HDMI eye diagram questions
This looks like pre-emphasis.  The idea is to pre-distort the signal before transmitting it down the cable so that the eye at the far end of the cable is more open.  If you check the pre-distorted eye at the transmitter, you'll likely see something like this with lots of overshoot.  If you check at the receiver after a decent length of cable, it should look more normal.  

The idea is that cables will attenuate high frequency components and slow down/round off transitions.  Intentionally overshooting on the transmit end means that the system will tolerate more high frequency attenuation in the cable.