kumquat-buildroot/fs/initramfs/Config.in
Valentine Barshak 391c82efa1 linux: Do not force GZIP initramfs compression
Initramfs compression does not make much sense for the architectures
that support compressed kernel images because in this case the data
would be compressed twice. This will eventually result in a bigger
kernel image and time overhead when uncompressing it.
The only reason to use compressed initramfs is to reduce memory
usage when the kernel prepares rootfs, and both the unpacked
filesystem and initramfs.cpio are present in the memory.

Buildroot attempts to force GZIP compression for initramfs,
however it doesn't always work because initramfs compression mode
depends on RAM disk compression supported by the kernel.
Thus, CONFIG_INITRAMFS_COMPRESSION_GZIP depends on CONFIG_RD_GZIP.
If CONFIG_RD_GZIP is not set, setting GZIP initramfs compression
will have no effect.

Besides, the kernel also supports other compression methods,
like BZIP2, LZMA, XZ and LZO. Forcing the good old GZIP does not
really make much sense any more.

This removes initramfs compression settings from Buildroot,
so that the default value preset in the kernel config is used,
which is CONFIG_INITRAMFS_COMPRESSION_NONE.

If initramfs compression is still needed, it can be set
in the kernel config (using make linux-menuconfig)

Signed-off-by: Valentine Barshak <gvaxon@gmail.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2013-07-08 14:50:31 +02:00

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config BR2_TARGET_ROOTFS_INITRAMFS
bool "initial RAM filesystem linked into linux kernel"
depends on BR2_LINUX_KERNEL
select BR2_TARGET_ROOTFS_CPIO
help
Integrate the root filesystem generated by Buildroot as an
initramfs inside the kernel image. This integration will
take place automatically.
A rootfs.cpio file will be generated in the images/ directory.
This is the archive that will be included in the kernel image.
The default rootfs compression set in the kernel configuration
is used, regardless of how buildroot's cpio archive is configured.
Note that enabling initramfs together with another filesystem
formats doesn't make sense: you would end up having two
identical root filesystems, one embedded inside the kernel
image, and one separately.
comment "initramfs requires a Linux kernel to be built"
depends on !BR2_LINUX_KERNEL