suspend/resume failure after upgrading to vivid HWE stack on 14.04

[Matthias Andree]

I upgraded X/Org and the kernel to the vivid HWE stack, on radeon hardware, and the system failed to suspend properly, and could not come back online - I had to power cycle to get it back.

With the stock trusty kernel + X/Org, things used to work properly.

ProblemType: KernelOops
DistroRelease: Ubuntu 14.04
Package: linux-image-3.19.0-28-generic 3.19.0-28.30~14.04.1
ProcVersionSignature: Ubuntu 3.19.0-28.30~14.04.1-generic 3.19.8-ckt5
Uname: Linux 3.19.0-28-generic x86_64
Annotation: This occured during a previous suspend and prevented it from resuming properly.
ApportVersion: 2.14.1-0ubuntu3.13
Architecture: amd64
Date: Mon Sep 21 07:14:54 2015
ExecutablePath: /usr/share/apport/apportcheckresume
ExecutableTimestamp: 1440703637
Failure: suspend/resume
InterpreterPath: /usr/bin/python3.4
ProcCmdline: /usr/bin/python3 /usr/share/apport/apportcheckresume
ProcCwd: /
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
SourcePackage: linux-lts-vivid
Title: suspend/resume failure
UpgradeStatus: Upgraded to trusty on 2014-08-29 (387 days ago)
UserGroups:

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[penalvch (penalvch)]

Matthias Andree, thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:
apport-collect 1497875

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]