Xorg uses 4MiB on RTX 2070 Mobile, causes it not to power off completely

Hello everyone. I have finally got a hands on with Manjaro on my laptop. I love it so far. But one small thing keeps me from having the perfect experience.

I have an NVIDIA Optimus system on my laptop with Intel UHD630 & RTX 2070 Mobile combination. Since the 2070 is a Turing architecture card, it can powered off completely if it’s not in use. But mine does not because the Xorg process uses about 4 MiB of GPU memory and prevents NVIDIA GPU to fully turn off.

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 ...  On   | 00000000:01:00.0 Off |                  N/A |
| N/A   36C    P8     6W /  N/A |      5MiB /  7982MiB |      0%      Default |
|                               |                      |                  N/A |
| Processes:                                                                  |
|  GPU   GI   CI        PID   Type   Process name                  GPU Memory |
|        ID   ID                                                   Usage      |
|    0   N/A  N/A       536      G   /usr/lib/Xorg                       4MiB |

cat /proc/driver/nvidia/gpus/0000:01:00.0/power output:

Runtime D3 status:          Enabled (fine-grained)
Video Memory:               Active

GPU Hardware Support:
 Video Memory Self Refresh: Supported
 Video Memory Off:          Supported

Power Limits:
 Default:                   N/A milliwatts
 GPU Boost:                 N/A milliwatts

How can I stop Xorg using that 4 MiB of GPU memory and enjoy my fully-powered off GPU when not in use?

It’s a newly installed system so I haven’t installed/deleted/changed any driver or driver-related settings. I have only enabled nvidia-persistenced service as advised in Arch Wiki.

Thanks in advance.