[U-Boot-Users] "Problem in increasing initrd(RAMDISK) size"

Leif Lindholm leif.lindholm at i3micro.com
Wed Jun 8 15:49:43 CEST 2005

Wolfgang Denk wrote:
>>Well, this is probably true in more sane cases, but when using embedded
>>ramdisk image (available for both mips and ppc I believe), the 4Mb
>>u-boot limit can indeed cause problems.
> No, it CANNOT.

Yes it CAN.

> I repeat: U-Boot does NOT uncompress  the  ramdisk.  It  just  passes
> information  about  the ramdisk as is (i. e. compressed) to the Linux
> kernel. It is the Linux kernel  which  uncompresses  the  ramdisk  if
> necessary.

The "embedded ramdisk image" option causes the ramdisk.gz (objcopied to
ramdisk.o) to be linked into vmlinux.
When using a 16Mb filesystem, if even somewhat filled, the likelihood of
the image size growing beyond 4Mb is quite large.

Yes, this is actually a braindead enough solution that the ramdisk is
compressed _twice_, but on the mips (2.4 series Linux), embedded ramdisk
has been so widely used that noone seems to have noticed that regular
initrd support is broken. This is fixed for 2.6 though.


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