iwndebug is a friendly tool to toggle debugging levels of the iwn(4) driver. It leverages the sysctl(8) framework using the debug oid of the driver. You need to build your kernel with options IWN_DEBUG in order to see the debugging messages of the driver on the console or via syslog(3).

It needs to be build from inside the freebsd-src sources.

• Clone sources

git clone --depth 1 -b main https://git.freebsd.org/src.git /usr/src
git clone https://github.com/sbz/iwndebug.git
cp -r iwndebug/tools /usr/src/tools/

• Build

cd /usr/src/tools/tools/iwn
make
make install

iwn(4) is an old driver and does not spark interests and attention anymore compare to more recent hardware but I'm still using an old thinkpad with it :)

You need super user (root or sudo) privileges to use it as it's installed under /usr/local/sbin folder.

iwndebug -h

iwndebug +trace

iwndebug none

iwndebug -?

By default log messages are displayed on the console via /dev/console, you can configure syslog(3) daemon to print driver messages from the kernel in the /var/log/debug.log file using the following:

# echo "kern.debug       /var/log/debug.log" > /etc/syslog.d/debug.conf
# service restart syslogd
# tail -n 0 -f /var/log/debug.log