The contents of this page are considered outdated and some of the information may be stale. Please use information here with caution, or update it.
The power limitation on USB power is currently 5W on production (XO-1 C2) laptops.
Increasing USB power to 7.5W
To increase the maximum power draw to 7.5W, replace R281 with a 140K, 1%, SMD0402 resistor. Please note that this decreases the maximum ambient temp. rating, and increases the total power dissipation of the laptop. A laptop supplying 7.5W to the USB should always have a battery present. If this power is going to be drawn from a single USB socket, it should be from one of the two sockets nearest the power button.