As some of you may have gathered, I've found a bug that is somewhere
between the kernel and an application I'm running.  I think.  It seems*
to have appeared about when I started compiling everything with -O2, but
I'm not sure.

I'm wondering where I can find answers to any of the following questions:

1.  What, if anything, does the kernel build depend on; are there things
other than arch/foo/compile/BAR/*.o that I need to remove to get a *complete*
rebuild, say, if I suspect that the -O2 is breaking me.

2.  Some drivers specify a fooselect() function, others don't.  What is the
calling chain from select(2) on down, and what happens if the fooselect()
routine isn't provided?  (i.e., what's the default behavior.)

3.  Where can I get documentation on splx()?  Or all the other functions -
there are lots of functions used in all the device drivers that I don't know
about, and one of them may be what's happening.

-s