Re: modules of different kernels (same version)

[Andreas Janssen <andreas.janssen@bigfoot.com>]

Hello

Robert Epprecht (<epprecht@solnet.ch>) wrote:

> I have read different documents about kernel compiling,
> but something is still not clear to me:
> 
> If I compile different kernels (of the same version) most documents
> say to rename the /lib/modules/x.x.x/ directory before doing the
> 'make modules_install' step.
> 
> How can I boot the system after that with an older version?
> 
> Could somebody please give a pointer to a document describing how
> to do that?

You can use the "EXTRAVERSION" of the Kernel to have the Modules
installed in different directories. Take a look at the Makefile in your
Kernel source directory. It begins with something like:

VERSION = 2
PATCHLEVEL = 4
SUBLEVEL = 22
EXTRAVERSION =

When you compile different Kernels from the same source and want to
install them on one system, set the extraversion to different values
(normally beginning with an "-"). This way the modules will not be
installed in the same directory. With the above configuration, modules
go to /lib/modules/2.4.22. If I set EXTRAVERSION to -custom, modules go
to /lib/modules/2.4.22-custom. The Kernel knows about its extraversion
and automatically looks for modules in the correct directory.

Maybe you also want to take a look at kernel-package and its make-kpkg
program. It allows you to make deb packages containing kernel source,
doc, image/modules and headers from your source.

best regards
        Andreas Janssen

-- 
Andreas Janssen
andreas.janssen@bigfoot.com
PGP-Key-ID: 0xDC801674
Registered Linux User #267976