Activate mic mute function key, ubuntu 18.04, HP Elitebook 820

61-hp-mic-mute-hotkey.hwdb

# see also: /lib/udev/hwdb.d/60-keyboard.hwdb
evdev:atkbd:dmi:bvn*:bvr*:bd*:svnHewlett-Packard*:pn*EliteBook*:pvr*
 KEYBOARD_KEY_81=f20                          # Fn+F8 on Elitebook, map to F20
# KEYBOARD_KEY_81=fn_esc                      # org entry

fix_mic_mute_Elitebook.txt

Problem: mic mute button (Fn+F8) does not work
Cause: mapped to wrong code (Fn+Esc)
Solve:
- create local .hwdb file with correct mapping in /etc/udev/hwdb.d/
- generate new /lib/udev/hwdb.bin file and reload it:
  sudo udevadm -d hwdb --update; sudo udevadm -d control --reload; sudo udevadm trigger

testing.txt

# see:
# https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1535219
# https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1535219
# https://yulistic.gitlab.io/2017/12/linux-keymapping-with-udev-hwdb/
#


cat /proc/bus/input/devices 

I: Bus=0011 Vendor=0001 Product=0001 Version=ab41
N: Name="AT Translated Set 2 keyboard"
P: Phys=isa0060/serio0/input0
S: Sysfs=/devices/platform/i8042/serio0/input/input3
U: Uniq=
H: Handlers=sysrq kbd event3 leds 
B: PROP=0
B: EV=120013
B: KEY=20000 20000000020 0 0 1500f02100000 3803078f900d401 feffffdfffefffff fffffffffffffffe
B: MSC=10
B: LED=7


sudo evtest /proc/input/event3

Event code 465 (KEY_FN_ESC)
..
Event: time 1546950805.062235, -------------- SYN_REPORT ------------
Event: time 1546950807.953693, type 4 (EV_MSC), code 4 (MSC_SCAN), value 81
Event: time 1546950807.953693, type 1 (EV_KEY), code 465 (KEY_FN_ESC), value 1
Event: time 1546950807.953693, -------------- SYN_REPORT ------------
Event: time 1546950808.116791, type 4 (EV_MSC), code 4 (MSC_SCAN), value 81
Event: time 1546950808.116791, type 1 (EV_KEY), code 465 (KEY_FN_ESC), value 0


sudo find /sys/ -name event3
: /sys/class/input/event3
: /sys/devices/platform/i8042/serio0/input/input3/event3


...

I tried using your scrip but mic mute still doesn't work, i then proceded with cat /proc/bus/input/devices and only difference i found between yours and mine is that S: Sysfs=/devices/platform/i8042/serio0/input/input3
U: Uniq=
H: Handlers=sysrq kbd event3 leds are different from mine. Mine says input4 and event4.
Could this be the problem for it not working,btw im using hp elitebook g6 830.
Any help would be highly appreciated.

G7

Did you get this solved on the G7? I can't get the mic-mute button working on the HP ZBook G8.
In the syslog I see:

[kernel] [24809.757040] atkbd serio0: Unknown key pressed (raw set 2, code 0xf6 on isa0060/serio0).
[kernel] [24809.757043] atkbd serio0: Use 'setkeycodes e076 <keycode>' to make it known.
[kernel] [24809.822499] atkbd serio0: Unknown key released (raw set 2, code 0xf6 on isa0060/serio0).
[kernel] [24809.822502] atkbd serio0: Use 'setkeycodes e076 <keycode>' to make it known.