Patching FrameBuffer for Lenovo Thinkpad W540 HD 4600 eDP to use proper ig-platform-id

[nysander]

Hello Guys,

 

I am looking for tips on how can I patch my FrameBuffer to be able to use mobile ig-platform-id for HD 4600 Intel Graphics. ATM the only way to have recognized full resolution and memory (1,5GB) is to use 0x0d220008 desktop Haswell profile.

 

Problem is that on this profile backlight patches do not work. I get blank screen during boot instead of apple logo.

 

As RehabMan suggested in my debug topic, this is possible because of the fact that my laptop uses eDP to connect LCD, and that eDP is not fully supported. But as far as I've found T440 laptop's LCD is also connected via eDP and they work with backlight. 

 

How can I debug / patch such situation? 

 

I am new to hackintosh knowledge but want to make my laptop work so any suggestions and help is much appreciated.