I want to unlock/wakeup/..., a kiosk system from power-saving/locked-state when the touchscreen is pressed. The touchscreen is the only input device on this machine. (For testing purposes I attached an USB keyboard.)
I installed Gnome, GDM, etc. using NixOS 25.05 (not sure if relevant).
services.xserver.displayManager.gdm = {
enable = true;
wayland = true;
};
services.xserver.desktopManager.gnome.enable = true;
services.gnome.core-apps.enable = false;
environment.gnome.excludePackages = (
with pkgs;
[
gnome-tour
gnome-backgrounds
]
);
services.libinput.enable = true; # Tried different values here...
environment.systemPackages = with pkgs; [libinput usbutils pciutils]; # For debugging...
Situation: I'm in the GDM lockscreen and wait half a minute or so. The display turns black. When this happens, I see the following in the SSH session ...
$ dbus-monitor
signal time=1749564736.400317 sender=org.freedesktop.DBus -> destination=:1.83 serial=2 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameAcquired
string ":1.83"
signal time=1749564736.400676 sender=org.freedesktop.DBus -> destination=:1.83 serial=4 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameLost
string ":1.83"
signal time=1749564763.491195 sender=:1.10 -> destination=:1.40 serial=477 path=/org/gnome/Mutter/IdleMonitor/Core; interface=org.gnome.Mutter.IdleMonitor; member=WatchFired
uint32 7
method call time=1749564763.491998 sender=:1.40 -> destination=:1.10 serial=69 path=/org/gnome/Mutter/IdleMonitor/Core; interface=org.gnome.Mutter.IdleMonitor; member=AddUserActiveWatch
method call time=1749564763.492312 sender=:1.40 -> destination=:1.10 serial=70 path=/org/gnome/Mutter/DisplayConfig; interface=org.freedesktop.DBus.Properties; member=Set
string "org.gnome.Mutter.DisplayConfig"
string "PowerSaveMode"
variant int32 3
method call time=1749564763.493924 sender=:1.10 -> destination=org.freedesktop.DBus serial=478 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetNameOwner
string ":1.40"
method return time=1749564763.494359 sender=org.freedesktop.DBus -> destination=:1.10 serial=442 reply_serial=478
string ":1.40"
method return time=1749564763.494633 sender=:1.10 -> destination=:1.40 serial=479 reply_serial=69
uint32 9
method return time=1749564764.038010 sender=:1.10 -> destination=:1.40 serial=480 reply_serial=70
signal time=1749564764.038385 sender=:1.10 -> destination=(null destination) serial=481 path=/org/gnome/Mutter/DisplayConfig; interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
string "org.gnome.Mutter.DisplayConfig"
array [
dict entry(
string "PowerSaveMode"
variant int32 3
)
]
array [
]
Now, after pressing ESC on the keyboard, I see ...
$ libinput debug-events
-event3 KEYBOARD_KEY +0.000s *** (-1) pressed
event3 KEYBOARD_KEY +0.120s *** (-1) released
... and ...
$ dbus-monitor
signal time=1749565006.666054 sender=:1.10 -> destination=:1.40 serial=482 path=/org/gnome/Mutter/IdleMonitor/Core; interface=org.gnome.Mutter.IdleMonitor; member=WatchFired
uint32 9
method call time=1749565006.667388 sender=:1.40 -> destination=:1.10 serial=71 path=/org/gnome/Mutter/DisplayConfig; interface=org.freedesktop.DBus.Properties; member=Set
string "org.gnome.Mutter.DisplayConfig"
string "PowerSaveMode"
variant int32 0
method return time=1749565006.693257 sender=:1.10 -> destination=:1.40 serial=483 reply_serial=71
signal time=1749565006.696749 sender=:1.10 -> destination=(null destination) serial=484 path=/org/gnome/Mutter/DisplayConfig; interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
string "org.gnome.Mutter.DisplayConfig"
array [
dict entry(
string "PowerSaveMode"
variant int32 0
)
]
array [
]
The keypress seems to emit a dbus event so that PowerSaveMode is changed from 3 to 0. The display turns on when this happens. This is the behavior I want for the touchscreen, too.
However, when using the touchscreen, I see ...
