1.  Should I use CONFIG_MODVERSIONS when compiling a Linux kernel?

Short answer:  No.  Long answer: MODVERSIONS allows you to safely
use a module on multiple kernel versions.  However, making comedi
work with CONFIG_MODVERSIONS is a real pain.  Sometimes it works,
sometimes it doesn't.


2. I get the error message:

Makefile:14: /usr/src/linux/.config: No such file or directory
make: *** No rule to make target `/usr/src/linux/.config'.  Stop.


It means you don't have the file /usr/src/linux/.config.  This file
contains all the configuration information about your linux kernel,
which comedi needs in order to compile correctly.  Some distributions
don't contain this file, so you will need to create your own, by
compiling your own kernel.  This file is automatically created
when you run 'make config', the first step in compiling a kernel.


3. When compiling programs that use libcomedi, I get error message:

/usr/lib/libcomedi.a(range.o): In function `comedi_from_phys':
range.o(.text+0x169): undefined reference to `floor'


This error messsage indicates that the linker cannot resolve the
reference to floor(), which is a function in the math library
that is used in the function comedi_from_phys().  This only
happens when you link statically.  Add '-lm' to your linking
command.