how to find outstanding patches in non-linux-2.6 repositories?

How do I get a list of commits in the 'powerpc' tree, which are not part of the 'linux-2.6' tree? The git tutorial has a section 'Working with Others', but the examples dont work for me. Probably because rsync://rsync.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc.git has no info that it is not the "mainline tree". All I need is a list of individual commits in that tree, which are not (yet) in "mainline". I could get them also from the ozlabs mailing lists, for the few patches I need. But it would be better if there is some sort of automated way to extract a list of differences between two trees.