Does it happen only in Ubuntu or have you seen it
in other distros? Hibernation problems are widespread and it is suggested that
some manufacturers add proprietary extensions to acpi that may mean that they
behave not as you might expect if Linux is set up with regular acpi
implementations. I am not sure how this fits in with Compiz. I am just throwing
out an idea. Some people have kernel patches and scripts to solve some acpi
problems with certain distros or else the recommend that you unload some kernel
modules in order to fix it. It sounds like a lot of work to me.