i have a macbook pro early 2011, and a dell u2412m attached via mini display port to display port. monitor works fine, but, the monitor's all 4 usb don't work at all, no idea why. monitor comes with a cd for drivers but that's just for windows, seems there's no osx drivers, or apps, nothing. so i wonder, maybe is the display port? should i use dvi? or all usb are dead.. any ideas? help?