Please apply this patch, included in 4.1-rc8, to the stable trees:

  commit ebaad1322d8080a1a8367ec631b345405d9879e2
  ntb: initialize max_mw for Atom before using it

Commit ab760a0 (ntb: Adding split BAR support for Haswell platforms)
caused a regression on Intel Atom systems with ntb hardware (in
particular, Atom S1200); on these systems, the ntb driver dereferences
a null pointer on startup and does not function correctly.

Applies to 4.0.y, 3.19.y, and 3.18.y.

Thanks,
-- Daniel Verkamp