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

>> Note that your FreeBSD installation writes something completely different
>> to the device.
> It has been pointed out off list that the FreeBSD ascii version is just
> differently encoded (with "." for unprintable character), and the
> packet written is actually identical.
> So I have no idea why the device answers differently (and no idea how to
> debug this unless the device itself offers some debug options).

Thanks so much for the time so far.  I appreciate it (using ktrace was a good skill to pick up).

I'm pretty sure there are differences in how NetBSD's USB modem class driver interacts with the device from how other platforms do.  For the time being, I'm trying to read the code of the NetBSD and the FreeBSD drivers, along with the USB CDC spec, to see what's going on.

Based on experience, I'm sure this would go a LOT faster if I had a USB sniffer device that showed me what was sent and what was received at the USB layer -- then I could go back to the code and understand that.  But unfortunately, I don't have access to a sniffer yet :-(.

There might be something in the USB code that already verbosely dumps I/O -- I'm still trying to get myself re-familiarized with the USB code in NetBSD, so maybe I'll find it.  If not, I may end up trying to add that.


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