Go to “Audio” and assign the mute, volume down and volume up keys by pressing the appropriate key on the keyboard

sudo apt-get install xdotool

xdotool key XF86MonBrightnessUp

xdotool key XF86MonBrightnessDown

• • Open a terminal. (The quickest way is the Ctrl-Alt-T shortcut.)
  • Enter “alsamixer” and press the Enter key.
  • You will now see a user interface. In this user interface, you can do the following:
    • Select your correct sound card using F6 and select F5 to see recording controls as well
    • Move around with left and right arrow keys.
    • Increase and decrease volume with up and down arrow keys.
    • Increase and decrease volume for left/right channel individually with “Q”, “E”, “Z”, and “C” keys.
    • Mute/Unmute with the “M” key. An “MM” means muted, and “OO” means unmuted. Note that a bar can be 100% full but still be muted, so do check for this.
    • Exit from alsamixer with the Esc key.
  • Test your audio switching by plugging in some headphones into the audio jack and listening if audio still comes out of the laptop’s builtin speakers
    • If so, make sure that you have completed all the steps, and if you are still stumped, create an error report in the comments describing your problem
  • If not, you are all done setting up your audio inputs
    • You can now close the terminal window 

 

Tested hardware

Device	Status
DP Port	OOB
Touchscreen	OOB
HDA Audio mic/output/line out	Define function Keys Line-out output
Sleep/Wake	OOB
Keyboard	OOB
Trackpad	OOB
Power button	OOB
Brightness control	Define function Keys
WiFi + Bluetooth	OOB

Note, if your installation of Linux is running too hot or the fan is occasionally blowing loudly, reduce your CPU clock speed.