Nvidia-smi problem

The system:
Distributor ID: Kali
Description: Kali GNU/Linux Rolling
Release: 2019.4
Codename: kali-rolling

The GPU is 820m hybrid i.e optimus so I have installed legacy drivers 390.xx as seen in the output below.

The drivers were installed using the commands
apt-get install nvidia-legacy-390xx-driver
apt-get install nvidia-legacy-390xx-smi
apt-get install nvidia-legacy-390xx-opencl-icd
I have disabled nouveau

Now coming to the question, as mentioned in kali linux here https://www.kali.org/docs/general-use/install-nvidia-drivers-on-kali-linux/
the output of nvidia-smi is different since my Pwr is N/A so what could be the possible problem.

output of nvidia-smi
| NVIDIA-SMI 390.132 Driver Version: 390.132 |
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
| 0 GeForce 820M Off | 00000000:09:00.0 N/A | N/A |
| N/A 54C P0 N/A / N/A | 0MiB / 1985MiB | N/A Default |

| Processes: GPU Memory |
| GPU PID Type Process name Usage |
| 0 Not Supported |

Power management and other things are not supported on most low end gpus. So just ignore the ‘N/A’ and ‘Not supported’ entries.
Since you have an optimus notebook, you’ll have to set it up to use PRIME: