Macbook Pro 5,4 volume hot keys no longer change the volume. Numerous reboots, remapping of the keys in system settings, still not working. mute key works fine but volume up and down are not responsive. The actual keystrokes register ie: keyboard settings.
This happened suddenly without rebooting a couple weeks ago after previously working without issue in 13.10 then 14.04 for a little while/
Best Answer
This worked for me on Mint18 with Cinnamon.. In synaptic package manager search for "pulse" then
mark:
pulseaudio-module-x11
for installlib cvc0
for reinstallgir1.2-cvc-1.0
for reinstallhit apply
in terminal:
sudo alsa force-reload
restart your machine.
The prob for me was that the keys were correctly bound and the OS was picking up the presses, but something was stopping it from being used for sound by cinnamon, just needed to reinstall normal settings