panic after new device layering commit

[Emiel Kollof]

Hi,

About faulty refcounts, I seem to have one in ums(4). But I'll go about that 
later.

I was getting the nvidia driver to work with the new layering system, and 
I managed to get X11 to work. But, when starting KDE, my system suddenly 
panics as of this commit. Funnily enough, it's not my driver :)

panic: impossible devtype 0

It paniced at dsp_open, I will get a backtrace. Since it happened at
dsp_open, I'll check out if I can trigger this panic again.

Cheers,
Emiel
-- 
The Seventh Commandments for Technicians
	Work thou not on energized equipment, for if thou dost, thy
fellow workers will surely buy beers for thy widow and console her in
other ways.