$ libinput debug-events
-event1 TOUCH_DOWN +87.149s 0 (0) 47.88/57.69 (126.53/95.47mm)
event1 TOUCH_FRAME +87.149s
event1 TOUCH_UP +87.242s 0 (0)
event1 TOUCH_FRAME +87.242s
event1 TOUCH_DOWN +90.434s 0 (0) 58.89/42.45 (155.61/70.25mm)
event1 TOUCH_FRAME +90.434s
event1 TOUCH_MOTION +91.188s 0 (0) 58.43/42.64 (154.40/70.57mm)
event1 TOUCH_FRAME +91.188s
event1 TOUCH_UP +92.771s 0 (0)
event1 TOUCH_FRAME +92.771s
... but no dbus event is emitted. The display stays black.
What could help me pinpoint the issue is to better understand how a libinput event is processed by Gnome, GDM, Mutter, Clutter, ..., but I just can't get to the core issue even after reading quite a lot documentation.
[kiosk@kiosk:~]$ uname -a
Linux kiosk 6.12.32 #1-NixOS SMP PREEMPT_DYNAMIC Wed Jun 4 12:43:54 UTC 2025 x86_64 GNU/Linux
[kiosk@kiosk:~]$ sudo libinput list-devices
Device: Power Button
Kernel: /dev/input/event6
Group: 1
Seat: seat0, default
Capabilities: keyboard
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: n/a
Middle emulation: n/a
Calibration: n/a
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Device: eGalax Inc. eGalaxTouch P81X32 2748 v02_S2 k4.18.203 Mouse
Kernel: /dev/input/event2
Group: 2
Seat: seat0, default
Size: 256x164mm
Capabilities: pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: disabled
Calibration: identity matrix
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Device: eGalax Inc. eGalaxTouch P81X32 2748 v02_S2 k4.18.203
Kernel: /dev/input/event1
Group: 2
Seat: seat0, default
Size: 264x165mm
Capabilities: touch
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: n/a
Middle emulation: n/a
Calibration: identity matrix
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Device: SteelSeries SteelSeries Apex M500 Gaming Keyboard
Kernel: /dev/input/event3
Group: 3
Seat: seat0, default
Capabilities: keyboard
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: n/a
Middle emulation: n/a
Calibration: n/a
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Device: SteelSeries SteelSeries Apex M500 Gaming Keyboard
Kernel: /dev/input/event4
Group: 3
Seat: seat0, default
Capabilities: keyboard pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: disabled
Middle emulation: n/a
Calibration: n/a
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Device: SteelSeries SteelSeries Apex M500 Gaming Keyboard
Kernel: /dev/input/event5
Group: 3
Seat: seat0, default
Capabilities: keyboard
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: n/a
Middle emulation: n/a
Calibration: n/a
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Device: AT Translated Set 2 keyboard
Kernel: /dev/input/event0
Group: 4
Seat: seat0, default
Capabilities: keyboard
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: n/a
Middle emulation: n/a
Calibration: n/a
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Device: ImExPS/2 Generic Explorer Mouse
Kernel: /dev/input/event7
Group: 5
Seat: seat0, default
Capabilities: pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: disabled
Calibration: n/a
Scroll methods: button
Click methods: none
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: flat *adaptive custom
Rotation: 0.0
[kiosk@kiosk:~]$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 009 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 009 Device 002: ID 0eef:c002 D-WAV Scientific Co., Ltd eGalaxTouch P81X32 2748 v02_S2 k4.18.203
Bus 009 Device 003: ID 1038:1607 SteelSeries ApS SteelSeries Apex M500 Gaming Keyboard
Bus 010 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
$ [kiosk@kiosk:~]$ busctl
NAME PID PROCESS USER CONNECTION UNIT >
