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[Mark Smith <mrksmith@xxxxxxxxxx>]

I'm on an E7240 running 12.04 LTS (anxiously awaiting my employeer to
certify 14.04 with all our internal tools and what-not) and I have this
problem.  I'm pretty sure it happens because my middle and ring fingers
accidentally touch the top edge of the pad while my pointer finger is
moving the cursor.  I can reproduce this on purpose by running "xinput
--test [device number]" and watching the events while I do the
following:

- Touch the pad near the middle or bottom.  The cursor moves slightly as my finger wiggles around.
- Without removing the first finger, touch the pad again with a second finger above the first finger.  The cursor shoots up to a[1]=0 (which is the y position).
- Without removing the first finger, remove the second (top) finger.  The cursor shoots back down to a[1]=<some large number>  Sometimes it takes it all the way to the bottom of the screen, sometimes it goes back to where it was, or somewhere else.  I haven't been able to figure out how it decides what to go back to.

With this, while I touching with my pointer finger and my middle or ring
finger accidentally touch the pad at the top, the cursor shoots where I
don't want it.  Then when my middle/ring finger leaves the pad (usually
because I started cursing (get it?) at my cursor), it shoots back down
again somewhere completely arbitrary.

Similarly:

- Touch the bad near the top.
- Without removing the top finger, touch somewhere near the bottom.  The cursor doesn't (yet) move.
- Lift the top finger.  The cursor shoots to the bottom.
- Put down the top finger again, without lifting the bottom.  The cursor shoots back up again.

You can make the cursor shoot up and down just by keeping your bottom
finger down and tapping the top finger.  The cursor follows the top
finger no matter what you do.

Interestingly, this does NOT happen from side-to-side.  Two touches
side-by-side trigger the multi-touch gestures and don't move the cursor.

If we could just get it so that going from single touch to multi-touch
top-to-bottom doesn't actually move the cursor, that would be grand.

Thank you very much for all your help. :-)

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1272624

Title:
  [Dell Latitude E7440] 14.04 Touchpad causing mouse pointer to
  spuriously jump around screen

Status in “linux” package in Ubuntu:
  Triaged

Bug description:
  From the live usb the touchpad seems less jerky compared to ubuntu
  13.10 but is still not as smooth as Windows 7.

  This may be due to how the touchpad is detected as a PS/2 mouse instead of a more appropriate touchpad driver:
  https://launchpadlibrarian.net/163664336/BootDmesg.txt
  [    4.088881] mousedev: PS/2 mouse device common for all mice

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.13.0-5-generic 3.13.0-5.20
  ProcVersionSignature: Ubuntu 3.13.0-5.20-generic 3.13.0
  Uname: Linux 3.13.0-5-generic x86_64
  ApportVersion: 2.13.1-0ubuntu1
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  ubuntu     4246 F.... pulseaudio
   /dev/snd/controlC1:  ubuntu     4246 F.... pulseaudio
  CasperVersion: 1.336ubuntu1
  CurrentDesktop: Unity
  Date: Sat Jan 25 06:50:44 2014
  LiveMediaBuild: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140124)
  MachineType: Dell Inc. Latitude E7440
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: noprompt cdrom-detect/try-usb=true persistent file=/cdrom/preseed/username.seed boot=casper initrd=/casper/initrd.lz quiet splash --
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-5-generic N/A
   linux-backports-modules-3.13.0-5-generic  N/A
   linux-firmware                            1.122
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 01/02/2014
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A07
  dmi.board.name: 0PPXP5
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A00
  dmi.chassis.type: 9
  dmi.chassis.vendor: Dell Inc.
  dmi.modalias: dmi:bvnDellInc.:bvrA07:bd01/02/2014:svnDellInc.:pnLatitudeE7440:pvr01:rvnDellInc.:rn0PPXP5:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.name: Latitude E7440
  dmi.product.version: 01
  dmi.sys.vendor: Dell Inc.

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