psensor doesn't unbind Nvidia GPU and disabling power save features

[Salih]

Hello,

I am a laptop user with 5900HX and RTX3080 Mobile. Today I noticed that psensor keeps my dGPU awake. When I close psensor I become able to see "D3Cold" in the power state of the GPU. Similar to this "nvidia-smi" command wakes up the dGPU.

To repeat the problem:
- Install psensor. Set up start on boot.
- Select "On-Demand" from Nvidia Settings. (So dGPU should be enabled when requested)
- Restart.
- Run "cat /sys/bus/pci/devices/0000:01:00.0/power_state", output shows "D0" instead of "D3Cold"

Description: Ubuntu 20.04.3 LTS
Release: 20.04

psensor:
  Installed: 1.1.5-1.1ubuntu1
  Candidate: 1.1.5-1.1ubuntu1
  Version table:
 *** 1.1.5-1.1ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        100 /var/lib/dpkg/status

nvidia-smi output:
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 470.63.01 Driver Version: 470.63.01 CUDA Version: 11.4 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|===============================+======================+======================|
| 0 NVIDIA GeForce ... Off | 00000000:01:00.0 Off | N/A |
| N/A 45C P0 21W / N/A | 10MiB / 16125MiB | 0% Default |
| | | N/A |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=============================================================================|
| 0 N/A N/A 1319 G /usr/lib/xorg/Xorg 4MiB |
| 0 N/A N/A 2375 G /usr/lib/xorg/Xorg 4MiB |
+-----------------------------------------------------------------------------+