On 04/21/2011 07:47 PM, Somebody in the thread at some point said:
On Thu, 21 Apr 2011, Andy Green wrote:
On 04/21/2011 07:08 PM, Somebody in the thread at some point said:
make ARCH=arm defconfig cat arch/arm/configs/omap4_defconfig>>.config make ARCH=arm oldnoconfigmake omap4_defconfig
Wow that is a lot simpler... if you know it.
When trying to figure this out I googled the original patch that added the savedefconfig and it doesn't mention this Makefile magic; I guess it was added later.
In fact, this has been there almost forever. The rule is in scripts/kconfig/Makefile on line 354.
Still, the fact is before you can just copy a whole config from arch/arm/configs to be .config and vice-versa which has been my usage pattern. Now with these optimized defconfigs, that doesn't work; it doesn't hurt to document how to use the new way (even better with your make target method). It's possible I'm the only guy who missed the day at school where they talked about arbitrary defconfig targets in Makefile but I doubt it.
There are a lot of nice Make targets available. Just try "make help".
For some years I used O= in my build scripts because when building multiple targets from the same tree continuously it can be a nice timesaver. Likewise I use sparse and so on from there. I agree there are lots of nice Make targets in there.
-Andy