This is a well-known issue (I had similar problems on one of my Laptops) but there is a solution. Generally speaking I was always able to resolve the “black screen” issue by going into “high performance mode” ergo disabling the intergrated GPU and enabling only the discrete graphics card (in your case the “Nvidia GeForce GTX 950M”). I presume that you’re currently using some sort of Hybrid mode which is “for the record” the most probable cause for this problem. I hope this helps.
Have a nice day.