1741006510.003884761
[   83.742760] pps pps0: capture assert seq #68
[   84.174059] pps pps0: PPS_FETCH
[   84.174074] pps pps0: timeout 0.000000000
[   84.742532] pps pps0: PPS event at 1741006511.003674338
[   84.742545] pps pps0: capture assert seq #69
[   85.175385] pps pps0: PPS_FETCH
[   85.175398] pps pps0: timeout 0.000000000
[   85.742731] pps pps0: PPS event at 1741006512.003888274
[   85.742744] pps pps0: capture assert seq #70
[   86.176491] pps pps0: PPS_FETCH
[   86.176506] pps pps0: timeout 0.000000000
[   86.742491] pps pps0: PPS event at 1741006513.003668092
[   86.742499] pps pps0: capture assert seq #71
[   87.177561] pps pps0: PPS_FETCH
[   87.177574] pps pps0: timeout 0.000000000
[   87.742657] pps pps0: PPS event at 1741006514.003853420
[   87.742663] pps pps0: capture assert seq #72
[   88.178618] pps pps0: PPS_FETCH
[   88.178632] pps pps0: timeout 0.000000000
[   88.742473] pps pps0: PPS event at 1741006515.003670486
[   88.742487] pps pps0: capture assert seq #73
[   89.179702] pps pps0: PPS_FETCH
[   89.179717] pps pps0: timeout 0.000000000
[   89.742676] pps pps0: PPS event at 1741006516.003889798
[   89.742690] pps pps0: capture assert seq #74
[   90.180812] pps pps0: PPS_FETCH
[   90.180827] pps pps0: timeout 0.000000000
[   90.742446] pps pps0: PPS event at 1741006517.003669360
[   90.742459] pps pps0: capture assert seq #75
[   91.181921] pps pps0: PPS_FETCH
[   91.181935] pps pps0: timeout 0.000000000
[   91.742636] pps pps0: PPS event at 1741006518.003881983
[   91.742646] pps pps0: capture assert seq #76
[   92.182999] pps pps0: PPS_FETCH
[   92.183013] pps pps0: timeout 0.000000000
[   92.742400] pps pps0: PPS event at 1741006519.003661897
[   92.742409] pps pps0: capture assert seq #77
[   93.184070] pps pps0: PPS_FETCH
[   93.184085] pps pps0: timeout 0.000000000
[   93.742603] pps pps0: PPS event at 1741006520.003878329
[   93.742611] pps pps0: capture assert seq #78
[   94.185135] pps pps0: PPS_FETCH
[   94.185149] pps pps0: timeout 0.000000000
[   94.742371] pps pps0: PPS event at 1741006521.003661123
[   94.742380] pps pps0: capture assert seq #79
[   95.186208] pps pps0: PPS_FETCH
[   95.186223] pps pps0: timeout 0.000000000
[   95.742574] pps pps0: PPS event at 1741006522.003878899
[   95.742583] pps pps0: capture assert seq #80
[   96.187280] pps pps0: PPS_FETCH
[   96.187294] pps pps0: timeout 0.000000000
[   96.742348] pps pps0: PPS event at 1741006523.003663421
[   96.742359] pps pps0: capture assert seq #81
[   97.188352] pps pps0: PPS_FETCH
[   97.188367] pps pps0: timeout 0.000000000
[   97.742550] pps pps0: PPS event at 1741006524.003880397
[   97.742560] pps pps0: capture assert seq #82
[   98.189423] pps pps0: PPS_FETCH
[   98.189439] pps pps0: timeout 0.000000000
[   98.821932] pps pps0: PPS event at 1741006525.083272992
[   98.821945] pps pps0: capture assert seq #83
[   99.190497] pps pps0: PPS_FETCH
[   99.190510] pps pps0: timeout 0.000000000
[   99.653897] pps pps0: PPS_GETPARAMS
[   99.653924] pps pps0: PPS_GETCAP
[   99.653928] pps pps0: PPS_GETPARAMS
[   99.653932] pps pps0: PPS_SETPARAMS
[   99.653960] pps pps0: PPS_FETCH
[   99.653964] pps pps0: timeout 3.000000000
[   99.742306] pps pps0: PPS event at 1741006526.003664515
[   99.742315] pps pps0: capture assert seq #84
[   99.742370] pps pps0: PPS_FETCH
[   99.742377] pps pps0: timeout 3.000000000
[  100.191568] pps pps0: PPS_FETCH
[  100.191580] pps pps0: timeout 0.000000000
[  100.742285] pps pps0: PPS event at 1741006527.003660816
[  100.742294] pps pps0: capture assert seq #85
[  100.742613] pps pps0: PPS_FETCH
[  100.742623] pps pps0: timeout 3.000000000
[  101.192640] pps pps0: PPS_FETCH
[  101.192655] pps pps0: timeout 0.000000000
[  101.742486] pps pps0: PPS event at 1741006528.003876672
