synaptics: Motion history change in b26125e412a130b7a8f8b6adf9ffc8e9cc8df42c

Daniel Stone daniel at
Wed Jan 11 10:19:24 PST 2012


On 11 January 2012 16:43, Chase Douglas <chase.douglas at> wrote:
> In Ubuntu, we have been shipping xf86-input-synaptics 1.4.1. Now we are
> upgrading to the latest code (which I hope to add multitouch support to
> soon). We noticed that the pointer speed is much faster now, across
> devices. When I reverted commit
> b26125e412a130b7a8f8b6adf9ffc8e9cc8df42c, things seemed to return to the
> way they were. This is the commit message:
> ====
> Replace the motion estimator
> [...]
> We feel the speed is too fast for a default, but I'm not sure how to
> best resolve the issue. I don't see any knobs that would affect the
> algorithm, so if we want to slow things down I'm not sure which knob
> would be best to turn.

Not really - we just used MinSpeed/MaxSpeed/etc.  Note that MaxSpeed
as read from xorg.conf is divided by MinSpeed, whereas it isn't when
you set it through xinput/synclient.

Subjectively though, it didn't seem to make a massive difference on my
test platforms -- my MacBook Air and Chromebooks as well -- but
acceleration does seem a little bit quicker.  *shrug*

The whole thing's a mess, really ...


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