I have the same model and I have made some progress with this question. At least my machine:
1) Suspended perfectly when using a USB stick installation of the 14.04.1
2) When I upgraded from 12.04 it refuses to suspend from the menu or when I close the lid
3) It won't suspend if I run sudo pm-suspend
4) However, it will suspend if I run as a root "echo mem > /sys/power/state". It also resumes perfectly
I will try to figure out how to get that relatively lower-level suspend to work with higher level tools.
EDITS: Figured it out, hope this helps
There is an offending script that makes pm-suspend fail. See: http://ubuntuforums.org/showthread.php?t=2240844
i.e. a thread that I started there to ask help and then ended up answering my own question.
Apologies for answering my own thread: after little digging through the logs (/var/log/pm-suspend.log) found out that /etc/pm/sleep.d/11_usb_s3 was the offending script and removing it solved the problem. For posteriority (for less technical users):
<p>sudo mv /etc/pm/sleep.d/11_usb_s3 ~ </p>
<p>This moves the file to your home directory. If this does not cure the problem you probably want to move it back to</p>
<p>sudo mv ~/11_usb_s3 /etc/pm/sleep.d/</p>
</blockquote>
Source: https://askubuntu.com/questions/39105...0-wont-suspend