xset -q intermittently reports wrong DPMS stats

[jippie]

###
### What I do
###

I have a simple script running in the background that every second checks the output of `xset -q` for the current monitor state. However, every couple days the output is erratic. The script runs as a regular unprivileged user. I am not sure if the error occures when the monitor is blanked or active.

To work around the problem I am restarting the xset command in the script until it comes back with proper output, yet unsure if that solves the problem though.

###
### What I expect (only showing last couple lines since the others are fine):
###

DPMS (Energy Star):
  Standby: 300 Suspend: 450 Off: 600
  DPMS is Enabled
  Monitor is On

###
### What I actually get
###

The problem is INTERMITTENT and I do not have a good method to reproduce it, apart from waiting/retrying ...

DPMS (Energy Star):
  Standby: 0 Suspend: 0 Off: 0
  DPMS is Disabled

Notice how:
- the last line "Monitor is ..." is missing;
- the numbers have changed from couple hundreds seconds to 0

###
### My environment
###

€ lsb_release -rd
Description: Ubuntu 14.04 LTS

€ apt-cache policy x11-xserver-utils
x11-xserver-utils:
  Installed: 7.7+2ubuntu1
  Candidate: 7.7+2ubuntu1
  Version table:
 *** 7.7+2ubuntu1 0
        500 http://nl.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

€ uname -a
Linux diablo 3.13.0-29-generic #53-Ubuntu SMP Wed Jun 4 21:00:20 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: x11-xserver-utils 7.7+2ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-29.53-generic 3.13.11.2
Uname: Linux 3.13.0-29-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
CurrentDesktop: KDE
Date: Fri Jul 4 16:30:08 2014
InstallationDate: Installed on 2013-08-13 (324 days ago)
InstallationMedia: Kubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
SourcePackage: x11-xserver-utils
UpgradeStatus: Upgraded to trusty on 2014-04-26 (69 days ago)

[jippie (jph4dotcom)]

I can reproduce the issue by playing a video using vlc (both mp4 and flv, probably other formats too).

€ vlc --version
VLC media player 2.1.4 Rincewind (revision 2.1.4-0-g2a072be)
VLC version 2.1.4 Rincewind (2.1.4-0-g2a072be)
Compiled by buildd on brownie.buildd (May 17 2014 14:52:46)
Compiler: gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)

[jippie (jph4dotcom)]

On second thought, I guess this may be by design.