I'm working on adding second screen functionality to AOSP for the LG V20.
So far, I've managed to set up the offsets so normal content doesn't overflow into the second screen area, and I've added the second screen window type (SIGNBOARD). The offsets are managed in LogicalDisplay.
For a lot of this, I've been following how LG originally did it (in Android 7.0, so things are slightly different on 7.1). The problem I have now is that nothing displays in the second screen area: I see some stuff LG did involving SurfaceControl, but that doesn't seem to be the actual solution, and I'm worried it might be in the native code.
I've tried Googling, but this doesn't seem to be documented anywhere, at least nowhere I could find.
So the question becomes: How can I force content to display outside of the bounds of the LogicalDisplay area?
These are the changes I've made so far: https://github.com/zacharee/android_frameworks_base/commit/cec4839c8cb1396810ce65d7ad9cae094f363ac4
