[Soekris] Net 4501 BIOS v1.31b Problems?

[Trevor Talbot]

On Aug 17, 2007, at 5:36 AM, Heather Lockridge wrote:

> I have loaded this version of linux on many net 4801s using the 
> approach of booting from a tftp sever with an append line parameter in 
> the tftpboot default file of root=/dev/nfs 
> nfsroot=192.168.1.121:/soekris-root and it works great on net4801s 
> with combios v1.31.
>
> With the 4501, I use the same parameters, just a new kernel built for 
> the correct CPU (AMD Elan).  What happens every time, no matter what 
> kernel version I try is that the kernel boots from nfs, but does not 
> find the root partition served by the nfs server.  I checked and a 
> 4801 still finds it so I know there is no problem with my nfs server.
>
> What I see is the following at the beginning of the kernel boot on the 
> net4501 console:
>
> Built 1 zonelists.  Total pages: 16256
> Kernel command line: console=ttyS0,9600n81 root=/dev/nfs 
> nfsroot=192.168.1.121:/soekris-root ip=dhcp panic=10 ramdisk_size=4096 
> rw BOOT_IMAGE=vmlinuz.net4501
>
> Then at the end of the boot process, I see the following:
>
> IP-Config: Complete:
>       device=eth0, addr=192.168.1.228, mask=255.255.255.0, 
> gw=192.168.1.2,
>      host=192.168.1.228, domain=localdomain, nis-domain=(none),
>      bootserver=192.168.1.121, rootserver=192.168.1.121, rootpath=
> Looking up port of RPC 100003/2 on 192.168.1.121
> Looking up port of RPC 100005/1 on 192.168.1.121
> VFS: Mounted root (nfs filesystem).
> Freeing unused kernel memory: 140k freed
>
> Then nothing further happens!  I have checked with tcpdump on the nfs 
> server watching the IP of the net4501 and I see no further traffic.
>
> Note the "empty" rootpath=  !!
>
> Could the "empty" rootpath= be due to a flaw in the BIOS?

Unlikely.  The PXE code in the BIOS is only involved for the first DHCP 
query, to find the TFTP server and PXE boot image.  Once the image from 
there is executed, everything is under its control, not BIOS's.  The 
problem is somewhere with your pxe bootloader or kernel.

> Any thoughts would be appreciated!

I'm not at all familiar with linux, but in some systems a second DHCP 
query happens to locate the NFS data, and the DHCP server is expected 
to return the root path as an attribute.  You do have the IP address 
coming from DHCP, so maybe the commandline you provided isn't enough to 
set the root path?  Did you perhaps set up a special config for the 
net4801 in the DHCP server and forget about it?

I also note the "VFS: Mounted root (nfs filesystem)" line, which seems 
a bit odd if it couldn't actually find the root path.  Maybe the 
problem isn't where you think -- the 4801 is a 586-class system, but 
the 4501 is 486-class.  Are the binaries on the NFS root compatible?

Again, I'm not familiar with what you're working with, so I may be 
totally off base, but hopefully one of these thoughts will lead in the 
right direction.