New comment by chrysos349 on void-packages repository

https://github.com/void-linux/void-packages/issues/48876#issuecomment-1960368147

Comment:
In my case, `gdm` behaves the same. So what? Log in, and THEN change the brightness.

I'm not sure this is a bug. 

Of course, if you insist on being able to change the brightness BEFORE logging in, run this command, and restart.

``` bash
$ sudo chsh -s /bin/bash gdm
```

P.S. `pkexec` complains, because by default, `gdm` user has `/sbin/nologin` as its shell (run `grep gdm /etc/passwd` to confirm), which is not in `/etc/shells`. the command above changes the default shell of `gdm` user to `/bin/bash`.