I have a desktop PC I assembled myself. It has an ASUS motherboard. I found a utility on the ASUS website called AICharger (IIRC). I have no idea how it works, but I can now charge my iPad 4 from any USB 2.0 socket on my PC. Previously I got the 'Not Charging' banner on my iPad.
The program was free and works like a dream.
It might be worth a look on your Laptop manufacturers website for something similar.