Re: Authentication prompt when changing brightness

[David Wilson]

On Mon, Oct 7, 2019, at 5:18 PM, Vagrant Cascadian wrote:
> 
> You have to configure the udev rule in your system configuration; using
> the rules shipped with the brightnessctl package works:
> 
>   (udev-configuration (inherit config)
>                                       (rules (cons brightnessctl
>                                                                
> (udev-configuration-rules config)))))
> 

Thank you Vagrant, that led me down the correct path!  I was able to use your 
suggestion plus a udev config snippet I found in Pierre Neidhardt's Guix config 
to get backlight controls to work:

https://gitlab.com/ambrevar/dotfiles/blob/master/.config/guix/system/default.scm#L22-30

Regarding xfce4-power-manager's inability to control the backlight, I believe 
that its polkit policy file has not been picked up by the polkit-service such 
that it doesn't end up in /etc/polkit-1/actions where it belongs.  I'm looking 
into submitting a patch to correct this behavior so that future Guixers aren't 
confounded by that issue as I was.

Thanks!

David