Upgrade from 18.04 to 18.10 lost trackpad/trackpoint

[Alexis Dinno]

I upgraded my Ubuntu from Bionic Beaver to Cosmic Cuttlefish on my laptop. The installation process seemed to go well, but on reboot my trackpad and trackpoint no longer move the pointer, register taps or click buttons, and are seemingly unrecognized by the system.

General information:
Laptop make/model: Lenovo Thinkpad P72 TYPE 20MB-CT01WW 18/11 (that might be a 'O' rather than an '0' on the sticker)
Touchpad maufacturer: (Lenovo?) UltraNav TrackPoint
When symptoms first appeared: On first reboot after the change to Cosmic. Also on subsequent reboots and waking from sleep and suspend.

No trackpad device is listed in /proc/bus/input/devices.

The trackpad and trackpoint and buttons work if I boot into another OS.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Kai-Heng Feng (kaihengfeng)]

Same as LP: #1803600?
Try boot with kernel parameter "psmouse.elantech_smbus=0".

[Alexis Dinno (lexicat)]

@kaihengfeng Your suggestion did the trick! I had tried a similar parameter I found elsewhere on the web (I *think* it was something like 'psmouse.elantech=0') to no avail.

Thank you Kai-Heng Feng!

[Kai-Heng Feng (kaihengfeng)]

Please attach output of `cat /sys/bus/serio/devices/serio1/firmware_id`, thanks!

[Kai-Heng Feng (kaihengfeng)]

The touchpad "LEN2134" is the same on as in LP: #1803600. I'll mark this one as duplicate.