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

[PseudoCylon]

> 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