Subject: Re: initramfs on PowerPC

From: "David H. Lynch Jr." <[email-masked]>
Date: Fri, 04 May 2007 15:02:22 -0400

I tried numerous approaches, I never got anything to work except pointing
CONFIG_INITRAMFS_SOURCE at a directory with my intramfs tree in it.
I am sure other ways work, but I never managed to figure out what I was
doing
wrong. Regardless that has worked well for me.

When I build I end up with a single file - zImage,.elf that has both my
kernel
and the initramfs tree in it. While there are a number of distro's that
seem to
use initramfs as a separate file - much like initrd, my loader has no
provisions for a 2nd file, and the kernel build process wraps everything
together
which works fine for me.

I have never seen your "junk in compressed archive" error, and I have
been doing this
for almost 2 years. But I have frequently had decompression errors.
These typically
have been the result of errors in the PPC zlib libraries. I beleive
somewhere between
2.6.16 and 2.6.18 these libraries got updated, and the PPC version of
the new ones
had problems. Anyway, after 2.6.18 the new ones are good - though somehow
once in a while the broken ones seem to creep into my development tree,
but updating it usually fixes things.

There also may be a total size issue. I am hazy on the details, but I
beleive if the
size of size of the kernel goes over 3mb that there are CONFIG values that
may need to be changed. I am not sure whether that is compressed size
decompressed size, kernel size, or combined kernel + initramfs size.

Regardless, one suguestion would be to try with a very minimal initramfs
tree
and add things until it blows up.

Richard Danter wrote:
> Hi all,
>
> I am having a problem booting a kernel with an initramfs. The kernel version 
> is 2.6.14. The target is a ppc 82xx board.
>
> I have tried both generating the cpio.gz file myself (find . | copi -o -H 
> newc | gzip > ../initramfs_data.cpio.gz) and pointing initramfs source to a 
> root FS directory (using xconfig) and then re-building my kernel.
>
> Usually the error is "junk in compressed archive" though I also see an 
> occasional error about padding.
>
> I am using U-Boot to load the kernel image (uImage).
>
> My host is SuSE 10.0 (x86), though I guess that shouldn't make any difference 
> (endianism?).
>
> Any thoughts on what I may be doing wrong?
>
> Thanks
> Rich
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