Thinkpad t420 touchpad and trackpad not working

[Jaewon Choi]

No response from touchpad (touchpad and trackpad not recognized).
No available drivers to install.

Following instruction from https://wiki.ubuntu.com/DebuggingTouchpadDetection

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-5.0.0-23-generic 5.0.0-23.24~18.04.1
ProcVersionSignature: Ubuntu 5.0.0-23.24~18.04.1-generic 5.0.15
Uname: Linux 5.0.0-23-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.15
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Jun 4 23:15:39 2020
InstallationDate: Installed on 2019-12-03 (184 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install)

[Jaewon Choi (cjw2020)]

I: Bus=0019 Vendor=0000 Product=0005 Version=0000
N: Name="Lid Switch"
P: Phys=PNP0C0D/button/input0
S: Sysfs=/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0D:00/input/input0
U: Uniq=
H: Handlers=event0
B: PROP=0
B: EV=21
B: SW=1

I: Bus=0019 Vendor=0000 Product=0003 Version=0000
N: Name="Sleep Button"
P: Phys=PNP0C0E/button/input0
S: Sysfs=/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0E:00/input/input1
U: Uniq=
H: Handlers=kbd event1
B: PROP=0
B: EV=3
B: KEY=4000 0 0

I: Bus=0019 Vendor=0000 Product=0001 Version=0000
N: Name="Power Button"
P: Phys=LNXPWRBN/button/input0
S: Sysfs=/devices/LNXSYSTM:00/LNXPWRBN:00/input/input2
U: Uniq=
H: Handlers=kbd event2
B: PROP=0
B: EV=3
B: KEY=10000000000000 0

I: Bus=0011 Vendor=0001 Product=0001 Version=ab54
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=402000000 3803078f800d001 feffffdfffefffff fffffffffffffffe
B: MSC=10
B: LED=7

I: Bus=0019 Vendor=17aa Product=5054 Version=4101
N: Name="ThinkPad Extra Buttons"
P: Phys=thinkpad_acpi/input0
S: Sysfs=/devices/platform/thinkpad_acpi/input/input6
U: Uniq=
H: Handlers=rfkill kbd event4
B: PROP=0
B: EV=33
B: KEY=10040 0 18040000 0 50000000000000 0 1701b02102004 c000280051115000 10e000000000000 0
B: MSC=10
B: SW=8

I: Bus=0003 Vendor=04f2 Product=b221 Version=0752
N: Name="Integrated Camera: Integrated C"
P: Phys=usb-0000:00:1a.0-1.6/button
S: Sysfs=/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.6/1-1.6:1.0/input/input7
U: Uniq=
H: Handlers=kbd event5
B: PROP=0
B: EV=3
B: KEY=100000 0 0 0

I: Bus=0019 Vendor=0000 Product=0006 Version=0000
N: Name="Video Bus"
P: Phys=LNXVIDEO/video/input0
S: Sysfs=/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input8
U: Uniq=
H: Handlers=kbd event6
B: PROP=0
B: EV=3
B: KEY=3e000b00000000 0 0 0

I: Bus=0019 Vendor=0000 Product=0006 Version=0000
N: Name="Video Bus"
P: Phys=LNXVIDEO/video/input0
S: Sysfs=/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:09/LNXVIDEO:01/input/input9
U: Uniq=
H: Handlers=kbd event7
B: PROP=0
B: EV=3
B: KEY=3e000b00000000 0 0 0

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel PCH Mic"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input10
U: Uniq=
H: Handlers=event8
B: PROP=0
B: EV=21
B: SW=10

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel PCH Dock Mic"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input11
U: Uniq=
H: Handlers=event9
B: PROP=0
B: EV=21
B: SW=10

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel PCH Dock Headphone"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input12
U: Uniq=
H: Handlers=event10
B: PROP=0
B: EV=21
B: SW=4

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel PCH Headphone"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input13
U: Uniq=
H: Handlers=event11
B: PROP=0
B: EV=21
B: SW=4

I: Bus=0003 Vendor=046d Product=c24c Version=0110
N: Name="Logitech G400s Optical Gaming Mouse"
P: Phys=usb-0000:00:1a.0-1.1/input0
S: Sysfs=/devices/pci0000:00/0000:00:1...