[yocto] Help with DISTRO settings

[Paul Eggleton]

On Mon, 25 Jul 2016 20:34:32 Khem Raj wrote:
> > On Jul 25, 2016, at 8:31 PM, Edward Wingate <edwingate8 at gmail.com> wrote:
> > 
> > On Mon, Jul 25, 2016 at 1:27 AM, Nicolas Dechesne
> > 
> > <nicolas.dechesne at linaro.org> wrote:
> >> hmm. you shouldn't set DISTRO in conf/layer.conf, that doesn't sound
> >> right. DISTRO needs to be set in local.conf (or any of the other build
> >> specific conf files).
> > 
> > I agree, I don't know why I had it in conf/layer.conf.  Just
> > beginner's mistake.
> > 
> > I moved DISTRO to local.conf (changed the existing DISTRO ?= "poky" to
> > DISTRO ?= "mydistro") and it still works.  But if I remove DISTRO from
> > conf/distro/mydistro.conf, DISTRO will revert to "poky", even though
> > it is set to my "mydistro" in local.conf.  So it seems I have to have
> > it in both places.
> 
> in your mydistro.conf you should first set the settings that you want to
> customize then include conf/distro/poky.conf not other way around. May be
> we should change poky.conf to use ??= so the substitution happens at the
> end of parsing. but thats for another time.

I'm clearly missing something - why must it be done that way around? If you 
were to set the values you want *after* the include/require then that should 
work just fine, and would be the way I would recommend doing it - it's also 
the way poky-lsb distro does it.

One thing to note is that poky.conf itself sets DISTRO, mostly for historical 
reasons I believe. Thus if you do include/require poky.conf then you may wish 
to set DISTRO back to whatever it should be and you'd have to do that after 
the include/require, not before it.

Another thing to consider is that any _poky overrides will only be applied if 
DISTRO = "poky", thus include/require of poky.conf won't incorporate those 
into your custom distro. You can set DISTROOVERRIDES to include "poky" to 
counter this. In practice though there aren't too many of these - in fact I 
can only see one in the psplash recipe.

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre