Comment 30 for bug 1652348

My apologies for any lack of clarity.

I tested against the head of ubuntu-xenial, reverting just that commit and it fixed it.

I tested against the head of the mainstream kernel and it didn't (last night I tried 4.9, 4.8, 4.5, 4.4, 4.2 tags of the mainstream kernel and in every place I find the general bug in effect). I'll try some larger leaps and see if I can track it down elsewhere.