[Bug 84760] Problem solved!!

[José M. Vaz]

I was using volume applet in the upper panel.

I ran "gnome-sound-properties" and by playing around and ticking "Enable
Software sound mixing (ESD)", I was able to restore volume keys
function.

Problem solved!

Thank you for pointing me to "gnome-sound-properties".
The thing is, how come "software sound mixing got disabled?"

Thank you for your concern!

-- 
Regression: Sound volume hotkeys stopped working 
https://launchpad.net/bugs/84760