Wiz,
no need to use "kernel_menuconfig" for that .. Simply enable the mmc
module in "menuconfig/Kernel Modules" as module or built-in and it will
be there as package/in the image.
regards ede
On 21.04.2010 01:50, RHS Linux User wrote:
Hi Felix and All,
Thanks so much for your note.
Very insightful :).
So I am trying to enable MMC on Kamikaze 8.0.9 [actually the village
telco version]. I need to wind up with 3 kernel modules related to gpio
and mmc. I gather I start with kernel_menuconfig at the main level and
then do menuconfig? It is still confusing to me which boxes in the two
menuconfigs I check to get the various kernel modules whose names I know
compiled in. i.e.- the names on the selection boxes don't make it clear
which modules are going to be compiled? I feel like I must be missing some
simple step?
That said I am pretty sure I am close to having it working :).
Again thank you for your insightful response.
warm regards to all,
Wiz
On Tue, 20 Apr 2010, Felix Fietkau wrote:
On 2010-04-19 11:40 PM, RHS Linux User wrote:
Hi All,
This whole config business IMHO is a real mess!
I disagree, it just takes a bit of getting used to.
Can someone clarify what happens with target config, and whatever other
.configs that happen to be around somewhere?
It works like this:
you have target/linux/generic-2.6/config-, which contains
the baseline settings for all targets. Each target can override and add
any config option relative to that. The delta is stored in
target/linux//config-.
The reason for that is that maintaining one individual .config for each
target would create a much bigger mess, as it makes common config
changes that affect all targets much harder to implement.
Also it seems to me HI TIME that .config became a VERY visible file. So
much depends on the "main" .config and the .config in the kernel
directory.
For reasons stated above, we can't just stick the plain .config files
from the kernel directories in the target dir, as this would mess up
other things.
Is running make kernel_menuconfig the same as going into the kernel
directory and doing menuconfig there? (I hope so.)
No, it's not. Make kernel_menuconfig does these things (simplified):
- Generate the kernel's .config by merging the following files:
- target/linux/generic-2.6/config-
- target/linux//config-
- run make menuconfig in the kernel tree
- subtract generic stuff from the kernel's .config and rebuild
target/linux//config- from that
The idea is that you only need to hand-edit stuff if you want to make
changes to the generic config template, which most of the time you don't
have to.
A bit more tricky is the interaction with the build system .config for
selecting modules. The idea behind that is to not let the kernel build
all modules all the time, but allow the user to select which modules to
throw in binary packages. For this to work, the build system needs to
make further modifications to the kernel's .config before launching the
kernel module build, as having making these changes ahead of time for
platform kernel configs would launch you into an unmanageable Dependency
Tree From Hell.
For all of the .config merges, scripts/kconfig.pl is used, which can do
some very simple config merging/splitting operation.
For the module selection it has a special operation that allows the
merged-in config to only *upgrade* config selections. That means if you
selected something as =y in kernel_menuconfig, the build system will not
change that. It will however select stuff as =m or =y depending on the
KCONFIG settings for kmod-* packages that you selected.
Normally you don't have to be concerned with this process at all,
however occasionally you may encounter undefined config symbols which
make kernel_menuconfig or kernel_oldconfig won't show you. In this case,
you need to add defaults for the missing symbols either to the KCONFIG
line of the package that triggered them, or simply stick them into
target/linux/generic-2.6/config-*
I hope this clears things up a bit
- Felix
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