Acer Aspire ONE running Linux and mini2440

I would like to directly connect these two items, but they won't work
together, with a direct cross-over connection.

I have enabled eth0 as it was broken in Ubuntu 10.04LTS on this netbook
model D255E, by using this HowTo:

http://www.cnx-software.com/2011/08/21/installing-ubuntu-10-04-lts-in-ac...

The netbook with now talk to a Desktop Dell running Linux, two mini2440s
will talk to each other and the mini2440 will talk to the Dell . . . all
using a cross-over cable.

But the netbook will NOT talk to the mini2440 or the other way around.

If I connect them to my local network, or interpose a switching or
non-switching hub or a USB to ethernet adapter they will talk to each
other.

The mini2440 appears not to receive ARP requests from the netbook, by
looking at /proc/interrupts (on the mini2440) and doing arp -n (on the
netbook) no HW MAC address for the mini2440 is seen.

Before I have to learn how to debug the driver for the DM9000 I was hoping
this problem might sound familiar to someone.

Appreciate any comments,
Thanks,
Dave

All I know is, the DM9000 does not support auto detection/swiching of
TX/RX. I will check your scenario this evening

My test environment: A DELL D610 laptop, regular network cable and a
Mini2440. My laptop comes with an auto RX/TX detection/switch feature.
I have connected both systems via this network cable, configured the
ethernet interfaces at both sides to the same network and was able to ping
my Laptop from the Mini2440 (inside Barebox and kernel) and vice versa when
the kernel was up and running at the Mini2440. Also TFTP/NFSroot has worked
with this kind of connection.
So sorry, but I have no idea why this config does not work at your side.

Juergen,

Correct on DM9000 capabilities.

I relented and actually made some measurements and discovered that the RX
levels at the mini2440 are about 1/2 the value when driven by the Acer
Aspire ONE as compared with the other machines.

Tells me that I need to talk to someone as Acer.  It uses the Atheros
AR8152 chip.

Thank you for taking the time to make some tests at your end.

Dave

Just an idea about the half levels: isn't ethernet a current driven
interface? So, maybe the impedance of the cable, the Mini2440 and/or your
laptop do not match the ethernet spec.

Discussed this with a ethernet interface specialist and yes just measuring
the voltage levels only gives me an indication that something is different
between the various machines. IE the netbook running a special driver to
enable eth0 using Ubuntu may not be setting the TX levels correctly.

I will check how well it works using Windows 7.