Why does p10 have abnormal printing during NVME hotplug?

[slzxt0621]

https://github.com/open-power/skiboot/blob/5c1dc620a01d1d488f1cc77c0431d54c8461818e/hw/phb4.c#L2611C2-L2611C2

During the development of the p10 nvme hotplug function, the hot plug function was normal, but compared to P9, there were some abnormal printing. When unplugging the nvme disk, it will print "PHB Free/Detected!", as shown in Figure 1. However, p9 does not print "PHB Free/fenced detected!". May I ask why p9 and p10 perform different processes?