AF_BUS is not part of the mainline Linux kernel so it isn't really a backport but rather just a feature addition.
Phoronix: Linux Foundation Puts Out Linux 3.4 "LTSI" Kernel
From the Linux Foundation's Consumer Electronics Workgroup is a Linux 3.4 kernel that's part of their Long-Term Support Initiative. The LTSI Linux 3.4 kernel will be maintained for two years while back-porting some of the features of newer Linux kernel releases...
http://www.phoronix.com/vr.php?view=MTI4MDk
AF_BUS is not part of the mainline Linux kernel so it isn't really a backport but rather just a feature addition.
Haha does this mean Debian will finally move on from 3.2?
Good thing Ubuntu 12.04 is at 3.2. Don't they release new versions just a bit too often? I mean do they really test these things before pushing a release? How many hours of testing does the kernel get?