The output here lets us know that systemd is running the service file and starting the script just fine. The echoed GPU temperature is making it to the journal, but the gpuTemp variable isn't being updated (staying at 0) because of a problem executing nvidia-settings. Specifically, it wants a display: "The control display is undefined".
Although if echo DISPLAY in your terminal gives you a different value, use that. There's a possibility that that will just push one error further down the line, but it's something to try.
Alternatively/additionally, you could try changing the User= line to your own username to see if it picks up the environment your manual executions work with.
● fan.service - NVIDIA Fan Control on Wayland Arch Loaded: loaded (/etc/systemd/system/fan.service; enabled; preset: disabled) Active: active (running) since Tue 2023-10-17 18:29:39 EDT; 4s ago Main PID: 2691 (sudo) Tasks: 3 (limit: 38401) Memory: 5.9M CPU: 39ms CGroup: /system.slice/fan.service ├─2691 sudo /home/rob/Documents/fan.sh ├─2692 /bin/bash /home/rob/Documents/fan.sh └─2699 sleep 5 Oct 17 18:29:39 robpc systemd[1]: Started NVIDIA Fan Control on Wayland Arch. Oct 17 18:29:39 robpc sudo[2691]: root : PWD=/ ; USER=root ; COMMAND=/home/rob/Documents/fan.sh Oct 17 18:29:39 robpc sudo[2691]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=0) Oct 17 18:29:39 robpc sudo[2694]: ERROR: The control display is undefined; please run `nvidia-settings --help` for usage information. Oct 17 18:29:39 robpc sudo[2692]: Current GPU temperature: 0 Oct 17 18:29:39 robpc sudo[2698]: ERROR: The control display is undefined; please run `nvidia-settings --help` for usage information.The output here lets us know that systemd is running the service file and starting the script just fine. The echoed GPU temperature is making it to the journal, but the
gpuTempvariable isn't being updated (staying at0) because of a problem executingnvidia-settings. Specifically, it wants a display: "The control display is undefined".You could add a line to the service file:—
Although if
echo DISPLAYin your terminal gives you a different value, use that. There's a possibility that that will just push one error further down the line, but it's something to try.Alternatively/additionally, you could try changing the
User=line to your own username to see if it picks up the environment your manual executions work with.You aren't the only one to run into problems trying to automate
nvidia-settings. You might end up needing to track down anXauthorityfile or use the display manager's initialisation options.