Here is my little workaround script for the hildon-desktop bug, that causes high CPU and battery drain.
This one just runs in background, checking from time to time CPU usage of hildon-dektop (and also hildon-home, but not occuring to me) when screen is off and device is locked, kills the process in case of high CPU and continues loop.

Download, remove '.txt' endiing, get root, put it in /etc/event.d, open x-term and type 'start custom-hildon-checker' (or reboot).
If someone needs a DEB, just let me know.


As there was already MohammadAG's 9-desktop out, which should/has solved it and there was no current thread out there claiming this problem, I did not open it to the community until yet (shame on me).


BUT:
I am still looking for a solution/workaround to detect "hanging" of hildon-home, not reacting on touches, and let me missing all notifications. I can not detect, when this happens. Any ideas?

can you please specify is this for every N900 or some specific senario,since my Hildon Home Never Hang.

This one is only for N900 experiencing the hildon-desktop bug, where it -absolutely not explainable/understandable- consumes about 5% or more of CPU continuously (hereby raising CPU of Xorg). So you experience a battery drain, but do not notify any other irregularities (everything works as normal).

I have also included hildon-home to be checked, but I did not experience that it helped me with "hanging of hildon-home".
But maybe it helps sixwheeledbeast here.