WiFi Direct Reverse Engineering

Question

Android

There was a good article here recently. in it, the author analyzed the work of Miracast. But miracast works on WiFi Direct.
That's why I'm wondering: when Direct appeared, it was claimed that the chip was purely software and any devices on Android 4 and above were compatible. But due to known circumstances, there is such a thing as drivers. more specifically: I have an Xperia S phone. The manufacturer and all all the stores claimed that he supports this direct, but in fact, nothing. even wifi in n mode does not work. after figuring it out, I found out that the phone runs on the qualcomm msm8260 chipset, which is the same as the 8660. I found three devices running on the same chipset with support for everything that I listed, I tried to port the firmware from them to my device, but it does not start.
Explain what is so difficult in this direct if it's just p2p and why it doesn't work for anyone on 2012 devices (most). I'm sure you can get it on them.