[Buildroot] [PATCH] board: add support for ARC AXS101 and AXS103 Software Development Platforms

[Alexey Brodkin <Alexey.Brodkin@synopsys.com>]

Hi Thomas,

On Tue, 2015-08-04 at 15:24 +0200, Thomas Petazzoni wrote:
> Dear Alexey Brodkin,

> > > Please force the version of the kernel headers, so that they match the
> > > kernel being built.
> > 
> > Well you see the problem here is we do need yet to be released Linux v4.2
> > because that's where both boards are finally exist.
> > 
> > So once v4.2 is released (in a couple of weeks now) and Buildroot is updated
> > I would assume v4.2 headers will become default version, right?
> > So then we're golden and there's no need to update these defconfigs.
> 
> You're wrong. After 4.2 becomes the default version, 4.3 will become
> the default version. And then your defconfigs are broken.

Hw, I do understand your concern with implicitly specified version of
kernel/headers but what I meant if I use "make savedefconfig" it eliminates
versions if they match today's defaults.

For example if today I select
--------->8---------
BR2_LINUX_KERNEL_VERSION="4.1.3"
BR2_DEFAULT_KERNEL_HEADERS="4.1.3"
--------->8---------

Then defconfig generated by "make savedefconfig" will be:
--------->8---------
BR2_arcle=y
BR2_TARGET_GENERIC_HOSTNAME="axs101"
BR2_TARGET_GENERIC_ISSUE="Welcome to the ARC Software Development Platform"
BR2_SYSTEM_DHCP="eth0"
BR2_ROOTFS_OVERLAY="board/synopsys/axs10x/fs-overlay"
BR2_LINUX_KERNEL=y
BR2_LINUX_KERNEL_DEFCONFIG="axs101"
BR2_TARGET_ROOTFS_INITRAMFS=y
BR2_TARGET_UBOOT=y
BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
BR2_TARGET_UBOOT_BOARD_DEFCONFIG="axs101"
--------->8---------

Note there's no version of kernel/headers.

So now if I understood you correctly you propose to insert:
--------->8---------
BR2_LINUX_KERNEL_CUSTOM_VERSION=y
BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.2-rc5"
BR2_DEFAULT_KERNEL_HEADERS="4.1.3"
--------->8---------

in defconfigs today and later once v4.2 is released change defconfigs
like that:
--------->8---------
BR2_LINUX_KERNEL_VERSION="4.2.0"
BR2_DEFAULT_KERNEL_HEADERS="4.2.0"
--------->8---------

Right?

-Alexey