In the last day or two (on CentOS 7)the speaker icon in the Mate top panel, which normally drops down to a volume control, has stopped working.
what does “stopped working” mean?
It means when I drop down the volume slider and slide it, it makes no difference at all in the output volume.
if I right-click that icon, it’ll open up “Sound Preferences”, which appears to be the same as “Mate Volume Control”. Within that program, the input or output level slider DOES work.
I fired up alsactrl and it seems to work fine, and will also control volume.
I dont have pavucontrol (or is it pavuctl) installed, so I don’t suppose it has gotten messed up.