Bugs ignoring submodules?

Hi,

I'm trying to format patches ignoring changes in the submodules, and so far everything I've tried is failing, which I think points to multiple bugs. I'm using 1.6.5.2.

First I tried: % git format-patch --ignore-submodules

That ignores the submodules, all right, but still generates an empty patch, just like 'git log' shows no diff.

Then I tried: % git log <committish> -- $(git ls-files -x <submodule>)

But the submodule is still listed: % git ls-files --exclude=common | grep ^common common

These are bugs, right? Is there some other recommendation?