Can't resume PCI Express on Juno

I am using Juno-R1 board with Linaro Release 16.02 Latest (juno-oe).

I can put Juno into system suspend, but can't resume as it is the suspend state forever.

Running the following command :

     # echo +5 > /sys/class/rtc/rtc0/wakealarm

     # echo mem > /sys/power/state

Also in the case of kernel removing PCI endpoint Device Driver (SATA controller and GbE controller) ,

though Juno could resume, it output ERROR log as follows :

     pcieport 0000:01:00.0: Refused to change power state, currently in D1

     pcieport 0000:02:02.0: Refused to change power state, currently in D1

     pcieport 0000:02:01.0: Refused to change power state, currently in D1

     pcieport 0000:02:03.0: Refused to change power state, currently in D1

     pcieport 0000:02:10.0: Refused to change power state, currently in D1

     pcieport 0000:02:0c.0: Refused to change power state, currently in D1

     pcieport 0000:02:1f.0: Refused to change power state, currently in D1

     pci 0000:03:00.0: Refused to change power state, currently in D1

     pci 0000:08:00.0: Refused to change power state, currently in D1

What could be happening?

I would appreciate any suggestions or information.

Thank you.