testptp sends timestamps 2 times faster than predicted

[LiaoU3]

Summary

The TGPIO testing tool testptp is built from tools/testing/selftests/ptp/testptp.c in branch 6.1/linux.
When sending timestamps with this tool built from the latest commit, it always send two times faster than the setting we did. NeverthelessI tried with the previous tag lts-v6.1.28-linux-230601T020337Z and it functioned well.

I suspect there is something wrong with the commits after 2023-06-01.

testptp built from the latest commit

u@u-Alder-Lake-Client-Platform:~/linux-intel-lts$ sudo ./tools/testing/selftests/ptp/testptp -d /dev/ptp1 -i 1 -L 1,1 -e 100 -o 10 -E
set pin function okay
external time stamp request okay
Event count: 2240
Event time time: 1512,000000052
Approx System time: 1498,127435181
Approx Translated Device time: 1309,655061421
Event count: 2241
Event time time: 1512,500000052
Approx System time: 1498,628027798
Approx Translated Device time: 1309,655061421
Event count: 2242
Event time time: 1513,000000052
Approx System time: 1499,127392644
Approx Translated Device time: 1309,655061421
Event count: 2243
Event time time: 1513,500000052
Approx System time: 1499,627848838
Approx Translated Device time: 1309,655061421
Event count: 2244
Event time time: 1514,000000052
Approx System time: 1500,127361857
Approx Translated Device time: 1309,655061421
Event count: 2245
Event time time: 1514,500000052
Approx System time: 1500,627841250
Approx Translated Device time: 1309,655061421
Event count: 2246
Event time time: 1515,000000052
Approx System time: 1501,127149896
Approx Translated Device time: 1309,655061421
Event count: 2247
Event time time: 1515,500000052
Approx System time: 1501,627649472
Approx Translated Device time: 1309,655061421
Event count: 2248
Event time time: 1516,000000052
Approx System time: 1502,127682698
Approx Translated Device time: 1309,655061421
Event count: 2249
Event time time: 1516,500000052
Approx System time: 1502,627060401
Approx Translated Device time: 1309,655061421
Event count: 2250
Event time time: 1517,000000052
Approx System time: 1503,127616692
Approx Translated Device time: 1309,655061421
Event count: 2251
Event time time: 1517,500000052
Approx System time: 1503,627290277
Approx Translated Device time: 1309,655061421
Event count: 2252
Event time time: 1518,000000052
Approx System time: 1504,127571425
Approx Translated Device time: 1309,655061421
Event count: 2253
Event time time: 1518,500000052
Approx System time: 1504,627211910
Approx Translated Device time: 1309,655061421
Event count: 2254
Event time time: 1519,000000052
Approx System time: 1505,127917676
Approx Translated Device time: 1309,655061421
Event count: 2255
Event time time: 1519,500000052
Approx System time: 1505,627533358
Approx Translated Device time: 1309,655061421
Event count: 2256
Event time time: 1520,000000052
Approx System time: 1506,127180974
Approx Translated Device time: 1309,655061421
Event count: 2257
Event time time: 1520,500000052
Approx System time: 1506,627500712
Approx Translated Device time: 1309,655061421
Event count: 2258
Event time time: 1521,000000052
Approx System time: 1507,127862884
Approx Translated Device time: 1309,655061421
Event count: 2259
Event time time: 1521,500000052
Approx System time: 1507,627123016
Approx Translated Device time: 1309,655061421
Event count: 2260
Event time time: 1522,000000052
Approx System time: 1508,127569882
Approx Translated Device time: 1309,655061421

testptp built from the tag lts-v6.1.28-linux-230601T020337Z

u@u-Alder-Lake-Client-Platform:~/linux-intel-lts-567d7c87ead22824f109a7914c7dcc667131e6f4$ sudo ./tools/testing/selftests/ptp/testptp -d /dev/ptp1 -i 1 -L 1,1 -e 100 -o 10 -E
set pin function okay
external time stamp request okay
Event count: 2627
Event time time: 1709,000000052
Approx System time: 1695,127975226
Approx Translated Device time: 1015,484370145
Event count: 2628
Event time time: 1710,000000052
Approx System time: 1696,127259545
Approx Translated Device time: 1015,484370145
Event count: 2629
Event time time: 1711,000000052
Approx System time: 1697,127229841
Approx Translated Device time: 1015,484370145
Event count: 2630
Event time time: 1712,000000052
Approx System time: 1698,127927988
Approx Translated Device time: 1015,484370145
Event count: 2631
Event time time: 1713,000000052
Approx System time: 1699,127154819
Approx Translated Device time: 1015,484370145
Event count: 2632
Event time time: 1714,000000052
Approx System time: 1700,127153471
Approx Translated Device time: 1015,484370145
Event count: 2633
Event time time: 1715,000000052
Approx System time: 1701,127469452
Approx Translated Device time: 1015,484370145
Event count: 2634
Event time time: 1716,000000052
Approx System time: 1702,127811835
Approx Translated Device time: 1015,484370145
Event count: 2635
Event time time: 1717,000000052
Approx System time: 1703,127058947
Approx Translated Device time: 1015,484370145
Event count: 2636
Event time time: 1718,000000052
Approx System time: 1704,127384770
Approx Translated Device time: 1015,484370145

Steps to reproduce

1. Prepare 2 mahcines that support TGPIO and make sure it is enabled in the BIOS.
2. Connect those 2 TGPIO pin together.
3. Build testptp on each machine
   1. git clone --depth=1 -b 6.1/linux https://github.com/intel/linux-intel-lts.git
   2. cd linux-intel-lts
   3. make headers_install ARCH=x86_64;make -C tools/testing/selftests TARGETS=ptp # To build testpt
4. Send timestamps on one machine
   • sudo ./tools/testing/selftests/ptp/testptp -d /dev/ptp1 -i 0 -L 0,2 -p 1000000000 # You may have to replace /dev/ptp1 and -i 0 -L 0 according to your machine
5. Receive timestamps on another machine
   • sudo ./tools/testing/selftests/ptp/testptp -d /dev/ptp1 -i 1 -L 1,1 -e 100 -o 10 -E # You may have to replace /dev/ptp1 and -i 0 -L 0 according to your machine