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I recently installed Ubuntu 20.04 dual booted with Windows 10 on my Lenovo v15 and the touchpad doesn't work when using Ubuntu, either at the login screen or after logging in. This is a valid question because none of the solutions in the other top question worked for me.

cat /proc/bus/input/devices Doesn't return a touchpad in its output.

This Ubuntu Wiki page says that this means the problem is in the kernel. Do I have any way of fixing this besides waiting for a new kernel or switching to an older kernel version that worked for others? Apparently people have had success with switching from 5.4.0-47-generic to 5.4.0-42-generic. The kernels I can currently choose from in GRUB are 5.8.0-44-generic and 5.8.0-43-generic. Neither of those kernels fixes the problem.

Reed Merrill
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1 Answers1

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The non-working touchpad is probably the result of a known bug. You can fix it by adding some flags to the /etc/default/grub file. Here’s how:

  1. Open Terminal (if it’s not already open)
  2. Edit the grub file as root: 
    sudo vi /etc/default/grub
    Note: Feel free to use a different text editor if you prefer.
  3. Add i8042.nopnp=1 pci=nocrs to the line containing GRUB_CMDLINE_LINUX_DEFAULT. This will give you a line that looks something like: 
    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i8042.nopnp=1 pci=nocrs"
    Note: The order of the flags (options) in this line are irrelevant. If you have additional options required by your installation, be sure to keep them as well.
  4. Save the file
  5. Update Grub: 
    sudo update-grub
    This is important! Do not skip this step.
  6. Reboot

This should give you a properly functioning touchpad