In terms of the kernel version I don't know exactly as I do not suspend very often, but I never saw the problem before upgrade from Utopic. I have just tried booting into a live Utopic image which was the release candidate on 17th Oct 14 and uname shows 3.16.0-22 and it suspends ok there. Perhaps it is not purely a kernel issue.
** Changed in: xorg (Ubuntu) Status: Incomplete => New -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1415958 Title: Laptop + external display does not suspend on lid close To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1415958/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp