[Buildroot] [PATCH] linux: CONFIG_KERNEL_LZO option requires host-lzop

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear Fabio Porcedda,

On Mon, 13 May 2013 09:58:40 +0200, Fabio Porcedda wrote:
> When the LZO compression mode is chosen the linux kernel requires
> lzop host utility at build time.
> 
> Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
> ---
>  linux/linux.mk | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/linux/linux.mk b/linux/linux.mk
> index d375cf0..3877c35 100644
> --- a/linux/linux.mk
> +++ b/linux/linux.mk
> @@ -34,7 +34,7 @@ endif
>  LINUX_PATCHES = $(call qstrip,$(BR2_LINUX_KERNEL_PATCH))
>  
>  LINUX_INSTALL_IMAGES = YES
> -LINUX_DEPENDENCIES  += host-module-init-tools
> +LINUX_DEPENDENCIES  += host-module-init-tools host-lzop

Yeah, I know about this problem, but I'm not entirely happy with this
solution. Since we can't have dependencies that depend on the kernel
configuration (because at the time make parses linux.mk, the kernel
configuration hasn't been created yet), we have to make host-lzop a
mandatory dependency. Then, later on, someone will came up with the
same problem for the LZMA compression. And then the kernel, in some
special case will need yet another tool installed on the host machine.

I agree that host-lzop is not huge, but it's a pain to have things
being built that will not be used.

The only alternative that I see is that the kernel compression should
be selected in Buildroot, which will then enforce this selection into
the kernel configuration. Therefore, Buildroot will have the knowledge
of which compression tools will be needed.

Now, whether this alternative really scales if the kernel starts to
have more and more host dependencies, I don't know.

Thoughts? Ideas? Maybe I'm just nitpicking here?

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com