git-status and git-diff now very slow in project with a submodule

Hello,

I've just upgraded from 1.6.something to 1.7.1.  All very nice.

The new submodule reporting is nice too; but I'd like to be able to turn it off :-)

The problem is that I have a (relatively) small project as the supermodule, and a linux kernel clone as a submodule and an ffmpeg clone as a submodule. Now I used to be able to do git-status or git-diff and it would be instant, it now takes a number of seconds to report. I guess (but don't know), that it is the detection of "dirty" status in the submodule's that is slowing down the supermodule processing.

I wouldn't like to see the feature go, because in almost all circumstances it is exactly right; however, I'd like to be able to turn off dirty detection in submodules. Is this already possible, and I've just missed the configuration option?

One additional small point: why do untracked files in a submodule make the module dirty? I've often got a few "temp.ps" or "debug.log" or "backtrace.log" files lying around -- inappropriate to add to an ignore file, but they don't make my working directory dirty. "Dirty" in a working directory means uncommitted changes to tracked files, why does it mean something different in a submodule?

Andy