Power management Agiilex 3/5 - Powerdown then HPS restart ?

I read in the power management section of (841346) Section 9 

"Only power-off operations are supported, and they are done one time as a static option through boot mode user configuration. After power is turned off, the power manager does not support powering back on the CPU cores or L3 cache blocks."

As I understand it = for a(partial ) power down , or power up of the HPS, the system needs to set some memory locations and then trigger a HPS restart and ther SDM has control then passes it to the FSBL.  , then the FSBL can look at these locations and see what power mode it needs to come up  or down as the system requires...... IE to change the power settings, there needs to be an HPS restart , or complete device  configuration  reload  ?

Perhaps put another way : In HPS boot-first mode :   When a power CHANGE is required in the HPS domain, can the fabric stay running (assuming that there are no outstanding HPS<> fabric DMA requests or transactions pending across the fabric<>HPS bridge ) ?

regards, glen.