questions about undocumented USB drivers

[nia <nia%NetBSD.org@localhost>]

I'd like to know more about these drivers so I can write man pages
for them, so any input is welcome.

sys/dev/usb/udsir.c

	Committed in 2013 by kiyohara@, log message was
	"Add KingSun/DonShine IRDA dongle."
	However, the copyright is 2001 dsainty@, perhaps copypasted
	from ustir(4)? I think this only supports one type of IRDA
	dongle and is based on the ustir(4) code.

sys/dev/usb/udl.c

	Driver for DisplayLink DL-1x0/1x5 based USB LCDs and USB-VGA
	adapters, ported from OpenBSD, easy enough. Committed in 2009
	by tsutsui@ with a dire message that the MI wscons API isn't
	yet ready for this device driver.  There were a few minor
	changes to the driver since by nat@, but some kinda nasty
	hacks remain in the code.
	Is it usable yet? It sounds interesting :)

sys/dev/usb/slurm.c

	This one caught my eye because it doesn't have the "u" prefix.
	Log message, from jakllsch@ in 2013:
	"Add slurm(4), a radio(4) driver for USB FM radio modules based
	on the Silicon Labs reference design."
	I can get a rough idea of the driver's capabilities by reading
	the code. It seems much better than udsbr(4), the only USB
	radio(4) driver we do document.