The Power Management module has an options named Screen Energy Saving (which is meant to put the screen into power saving mode when not in use) and Dim Screen (which is supposed to dim the screen after inactivity). However, neither of them work reliably. Even with the Screen Energy Saving option enabled, the screens will usually not go into power saving mode. I have observed this on three computers (one laptop, two desktops) with a total of 5 monitors. For reasons I don't understand, sometimes it works -- usually on my laptop screen, but sometimes on screens attached to the desktops. However, in the vast majority of cases, nothing happens and the screen stays on. The Dim screen option on my laptop is also unreliable. Sometimes it does not dim. Sometimes it does. Sometimes, after dimming or putting the screen into energy saving mode, the laptop screen will not undim. I haven't figured out a pattern to any of this. These features worked before I upgraded to Kubuntu 15.05 and KDE 5. Reproducible: Always
Really, no one else has this problem? FWIW, it's not a hardware problem. If I run: sudo sh -c 'vbetool dpms off; read ans; vbetool dpms on' Then the screen turns off and then turns back on when I hit enter. (See http://askubuntu.com/questions/62858/turn-off-monitor-using-command-line ) So, there must be a problem in some higher level piece of software .
I also have this problem. Energy saving settings are ignored when AC is attached. Though my settings specify the screen should dim after 5 minutes and the laptop should go to sleep after 15 minutes, neither happen; the screen stays at full power. Energy Saving seems to work fine when on battery.
Currently, I cannot get my monitor backlight to go out. xset dpms force off merely blanks the screen Turning on the kscreensaver always reenables the screen, and no longer ever lets it go into power save. I now have to resort to physically turning my monitor off and on. This is highly irritating.
@John Can you check whether some application is blocking power management when AC is plugged in, for whatever reason? @Nick You mean when the lock screen automatically kicks in the screen turns on again?
I mean: sleep 5; xset dpms force off; # then go click the lock sceen button The screenlock comes on. after 5 seconds it goes blank, and then a second later the screen turns back on w/the login screen. Also, if I just lock the screen and go away, it no longer ever goes into power save mode and turns off the screen--it will go blank, but the backlight stays on all night.
I have the same problem John describes. I am using KDE 5.8 on a pretty vanilla Arch install on a Gen 1 Lenovo X1 Carbon, with the 4.7.6.-1-ARCH kernel. The power management settings work fine on battery mode, but suspend does not work on AC. On AC it will dim and turn off the display when configured to do so, but it will never suspend. I've tried disabling the display features and various combinations thereof and nothing makes any difference. I am not running any different programs when the AC is plugged in; in fact I can reproduce the issue on a brand new test account which is not running any programs on startup. As a workaround I'm using xautolock to invoke systemd suspend, which works fine. I do think there is likely an issue in KDE here and would appreciate suggestions for how to troubleshoot further.
(In reply to Kai Uwe Broulik from comment #4) > @John Can you check whether some application is blocking power management > when AC is plugged in, for whatever reason? How I can list applications, which are blocking power management?
(In reply to Ralf HArtmann from comment #7) > (In reply to Kai Uwe Broulik from comment #4) > > @John Can you check whether some application is blocking power management > > when AC is plugged in, for whatever reason? > > How I can list applications, which are blocking power management? Click on the "Battery and Brightness" system tray item. If any apps are blocking power management, they'll be listed there. Let us know what you find!
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This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!