Strangeness (or pilot error) building network driver modules
I have a stock FC2 install on an ASUS A7V600 mobo and I need to make a small change in the network driver for the onboard 3c940 (gigabit ethernet). Before I make any code changes, I like to first try to rebuild the module "as-is" using the existing build configuration from the stock install. I like to do this to make sure that I can reproduce what originally came with the distribution before I start hacking
I first did a 'make oldconfig' (based on /boot/config-2.6.5-1.358), followed by a 'make modules' which builds all of the modules in the FC2 distro, including the 'sk98lin.ko' which drives the 3c940. What I'm trying to understand is why the module that I build is almost 4MB in size, whereas the module provided in the stock FC2 distro is just a little over 150k?
My understanding of 'make oldconfig' is that it will create a 'Makefile' with the same build parameters as the current config. If one uses the same source code (/usr/src/linux-2.6.5-1.358) with the same build parameters, then one should expect to get the same object - but that didn't happen.
Can anyone tell me what I'm forgetting or doing wrong here?