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[Bug 1328313] Re: [Dell Latitude E7240] Alps Touchpad acts erratically when multi-touch is vertical, not horizontal


Mark Smith, just to focus the scope, I have a similar laptop touchpad
design, and using my right hand, I move the cursor with my index, scroll
on the right-hand side with the middle, and primary click with my thumb.

When I am moving the cursor with my index, my middle is either hovering
on slightly raised portion beyond the touchpad at the top. My thumb
would rest on the primary click. With this method of use, I don't have
any stray clicks, or mis-movements.

Given this, I would expect non-desirable behavior if I have three
fingers not quite altogether on the touchpad, in Windows, Ubuntu, or

Could you please re-word the one specific problem here, and is their a
configuration one would do in Windows that either minimizes or
eliminates what you are referring to here?

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  [Dell Latitude E7240] Alps Touchpad acts erratically when multi-touch
  is vertical, not horizontal

Status in “linux” package in Ubuntu:

Bug description:
  I'm on a Dell Latitude E7240 running 12.04 LTS and my touch pad acts erratically. 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.

  - 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

  This problem does not happen in Windows 7.

  AlsaVersion: Advanced Linux Sound Architecture Driver Version k3.13.0-29-generic.
  ApportVersion: 2.0.1-0ubuntu17.6
  Architecture: amd64
   **** List of CAPTURE Hardware Devices ****
   card 1: PCH [HDA Intel PCH], device 0: ALC292 Analog [ALC292 Analog]
     Subdevices: 1/1
     Subdevice #0: subdevice #0
   /dev/snd/controlC1:  mrksmith   2576 F.... pulseaudio
   /dev/snd/controlC0:  mrksmith   2576 F.... pulseaudio
  CRDA: Error: [Errno 2] No such file or directory
   Card hw:0 'HDMI'/'HDA Intel HDMI at 0xf7e34000 irq 64'
     Mixer name	: 'Intel Haswell HDMI'
     Components	: 'HDA:80862807,80860101,00100000'
     Controls      : 21
     Simple ctrls  : 3
   Card hw:1 'PCH'/'HDA Intel PCH at 0xf7e30000 irq 65'
     Mixer name	: 'Realtek ALC292'
     Components	: 'HDA:10ec0292,102805ca,00100001'
     Controls      : 28
     Simple ctrls  : 13
  DistroRelease: Ubuntu 12.04
  HibernationDevice: RESUME=UUID=303359b5-1c66-468d-935e-a6d9bc56e4e9
  MachineType: Dell Inc. Latitude E7240
  MarkForUpload: True
  Package: linux (not installed)
   PATH=(custom, no user)
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-29-generic root=/dev/mapper/vg0-root ro quiet splash vt.handoff=7
  ProcVersionSignature: Ubuntu 3.13.0-29.53~precise1-generic
   linux-restricted-modules-3.13.0-29-generic N/A
   linux-backports-modules-3.13.0-29-generic  N/A
   linux-firmware                             1.79.14
  Tags:  precise running-unity
  Uname: Linux 3.13.0-29-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm cdrom dialout lpadmin plugdev sambashare sudo
  dmi.bios.date: 02/18/2014
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A08
  dmi.board.asset.tag: 1201037379
  dmi.board.name: 0531FD
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A00
  dmi.chassis.asset.tag: 1201037379
  dmi.chassis.type: 9
  dmi.chassis.vendor: Dell Inc.
  dmi.modalias: dmi:bvnDellInc.:bvrA08:bd02/18/2014:svnDellInc.:pnLatitudeE7240:pvr01:rvnDellInc.:rn0531FD:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.name: Latitude E7240
  dmi.product.version: 01
  dmi.sys.vendor: Dell Inc.

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