XFCE - DPMS settings are not applied

[damix9]

$ inxi -SMG
System:
  Host: ryzen Kernel: 5.10.198-std-def-alt1 arch: x86_64 bits: 64
    Desktop: Xfce v: 4.18.1 Distro: Simply Linux 10.4 (Captain Finn)
Machine:
  Type: Desktop Mobo: Micro-Star model: B350 PC MATE (MS-7A34) v: 2.0
    serial: <superuser required> UEFI: American Megatrends v: A.J0
    date: 01/23/2019
Graphics:
  Device-1: AMD Raven Ridge [Radeon Vega Series / Radeon Mobile Series]
    driver: amdgpu v: kernel
  Display: x11 server: X.Org v: 1.20.14 driver: X: loaded: amdgpu
    unloaded: fbdev,modesetting,vesa dri: radeonsi gpu: amdgpu
    resolution: 1920x1080~60Hz
  API: OpenGL v: 4.6 vendor: amd mesa v: 23.1.9 renderer: AMD Radeon Vega 8
    Graphics (raven LLVM 15.0.7 DRM 3.40 5.10.198-std-def-alt1)

In xfce4-screensaver-preferences I set it up this way

Expected behavior - the monitor (connected by HDMI) is off after 20 minutes.
Actual behavior - the screen is always on.

If I reboot, the screen starts turning off after 20 minutes of inactivity. If I enter suspend to RAM and wake the PC up again, or edit any settings in screensaver, the screen never turns off before reboot.

 

[Fanboi]

I don't run a Display Manager, I don't have a screensaver installed. That said...

DPMS: xset +dpms to enable and xset dpms <seconds to idle> 0 <time until off> The three args are "idle", "suspend" and "off". I have no idea what suspend is for, so it's off. My monitor (Dell) has built-in power saving anyway.

...Not sure if things like a DM or screensaver will mess with this. If the above doesn't work across suspends, maybe try uninstalling the screensaver and restarting your xsession and then trying again as you mentioned editing screensaver settings. You don't need a screensaver if all you want is a blank screen that'll idle, then poweroff.

Everything works fine for me

 

[damix9]

I don't have a screensaver installed

So, how do you save your screen from wearing out?

My monitor (Dell) has built-in power saving anyway.

How it works? It goes blank when image is not updated for some time?

I have no idea what suspend is for

To sleep without PC coolers and leds. I use PC in my bedroom, so I can't keep it on all the time.

You don't need a screensaver if all you want is a blank screen that'll idle, then poweroff.

Yeah, Power manager also can do it. But it's settings are ignored the same way.

Some new info: if I wait some hours after suspend-resume, DPMS can start working as expected. It happened at least once.

DPMS: xset +dpms to enable and xset dpms <seconds to idle> 0 <time until off>

You mean you recommend to check if it works to use DPMS manually?

Is it a bug? Mat be I should report it to my distro's maintainers?

$ xset q
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:  500    repeat rate:  20
  auto repeating keys:  00ffffffdffffbbf
                        fadfffefffedffff
                        9fffffffffffffff
                        fff7ffffffffffff
  bell percent:  0    bell pitch:  400    bell duration:  100
Pointer Control:
  acceleration:  2/1    threshold:  4
Screen Saver:
  prefer blanking:  no    allow exposures:  no
  timeout:  1200    cycle:  1200
Colors:
  default colormap:  0x20    BlackPixel:  0x0    WhitePixel:  0xffffff
Font Path:
  catalogue:/etc/X11/fontpath.d,built-ins
DPMS (Energy Star):
  Standby: 0    Suspend: 0    Off: 0
  DPMS is Enabled
  Monitor is On

 

[Fanboi]

So, how do you save your screen from wearing out?
How it works? It goes blank when image is not updated for some time?

My monitor goes onto standby the moment the screen blanks (no HDMI signal). IDK what other monitors are like, never owned anything fancy, but the Dell one of mine is brilliant on power saving.

To sleep without PC coolers and leds. I use PC in my bedroom, so I can't keep it on all the time.

Ah, so same as suspend. Thought it was just for the monitor, lol.

Yeah, Power manager also can do it. But it's settings are ignored the same way.
Some new info: if I wait some hours after suspend-resume, DPMS can start working as expected. It happened at least once.
Is it a bug? Mat be I should report it to my distro's maintainers?

Sounds like a bug. IDK if it's the distro though. You'd have to find out if it's the screensaver or Xorg or something more exotic, then see if the distro compiles the packages themselves or just grabs prebuilds. If they're just (re)packaging binaries, it's likely an upstream issue. You'd have to check with your distro, it'll usually be in their site's packaging/maintainers section.

You mean you recommend to check if it works to use DPMS manually?

Yup. Best way to test if things work is to avoid the GUI because you can't see what's happening underneath, so it's hard to debug (that's why I cannot take Windows, lol)

$ xset q
DPMS (Energy Star):
Standby: 0    Suspend: 0    Off: 0
DPMS is Enabled
Monitor is On

So all power saving modes are disabled based on that output, but DPMS is enabled. First try xset dpms 1200 0 2100 (or whatever your preferred behaviour is). Then if that's overwritten, I would definitely try uninstalling the screensaver. It shouldn't be a dependency for any other components. If that works, then you're good to go. I'd suggested a reboot after removing the screensaver package just in case.