Okay, so I took a look at all that MIPI stuff tonight and hope I can be a bit of help.
As we know, MIPI only gives out specifications if you become a member (which is horribly expensive).
OculusVR is a member, so I could get more needed details from Palmer if we need them. Additionally, TI is a founder of the MIPI alliance, so they might be able to help us out with further documentation as well.
However, I was able to find PDF copies of the MIPI Specifications, that might be of help. The most important one is probably the DCS command set documentation. It tells us a lot about how to speak to the display, and even request diagnostic information back!
Maybe in there there's the hidden clue to get it working - maybe after you initialize it, you need to send a DCS to tell it to become active... who knows.
Well, I attached all these documents, together with a copy of "DSI Demystified" by TI - which seems to give more information about MIPI and the OMAP as well.
I hope that helps. Let me know if there's anything else I can look for.
I'll phone up Renesas about the IC driver datasheet as well (though as far as I understood, MIPI DCS is standard, so I'm not sure we learn more about that here).