suspend on asus 3500

[Eugenio]

i use freebsd 5.3 -stable on this asus 3500. all seems to work well 
except the suspend states. S4 cruelly shut down the machine, while S3 
suspends it, but on resume  i receive on console an error like this:

ad0: FAILURE ATA_IDENTIFY timed out
ad0: WARNING removed from configuration

the machine then hangs (mouse and keyboard worked for the first seconds) 
and the fun starts to make a lot of noise.
any hint?

P.S.
is there something to catch acpi events (like low battery) and execute 
some command?

thank you.

Eugenio
eugenio at lumachedelcervello.cjb.net