>> ---------------------------------------------------------------------
>
> Got it! Excellent explanation! That is the practical - this is how to
> reset your
> tree to an earlier point in time I need. I had a bunch to do today, but I
> will
> have a bit of time tomorrow to focus on this problem. I'll start at 4/4
> and work
> backwards. I've been through each commit in the
> http://trinitydesktop.org/patches/ list and looking and looking at the
> diffs for
> likely ones by title (and even the unlikely ones) didn't turn up anything.
> It is
> truly a bisect and build problem. bummer ... :)
>

Beware that the correct method is actually to do this from within each
module (tdelibs/, tdebase/, etc.):
git reset --hard HEAD
git checkout <hash>

Tim