This bug has been fixed in upstream as of 2.6.21-rc7-git7 (http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=32bd33e21eeab63e7265bb3cba9ed94ab1ab816e). The problem was introduced into the kernel with version 2.6.20.4 by the now-notorious "adjust legacy IDE resource setting (v2)" patch. The fix, applied by Linus, was simply to revert the patch. Hopefully the Debian kernel guys can revert this single patch to close this bug?