powerpc: mpc85xx regression since 2.6.39-rc2, one cpu core lame

[Richard Cochran]

Ben,

Recent 2.6.39-rc kernels behave strangely on the Freescale dual core
mpc8572 and p2020. There is a long pause (like 2 seconds) in the boot
sequence after "mpic: requesting IPIs..."

When the system comes up, only one core shows in /proc/cpuinfo. Later
on, lots of messages appear like the following:

   INFO: task ksoftirqd/1:9 blocked for more than 120 seconds.

I bisected [1] the problem to:

   commit c56e58537d504706954a06570b4034c04e5b7500
   Author: Benjamin Herrenschmidt <benh at kernel.crashing.org>
   Date:   Tue Mar 8 14:40:04 2011 +1100

       powerpc/smp: Create idle threads on demand and properly reset them

I don't see from that commit what had gone wrong. Perhaps you can
help resolve this?

Thanks,
Richard


1. I had to patch commit e5462d16 by hand when bisecting, which is a
   fixup for commit fa3f82c8 and not yet merged in c56e5853.