If you hit this page, I think you have encountered an issue similar to what I have faced in my production environment yesterday. But still let me give you a brief about what I had seen so that you can compare it with your problem and apply the fix if needed.
Problem:-
Couple of PCs which were connected to our access layer switch WS-C2960X-48LPS-L were continuously flapping. It was not the link flap, but a POE related flap. Look at the strange alerts on the interfaces,
%ILPOWER-3-CONTROLLER_PORT_ERR: Controller port error, Interface Gi1/0/32: Power given, but Power Controller does not report Power Good
%ILPOWER-7-DETECT: Interface Gi1/0/32: Power Device detected: IEEE PD
%ILPOWER-5-POWER_GRANTED: Interface Gi1/0/32: Power granted
%ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/32: PD removed
%ILPOWER-7-DETECT: Interface Gi1/0/32: Power Device detected: IEEE PD
Solution:-
This just kept happening again and again. Though the device doesn't need POE, it appeared to be related to POE negotiation. So as a workaround I just disabled POE on the interface using below command after which the alerts just disappeared.
Switch(config-if)int g1/0/32
Switch(config-if)#power inline never
And when we checked with Cisco for the solution, they said it is a hardware fault and raised RMA for the device.
I hope this piece of information was useful for you.
