as subj$ Recoverable by enabling. Reproducible: Always Steps to Reproduce:
Not really a bug report. But anyway, this is a hal/evdev problem, more exactly you failed to configure things properly in hal. (at least that what I think the problem is, as you failed to provide any relevant data).
Umm, in my humble opinion a X configuration should never break between minor versions. If you disagree on that, please elaborate.
http://who-t.blogspot.com/2008/07/input-configuration-in-nutshell.html If you still need help after reading that article, attach your 'emerge --info' output, Xorg.0.log, and xorg.conf
You forgot about output of 'hal-device' for your keyboard and your input fdi file. What's more, parts of that article are no longer valid for 1.5.3 - evdev now only grabs if requested and disables mouse/kbd drivers if evdev is available and AllowEmptyInput is true (on Linux it's default).
*** This bug has been marked as a duplicate of bug 251093 ***