Logitech High Resolution Scrolling Support Dropped From Linux 4.20

Yet more fallout from the Linux 4.20 development kernel is over the newly-added Logitech "high resolution scrolling" functionality that is now being disabled until a better solution is in place.

The past few months there has been patches working on high resolution scroll wheel support that is more precise than the standard behavior offered for Logitech mice on Linux up to this point. This code was worked on by Google's Chrome OS team and intended to vastly improve the scroll wheel experience with Logitech's high-end mice. The code was merged to Linux 4.20.

This high resolution scrolling is exposed via a scrolling acceleration bit exposed in the HID++ protocol. The functionality is supposed to work on Logitech mice ranging from the Logitech Anywhere MX through the M720 and MX Master series. The complete list can be found from the earlier patch.

But now this weekend ahead of Linux 4.20-rc4, it's been dropped. It turns out that this high resolution scrolling broke some hardware support in the process "due to incompatibilities between Logitech and Microsoft worlds."

A new patch series is being worked on by Red Hat's input expert, Peter Hutterer. However, given we are half-way through the Linux 4.20 RC cycle already, that new code probably won't land until the Linux 4.21 merge window.