[  101.742495] pps pps0: capture assert seq #86
[  101.742812] pps pps0: PPS_FETCH
[  101.742827] pps pps0: timeout 3.000000000
[  102.193737] pps pps0: PPS_FETCH
[  102.193753] pps pps0: timeout 0.000000000
[  102.819074] pps pps0: PPS event at 1741006529.080477228
[  102.819085] pps pps0: capture assert seq #87
[  102.819436] pps pps0: PPS_FETCH
[  102.819448] pps pps0: timeout 3.000000000
[  103.194869] pps pps0: PPS_FETCH
[  103.194890] pps pps0: timeout 0.000000000
[  103.742249] pps pps0: PPS event at 1741006530.003662935
[  103.742261] pps pps0: capture assert seq #88
[  103.742666] pps pps0: PPS_FETCH
[  103.742677] pps pps0: timeout 3.000000000
[  104.195964] pps pps0: PPS_FETCH
[  104.195978] pps pps0: timeout 0.000000000
[  104.742225] pps pps0: PPS event at 1741006531.003659972
[  104.742233] pps pps0: capture assert seq #89
[  104.742558] pps pps0: PPS_FETCH
[  104.742568] pps pps0: timeout 3.000000000
[  105.197046] pps pps0: PPS_FETCH
[  105.197058] pps pps0: timeout 0.000000000
[  105.742444] pps pps0: PPS event at 1741006532.003883796
[  105.742456] pps pps0: capture assert seq #90
[  105.742789] pps pps0: PPS_FETCH
[  105.742810] pps pps0: timeout 3.000000000
[  106.198143] pps pps0: PPS_FETCH
[  106.198157] pps pps0: timeout 0.000000000
[  106.742201] pps pps0: PPS event at 1741006533.003661949
[  106.742210] pps pps0: capture assert seq #91
[  106.742533] pps pps0: PPS_FETCH
[  106.742542] pps pps0: timeout 3.000000000
[  107.199221] pps pps0: PPS_FETCH
[  107.199233] pps pps0: timeout 0.000000000
[  107.624570] pps pps0: pending signal caught
[  107.742407] pps pps0: PPS event at 1741006534.003880749
[  107.742416] pps pps0: capture assert seq #92
[  108.200521] pps pps0: PPS_FETCH
[  108.200532] pps pps0: timeout 0.000000000
[  108.742172] pps pps0: PPS event at 1741006535.003661655
[  108.742180] pps pps0: capture assert seq #93
[  109.201805] pps pps0: PPS_FETCH
[  109.201817] pps pps0: timeout 0.000000000
[  109.742377] pps pps0: PPS event at 1741006536.003878247
[  109.742386] pps pps0: capture assert seq #94
[  110.202873] pps pps0: PPS_FETCH
[  110.202886] pps pps0: timeout 0.000000000
[  110.742142] pps pps0: PPS event at 1741006537.003659857
[  110.742151] pps pps0: capture assert seq #95
[  111.203962] pps pps0: PPS_FETCH
[  111.203981] pps pps0: timeout 0.000000000
[  111.742344] pps pps0: PPS event at 1741006538.003871233
[  111.742354] pps pps0: capture assert seq #96
[  112.205040] pps pps0: PPS_FETCH
[  112.205055] pps pps0: timeout 0.000000000
[  112.742116] pps pps0: PPS event at 1741006539.003659883
[  112.742126] pps pps0: capture assert seq #97
[  113.206343] pps pps0: PPS_FETCH
[  113.206359] pps pps0: timeout 0.000000000
[  113.742327] pps pps0: PPS event at 1741006540.003880666
[  113.742340] pps pps0: capture assert seq #98
[  114.207648] pps pps0: PPS_FETCH
[  114.207664] pps pps0: timeout 0.000000000
[  114.742096] pps pps0: PPS event at 1741006541.003659588
[  114.742109] pps pps0: capture assert seq #99
[  115.208725] pps pps0: PPS_FETCH
[  115.208738] pps pps0: timeout 0.000000000
[  115.742339] pps pps0: PPS event at 1741006542.003907477
[  115.742355] pps pps0: capture assert seq #100
[  116.209822] pps pps0: PPS_FETCH
[  116.209839] pps pps0: timeout 0.000000000
[  116.742055] pps pps0: PPS event at 1741006543.003654782
[  116.742063] pps pps0: capture assert seq #101
[  117.211176] pps pps0: PPS_FETCH
[  117.211189] pps pps0: timeout 0.000000000
[  117.742261] pps pps0: PPS event at 1741006544.003876814
[  117.742272] pps pps0: capture assert seq #102
[  118.212504] pps pps0: PPS_FETCH
[  118.212520] pps pps0: timeout 0.000000000
[  118.742026] pps pps0: PPS event at 1741006545.003657175
[  118.742034] pps pps0: capture assert seq #103
