[Buildroot] [PATCH] linux: Fix initramfs compression

[Valentine Barshak <gvaxon@gmail.com>]

On 10/07/2012 03:31 PM, Arnout Vandecappelle wrote:
> On 06/10/12 21:22, Valentine Barshak wrote:
>> -        $(call
>> KCONFIG_DISABLE_OPT,CONFIG_INITRAMFS_COMPRESSION_NONE,$(@D)/.config)
>> -        $(call
>> KCONFIG_ENABLE_OPT,CONFIG_INITRAMFS_COMPRESSION_GZIP,$(@D)/.config))
>> +        for c in GZIP BZIP2 LZMA XZ LZO; do \
>> +            if grep -qm1 "CONFIG_RD_$$c=y" $(@D)/.config; then \
>> +                $(call
>> KCONFIG_DISABLE_OPT,CONFIG_INITRAMFS_COMPRESSION_NONE,$(@D)/.config); \
>> +                $(call
>> KCONFIG_ENABLE_OPT,CONFIG_INITRAMFS_COMPRESSION_$$c,$(@D)/.config); \
>> +                break; \
>> +            fi; \
>> +        done)
>
>   I think this is a bit too complex for something that won't really be
> used by
> most people.  Why not just remove the COMPRESSION lines from linux.mk?
> Then
> we fall back on the default if the user hasn't configured it
> explicitly.  Gives
> the user the possibility to choose something else than the default,
> without adding
> complexity to buildroot.

The problem here is that we can't set initramfs compression mode unless 
the initramfs source (CONFIG_INITRAMFS_SOURCE) is set. We can only set 
RAM disk compression modes that should be supported by the kernel 
(CONFIR_RD_...).

The source is set by buildroot. So the user has no capability to 
configure compression explicitly, unless he (she) sets a fake initramfs 
source file, which will be overridden by buildroot. IMHO, this is a bit 
hackish way to set anything other than default, which is COMPRESSION_NONE.

Yes, that is what most people want. I just didn't want to drop other 
options in case somebody wants a compressed initramfs image.
This could be needed for systems with low memory, for example.

>
>   Regards,
>   Arnout

Thanks,
Val.