[oe] [OE-core] [RFC] Layers, PRINC and bbappends

[Paul Eggleton]

On Wednesday 22 May 2013 11:17:38 Martin Jansa wrote:
> On Wed, May 22, 2013 at 09:47:39AM +0100, Paul Barker wrote:
> > I've just sent a patch to the yocto@ list to fix this but it's brought
> > up two things:
> > 
> > 1) In openembedded-core/meta/classes/image.bbclass SPLASH is set with
> > '?='. I'm overriding this with '=' in
> > meta-raspberrypi/conf/machine/raspberrypi.conf which means it can't be
> > overridden further in local.conf. Is this worth changing to '??=' in
> > image.bbclass, '?=' in the machine conf so that it can be overridden
> > with '=' in local.conf? Is my understanding of the overrides correct
> > here?
> 
> You can still use:
> SPLASH_forcevariable = "foo"
> SPLASH_your-distro = "foo"
> SPLASH_your-machine = "foo"
> or any other OVERRIDE in local.conf.

This is true; FWIW as the original author of that line in image.bbclass I
wouldn't object to changing it to ??= though.

Having said that, I would note that people are best advised not to try to set
too much from local.conf, especially when it's stuff that affects what is in the
final image. Anyone doing anything moderately custom should really have their
own distro config. FYI, we now have a section in the Yocto Project development
manual documenting this:

http://www.yoctoproject.org/docs/current/dev-manual/dev-manual.html#creating-your-own-distribution

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre