[LightDM] change volume when greeter appears

[Vojtěch Polášek]

     Hello all,

my name is Vojta and I am working on a Linux distribution for visually 
impaired and blind users. It is currently based on Fedora.

As the distribution needs to be accessible, I am configuring LightDM GTK 
greeter to start the Orca screenreader when login screen appears. 
However, sometimes it happens that the audio gets muted or volume is 
lowered. This is probably not related to Lightdm but I would like to 
solve it by running a script which would unmute the sound card and set 
some reasonable volume.

Therefore I am asking: Is there any way how to run shell commands in 
scope of the lightdm user when the login screen appears and before the 
screenreader is started?

Thank you,

Vojta