:1.0 411 systemd-oomd systemd-oom :1.0 systemd-oomd.service >
:1.1 714 systemd-machine root :1.1 systemd-machined.service >
:1.10 832 gdm root :1.10 display-manager.service >
:1.101 2222 busctl kiosk :1.101 session-6.scope >
:1.18 927 rtkit-daemon root :1.18 rtkit-daemon.service >
:1.19 952 .colord-wrapped colord :1.19 colord.service >
:1.2 1 systemd root :1.2 init.scope >
:1.24 994 upowerd root :1.24 upower.service >
:1.3 444 systemd-timesyn systemd-timesync :1.3 systemd-timesyncd.service >
:1.38 1157 power-profiles- root :1.38 power-profiles-daemon.servi>
:1.4 738 systemd-logind root :1.4 systemd-logind.service >
:1.5 439 systemd-resolve systemd-resolve :1.5 systemd-resolved.service >
:1.50 1295 gdm-session-wor root :1.50 session-2.scope >
:1.54 1311 systemd kiosk :1.54 user@1000.service >
:1.55 1325 .gnome-keyring- kiosk :1.55 session-2.scope >
:1.56 1333 gdm-wayland-ses kiosk :1.56 session-2.scope >
:1.57 1373 .gnome-session- kiosk :1.57 user@1000.service >
:1.58 1399 .gnome-shell-wr kiosk :1.58 user@1000.service >
:1.6 709 avahi-daemon avahi :1.6 avahi-daemon.service >
:1.60 1492 .org.gnome.Shel kiosk :1.60 user@1000.service >
:1.61 1506 .gsd-sharing-wr kiosk :1.61 user@1000.service >
:1.63 1501 .gsd-print-noti kiosk :1.63 user@1000.service >
:1.64 1510 .gsd-usb-protec kiosk :1.64 user@1000.service >
:1.66 1504 .gsd-rfkill-wra kiosk :1.66 user@1000.service >
:1.68 1625 .gsd-printer-wr kiosk :1.68 user@1000.service >
:1.69 1631 .org.gnome.Scre kiosk :1.69 user@1000.service >
:1.7 730 accounts-daemon root :1.7 accounts-daemon.service >
:1.70 1652 .gvfs-udisks2-v kiosk :1.70 user@1000.service >
:1.71 1663 udisksd root :1.71 udisks2.service >
:1.73 1697 .evolution-addr kiosk :1.73 user@1000.service >
:1.74 1399 .gnome-shell-wr kiosk :1.74 user@1000.service >
:1.75 1735 pipewire kiosk :1.75 user@1000.service >
:1.76 1736 wireplumber kiosk :1.76 user@1000.service >
:1.77 1737 pipewire-pulse kiosk :1.77 user@1000.service >
:1.78 1499 .gsd-media-keys kiosk :1.78 user@1000.service >
:1.79 1500 .gsd-power-wrap kiosk :1.79 user@1000.service >
:1.8 756 polkitd polkituser :1.8 polkit.service >
:1.80 1498 .gsd-keyboard-w kiosk :1.80 user@1000.service >
:1.82 1736 wireplumber kiosk :1.82 user@1000.service >
:1.83 1736 wireplumber kiosk :1.83 user@1000.service >
:1.85 1866 .xdg-desktop-po kiosk :1.85 user@1000.service >
:1.86 1852 .xdg-desktop-po kiosk :1.86 user@1000.service >
:1.87 1885 .xdg-desktop-po kiosk :1.87 user@1000.service >
:1.88 1852 .xdg-desktop-po kiosk :1.88 user@1000.service >
:1.9 818 systemd-network systemd-network :1.9 systemd-networkd.service >
net.hadess.PowerProfiles 1157 power-profiles- root :1.38 power-profiles-daemon.servi>
org.freedesktop.Accounts 730 accounts-daemon root :1.7 accounts-daemon.service >
org.freedesktop.Avahi 709 avahi-daemon avahi :1.6 avahi-daemon.service >
org.freedesktop.ColorManager 952 .colord-wrapped colord :1.19 colord.service >
org.freedesktop.DBus 1 systemd root - init.scope >
org.freedesktop.GeoClue2 - - - (activatable) - >
org.freedesktop.PolicyKit1 756 polkitd polkituser :1.8 polkit.service >
org.freedesktop.RealtimeKit1 927 rtkit-daemon root :1.18 rtkit-daemon.service >
org.freedesktop.UDisks2 1663 udisksd root :1.71 udisks2.service >
org.freedesktop.UPower 994 upowerd root :1.24 upower.service >
org.freedesktop.UPower.PowerProfiles 1157 power-profiles- root :1.38 power-profiles-daemon.servi>
org.freedesktop.bolt - - - (activatable) - >
org.freedesktop.home1 - - - (activatable) - >
org.freedesktop.hostname1 - - - (activatable) - >
org.freedesktop.import1 - - - (activatable) - >
