Logitech Marble Mouse lags in Ubuntu Studio 18.04

Question

This is not a 'How to Configure Scroll/Buttons' type question.

I have a Logitech Marble Mouse (a two-button trackball), model number T-CM14.

Problem: The mouse pointer on screen is very laggy, to the point of not being usable: approximately ten full rotations of the trackball to get the pointer from the top of the screen to the bottom, for example.

System specification:

• OS: Ubuntu Studio 18.04 (Xfce) x64
• Newly installed, Partner Repositories enabled and Restricted-Extras added
• PC: Dell Insperon with USB-only connections

The trackball is attached using a USB-to-PS/2 adapter:

$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 004: ID 04d9:1400 Holtek Semiconductor, Inc. PS/2 keyboard + mouse controller
Bus 002 Device 006: ID 046d:c077 Logitech, Inc. M105 Optical Mouse
Bus 002 Device 002: ID 413c:2107 Dell Computer Corp. 
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

(I should point out that the 'M105 Optical Mouse' is a second pointing device I have plugged in to get a working pointer on-screen, having it plugged in, or not, doesn't seem to affect the problem with the trackball's lack of performance.)

Funny thing was one time I had rebooted with just the trackball/adapter installed, this time in the front USB port, and it started working like normal. But this condition did not last and I am back to adding the standard mouse to get that pointer where it needs to be, on-screen.

How to fix my mouse pointer to respond to the trackball's rotation like it's supposed to?

Answer 1

The effect you are describing may be dependent on the resolution of the screen. I have found that for a high resolution screen, I need to scroll more as well.

Two settings:

• Acceleration to max. This can be set in gnome config, or via xinput set-prop "Logitech USB Trackball" 328 1.0 or via the equivalent in xorg conf, in general, I use the following /etc/X11/xorg.conf.d/10-libinput.conf

Section "InputClass"
     Identifier "Marble Mouse"
     MatchProduct "Logitech USB Trackball"
     Driver "libinput"
     Option "ScrollMethod" "button"
     Option "ScrollButton" "8"
     Option "AccelSpeed" "1"
     # Option "TransformationMatrix" "2.4 0 0 0 2.4 0 0 0 1"
EndSection

as I also want scrolling with wheel by clicking on the left small button. The commented TransformationMatrix allows to skip pixels and move faster, but I prefer to change the DPI as below instead.

• Set a custom DPI through /etc/udev/hwdb.d/71-mouse-local.hwdb

# Logitech Marble Mouse
#id obtained by: mouse-dpi-tool  /dev/input/event4
mouse:usb:v046dpc408:name:Logitech USB Trackball:
# keep space below
 MOUSE_DPI=100@125

and then udevadm hwdb --update, udevadm control --reload-rules && udevadm trigger and unplug, plug mouse. The DPI of 100 may be too sensitive for some, you could replace by 200@125.

In your case, the id is likely v04d9p1400, you probably need to check with mouse-dpi-tool.