[U-Boot] Root-Filesystem ober NFS doesn't work... --> Kernel panic

[Wolfgang Denk]

Dear "Michael Schmid",

In message <20091019165934.319480 at gmx.net> you wrote:
>
> I'm trying to get root-filesystem over NFS running. I'm a bit
> confused about all the new stuff and I don't know where I shall start
> searching for the problem :-(
>
> I have:
> Board: Artila M501 board with AT91RM9200
> U-Boot: 1.1.2

more than 4.5 years old!

> Linux: 2.6

2.6.14 according to your log => 4 years old

...
> bootcmd=bootm 10040000 101a0000

This setting means you are trying to boot with a ramdisk. If you want
to boot with root file system over NFS, you MUST NOT pass a ramdiska
ddress, i. e. you must not use two arguments to the "bootm" command.

> bootargs=root=/dev/nfs rw nfsroot=192.168.2.40:/opt/arm ip=192.168.2.196:192.168.2.40:192.168.2.254:255.255.255.0:michael-laptop::off console=ttyS0,115200

I don't think you want to assign the host name "michael-laptop" to
your target board (but this is no really critical at this moment yet).

> bootm=10040000 - 101a0000

This setting is completely bogus. It has no meaning. Delete it.

>  Linux version 2.6.14-M5 (Alan at ace-yang) (gcc version 3.3.2) #837 Tue 
> Aug 14 14:14:03 CST 2007
>  CPU: ARM920Tid(wb) [41129200] revision 0 (ARMv4T)
>  Machine: Artila M501 SOM
...
>  RAMDISK: Compressed image found at block 0
>  VFS: Mounted root (ext2 filesystem).

Here you can see that the kernel mounts the ramdisk image which you
provided.

>  VFS: Cannot open root device "nfs" or unknown-block(0,255)
>  Please append a correct "root=" boot option
>  Kernel panic - not syncing: VFS: Unable to mount root fs on 
> unknown-block(0,255)

...and then it gets confused. 

> Do you have any hints what the problems might be. I'm pretty sure
> that the NFS-Server works fine, but I'm not sure 100% (How can I find
> out if it works? Any Idea?).

Well, just mount the root file system from another host?

Best regards,

Wolfgang Denk

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