ELAN Touchpad not working on Lenovo IdeaPad with Ubuntu 16.04

Solution 1:

So, eventually I managed to get the touchpad working on Ubuntu 18.04, kernel version: 5.3.0-46-generic thanks to comments on this link: https://www.reddit.com/r/linuxquestions/comments/f9h0q4/touchpad_issue_lenovo_s14515iil/

Basically what needs to be done is:

1. Open the file /etc/default/grub for editing, for example by running

   sudoedit /etc/default/grub
   

2. Add to the line beginning GRUB_CMDLINE_LINUX_DEFAULT: "i8042.nopnp=1 pci=nocrs" so that it reads:

   GRUB_CMDLINE_LINUX_DEFAULT="i8042.nopnp=1 pci=nocrs"
   

   If other parameters are there between the double quotes, it may be OK to leave them.

3. Save the file and exit

4. Run this command to update the GRUB configuration:

   sudo update-grub
   

5. Reboot