Dear Maintainer,

   * What led up to the situation?

We image a lot of Debian machines that are used for videoconferencing and we want to activate the input / output of the sound after imaging. We have some machines (Dell OptiPlex 745) that do not have an available Pulseaudio input port unless a microphone is plugged in. So when opening the GNOME sound control without the microphone plugged in, the volume bar and mute button are greyed out and inaccessible. There is also no device listed that can be chosen. Everything good so far, this makes sense. When I plug in the microphone in the line-in while the GNOME sound control is still open, a new line-in device appears in the available input devices. But the volume bar and mute button remain greyed out.

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

I closed and reopened the GNOME sound control application after having plugged in the microphone.

   * What was the outcome of this action?

This solved the greyed out volume bar and mute button. I could now unmute the microphone and set the volume.

   * What outcome did you expect instead?

I expected the volume bar and mute button to be 'ungreyed' as soon as I plugged in the microphone.

   * Other notes:

This behaviour does not happen on computers that always have at least one input device available. In that case the available devices list is never empty, despite no microphones being detected. This seems to make sure that the volume bar and mute button are never greyed out.

Included are some screenshots of the GNOME sound control panel.