Nouveau Atomic + DP MST Support Already Staged For Linux 4.10 Via DRM-Next
The Nouveau atomic mode-setting support along with the DisplayPort MST support has been pulled into David Airlie's DRM-Next tree of material that will then be pulled into the Linux 4.10 kernel when its merge window opens in December. If you aren't familiar with atomic mode-setting or DP MST, see the aforelinked article.
This big change to the Nouveau KMS driver is in addition to other Nouveau DRM drivers already queued for Linux 4.10 including the long-awaited "boost" patches as well as the NVIDIA LED driver for relevant graphics cards.
Linux 4.10 is looking to be yet another exciting kernel version.