desktop-packages team mailing list archive

[Julien-Charles Lévesque <1028617@xxxxxxxxxxxxxxxxxx>]

The problem is related to electrical interference from the power supply
(see http://superuser.com/questions/76649/laptop-touchpad-works-
incorrectly-when-on-power-supply). As suggested by users here,
increasing the noise threshold helps.

In my case, this problem happens because I am using a cheap ebay power
supply that was not manufactured by my laptop's maker.

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https://bugs.launchpad.net/bugs/1028617

Title:
  Cursor shakes violently when connected to power source - makes
  touchpad cursor unusable

Status in xserver-xorg-input-synaptics package in Ubuntu:
  Incomplete

Bug description:
  Using Ubuntu 12.04, 64-bit version, installed on Lenovo X220 laptop.
  Fresh "default" install and settings configuration.

  When the laptop is plugged into a power source, the touchpad's
  onscreen cursor (the white arrow that shows position) shakes
  excessively when trying to use the touchpad to control the cursor. The
  shaking is so bad that it essentially makes the touchpad unusable. For
  example, trying to click the minimize button in a window's upper left
  corner will routinely result in accidentally clicking the close button
  because of the cursor's shaking.

  The problem is NOT present when Ubuntu is running on battery. But this
  means I can never have Ubuntu plugged in and charging while I use it,
  which is very inconvenient at times.

  I'm using the power block and cable that came with the X220. But I
  also tried using a larger power block and cable that came with another
  Lenovo model - this power block is approved for use with the X220 and
  is sold on the Lenovo website as an X220 accessory. But this larger
  power block did not improve the shaking behavior either.

  I have no special settings enabled for the touchpad. But changing the
  settings has no effect on this shaking behavior either. I attached a
  screenshot of my Touchpad settings [please excuse the HUD's presence -
  I cannot get the HUD to NOT appear when I press ALT+PrtSc to take a
  screenshot (I guess this is another bug)].

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