Subject: Re: how can I troubleshoot ulpt0 causing errors with my ural0?
To: Jeremy C. Reed <reed@reedmedia.net>
From: Greg Troxel <gdt@ir.bbn.com>
List: netbsd-help
Date: 04/04/2007 12:23:48
"Jeremy C. Reed" <reed@reedmedia.net> writes:

> ral0: Cisco-Linksys Wireless-G USB Network Adapter, rev 2.00/0.04, addr 2
> ral0: MAC/BBP RT2570 (rev 0x03), RF RT2526

> ulpt0 at uhub2 port 2 configuration 1 interface 0
> ulpt0: Brother HL-5150D, rev 2.00/1.00, addr 3, iclass 7/1
> ulpt0: using bi-directional mode
>
> My networking started hanging a lot. I looked at netstat -i and saw a 
> bunch of "errs".
>
> netstat man page says:
>
>      		The notion of errors is ill-defined.

At the netstat level it is ill-defined because there's no specification
for how drivers count errors.  At the driver level, there's a counter and
when incremented that's an error.  So see the ral source for
ifp->if_oerrors++.   This can happen due to missing interrupts, or the
card reporting that it never got an ack (excessive retries).

  [output errors increase while printer is attached]

> Any suggestions on how I can troubleshoot this? (Anything to look at with 
> "systat vmstat" for example??)

Look in the ral source (sys/dev/ic/rt2560.c?), and turn on debugging so
you'll get a printf at each oerrors++.   When you know which case is
being hit, you can try to figure out why.

I wonder if something in the usb stack is locking out interrupts for too
long.