Debug levels for kernel modules?

[Ian Lepore]

On Mon, 2016-03-21 at 10:33 -0700, Lundberg, Johannes wrote:
> Hi
> 
> Is there a general rule for debug level ranges (set with sysctl) in
> kernel
> modules or is it different from module to module?
> 
> Like what is max level, what does the different numerical levels
> mean, etc?
> If not a general rule, is there a way to get the max or set the max
> verbosity level without knowing the value?
> 
> 
> Thanks
> 

In my experience there is no standard other than "bigger numbers
usually mean more-noisy-and-detailed output".  In a few places the
debug value is a bitmask of categories rather than a "volume knob"; it'
s nice when that's indicated with a name like kern.geom.debugflags
instead of just "debug".

-- Ian