Setting up the STP support

7.1 LPAR mode

Set up a deamon and define udev rules for stable device names.

Adding a time synchronization deamon

The time synchronization daemon must be configured to use the PTP s390 driver as clock reference. For example, for chrony, add the following line to the configuration:

refclock PHC /dev/ptp_s390_stcke

After this change chrony output should look like this:

# chronyc sources
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
#* PHC0                  0    4    77   11   -1ns[ -1ns] +/- 8ns

Obtaining stable device names

To obtain stable device names, add the following udev rules to the system if they are not present:

ACTION=="add" SUBSYSTEM=="ptp" ATTR{clock_name}=="s390 STCKE Clock" SYMLINK+="ptp_s390_stcke"
ACTION=="add" SUBSYSTEM=="ptp" ATTR{clock_name}=="s390 Physical Clock" SYMLINK+="ptp_s390_physical"