PTP devices not available

[adanielov]

We are trying to use PTP devices for time sync. But simply cannot see the devices.

kernel: 3.10.0-957.5.1.el7.x86_64

fg@rac1 hv]$ rpm -qa | grep microso
kmod-microsoft-hyper-v-4.2.8.1-20190205.x86_64
microsoft-hyper-v-4.2.8.1-20190205.x86_64

[fg@rac1 hv]$ lsmod | grep hv_
hv_utils               25808  2
hv_netvsc              50430  0
hv_balloon             22754  0
ptp                    19231  1 hv_utils
hv_storvsc             22726  9
scsi_transport_fc      64007  1 hv_storvsc
hv_vmbus              137382  6 hv_balloon,hyperv_keyboard,hv_netvsc,hid_hyperv,hv_utils,hv_storvsc

[fg@rac1 hv]$ dmesg | grep -i ptp
[    9.056052] PTP clock support registered

But $ ls -la /sys/class/ptp/ produces empty output.
Any suggestions how to make the PTP devices show up?

[chvalean]

@adanielov please check if Time sync Integration service is enabled for your VM.

PS > Get-VMIntegrationService rhel_7.5

VMName   Name                    Enabled PrimaryStatusDescription SecondaryStatusDescription
------   ----                    ------- ------------------------ --------------------------
rhel_7.5 Time Synchronization    True    OK

Try to toggle this On/Off from the VM settings or via PS, inside the VM this will be presented by an event in dmesg similar to this:
hv_utils: TimeSync IC version 3.0

If you're missing that line in dmesg, then most likely the TimeSync Integration Service is not enabled for the VM.