I wanted to hold off until I was sure, but I've confirmed this was a (second) hardware problem. Dell replaced my laptop's touchpad a second time yesterday, and after deleting the device in Windows 10 and refreshing, the OS detected the new touchpad fine. I reinstalled Ubuntu yesterday and it's also working fine, with scrolling etc. functioning as normal.
So basically, Dell gave me a laptop with a "broken hardware" touchpad and improbably replaced it with a "bad firmware" touchpad. I appreciate all the help with this issue, and I'll mark this bug resolved, and update the other bugs. Some takeaways: 1. Try other kernels / distros. 2. Try Windows (if available). Dual-boot would have been super handy in this case, even if the Windows installation is for break-glass emergencies. 3. Dell only replaces broken hardware with the same model as the original, so inconsistent hardware detection probably means bad hardware. ** Changed in: linux (Ubuntu) Assignee: (unassigned) => Ed Holden (edholden) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1923515 Title: [Dell XPS 15 9500] New touchpad detected as "PS/2 Logitech Wheel Mouse" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1923515/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs