I have a Samsung 10.1" (older Costco version) but it will not fit into the P4 controller. You need not go taller than 6.6" in width to barley fit the stock controller clamp, but the 10.1" Samsung is 6.9" tall and will not fit unless you buy the plastic clamp extender off Amazon for $11. That makes it fit, but on my 10.1" Samsung, the USB mini-port jack is on the bottom and dead-center so when it is placed into the controller in landscape mode, the USB cable connector is right where that small slot is in the bottom clamp of the controller. Really a bad design there as the slot is far too narrow for the plug. So with the cable added it cannot sit flat on the clamp even with the extender, and it can rock on the USB plug if you try it. It sort of works, but it's not that stable. You can slide it off to the side so the plug is off the clamp's side and not in the slot, but then the whole thing feels off center.
I bought a 9.7" screen (Apple iPad
Air 2 + Cellular for the GPS part) and it barely fits into the controller clamps by a 1mm clearance and doesn't need the extender, and the cable exits the right side and not downward into the controller's clamp. Much better fit. The Apple also is far superior in that it breaks video up less, okay no breakups on mine at all, over the Samsung 10.1" and even their S6 Edge phone too. I suspect that is more to do with the DJI-Go Android app, or maybe the data stream over the Apple Lightning plug is faster than the USB-mini system on the Android.
Mack