I use a Logitech Trackman / Marble USB trackball on my F43 Gnome/Wayland install. This trackball does not have a hardware scroll wheel. I wanted to try defining a scroll modifier in hopes that it would allow me to hold down one mouse button and move the ball to emulate a scroll wheel.
As usual, the Arch wiki has the the exact instructions on how to do this but I haven’t been able to get it to work:
Since I’m using Gnome/Wayland, I did:
gsettings set org.gnome.desktop.peripherals.trackball scroll-wheel-emulation-button 8
Then I checked it to make sure it worked:
gsettings list-recursively org.gnome.desktop.peripherals.trackball
org.gnome.desktop.peripherals.trackball accel-profile ‘default’
org.gnome.desktop.peripherals.trackball middle-click-emulation true
org.gnome.desktop.peripherals.trackball scroll-wheel-emulation-button 8
org.gnome.desktop.peripherals.trackball scroll-wheel-emulation-button-lock false
However, when I hold down the Small left button and moved the ball, it doesn’t scroll. I’ve tried it in Firefox, Chrome in the Gnome mouse settings Test Settings. Instead, it does the default mapping for that button which is browser back.
I have several potential complications that could be to blame. First, I use the trackball left handed but I’ve tried all the buttons. Second, I have input-remapper installed and I use that to remap the small right button to send the Meta key. Third, my trackball is connected through a Level1Tech KVM.
sudo libinput list-devices lists both the trackball and a virtual one created by input-remapper (I removed devices I didn’t think mattered from the output) :
sudo libinput list-devices
Device: Logitech USB Trackball
Kernel: /dev/input/event2
Id: usb:046d:c408
Group: 4
Seat: seat0, default
Capabilities: pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap button map: n/a
Tap drag lock: n/a
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: n/a
Calibration: n/a
Scroll methods: button
Scroll button: BTN_SIDE
Scroll button lock: disabled
Click methods: none
Clickfinger button map: n/a
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: flat *adaptive custom
Rotation: 0.0
Area rectangle: n/a
Device: Generic Virtual HID Mouse
Kernel: /dev/input/event5
Id: usb:09eb:0131
Group: 6
Seat: seat0, default
Capabilities: pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap button map: n/a
Tap drag lock: n/a
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: disabled
Calibration: n/a
Scroll methods: button
Scroll button: BTN_MIDDLE
Scroll button lock: disabled
Click methods: none
Clickfinger button map: n/a
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: flat *adaptive custom
Rotation: 0.0
Area rectangle: n/a
Device: Generic Virtual HID Consumer Control
Kernel: /dev/input/event7
Id: usb:09eb:0131
Group: 6
Seat: seat0, default
Capabilities: keyboard pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap button map: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: disabled
Middle emulation: n/a
Calibration: n/a
Scroll methods: none
Scroll button: n/a
Scroll button lock: n/a
Click methods: none
Clickfinger button map: n/a
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: n/a
Rotation: 0.0
Area rectangle: n/a
Device: input-remapper Logitech USB Trackball forwarded
Kernel: /dev/input/event22
Id: usb:046d:c408
Group: 9
Seat: seat0, default
Capabilities: pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap button map: n/a
Tap drag lock: n/a
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: n/a
Calibration: n/a
Scroll methods: button
Scroll button: BTN_SIDE
Scroll button lock: disabled
Click methods: none
Clickfinger button map: n/a
Disable-w-typing: n/a
Disable-w-trackpointing: n/a
Accel profiles: flat *adaptive custom
Rotation: 0.0
Area rectangle: n/a
When I run sudo libinput debug-events and then click the small left button I get:
sudo libinput debug-events
-event1 DEVICE_ADDED Power Button seat0 default group1 cap:k
-event3 DEVICE_ADDED Video Bus seat0 default group2 cap:k
-event0 DEVICE_ADDED Power Button seat0 default group3 cap:k
-event2 DEVICE_ADDED Logitech USB Trackball seat0 default group4 cap:p left scroll-nat scroll-button
-event19 DEVICE_ADDED Microsoft Natural® Ergonomic Keyboard 4000 seat0 default group5 cap:k
-event20 DEVICE_ADDED Microsoft Natural® Ergonomic Keyboard 4000 seat0 default group5 cap:kp scroll-nat
-event4 DEVICE_ADDED Generic Virtual HID seat0 default group6 cap:k
-event5 DEVICE_ADDED Generic Virtual HID Mouse seat0 default group6 cap:p left scroll-nat scroll-button
-event6 DEVICE_ADDED Generic Virtual HID System Control seat0 default group6 cap:k
-event7 DEVICE_ADDED Generic Virtual HID Consumer Control seat0 default group6 cap:kp scroll-nat
-event9 DEVICE_ADDED Eee PC WMI hotkeys seat0 default group7 cap:k
-event21 DEVICE_ADDED input-remapper keyboard seat0 default group8 cap:k
-event22 DEVICE_ADDED input-remapper Logitech USB Trackball forwarded seat0 default group9 cap:p left scroll-nat scroll-button
event22 POINTER_BUTTON +0.000s BTN_SIDE (275) pressed, seat count: 1
event22 POINTER_BUTTON +0.080s BTN_SIDE (275) released, seat count: 0
I also tried enabling middle-click-emulation and it worked immediately.
Any ideas what I might be doing wrong? It may very well be user error as I’ve never tried to do a scroll modifier.
Thanks.