Your ipad is completely normal. The USB ports do not provide enough power. As someone above mention you may get it to charge if the ipad is not being used and asleep. But it will still be a very slow charge. iPhones and iPads require different amounts of power to charge.
Only an USB 3.0 port or a special tweaked USB 2.0 like those used by Gigabyte will provide enough juice to charge an iPad. The other USB port will not, hence the message.