[Buildroot] [PATCH 1/1] boot/uboot: Really use host-dtc

[Thomas Petazzoni]

Hello,

On Wed, 1 Aug 2018 00:14:08 +0200, Arnout Vandecappelle wrote:

> > I think the optional dependency on host-dtc depends from a time where
> > U-Boot did not have its own copy of DTC. I'm not sure it makes a lot of
> > sense now.  
> 
>  ... but we still want to support those older U-Boot versions, so we can't
> remove it.

Absolutely.

But the case found by David is not a case where U-Boot needs a DTC
available on the host: it tries to use its own internal DTC, but
forgets to build it. That's a bug in U-Boot.

>  Ideally, we should find out between which two versions it is needed, and
> mention that in the help text.
> 
> > If U-Boot tries to use ./scripts/dtc/dtc, then it should have built it.
> > If it didn't build it but tries to use it nonetheless, it sounds like a
> > bug in U-Boot.  
> 
>  Oh yes, now I see it, it's indeed a bug in U-Boot. CONFIG_OF_LIST should either
> depend on CONFIG_OF_CONTROL or select it, otherwise dtc is not built.

Right, so it's indeed a bug in U-Boot. That being said, the change
proposed by David is not too bad: it makes sense to use the host DTC if
it was built, rather than the one built by U-Boot. It's just that the
initial problem explanation wasn't really complete enough, so I was a
bit confused.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com