Jtdcftul

Problem Definition

When using the touchpad, the cursor sometimes jumps around a small amount and often fails to detect touch-click.

Attempted Solutions

Some searching suggested installing the old synaptics stuff, which had a dependency on xserver-xorg-core, which was not installed. Installing the package and all its concommitant dependencies yielded a GUI that not only didn't honor the touchpad, but didn't permit keyboard input. Reinstalled Linux from scratch.

Some History

https://bugs.freedesktop.org/show_bug.cgi?id=104828

It looks like Wayland is now the main vehicle, and some very good work has been done here. One of the commenters expresses concern about CPU usage, a concern I would take issue with given the critical nature of human-mouse pointer coupling (i.e. we're doing this for one process, not 1,000 processes; a little extra CPU for something critical isn't a big deal).

xinput list

xinput list

⎡ Virtual core pointer                      id=2    [master pointer  (3)]

⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]

⎜   ↳ AlpsPS/2 ALPS DualPoint TouchPad          id=13   [slave  pointer  (2)]

⎜   ↳ AlpsPS/2 ALPS DualPoint Stick             id=14   [slave  pointer  (2)]

⎣ Virtual core keyboard                     id=3    [master keyboard (2)]

    ↳ Virtual core XTEST keyboard               id=5    [slave  keyboard (3)]

    ↳ Power Button                              id=6    [slave  keyboard (3)]

    ↳ Video Bus                                 id=7    [slave  keyboard (3)]

    ↳ Video Bus                                 id=8    [slave  keyboard (3)]

    ↳ Power Button                              id=9    [slave  keyboard (3)]

    ↳ Sleep Button                              id=10   [slave  keyboard (3)]

    ↳ Dell WMI hotkeys                          id=11   [slave  keyboard (3)]

    ↳ AT Translated Set 2 keyboard              id=12   [slave  keyboard (3)]

    ↳ 40:EF:4C:BE:00:4C                         id=15   [slave  keyboard (3)]

xinput list-props "AlpsPS/2 ALPS DualPoint TouchPad"

xinput list-props "AlpsPS/2 ALPS DualPoint TouchPad"

Device 'AlpsPS/2 ALPS DualPoint TouchPad':

    Device Enabled (149):   1

    Coordinate Transformation Matrix (151): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000

    libinput Tapping Enabled (284): 1

    libinput Tapping Enabled Default (285): 0

    libinput Tapping Drag Enabled (286):    0

    libinput Tapping Drag Enabled Default (287):    1

    libinput Tapping Drag Lock Enabled (288):   0

    libinput Tapping Drag Lock Enabled Default (289):   0

    libinput Tapping Button Mapping Enabled (290):  1, 0

    libinput Tapping Button Mapping Default (291):  1, 0

    libinput Natural Scrolling Enabled (292):   0

    libinput Natural Scrolling Enabled Default (293):   0

    libinput Disable While Typing Enabled (294):    1

    libinput Disable While Typing Enabled Default (295):    1

    libinput Scroll Methods Available (296):    1, 1, 0

    libinput Scroll Method Enabled (297):   1, 0, 0

    libinput Scroll Method Enabled Default (298):   1, 0, 0

    libinput Middle Emulation Enabled (299):    1

    libinput Middle Emulation Enabled Default (300):    1

    libinput Accel Speed (301): 0.000000

    libinput Accel Speed Default (302): 0.000000

    libinput Left Handed Enabled (303): 0

    libinput Left Handed Enabled Default (304): 0

    libinput Send Events Modes Available (269): 1, 1

    libinput Send Events Mode Enabled (270):    0, 0

    libinput Send Events Mode Enabled Default (271):    0, 0

    Device Node (272):  "/dev/input/event6"

    Device Product ID (273):    2, 8

    libinput Drag Lock Buttons (305):   <no items>

    libinput Horizontal Scroll Enabled (306):   1

Note there is no "FingerHigh", "FingerLow" or the other usual properties people suggest changing.

Workaround

Notice the matrix in the properties above. The AlpsPS/2 DualPoint Stick also has such a matrix; by setting the x and y values to something really small, I'm able to achieve precise control using the stick, ergo:

    Coordinate Transformation Matrix (151): 0.050000, 0.000000, 0.000000, 0.000000, 0.050000, 0.000000, 0.000000, 0.000000, 1.000000

This gives me fine-tuned control for 3D model building and CAD work.

My Question to the Community

If anyone has been successful achieving smoother TouchPad operation with this hardware, I would be most interested to know how. My system is a solid older Dell which otherwise mates up very nicely with Ubuntu 18.04.

Thank you.