Giuliano Pochini writes:

Out of curiosity, is there any advantage in using a 32 bits
kernel on ppc64 over a 64 bits kernel ?  Speed ?  Complexity ?
Compatibility ?  Memory ?

Not really.  The main thing in the past has been that DRI with 32-bit
X server and clients would work with a 32-bit kernel but not a 64-bit
kernel, but that's fixed now.  A 64-bit kernel is faster on most
lmbench tests.  I guess a 32-bit kernel might end up a little smaller,
but that's the only possible advantage I can think of.

Paul.