Physical scroll wheel of the trackball (libinput, x11) won't work

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1

I have a Kensington SlimBlade Trackball that has a sensor for scroll wheel.
I tried it in blender, it can’t neither zoom or scroll the view, actually it doesn’t have any response when I rotate the ball.

I used the libinput to capture the event, it should work. And the firefox doesn’t have any problem with it.
Any thing I could try to the blender preference or xorg’s configure ?

^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.008s      vert 15.00/1* horiz 0.00/0 (wheel)  
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.032s      vert 15.00/1* horiz 0.00/0 (wheel)  
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.056s      vert 15.00/1* horiz 0.00/0 (wheel)  
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.072s      vert 15.00/1* horiz 0.00/0 (wheel)  
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.096s      vert 15.00/1* horiz 0.00/0 (wheel)
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.120s      vert 15.00/1* horiz 0.00/0 (wheel)
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.152s      vert 15.00/1* horiz 0.00/0 (wheel)
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_AXIS     +2.200s      vert 15.00/1* horiz 0.00/0 (wheel)  
^[[B^[[B^[[B^[[B^[[B^[[B event14  POINTER_MOTION   +2.424s        0.00/ -0.32 ( +0.00/ -1.00)       
 event14  POINTER_MOTION   +2.432s        0.00/ -0.84 ( +0.00/ -1.00)                                                                                                               
 event14  POINTER_AXIS     +2.472s      vert 15.00/1* horiz 0.00/0 (wheel)

Here is my configure for X11.

Section "InputClass"
        Identifier      "Trackball"
        MatchVendor     "Kensington"
        Driver  "libinput"
        Option  "ButtonMapping" "1 2 0 0 0 0 0 3"
EndSection
2

try running xev in a terminal and see if the wheel reacts when used in the xev window (watch terminal output). You may need custom mapping.

3

Yes, it looks like when my cursor in this that X window, scrolling the ball won’t produce any new event.
I am not sure which custom mapping I need to do here, any document ?

4

Perhaps start at https://wiki.archlinux.org/index.php/Map_scancodes_to_keycodes.

5

Thank you,
but I use the evtest to check the event report by this trackball,
they are not different from a normal mouse, I wonder whether I need to touch keycode mapping here ?

I compared the response from trackball with the one from the mouse in xev, the only different is that scrolling the wheel in a mouse would become button 4 or button 5 it in.

vent: time 1619767856.884535, -------------- SYN_REPORT ------------
^[[B^[[B^[[B^[[B^[[B^[[BEvent: time 1619767856.956532, type 2 (EV_REL), code 8 (REL_WHEEL), value -1
Event: time 1619767856.956532, type 2 (EV_REL), code 11 (REL_WHEEL_HI_RES), value -120
Event: time 1619767856.956532, -------------- SYN_REPORT ------------
^[[B^[[B^[[B^[[B^[[B^[[BEvent: time 1619767857.036531, type 2 (EV_REL), code 8 (REL_WHEEL), value -1
Event: time 1619767857.036531, type 2 (EV_REL), code 11 (REL_WHEEL_HI_RES), value -120
Event: time 1619767857.036531, -------------- SYN_REPORT ------------
^[[B^[[B^[[B^[[B^[[B^[[BEvent: time 1619767857.660525, type 2 (EV_REL), code 8 (REL_WHEEL), value -1
Event: time 1619767857.660525, type 2 (EV_REL), code 11 (REL_WHEEL_HI_RES), value -120
Event: time 1619767857.660525, -------------- SYN_REPORT ------------
6

It’s the button assignments you need to look at. It’s been a long time since I needed to tweak, but rules matter.

7

Thank you, I figured out what the problem is
I trace the code the emulate_scroll_button_events() is the function generate the button pressing and releasing event from wheel scrolling. I work fine for both the trackball and the mouse.

From the document:
The ButtonMapping option adjusts the logical button mapping, it does not affect how a physical button is mapped to a logical button.
I should not disable the scroll up/down for there is not a physical button for it.

Section "InputClass"
        Identifier      "Trackball"
        MatchVendor     "Kensington"
        Driver  "libinput"
        Option  "ButtonMapping" "1 2 0 4 5 0 0 3"
EndSection