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Alps touchpad jumpy when laptop is connected to AC power

asked 2014-06-25 08:06:54 -0600

fat-lobyte gravatar image

updated 2014-09-28 15:56:52 -0600

mether gravatar image

Hi! I am running Fedora 20 with Kernel 3.14.8-200.fc20.i686 on a "Packard Bell Dot S 2" netbook. It has an "ALPS GlidePoint" touchpad, as indicated by the folllowing dmesg lines:

[    4.019174] input: ALPS PS/2 Device as /devices/platform/i8042/serio1/input/input7
[    4.042860] input: AlpsPS/2 ALPS GlidePoint as /devices/platform/i8042/serio1/input/input6

When running from battery, everything works fine. However, as soon as I plug in the AC power, the touchpad starts acting "weird". By "weird", I mean the following

  • Running a finger smoothly over the touchpad does not produce a smooth motion, instead it is jagged/jumpy
  • "Taps" are usually not interpreted as single taps, but the mouse curser jumps around, and produces no clicks at all or multiple clicks
  • Hovering with the finger about 0.5 cm above the touchpad still procues input, raning from random clicks to a moving cursor

So basically, it is completely unusable.

Does anybody know what the problem is and how to fix it?

Here are the logfiles for this boot. I booted up unplugged, plugged it in, unplugged it, plugged it in again, and finally unplugged ac power.

If you need more info and/or log files, please don't hesitate to ask.

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Please yes - provide dmesg, log files and links from . Ty.

zoltanh721 gravatar imagezoltanh721 ( 2014-06-27 18:02:14 -0600 )edit

@zoltanh721 I added the log files to my original question. Do you need something else?

fat-lobyte gravatar imagefat-lobyte ( 2014-07-04 02:10:35 -0600 )edit

Is this problem persistent ? Have you tried other kernels? Can you try another Linux distribution (don't install - boot from a Live image /USB/DVD). If the problem is persistent, then it is likely a power supply fail. It happened before to some folks (same behavior with touchpad jumps). Also, is the touchpad driver loaded ? What's the output of synclient ?

NickTux gravatar imageNickTux ( 2014-07-04 03:00:35 -0600 )edit

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answered 2016-11-22 08:11:45 -0600

fat-lobyte gravatar image

It turns out this is caused by the replacement power supply that was of inferior quality to the original.

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Asked: 2014-06-25 08:06:54 -0600

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Last updated: Nov 22 '16