iOS 9.2 should fix the iPad Pro freezing glitch

Apple says that iOS 9.2 should fix a glitch in which the iPad Pro doesn't respond after a full recharge when you press buttons or tap on the screen, and the screen is black.

If iOS 9.2 doesn’t resolve the issue, you can get back to using your iPad Pro this way: force restart it by pressing and holding both the Sleep/Wake and Home buttons for at least 10 seconds, until you see the Apple logo.