> Got this when I tried to run hal-trinity manually:
>
> Nov  2 10:25:03 toto kernel: [ 6448.428655] hald[3942]: segfault at 0 ip
000000000041059b sp 00007fff40a1d690 error 4 in hald[400000+52000] Nov 
2 10:25:03 toto init: hal-trinity main process (3942) killed by SEGV
signal

<snip>

There is no way to run 3.5.12 on Natty without a reinstall, and even then
you will probably run into some odd dependency problems.

My suggestion is this:
1. Use dpkg --purge --force-all to remove all hal related packages (i.e.
all packages with hal in their name; use dpkg -l | grep hal to find them)
2. apt-get update
3. apt-get -f install
4. Reboot

I have seen the HAL files end up in an inconsistent state on distribution
upgrades before, which causes all kinds of havoc in HAL-dependent
programs.  This sequence has always fixed the problem for me.

Tim