Re: [stable] [patch 44/47] pxamci: fix byte aligned DMA transfers

Linus Torvalds
2008-07-24T19:29:21Z

On Thu, 24 Jul 2008, pHilipp Zabel wrote:
> > On Wed, Jul 23, 2008 at 01:24:12PM -0700, Linus Torvalds wrote:
> >>
> >> Hmm. I think it's commit 4fe16897c59882420d66f2d503106653d026ed6c
> >> upstream. I don't know why it has a different SHA1 in the mmc tree, but I
> >> assume that it's because the MMC tree has rebased at some point. Ugh.
>
> Thank you, I think when I wrote my mail it wasn't pulled yet.

Pulling doesn't change the SHA1 ID of a commit, so _if_ it had been stable
in the -mmc tree, it would have had the same commit in the kernel too.
That's very much a design issue in git: the same commit always has the
same ID. _ALWAYS_.

So the fact that the ID changed implies that something odd happened in the
-mmc tree. Most likely a rebase. And again, this implies that somebody
rebased already-public commits, since otherwise nobody would have ever
even seen the original SHA1 ID.

Which is not good behaviour, _exactly_ because it makes it much harder for
people to work together - suddenly a commit that got reported (for
whatever reason: bug-report or 'please backport', it's all the same issue
in the end) no longer exists.

Linus