org.freedesktop.locale1 - - - (activatable) - >
org.freedesktop.login1 738 systemd-logind root :1.4 systemd-logind.service >
org.freedesktop.machine1 714 systemd-machine root :1.1 systemd-machined.service >
org.freedesktop.network1 818 systemd-network systemd-network :1.9 systemd-networkd.service >
org.freedesktop.oom1 411 systemd-oomd systemd-oom :1.0 systemd-oomd.service >
org.freedesktop.portable1 - - - (activatable) - >
org.freedesktop.resolve1 439 systemd-resolve systemd-resolve :1.5 systemd-resolved.service >
org.freedesktop.systemd1 1 systemd root :1.2 init.scope >
org.freedesktop.timedate1 - - - (activatable) - >
org.freedesktop.timesync1 444 systemd-timesyn systemd-timesync :1.3 systemd-timesyncd.service >
org.gnome.DisplayManager 832 gdm root :1.10 display-manager.service >
org.gnome.RemoteDesktop.Configuration - - - (activatable) - >
Firstly, I really appreciate the way of asking questions, most of the question on this platform is kind of incomplete, and even if I know the answer then I won't bother to answer them because they haven't put enough effort into asking then they do not deserve to get answered.
Now let's understand what is wrong in your scenario.
On GNOME GDM (Wayland), direct touchscreen interaction does not wake the screen from the lock state, only tracked by Mutter’s idle/power-saving behavior. In your dbus-monitor logs, you observed:
Mutter’s IdleMonitor triggers PowerSaveMode = 3 (screen off).
Touch input does nothing, since GDM doesn’t handle wake-up events from touchscreen presses.
As of now, it appears this is expected behavior within GNOME/GDM. The compositor won't listen to touch events to re-awaken the screen, it only responds to keyboard, mouse, or other connected input devices.
1. Install Prerequisites:
Ensure your user has permission to write /dev/uinput, either by being in the input group or via udev rules (tools like Steam do this automatically)
sudo apt update
sudo apt install python3 python3-pip libudev-dev
sudo pip3 install python-uinput evdev
sudo modprobe uinput
There is a little workaround is that we can simulate Input via Script
2. Python Script: touch_wake.py
#!/usr/bin/env python3
import time
from evdev import InputDevice, categorize, ecodes
from evdev import UInput, AbsInfo
# Path to your touchscreen device (adjust with `ls /dev/input/by-id/`)
TOUCH_DEV = '/dev/input/event0'
# 1) Open touchscreen
ts = InputDevice(TOUCH_DEV)
# 2) Create virtual keyboard to simulate 'KEY_ENTER' or pointer movement
cap = {ecodes.EV_KEY: [ecodes.KEY_ENTER], ecodes.EV_REL: [ecodes.REL_X, ecodes.REL_Y]}
ui = UInput(cap, name="touch-wake-sim", version=0x3)
print(f"Watching {ts.path} for touch events…")
try:
for event in ts.read_loop():
if event.type == ecodes.EV_KEY and event.code == ecodes.BTN_TOUCH and event.value == 1:
# Simulate wake: pointer move + ENTER press
ui.write(ecodes.EV_REL, ecodes.REL_X, 0)
ui.write(ecodes.EV_REL, ecodes.REL_Y, 0)
ui.write(ecodes.EV_KEY, ecodes.KEY_ENTER, 1)
ui.write(ecodes.EV_KEY, ecodes.KEY_ENTER, 0)
ui.syn()
print("Touch detected → wake simulated.")
time.sleep(0.5)
except KeyboardInterrupt:
pass
finally:
ui.close()
ts.close()
How it works:
Listens for BTN_TOUCH events from your touchscreen.
When touched, emits a zero-distance mouse move + KEY_ENTER, which GDM recognizes and wakes the screen.
3. Find Your Touchscreen Device and update TOUCH_DEV with the correct path:
ls /dev/input/by-id/*
3. Run and Test:
Now lock your device and touch it, it should wake it up.
sudo python3 touch_wake.py
Let me know if you have any more questions.
PS> This works for GNOME/GDM (Wayland), but not all devices, like Lenovo X11 / X11 Yoga.