why does image config not match patched kernel source config?

[Fabio Massimo Di Nitto]

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Hi

Toni L. Harbaugh-Blackford [Contr] wrote:
> Mr. Di Nitto:

Please call me Fabio :) you make feel really old ehehhe.

> 
> I apologize for contacting you directly about this, but I have posted
> to the Ubuntu forums and nobody is willing or able to answer my question.

Don't worry.. for the next time i suggest you to use the kernel-team mailing
list (that i am CC'ing now for the records). It is extremely low traffic.

> 
> I have the latest *patched* kernel source for 2.6.10 on hoary (via
> linux-tree-2.6.10).  But the config file from my current kernel
> (from linux-image-2.6.10-5-amd64-k8) does not match the amd64-k8
> config in the patched source.
> 
> I was under the impression that the linux-tree-2.6.10 would give
> me all the sources necessary to compile a kernel essentially identical
> to the one I have installed.  But if this is the case, how did I
> fail to get the correct config file?

Oh yes.. now this go down to some black magic i do to update the configurations.

They should be 100% the same and to verify it do the following:

cat config1 | grep ^CONFIG | sort -u > config1.sorted

same for config2

diff -u config1.sorted config2.sorted | less

There should be no differences.

> 
> Here is the top of the config from the patched kernel source:
> 
> $ head -5 /usr/src/linux-source-2.6.10-2.6.10/debian/config/amd64/amd64-k8
> #
> # Automatically generated make config: don't edit
> # Linux kernel version: 2.6.10-1-amd64-k8
> # Tue Dec 28 15:15:46 2004
> #
> 
> Here is the top of the config that came with my kernel image:
> 
> $ head -5 /boot/config-2.6.10-5-amd64-k8
> #
> # Automatically generated make config: don't edit
> # Linux kernel version: 2.6.10-5-amd64-k8
> # Tue Apr  5 12:09:59 2005
> #
> 

Now the real black magic happens at build time. I will try to keep the explanation
simple, but if you want a very techy one let me know.

It is impossible to preserve the date/time header into the configuration, since it is
generated at buildtime. So even if i update a config in the source package, it will
be "automatically" obsoleted in 1 second.

Now the real black magic come when i need to edit the config. Most people uses these
neat kernel config tools like menuconfig xconfig gconfig... i just use sed on the pure
configfile and it would surprise me at all that I didn't change the header since that
date :)

Fabio

- --
Self-Service law:
The last available dish of the food you have decided to eat, will be
inevitably taken from the person in front of you.
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