Core Issue:
User received error message "%ILPOWER-3-CONTROLLER_PORT_ERR: Controller port error, Interface" received on Catalyst 3750 while failing over back to mainline power supply from RPS 2300.
Resolution:
As per the following document, the chassis will reboot and everything should be back to normal after that. However, you might run into a scenario where the switch doesn't reboot and we start getting the above mentioned error message.
Release Notes for the Cisco Redundant Power System 2300
As per my research and lab recreate, this can be fixed by doing "shutdown" and "no shutdown" on the affected interfaces.
This is a hardware limitation that cannot be fixed on 3750 platform. However, this has been taken care on 3750-E chassis.