[  119.213803] pps pps0: PPS_FETCH
[  119.213814] pps pps0: timeout 0.000000000
[  119.742226] pps pps0: PPS event at 1741006546.003872615
[  119.742234] pps pps0: capture assert seq #104
[  120.215096] pps pps0: PPS_FETCH
[  120.215110] pps pps0: timeout 0.000000000
[  120.741994] pps pps0: PPS event at 1741006547.003654769
[  120.742003] pps pps0: capture assert seq #105
[  121.216392] pps pps0: PPS_FETCH
[  121.216404] pps pps0: timeout 0.000000000
[  121.742198] pps pps0: PPS event at 1741006548.003872289
[  121.742206] pps pps0: capture assert seq #106
[  122.217449] pps pps0: PPS_FETCH
[  122.217460] pps pps0: timeout 0.000000000
[  122.741964] pps pps0: PPS event at 1741006549.003652331
[  122.741973] pps pps0: capture assert seq #107
[  123.218508] pps pps0: PPS_FETCH
[  123.218520] pps pps0: timeout 0.000000000
[  123.762058] pps pps0: PPS event at 1741006550.023752309
[  123.762070] pps pps0: capture assert seq #108
[  124.219578] pps pps0: PPS_FETCH
[  124.219589] pps pps0: timeout 0.000000000
[  124.741935] pps pps0: PPS event at 1741006551.003651556
[  124.741943] pps pps0: capture assert seq #109
[  125.220644] pps pps0: PPS_FETCH
[  125.220657] pps pps0: timeout 0.000000000
[  125.742140] pps pps0: PPS event at 1741006552.003867956
[  125.742151] pps pps0: capture assert seq #110
[  126.221702] pps pps0: PPS_FETCH
[  126.221716] pps pps0: timeout 0.000000000
[  126.741902] pps pps0: PPS event at 1741006553.003647966
[  126.741912] pps pps0: capture assert seq #111
[  127.223019] pps pps0: PPS_FETCH
[  127.223032] pps pps0: timeout 0.000000000
[  127.768946] pps pps0: PPS event at 1741006554.030704171
[  127.768956] pps pps0: capture assert seq #112
[  128.224137] pps pps0: PPS_FETCH
[  128.224158] pps pps0: timeout 0.000000000
[  128.741885] pps pps0: PPS event at 1741006555.003654136
[  128.741894] pps pps0: capture assert seq #113
[  129.225455] pps pps0: PPS_FETCH
[  129.225470] pps pps0: timeout 0.000000000
[  129.742079] pps pps0: PPS event at 1741006556.003866216
[  129.742086] pps pps0: capture assert seq #114
[  130.225890] pps pps0: PPS_FETCH
[  130.225900] pps pps0: timeout 0.000000000
[  130.741848] pps pps0: PPS event at 1741006557.003648593
[  130.741858] pps pps0: capture assert seq #115
[  131.226020] pps pps0: PPS_FETCH
[  131.226032] pps pps0: timeout 0.000000000
[  131.742051] pps pps0: PPS event at 1741006558.003825628
[  131.742062] pps pps0: capture assert seq #116
[  132.227214] pps pps0: PPS_FETCH
[  132.227295] pps pps0: timeout 0.000000000
[  132.741826] pps pps0: PPS event at 1741006559.003572706
[  132.741835] pps pps0: capture assert seq #117
[  133.228624] pps pps0: PPS_FETCH
[  133.228636] pps pps0: timeout 0.000000000
[  133.742027] pps pps0: PPS event at 1741006560.003747869
[  133.742036] pps pps0: capture assert seq #118
[  134.229014] pps pps0: PPS_FETCH
[  134.229026] pps pps0: timeout 0.000000000
[  134.741787] pps pps0: PPS event at 1741006561.003483620
[  134.741794] pps pps0: capture assert seq #119
[  135.230121] pps pps0: PPS_FETCH
[  135.230134] pps pps0: timeout 0.000000000
[  135.741993] pps pps0: PPS event at 1741006562.003658975
[  135.742004] pps pps0: capture assert seq #120
[  136.231242] pps pps0: PPS_FETCH
[  136.231257] pps pps0: timeout 0.000000000
[  136.741757] pps pps0: PPS event at 1741006563.003399398
[  136.741763] pps pps0: capture assert seq #121
[  137.232355] pps pps0: PPS_FETCH
[  137.232368] pps pps0: timeout 0.000000000
[  137.741744] pps pps0: PPS event at 1741006564.003355591
[  137.741755] pps pps0: capture assert seq #122
[  138.233453] pps pps0: PPS_FETCH
[  138.233465] pps pps0: timeout 0.000000000
[  138.741728] pps pps0: PPS event at 1741006565.003313384
[  138.741738] pps pps0: capture assert seq #123
