I recently received my precision 7720 laptop, and everything work like a charm except the DDA support for Hyper-V is not available. 

Hyper-v Discrete Device Assignment support, which is to say exposing ACS(Access control service) control from BIOS to OS so that users can assign PCI-E device to Hyper-V Virtual Machines, assign GPU to VM for CUDA computation, in my case.

Does dell have plan to support Hyper-V DDA for precision 7xxx laptop? Any information would be helpful.