Thanks !! A lot, that worked perfect. I was able to get s2disk to hibernate my Toshiba C640, but not restore it. By updating /etc/pm/config.d/00sleep_module and purging cryptsetup as per post on Ask Ubuntu , things started working well.
Although waking from hibernate Grub 2 looks like something is wrong as it is stuck
on background for few seconds. Maybe its just grub or large 4 GB ram snapshot
being loaded from disk. I will have to check.
Also, my LAN connection came back. I had serious doubts about it, since I had to
custom compile Atheros Fast Ethernet card module into Kernel.
I am using kernel 3.2.0-27-generic with Ubuntu 12.04 LTs on Toshiba Satellite C640 Hardware. Steps I have followed
sudo nano /etc/pm/config.d/00sleep_module
If you never touched this file OOTB it should be entirely commented. Please read it entirely. Add following line to end of file
Finally purge cryptsetup, I am not sure about this step, it may or may not help
sudo apt-get purge cryptsetup