If you are not sure, leave it set to "0".
config RD_GZIP
- bool "Support initial ramdisks compressed using gzip" if EMBEDDED
+ bool "Support initial ramdisks compressed using gzip" if EXPERT
default y
depends on BLK_DEV_INITRD
select DECOMPRESS_GZIP
If unsure, say Y.
config RD_BZIP2
- bool "Support initial ramdisks compressed using bzip2" if EMBEDDED
- default !EMBEDDED
+ bool "Support initial ramdisks compressed using bzip2" if EXPERT
+ default !EXPERT
depends on BLK_DEV_INITRD
select DECOMPRESS_BZIP2
help
If unsure, say N.
config RD_LZMA
- bool "Support initial ramdisks compressed using LZMA" if EMBEDDED
- default !EMBEDDED
+ bool "Support initial ramdisks compressed using LZMA" if EXPERT
+ default !EXPERT
depends on BLK_DEV_INITRD
select DECOMPRESS_LZMA
help
Support loading of a LZMA encoded initial ramdisk or cpio buffer
If unsure, say N.
-if INITRAMFS_SOURCE!=""
+config RD_XZ
+ bool "Support initial ramdisks compressed using XZ" if EXPERT
+ default !EXPERT
+ depends on BLK_DEV_INITRD
+ select DECOMPRESS_XZ
+ help
+ Support loading of a XZ encoded initial ramdisk or cpio buffer.
+ If unsure, say N.
+
+config RD_LZO
+ bool "Support initial ramdisks compressed using LZO" if EXPERT
+ default !EXPERT
+ depends on BLK_DEV_INITRD
+ select DECOMPRESS_LZO
+ help
+ Support loading of a LZO encoded initial ramdisk or cpio buffer
+ If unsure, say N.
choice
- prompt "Built-in initramfs compression mode"
+ prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!=""
help
This option decides by which algorithm the builtin initramfs
will be compressed. Several compression algorithms are
bool "Gzip"
depends on RD_GZIP
help
- The old and tried gzip compression. Its compression ratio is
- the poorest among the 3 choices; however its speed (both
- compression and decompression) is the fastest.
+ The old and tried gzip compression. It provides a good balance
+ between compression ratio and decompression speed.
config INITRAMFS_COMPRESSION_BZIP2
bool "Bzip2"
depends on RD_BZIP2
help
Its compression ratio and speed is intermediate.
- Decompression speed is slowest among the three. The initramfs
+ Decompression speed is slowest among the four. The initramfs
size is about 10% smaller with bzip2, in comparison to gzip.
Bzip2 uses a large amount of memory. For modern kernels you
will need at least 8MB RAM or more for booting.
help
The most recent compression algorithm.
Its ratio is best, decompression speed is between the other
- two. Compression is slowest. The initramfs size is about 33%
+ three. Compression is slowest. The initramfs size is about 33%
smaller with LZMA in comparison to gzip.
-endchoice
-
-endif
-
-if INITRAMFS_SOURCE=""
-# The builtin initramfs is so small so we don't want to bug the user...
-
-config INITRAMFS_COMPRESSION_NONE
- bool
- default y
+config INITRAMFS_COMPRESSION_XZ
+ bool "XZ"
+ depends on RD_XZ
+ help
+ XZ uses the LZMA2 algorithm. The initramfs size is about 30%
+ smaller with XZ in comparison to gzip. Decompression speed
+ is better than that of bzip2 but worse than gzip and LZO.
+ Compression is slow.
+
+config INITRAMFS_COMPRESSION_LZO
+ bool "LZO"
+ depends on RD_LZO
+ help
+ Its compression ratio is the poorest among the four. The kernel
+ size is about 10% bigger than gzip; however its speed
+ (both compression and decompression) is the fastest.
-endif
+endchoice