Screen goes black after 20 minutes

[orestis]

Hello, I have Kubuntu 14.04 on laptop. The screen saver is disabled but still I get a black screen after 20 minutes. I search internet for two days but I could not find anything.

[kubicle]

The first thing to check, is the screen power management settings in SystemSettings>PowerManagement (separate tabs for AC connected, battery and low battery)

[orestis]

Yeah the screen saver is disabled

[kubicle]

Ok, so powermanagement is disabled in Systemsettings. Since you talked about "screen saver" I thought you meant you had disabled screen locker (in SystemSettings>Display>ScreenLock).

what does the command xset q report? (The relevant sections of the output are "Screen Saver" and "DPMS")

[orestis]

Keyboard Control:  auto repeat:  on    key click percent:  0    LED mask:  00000002
  XKB indicators:
    00: Caps Lock:   off    01: Num Lock:    on     02: Scroll Lock: off
    03: Compose:     off    04: Kana:        off    05: Sleep:       off
    06: Suspend:     off    07: Mute:        off    08: Misc:        off
    09: Mail:        off    10: Charging:    off    11: Shift Lock:  off
    12: Group 2:     off    13: Mouse Keys:  off
  auto repeat delay:  660    repeat rate:  25
  auto repeating keys:  00ffffffdffffbbf
                        fadfffefffedffff
                        9fffffffffffffff
                        fff7ffffffffffff
  bell percent:  50    bell pitch:  400    bell duration:  100
Pointer Control:
  acceleration:  20/10    threshold:  4
Screen Saver:
  prefer blanking:  yes    allow exposures:  yes
  timeout:  0    cycle:  600
Colors:
  default colormap:  0x20    BlackPixel:  0x0    WhitePixel:  0xffffff
Font Path:
  /usr/share/fonts/X11/misc,/usr/share/fonts/X11/Type1,built-ins,/home/orestis/.fonts
DPMS (Energy Star):
  Standby: 1200    Suspend: 1500    Off: 1800
  DPMS is Enabled
  Monitor is On

[kubicle]

DPMS (Energy Star):
  Standby: 1200    Suspend: 1500    Off: 1800
  DPMS is Enabled
  Monitor is On

Well that's odd, DPMS is still enabled and the standby timeout is set to 1200 seconds (20 minutes).

Here's a couple of things you can try:
1. Try enabling "turn off display" (in systemsettings>powermanagement) and then apply changes. After that, disable it again and apply changes. Is there any change to "xset q" output?
2. If that doesn't work, try running "xset -dpms" to turn of DPMS (you can also run "xset dpms 0 0 0" to change the timeouts to 0). This is for testing only at this point, the setting won't survive a reboot.

[orestis]

well I enable and disable everything and no it works. Thank you (y)