I suspect this behaviour is caused by the interaction of a couple of
factors:
* the touchpad is anisotropic, about 2500DPI vertically but only 1500DPI
horizontally
* both the synaptics driver and X are making making pointer acceleration
calculations
These can be mostly fixed by tweaking the config; I'm currently using
(add this as "/etc/X11/xorg.conf.d/50-touchpad.conf" and restart your
Xserver):
Section "InputClass"
Identifier "touchpad"
MatchProduct "SynPS/2 Synaptics TouchPad"
Driver "synaptics"
# fix touchpad resolution
Option "VertResolution" "100"
Option "HorizResolution" "65"
# disable synaptics driver pointer acceleration
Option "MinSpeed" "1"
Option "MaxSpeed" "1"
# tweak the X-server pointer acceleration
Option "AccelerationProfile" "2"
Option "AdaptiveDeceleration" "16"
Option "ConstantDeceleration" "16"
Option "VelocityScale" "32"
EndSection
See also:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/621432
** Attachment added: "50-touchpad.conf"
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1042069/+attachment/3402410/+files/50-touchpad.conf
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You received this bug notification because you are a member of Desktop
Packages, which is subscribed to xserver-xorg-input-synaptics in Ubuntu.
https://bugs.launchpad.net/bugs/1042069
Title:
Jumpy Mouse Cursor using Thinkpad X230 Touchpad
Status in “xserver-xorg-input-synaptics” package in Ubuntu:
Confirmed
Bug description:
Really annoying bug!
Trackpoint moves the mouse cursor smootly,
when using the touchpad i have a jumpy cursor. (vertically it moves fine,
horizontally it moves always 4 pixels at once).
Please see the following demonstration video:
http://www.youtube.com/watch?v=XUVRKFUsAmc
ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: xserver-xorg-input-synaptics 1.6.2-1ubuntu4
ProcVersionSignature: Ubuntu 3.5.0-11.11-generic 3.5.2
Uname: Linux 3.5.0-11-generic x86_64
ApportVersion: 2.5.1-0ubuntu2
Architecture: amd64
Date: Mon Aug 27 08:08:27 2012
InstallationMedia: Kubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120824)
ProcEnviron:
LANGUAGE=
TERM=xterm
PATH=(custom, no user)
LANG=de_DE.UTF-8
SHELL=/bin/bash
SourcePackage: xserver-xorg-input-synaptics
UpgradeStatus: No upgrade log present (probably fresh install)
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1042069/+subscriptions
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