DPMS disabled for external monitor even when "put display to sleep" is enabled

[cryobry]

Expected behaviour

External HDMI display goes to sleep after 10 minutes

Actual behaviour

Display does not go to sleep

Steps to reproduce the behaviour

In mate-power-manager:

On AC Power: Put display to sleep when inactive for: 10 minutes When laptop lid is closed: Do nothing

MATE general version

1.22.1

Package version

mate-power-manager-1.22.1-1.fc30.rpm

Linux Distribution

Fedora

Additional info

systemd-inhibit WHO UID USER PID COMM WHAT WHY MODE ModemManager 0 root 1249 ModemManager sleep ModemManager needs to reset devices delay NetworkManager 0 root 1334 NetworkManager sleep NetworkManager needs to turn off networks delay UPower 0 root 2172 upowerd sleep Pause device polling delay bryan 1000 bryan 1994 mate-power-mana handle-power-key:handle-suspend-key:handle-lid-switch Mate power manager handles these events block 4 inhibitors listed.

Mate-screensaver kicks in fine after 15 minutes of inactivity.

Thinkpad T480s

[cryobry]

>xset q
Keyboard Control:
  auto repeat:  on    key click percent:  0    LED mask:  00000000
  XKB indicators:
    00: Caps Lock:   off    01: Num Lock:    off    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:  30
  auto repeating keys:  00ffffffdffffbbf
                        fadfffefffedffff
                        9fffffffffffffff
                        fff7ffffffffffff
  bell percent:  50    bell pitch:  400    bell duration:  100
Pointer Control:
  acceleration:  2/1    threshold:  4
Screen Saver:
  prefer blanking:  yes    allow exposures:  yes
  timeout:  0    cycle:  0
Colors:
  default colormap:  0x22    BlackPixel:  0x0    WhitePixel:  0xffffff
Font Path:
  catalogue:/etc/X11/fontpath.d,built-ins
DPMS (Energy Star):
  Standby: 0    Suspend: 0    Off: 0
  DPMS is Disabled