I had upgraded my kernel to 4.2.3-1 and the crackling issue had mostly gone away (there was a single quiet pop during boot, rather than an awful crackle). However, after a couple of weeks (and a bunch of updates) the crackle is back and just as bad as ever.
Lenovo ThinkPad w540 Debian Testing (stretch) linux-image-4.2.0-1-amd64 = 4.2.3-2
