Apparently, in the current chip sets, anyway. The problem Redmere has to overcome is the same as any HDMI device that relies on the 5V line for its power. The 5V line is there for hot plug detect, not to power devices. The HDMI specification only requires the source to supply 55mA. Some can supply more, but there is no guarantee. Also, the fact that Redmere cables tend to use smaller wire than passive cables, sometimes as small as 36 AWG, doesn't help any because of the increased voltage drop. A patent licensed to Redmere mentions harvesting power from at least one differential line and one control line, IIRC CEC.