There is some issue with the eDP port. First it has only 2 lane, second the maximum Vin which is around 19V is simple not enough for drive the LED strings on the panel. We need 48V. So what should we do? There is a few LED driver IC on the market, but most of them not supported the 48V, just under. After a research I found the perfect candidate: Texas Instruments TPS61199. It has a wide range input from 8V-30V and 60V output, can handle 8 LED strings with max. 70mA each (we need only 6 and 20mA). That's more than enough.
If we got everything on board we need a cable from the LCD panel to the motherboard. It's a little bit tricky, I'm not sure right now the motherboard's eDP port can actually drive the panel, I mean the 2 lane is enough or not. Theoretically is enough for 2560x1600 with 30Hz. So I don't know if we should use a normal displayport or not. And because of this I designed a breakout board PCB.
The plane is to connect the eDP cable(previous post) to the breakout board, set some jump wire and connect the LED driver board then the LCD panel's IPEX plug too. If this is not working somehow I just replace the eDP cable with a normal displayport cable, then reset the jump wires. That's it.