From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yann E. MORIN <yann.morin.1998@free.fr>
Date: Wed, 20 Jan 2016 22:58:21 +0100
Subject: [Buildroot] [PATCH 2/3] defconfigs: use the new
 headers-version-same-as-kernel-version option
In-Reply-To: <20160120213824.686c94fb@free-electrons.com>
References: <cover.1453314776.git.yann.morin.1998@free.fr>
 <811e1f5fe52c239010c412ce9f22b307d115cfcf.1453314776.git.yann.morin.1998@free.fr>
 <20160120213824.686c94fb@free-electrons.com>
Message-ID: <20160120215821.GD3992@free.fr>
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To: buildroot@busybox.net

Thomas, All,

On 2016-01-20 21:38 +0100, Thomas Petazzoni spake thusly:
> On Wed, 20 Jan 2016 19:34:29 +0100, Yann E. MORIN wrote:
> > Now that we can say that the linux headers version should match that of
> > the kernel to be built, we inverse the logic in our defconfigs, as it is
> > more sensible that way.
> > 
> > And also because we'll get rid of the former, converse kernel-same-as-headers
> > option.
> > 
> > Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> 
> In this commit, you are changing the defconfigs that use
> BR2_LINUX_KERNEL_SAME_AS_HEADERS. But I am wondering if we shouldn't
> simply change *all* defconfigs to use this new feature. Essentially all
> defconfigs have to worry about selecting a kernel headers version that
> matches the kernel version they use. We could switch them all to use
> your new mechanism, no?

Well, I think it may be worse than that, in fact... Let's see what
happens with a trivial defconfig from before this patch, with the
default toolchain and the kernel settings:

    BR2_LINUX_KERNEL=y

This would give:

    BR2_KERNEL_HEADERS_4_4=y
    BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_4=y
    BR2_TOOLCHAIN_HEADERS_AT_LEAST="4.4"
    BR2_LINUX_KERNEL=y
    BR2_LINUX_KERNEL_LATEST_VERSION=y

Now we use that defconfig after this patch, this gives:

    BR2_KERNEL_HEADERS_AS_KERNEL=y
    BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_REALLY_OLD=y
    BR2_LINUX_KERNEL=y
    BR2_LINUX_KERNEL_VERSION="4.4"

And boom, we've lost BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_4=y

I have no idea how we could solve this. I doubt we want to add anything
like BR2_LINUX_KERNEL_AT_LEAST_4_4 and the likes... :-/

Ideas?

Regards,
Yann E. MORIN.

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