If when running vcgencmd on a raspberry pi you get VCHI initialization failed then you need to add the video group to your user. The vcgencmd tool requires you have this group role so without it, it will give VCHI initialization failed.
To add the user group to your user you can run:
sudo usermod -aG video <username>
Where <username> is the user you want to run the vcgencmd command with. This command adds the video group to the the user you specify.
Once you have ran the command any new logins will run the command successfully. Logging out and back into the pi will let you use the command.
Why this problem occurs
This issue happens when you try and use the vcgencmd command with a user that isn’t a member of the video group. This typically happens when you create a new user for the raspberry pi and don’t give it the same groups that the pi user has.
The solution above fixes this by adding the correct video group to the created user.