A little background information: we are having some trouble passing test ID 7.2 (TMDS - VL) of the HDMI CTS 1.4b. We seem to be ~100mV low on the spec (2.6V when passing is between 2.7V and 2.9V. Our signal routing is very short and pretty clean so we don't believe this is a routing issue and I've found very little control over the HDMI Phy from it's registers.
In researching a solution, we noticed there was a recent change to the DM8168 Datasheet (SPRS614E released in Feb. 2014) that changed recommended resistance value of the pull down resistor on HDMI_EXTSWING from 5.9K +/- 1% to 6.8K +/- 1%.
1) Does anyone know the reason for this change?
2) What effects does this change have on the HDMI Phy?
3) What is the purpose of the HDMI_EXTSWING pin?