iwn(4) doesn't associate anymore
The iwn wireless interface in recent versions of 4.7 master can no longer associate with a base station. ifconfig reports "no carrier" and the scan_results command in wpa_cli requently returns "FAIL-BUSY", but not always.
Backing out commit 3aca8a4433acf84c92d5511261b53f2749a67ba8 restores the functionality. That commit was a logic change to 'full-offload scanning'.
Here is the dmsesg line specifically describing the hardware in question:
iwn0: <Intel Centrino Advanced-N 6205> mem 0xf0c00000-0xf0c01fff irq 17 at device 0.0 on pci3
I have two laptops that exhibit this behavior (they have the same wireless interface): a Lenovo x220 and a Lenovo X1 Carbon