[  139.234551] pps pps0: PPS_FETCH
[  139.234564] pps pps0: timeout 0.000000000
[  139.741728] pps pps0: PPS event at 1741006566.003274505
[  139.741742] pps pps0: capture assert seq #124
[  140.235893] pps pps0: PPS_FETCH
[  140.235904] pps pps0: timeout 0.000000000
[  140.741715] pps pps0: PPS event at 1741006567.003232362
[  140.741731] pps pps0: capture assert seq #125
[  141.237042] pps pps0: PPS_FETCH
[  141.237058] pps pps0: timeout 0.000000000
[  141.741909] pps pps0: PPS event at 1741006568.003405925
[  141.741921] pps pps0: capture assert seq #126
[  142.238394] pps pps0: PPS_FETCH
[  142.238407] pps pps0: timeout 0.000000000
[  142.741673] pps pps0: PPS event at 1741006569.003144844
[  142.741683] pps pps0: capture assert seq #127
[  143.239733] pps pps0: PPS_FETCH
[  143.239745] pps pps0: timeout 0.000000000
[  143.741880] pps pps0: PPS event at 1741006570.003321415
[  143.741890] pps pps0: capture assert seq #128
[  144.240844] pps pps0: PPS_FETCH
[  144.240859] pps pps0: timeout 0.000000000
[  144.741647] pps pps0: PPS event at 1741006571.003060174
[  144.741658] pps pps0: capture assert seq #129
[  145.242194] pps pps0: PPS_FETCH
[  145.242207] pps pps0: timeout 0.000000000
[  145.741848] pps pps0: PPS event at 1741006572.003235081
[  145.741858] pps pps0: capture assert seq #130
[  146.243303] pps pps0: PPS_FETCH
[  146.243316] pps pps0: timeout 0.000000000
[  146.741608] pps pps0: PPS event at 1741006573.002970160
[  146.741617] pps pps0: capture assert seq #131
[  147.244648] pps pps0: PPS_FETCH
[  147.244661] pps pps0: timeout 0.000000000
[  147.741817] pps pps0: PPS event at 1741006574.003149323
[  147.741827] pps pps0: capture assert seq #132
[  148.245987] pps pps0: PPS_FETCH
[  148.246002] pps pps0: timeout 0.000000000
[  148.819909] pps pps0: PPS event at 1741006575.081200875
[  148.819923] pps pps0: capture assert seq #133
[  149.247292] pps pps0: PPS_FETCH
[  149.247306] pps pps0: timeout 0.000000000
[  149.741582] pps pps0: PPS event at 1741006576.002850898
[  149.741593] pps pps0: capture assert seq #134
[  150.248628] pps pps0: PPS_FETCH
[  150.248641] pps pps0: timeout 0.000000000
[  150.741555] pps pps0: PPS event at 1741006577.002802995
[  150.741566] pps pps0: capture assert seq #135
[  151.249962] pps pps0: PPS_FETCH
[  151.249976] pps pps0: timeout 0.000000000
[  151.741766] pps pps0: PPS event at 1741006578.002983822
[  151.741775] pps pps0: capture assert seq #136
[  152.251325] pps pps0: PPS_FETCH
[  152.251340] pps pps0: timeout 0.000000000
[  152.816853] pps pps0: PPS event at 1741006579.078038594
[  152.816864] pps pps0: capture assert seq #137
[  153.252740] pps pps0: PPS_FETCH
[  153.252759] pps pps0: timeout 0.000000000
[  153.741744] pps pps0: PPS event at 1741006580.002898864
[  153.741756] pps pps0: capture assert seq #138
[  154.254088] pps pps0: PPS_FETCH
[  154.254102] pps pps0: timeout 0.000000000
[  154.741497] pps pps0: PPS event at 1741006581.002633079
[  154.741505] pps pps0: capture assert seq #139
[  155.255430] pps pps0: PPS_FETCH
[  155.255443] pps pps0: timeout 0.000000000
[  155.741703] pps pps0: PPS event at 1741006582.002809938
[  155.741715] pps pps0: capture assert seq #140
[  156.256775] pps pps0: PPS_FETCH
[  156.256789] pps pps0: timeout 0.000000000
[  156.741474] pps pps0: PPS event at 1741006583.002551801
[  156.741485] pps pps0: capture assert seq #141
[  157.258097] pps pps0: PPS_FETCH
[  157.258110] pps pps0: timeout 0.000000000
[  157.741670] pps pps0: PPS event at 1741006584.002721300
[  157.741679] pps pps0: capture assert seq #142
[  158.259460] pps pps0: PPS_FETCH
[  158.259474] pps pps0: timeout 0.000000000
[  158.741443] pps pps0: PPS event at 1741006585.002467771
[  158.741455] pps pps0: capture assert seq #143

