Re: problems with USB/CDC serial (umodem) - devices work with Linux, Mac OS X, and FreeBSD, but not NetBSD

[Martin Husemann <martin%duskware.de@localhost>]

On Sun, Feb 17, 2019 at 08:21:23PM -0800, Rob Newberry wrote:
> > Please show us more details, like:
> > 
> > - kernel messages how the devices attach
> 
> On NetBSD:
> 
> 	umodem0 at uhub2 port 1 configuration 1 interface 1
> 	umodem0: Nordic Semiconductor (0x1915) nRF52840 OpenThread Device (0xcafe), rev 2.00/1.00, addr 4, iclass 2/2
> 	umodem0: data interface 2, has CM over data, has no break
> 	umodem0: status change notification available
> 	ucom0 at umodem0

So this looks like it is working just fine.

> NetBSD writes 7 bytes, selects and gets back 1 byte, but it's clearly not the data we're expecting.  I do understand that data arriving over serial ports can be corrupted, but this seems odd for "corruption" -- the data IS NOT what we expect every time on NetBSD, and IS what we expect every time on FreeBSD.
> 
> 	NetBSD:
> 
> 	   600      1 wpantund GIO   fd 4 wrote 7 bytes
> 		   "~\M^A\^B\^A\M-E\M-2~"

> FreeBSD writes 7 bytes, then reads back about 8 bytes:
> 
> 	   907 wpantund GIO   fd 4 wrote 7 bytes
> 		   0x0000 7e81 0201 c5b2 7e 
>                  |~.....~|

Note that your FreeBSD installation writes something completely different
to the device.

You will have to find out how it comes to that command and what it actually
sends, and why on NetBSD wpantund seems to write pure giberish.

Martin