https://bugs.freedesktop.org/show_bug.cgi?id=92005
--- Comment #4 from Adam J. Richter adam_richter2004@yahoo.com --- Hi, Dave.
I have tried the patch you attached to this bug report on 2015-09-16 on a couple of different systems with Linux 4.3-rc2, and confirm that I have so far not seen any DP-MST related kernel null pointer dereferences. I do see such oopses on Linux-4.3-rc2 without your patch. So, I would encourage you to send it or something similar upstream if you have not done so already.
By the way, just to warn you that not everything is perfect, I still see apparently invalid video from one of two DP-MST hubs that I have been using with 4.3-rc2 + your patch, but that is outside the scope of this freedesktop.org bug report. So, I expect to test a little more and close this bug as "resolved" once your patch or the equivalent appears in a mainline Linux release candidate.
Thank you very much for your help!