[Buildroot] [PATCH 1 of 3] linux: add linux-update-config and linux-update-defconfig targets

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Le Wed, 28 Sep 2011 08:08:12 +0200,
Thomas De Schampheleire <patrickdepinguin+buildroot@gmail.com> a ?crit :

> > ?* Whether this configuration update shouldn't be done automatically
> > ? when one does "make linux-menuconfig" or "make linux-xconfig".
> > ? People have often found strange to loose their configuration changes
> > ? in Linux/Busybox/uClibc when they do a make clean.
> 
> Such a feature would be good indeed. But, some remarks:
> * hooking it to menuconfig/xconfig wouldn't cover the case where the
> .config is manually changed. This different behavior may be confusing
> as well.

Correct, even though manually changing the .config is a bit of a corner
case.

> What if we execute the automatic saving just before the build step?
> This of course requires to start building; you cannot just change the
> config and hope that it is copied automatically. In that last case, a
> manual linux-update-config would be necessary.
> Is this acceptable?

Yes, sounds good.

> * previously you raised the point of busybox-update / uclibc-update
> potentially overwriting the standard buildroot files. If we do not
> want this and we want automatic saving of custom configs, then we need
> to be able to differentiate between custom and default configuration
> files.
> On the other hand, if there are users that purposefully put their
> project's configuration in the default files (overwriting them), then
> they would not be able to benefit from the automatic saving, and
> possibly not from -update-config either. But I'm not sure if we ought
> to support such practice...

Maybe we can change a bit the selection of the Busybox/uClibc
configuration file. We could do something like:

 [X] Use default Busybox configuration file

in which case Busybox would use the default configuration file
integrated in Buildroot.

If this option is disabled:

 [ ] Use default Busybox configuration file
 (/some/path/busybox.config) Path to Busybox config file

then Buildroot uses the specified configuration file.

With this change, busybox-config-update would output an error if the
default config file is used and would work properly if a specific
config file is given.

What do you think?

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com