Re: Magma bizarrity?

[Jonathan Groll <lists%groll.co.za@localhost>]

On Wed, Feb 25, 2009 at 04:01:51AM -0500, der Mouse wrote:
> Thanks to a fellow Sun fan's generosity, I just acquired a Magma
> 16-port serial card.  It's got a breakout box which mounts directly on
> the back of the card, with 16 8P8C jacks on it.  I've worked out the
> pinout of ecah port, and it looks a little odd, but that's not a
> problem since I'm going to be doing my own cabling anyway.

Magma pinouts:
http://www.magma.com/support/faqs/sbus/sun.htm
> But there's a stranger surprise lurking.  The ports on the breakout box
> are arranged in a 4x4 grid and marked with the numbers 0 through 15 in
> an obvious way:
>
> 0  1  2  3
> 4  5  6  7
> 8  9 10 11
> 12 13 14 15
>
> But the arrangement of the ports in terms of minor device number,
> rather than of the printing on the breakout box, is
>
> 14  5  0 10
> 13  4  8  9
> 12  7  3 11
> 15  6  1  2
>
> This looks totally bizarre.  I looked at the code, thinking maybe it
> was some kind of race which port got which tty unit, but the code is
> saner than that; port numbering is based on chip and channel numbers,
> not something quasi-random like scheduling of kernel threads.  (Also,
> the arrangement does not change with a reboot, though that's a fairly
> weak test.)

I assume you used MAKEDEV under netbsd to make the device special
files? How has that file changed since 1.4T and -current?

Cheers,
Jonathan.