on the subcommand:
git bisect start [--term-(new|bad)=<term-new> --term-(old|good)=<term-old>]
- [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]
+ [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<pathspec>...]
git bisect (bad|new|<term-new>) [<rev>]
git bisect (good|old|<term-old>) [<rev>...]
git bisect terms [--term-good | --term-bad]
You can further cut down the number of trials, if you know what part of
the tree is involved in the problem you are tracking down, by specifying
-path parameters when issuing the `bisect start` command:
+pathspec parameters when issuing the `bisect start` command:
------------
$ git bisect start -- arch/i386 include/asm-i386