I have a Logitech T650. Long ago, I encountered a problem with about 1cm of the perimeter of the trackpad being "dead" -- no POINTER_MOTION events, no clicks, nothing in any of
xinput test. Unfortunately, my mousing style mostly involves the lower-left corner of the touchpad, so this discards the majority of my input.
I found that downgrading to the 3.18 kernel reverted the problem, which suggests that it's related https://lkml.org/lkml/2015/3/23/155 -- which looks unsolved. I've now upgraded to Fedora 22 which no longer supports the 3.18 kernel.
Given the lack of output from userland tools, I assume that the issue is in the kernel driver. How can I determine which kernel driver is responsible, and what options I might tweak to restore this functionality?