Maybe it depends on the browser and the operating system, but I can tell you that using Firefox 32.0.1 in Windows 7 64-bit, whenever a sound is played by the Flash plugin, it prevents the display from turning off. This can be seen by running powercfg -requests
while a sound is playing (run cmd.exe
as an administrator before typing the command):
C:\Windows\system32>powercfg -requests
DISPLAY:
[PROCESS] \Device\HarddiskVolume1\Program Files (x86)\Mozilla Firefox\firefox.exe
SYSTEM:
[DRIVER] IDT High Definition Audio CODEC (HDAUDIO\FUNC_01&VEN_111D&DEV_76DF&SUBSYS_1028053F&REV_1002\4&313bea4d&0&0001)
An audio stream is currently in use.
AWAYMODE:
None.
Two things are shown in this example output. It's the firefox.exe process under DISPLAY:
that is preventing the display from turning off. The sound playing through the audio driver prevents the system from going to sleep.
I consider Firefox's behavior undesirable, as I seldom watch long YouTube videos, and I don't want every message notification from Facebook Chat to turn my screen on. The behavior can be changed by using a powercfg -REQUESTSOVERRIDE
command, like this:
powercfg -REQUESTSOVERRIDE process "\Device\HarddiskVolume1\Program Files (x86)\Mozilla Firefox\firefox.exe" display
Type powercfg /?
for help.
Are you asking what your options are instead of changing the settings to never dim and/or turn the monitor off? – Mark – 2010-01-22T19:25:33.387
Yes, as I said I like the power saving stuff, so when I don't use the computer, it should turn off the monitor. But full screen video is a different story. It should detect if a full screen video is playing and it shouldn't turn off the monitor then. – Tom – 2010-01-22T19:34:14.303
But this is how it should work. Surely, lots of people watch full screen videos, it's a pretty common scenario, so there must be a better solution than simply disabling power saving altogether. – Tom – 2010-01-22T19:39:25.290