The following reply was made to PR kern/50038; it has been noted by GNATS.
From: MOCHIDA Shuji <mochid%netside.co.jp@localhost>
To: skrll%netbsd.org@localhost
Cc: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost,
gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/50038: udl (DisplayLink GX-DVI_U2B) alignment fault on
earmv6hf NETWALKER
Date: Fri, 18 Nov 2016 03:08:11 +0900 (JST)
> You could try removing BUS_DMA_COHERENT from the bus_dmamem_map call - see diff.
That change seems to cause USB errors. USB ports are unusable.