kernel compile with make oldconfig

[kowalsky]

Hi all,
i wanted to do something very simple. I needed the shared memory param increased from 2000000 to 20000000.
I saw there's a newer kernel (i have 2.217 and i downloaded 2.2.19).
So, after extracting the new source in /usr/src and changing the linux link to /usr/src/linux-2.2.19mdk i did: vi /usr/src/linux/include/asm/shmparam.h
change the line with shmmax and save the file. Next step recompile the kernel.
Instead of make xconfig I just said make oldconfig. Everything OK, no errors with make dep, make clean, make modules (just a few warnings for some variable names) and eveything went OK until I booted the new kernel where it seemed it missed quite a whole bunch of things (sound support for instance). What happened?
I did look for /usr/src/linux/.config but I did not find any just before I launched make oldconfig. Is it because the precompiled kernel that comes in the install kit does not have one?
How do I go about this further?

Suppose I give up the 2.2.19. I only need to change the shmparam.h line and then recompile the very same 2.2.17 kernel. How do I do it?
Thanks,
kowalsky

[kowalsky]

forgot to ask something else,
in the nhf it sais make install_modules, in all other documentation it sais make modules. What is the difference?
thanks,
kowalsky

[johnwebb]

Not sure about Mandrake, but with RedHat the default .config files are located in /usr/src/linux/configs. They are named something like kernel-2.2.19-i586.config, kernel-2.2.19-i386-smp.config. By copying the one that matches the install to /usr/src/linux/.config before running "make oldconfig" results in the "factory" settings.

[johnwebb]

"make modules" builds the modules and "make modules_install" puts them in /lib/modules/(kernel version). It will overwrite what is there so you may want to make a backup before running "make modules_install". "mv /lib/modules/(kernel version) /lib/modules/(kernel version).orig

[kowalsky]

but if i compile a new kernel, i don't have to back up the modules; my understanding is that modules for 2.2.19 will go in a 2.2.19 directory. true or false?
thanks,
kowalsky

[johnwebb]

True, if you are upgrade kernel versions there is nothing to backup.