[urtw] Wifi link dying randomly. reboot required to reconnect.

[Chuck Burns]

On Tuesday, October 11, 2011 1:04:59 AM you wrote:
> > Date: Thu, 6 Oct 2011 19:02:15 -0500
> > From: Chuck Burns <break19 at gmail.com>
> > Subject: Re: [urtw] Wifi link dying randomly. reboot required to
> >        reconnect.
> > To: Gary Palmer <gpalmer at freebsd.org>
> > Cc: freebsd-net at freebsd.org
> > Message-ID: <201110061902.15838.break19 at gmail.com>
> > Content-Type: Text/Plain;  charset="iso-8859-1"
> > 
> > 
> > options         KDB                     # Kernel debugger related code
> > options         KDB_TRACE               # Print a stack trace for a panic
> > #options        KDB_UNATTENDED          # Reboot on panic
> 
> options	WITNESS		# add me
> 
> 
> With run(4) (another usb dangle), there is a LOR between node lock and
> driver lock in if_raw_xmit(). Maybe, stuck on sending mgmt frames ->
> hang/disconnected from AP?
> 
> With run(4), the LOR hasn't caused dead lock in 11abg mode, but in 11n
> mode, it causes dead lock every time. You run it in 11g mode,  but it
> might be having bad hair day occasionally. Next time, rather than
> unplugging the device to induce a panic, wait and see if the computer
> will completely be locked up.
> 
> 
> AK

I've seen it completely lock up very seldomly.. But generally, if it hasn't 
locked up by the time I notice the connection is dead, it won't.

I've added witness to options now.

Chuck