Comment 16 for bug 1700657

I compiled 4.13rc1 including the patch adding the ELAN0651 to the acpi device id array.
It did not help. I think the device is connected over USB:

$ lsusb -vv
...
Bus 001 Device 003: ID 06cb:0081 Synaptics, Inc.
...

There was some discussion here: https://www.reddit.com/r/Lenovo/comments/6alxy3/trackpad_not_working_on_linux_lenovo_yoga_720/