When I use ppstest:

ppstest /dev/pps0
[sudo] password for orin:
trying PPS source "/dev/pps0"
found PPS source "/dev/pps0"
ok, found 1 source(s), now start fetching data...
source 0 - assert 1741006526.003664515, sequence: 84 - clear  0.000000000, sequence: 0
source 0 - assert 1741006527.003660816, sequence: 85 - clear  0.000000000, sequence: 0
source 0 - assert 1741006528.003876672, sequence: 86 - clear  0.000000000, sequence: 0
source 0 - assert 1741006529.080477228, sequence: 87 - clear  0.000000000, sequence: 0
source 0 - assert 1741006530.003662935, sequence: 88 - clear  0.000000000, sequence: 0
source 0 - assert 1741006531.003659972, sequence: 89 - clear  0.000000000, sequence: 0
source 0 - assert 1741006532.003883796, sequence: 90 - clear  0.000000000, sequence: 0
source 0 - assert 1741006533.003661949, sequence: 91 - clear  0.000000000, sequence: 0

chrony.conf:

refclock PPS /dev/pps0 lock NMEA prefer

#refclock SHM 0 offset 0.0 delay 0.5 refid NMEA
refclock SHM 0 offset -5.469 delay 0.5 refid NMEA

chrony sources shows:

chronyc sources
210 Number of sources = 14
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
#? PPS0                          0   4     0     -     +0ns[   +0ns] +/-    0ns
#? NMEA                          0   4     0     -     +0ns[   +0ns] +/-    0ns
^- prod-ntp-4.ntp4.ps5.cano>     2   6    77     1    -14ms[  -14ms] +/-  149ms
^- prod-ntp-5.ntp4.ps5.cano>     2   6    77     2    -14ms[  -14ms] +/-  150ms
^- alphyn.canonical.com          2   6    77     2  +9815us[+9815us] +/-  156ms
^? prod-ntp-3.ntp4.ps5.cano>     0   6     0     -     +0ns[   +0ns] +/-    0ns
^? prod-ntp-5.ntp1.ps5.cano>     0   6     0     -     +0ns[   +0ns] +/-    0ns
^? prod-ntp-4.ntp4.ps5.cano>     0   6     0     -     +0ns[   +0ns] +/-    0ns
^* 119.28.206.193                2   6    37    72   +327us[+3346us] +/-   39ms
^- mail.moe.cat                  2   6    77     5    +22ms[  +22ms] +/-  200ms
^- a.chl.la                      2   6    77     7    +23ms[  +23ms] +/-  121ms
^? ntp6.flashdance.cx            0   6     0     -     +0ns[   +0ns] +/-    0ns
^? 2402:f000:1:416:101:6:6:>     0   6     0     -     +0ns[   +0ns] +/-    0ns
^? 2001:67c:21bc:1e::123         0   6     0     -     +0ns[   +0ns] +/-    0ns

My GPSD config:

/etc/default/gpsd
START_DAEMON="true"
GPSD_OPTIONS="-n"
DEVICES="/dev/ttyUSB0 /dev/pps0"
USBAUTO="false"
GPSD_SOCKET="/var/run/gpsd.sock"

/dev/ttyUSB0 output NMEA info and /dev/pps0 output PPS signal.

Please help me check why chrony did not select the NMEA timing source, thank you.

From the dmesg you shared, it seems pps working as expected and you can get pps timestamp.

Is you issue specific to chrony?

Hi, KevinFFF,
Is anything wrong with my chrony.conf? Please help me check, thanks.

Could you try to configure it as following?

refclock SHM 0 refid GPS precision 1e-3 offset 0.128

Please check if there’s error in /var/log/syslog when you run the test.
You can also ask the help from your vendor for these configurations.

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