The value should be false when you unplugged
amixer -c0 contents
numid=33,iface=CARD,name='Headphone Jack',index=0 ; type=BOOLEAN,access=r-------,values=1 : values=off
The value should be false when you unplugged
amixer -c0 contents
numid= 33,iface= CARD,name= 'Headphone Jack',index=0 access= r------ -,values= 1
; type=BOOLEAN,
: values=off