Brain storm: how do I debug this?

[Shachar Shemesh]

In 2009 I won a SheevaPlug as part of Hamakor Prize. At the time, I made 
sure it was actually working (it wasn't at first. The problem turned out 
to be that the MiniUSB cable that was bundled with the device was too 
short to make contact with the MiniUSB connector inside the device), and 
that I can connect to it, and that was it.

A little while ago I picked it up again, and found out it wasn't 
booting. I managed to bootstrap uboot on it (which i compiled from the 
kirkwood git repository), and boot it into the bundled jffs2 Ubuntu 9.04 
image that came with it, using a kernel I compiled from git (2.6.38-rc8, 
and later 2.6.38). So far, so good.

Now I wanted to replace the image on it with Debian. I managed to 
debootstrap debian onto a disk on key, but when I try to boot it, it 
hangs during boot. I moved the image to a UBIFS image on the internal 
nand, but the problem persist. I can boot into single user mode, and 
everything works, but if I try to let the system boot completely, it 
just hangs.

Symptoms:

    * Pressing anything on the keyboard does not echo
    * Magic sysrq key does not work (it does if I send the break before
      the hang)
    * The boot sequence starts a couple of the init processes, and does
      not continue.
    * The console is working. If I plug a disk on key, I see the console
      message about it, and it detects the partitions on it a second later.

I tried to connect via jtag and get a backtrace - the system is in the 
cpu_idle routine - no panic and nothing out of the ordinary, except that 
it is not doing what it was supposed to be doing at this point.

I tried to remove the last loaded service from the startup. The result 
is that it still loads two services and hangs (just, different services).

Now I'm stuck for idea as to what to try next. Anyone?

Shachar

-- 
Shachar Shemesh
Lingnu Open Source Consulting Ltd.
http://www.lingnu.com

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.cs.huji.ac.il/pipermail/linux-il/attachments/20110319/66c3c008/attachment.html>