Multi-Display support for Android over USB

[hacker1024]

Originally Posted by AlbanRampon

You have the mouse cursor on one display, not dealing moving it between displays.
The changes are needed are in the OS. We customised the ROM.

I know this thread hasn't been active for a while, I have a question:
Where can I find the OS changes necessary to support multiple screens? I build my own ROM for my phone, and I'd like to include this feature.