The Asus X750L touchpad manufactured by elantech (ETD0108) isn't detected in recent versions of Ubuntu and Arch Linux. To get it working, add the following kernel parameter to your grub line:
i8042.noloop
To make it permanent, add it to the GRUB_CMDLINE_LINUX_DEFAULT variable in /etc/default/grub:
GRUB_CMDLINE_LINUX_DEFAULT="i8042.noloop quiet splash"
Then run: