Messages in this thread | | | From | Linus Torvalds <> | Date | Tue, 30 Oct 2018 09:29:16 -0700 | Subject | Re: Logitech high-resolution scrolling.. |
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On Mon, Oct 29, 2018 at 11:27 PM Peter Hutterer <peter.hutterer@who-t.net> wrote: > > Other issues I found with an MX Anywhere 2S is that on slow scroll and in > ratchet mode we get some scroll jitter. In ratchet mode we can get this > sequence if you scroll just past the notch and it snaps back: > [1, 1, 1, 1, 1, 1, 1, 1, -1] > That's quite easy to trigger. In free-wheel mode we may get the same for > slow motion due to human finger jitter (the Anywhere 2S didn't have HW > jitter, but other devices may). So a perceived-consistent scroll motion may > really look like this: > [1, 1, 1, 1, 1, -1, 1, 1] > Hard to triggger but when it does, it feels like we're dropping events. > The former isn't that much of an issue as long as the ratchet is enabled so > you get the haptic feedback and we (usually) don't drop events.
Both of these actually argue that doing the reset on direction change can be a real problem.
But equally clearly, _not_ doing the reset is unacceptable too.
I wonder if there's some docs on what Logitech does internally in the mouse. It might involve a timeout (ie "if not moving for a while, do the rounding _and_ reset), which would probably be too expensive to do on the host side.
Linus
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