How to disable Auto-Mute Mode?

Press right arrow to get to "auto-mute mode", then up or down arrow to change it, then Escape to exit.

You can make this automatic on boot by executing (perhaps in /etc/rc.local):

/usr/bin/amixer -c 0 sset "Auto-Mute Mode" Disabled

Late answer.

I had the same problem, including @limited-atonement one.

To resume:

root@darkstar:~# amixer | grep -i mute
Simple mixer control 'Auto-Mute Mode',0
root@darkstar:~# amixer -c 0 sset 'Auto-Mute Mode' Disabled
amixer: Unable to find simple control 'Auto-Mute Mode',0

I solved it by running alsamixer, then:

• F5 (show all controls)
• use arrows → to move until hitting the <Auto-Mute> control, which show as Enabled
• use the minus - key to switch it to Disabled
• hit Esc to exit
• run alsactl store as root to save

Hope this help.

Building on Sam's answer, here is a script that toggles the status of Auto-Mute Mode:

# toggle status of Auto-Mute
if amixer -c 0 sget 'Auto-Mute Mode' | grep --quiet -F "Item0: 'Enabled"
then
    amixer -c 0 sset 'Auto-Mute Mode' Disabled
else
    amixer -c 0 sset 'Auto-Mute Mode' Enabled
fi

I'm using this so I can easily mute or un-mute my speakers without unplugging my headphones.

Edit: one-liner

amixer -c 0 sget 'Auto-Mute Mode' | fgrep -q "Item0: 'E" && _M=Disabled || _M=Enabled; amixer -c 0 sset 'Auto-Mute Mode' $_M