[OLPC-devel] Upgrading to LinuxBIOS. (problem on a subset of ATest boards).

[Jim Gettys]

If you are using ATest boards, please read this message carefully.

In the early conversion to LinuxBIOS, we found a hardware problem.  This
is good: it is the purpose of testing. 

To meet demand of high volume components that may be in short supply
sometimes, such as DRAM, it is normal to "qualify" a number of sources
for those components. 

The ATest boards were therefore manufactured with three different DRAM
vendor's chips.  Unfortunately, a mistake was made in the selection of
the proper component from Infineon, and a DRAM chip version was used
that is too slow for the Geode GX.  This is not a problem with
Infineon's memory chips; the wrong speed chip was used by mistake,
rather than the parts themselves not working to specification.

Therefore, as the warning in the "Upgrading to LinuxBIOS" page says in
more detail: http://wiki.laptop.org/go/Upgrading_to_LinuxBIOS#Warnings
please do *NOT* install LinuxBIOS right now onto boards with Infineon
DRAM's, but wait until we say to.  

We will probably make a version of LinuxBIOS for use on such boards that
sets the memory controller slow enough for those boards to work as well
as they have under Insyde's BIOS, which we believe was running at the
slower speed.  But that slower speed, which is as slow as the Geode GX
can run, is still nominally too fast for the memory chips used.  We are
working on a strategy of how to handle this issue, though clearly most
boards have been stable at this slower speed (or we would have had many
complaints by now).

If you have already converted to LinuxBIOS on boards with the Infineon
memory, and your board appears to be working OK, leave it alone for now
and continue to run LinuxBIOS.

Please *DO* continue to install LinuxBIOS onto boards you have with
Hynix or PSC memory chips.  We do need to test both LinuxBIOS and the
use of those manufacturer's memory chips at the higher intended speed.

                  Thank you all for your efforts!
                           - Jim Gettys

My great thanks to Tom Sylla, Ron Minnich, Richard Smith, Jordan Crouse,
Chris Ball, Marcelo Tosatti, James Cameron and Mitch Bradley for helping
figure out this problem.

This problem is: http://dev.laptop.org/ticket/53

-- 
Jim Gettys
One Laptop Per Child