unknown audio device dialog on resume from suspend

[Steve Magoun]

Sometimes when I resume from suspend, I get the "Unknown Audio Device" dialog that asks whether a device is headphones/microphone/headset. This happens sometimes when there are no audio devices plugged in, which seems like a bug.

To reproduce:
1) Suspend
2) Unplug any audio devices such as headphones or USB headsets
3) Resume

Expected results:
The machine resumes normally; there is no Unknown Audio Device dialog

Actual results:
The machine resumes normally. The Unknown Audio Device dialog appears onscreen when you resume.

alsa-info.sh output for my machine (Dell XPS 13) is attached

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity-settings-daemon 14.04.0+14.04.20140407-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-23.45-generic 3.13.8
Uname: Linux 3.13.0-23-generic x86_64
ApportVersion: 2.14.1-0ubuntu1
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Apr 8 16:55:47 2014
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-precise-amd64-20130203-1
EcryptfsInUse: Yes
InstallationDate: Installed on 2013-12-02 (126 days ago)
InstallationMedia: Ubuntu 12.04 "Precise" - Build amd64 LIVE Binary 20130203-13:50
SourcePackage: unity-settings-daemon
UpgradeStatus: Upgraded to trusty on 2014-02-12 (55 days ago)