On Wed, 12 Mar 2008 19:32:30 PDT, Andrew Morton said:

quoted text
> Yes, it's all a bit mysterious.  I just look in the changelog, which was
> pull edout of the git diff via various means.
> 
> See how
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.25-rc5/2.6.25-rc5-mm...
> starts with 5813a19cba5735b629cdeb156863dab814759128 and ends with
> 816543f9bf2fb77ff52083216a4537eb4e3058ec.  Use
> 5813a19cba5735b629cdeb156863dab814759128 as good and
> 816543f9bf2fb77ff52083216a4537eb4e3058ec as bad.

I *hope* I'm mis-reading Ingo's directions when I cut-n-pasted them -
first I pulled down the two trees, tried to bisect, had it give me the
"need a single revision" error, then I checked out a tree - and got a
*different* funky opaque error message when I tried to bisect:

[/usr/src/valdis/x86.git] git-init-db
Initialized empty Git repository in .git/
[/usr/src/valdis/x86.git] git-remote add linus git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[/usr/src/valdis/x86.git] git-remote add x86 git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git
[/usr/src/valdis/x86.git] git-remote update
Updating linus
warning: no common commits
(...)
Resolving deltas: 100% (598008/598008), done.
From git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
 * [new branch]      master     -> linus/master
remote: Counting objects: 105, done.
(...)
From git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
 * [new tag]         v2.6.12    -> v2.6.12
 * [new tag]         v2.6.12-rc2 -> v2.6.12-rc2
 (...)
 * [new tag]         v2.6.25-rc4 -> v2.6.25-rc4
 * [new tag]         v2.6.25-rc5 -> v2.6.25-rc5
Updating x86
remote: Counting objects: 2651, done.
(...)
Resolving deltas: 100% (1979/1979)
s: 100% (1979/1979), completed with 310 local objects.
From git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86
 * [new branch]      base       -> x86/base
 * [new branch]      for-akpm   -> x86/for-akpm
 * [new branch]      for-linus  -> x86/for-linus
 * [new branch]      latest     -> x86/latest
 * [new branch]      master     -> x86/master
 * [new branch]      origin     -> x86/origin
 * [new branch]      testing    -> x86/testing
[/usr/src/valdis/x86.git] git bisect start
[/usr/src/valdis/x86.git] git bisect good 5813a19cba5735b629cdeb156863dab814759128
fatal: Needed a single revision
Bad rev commit: ^{commit}
[/usr/src/valdis/x86.git] git branch list
fatal: Not a valid object name: 'master'.
[/usr/src/valdis/x86.git] git checkout -b x86-off x86/for-akpm
warning: You appear to be on a branch yet to be born.
warning: Forcing checkout of x86/for-akpm.
Checking out files:  25% (5948/23789)
Checking out files:  31% (7375/23789)
Checking out files:  37% (8809/23789)
Checking out files:  43% (10230/23789)
Checking out files:  48% (11466/23789)
Checking out files:  54% (12847/23789)
Checking out files:  58% (13811/23789)
Checking out files:  64% (15225/23789)
Checking out files:  69% (16415/23789)
Checking out files:  75% (17842/23789)
Checking out files:  81% (19032/23789)
Checking out files:  87% (20659/23789)
Checking out files:  92% (21886/23789)
Checking out files:  97% (23076/23789)
Checking out files: 100% (23789/23789), done.
Branch x86-off set up to track remote branch refs/remotes/x86/for-akpm.
Switched to a new branch "x86-off"
[/usr/src/valdis/x86.git] git bisect start
won't bisect on seeked tree

(Google tells me that last message is gone in git 1.5.4.4 - I'm still
on 1.5.4.3).  Obviously I'm missing some important clue with working with
more than one remote tree....