DragonFlyBSD

I am working on a wiki page
[ http://wiki.dragonflybsd.org/index.cgi/HowTo_Develop_Kernel_Modules
] dealing with the mentioned subject and have a few questions:

How can you see the debug output of a module?
How can you redirect the debug output to dmesg?
Which debug output facility you should use (not dmesg?) to look at
debug messages from a module?

These questions should be answered in this tutorial. Since I want to
contribute source code myself, all I do, is to document my work.