On 28/02/2021 19:29, bob prohaska wrote:
> For some time  I lived with a an erratic scroll wheel on a Pi4.
> The pointing worked perfectly, scrolling down worked fine, but
> scrolling up was erratic, sometimes not reacting and occasionally
> "bouncing" backwards. At first I suspected mechanical trouble in
> the scroll wheel but could find nothing demonstrably wrong.
>
> Finally, on a whim, I unplugged the mouse from the keyboard hub
> and plugged it directly into the remaining USB 2.0 port on the Pi.
> That completely solved the problem.
>
> Anybody got a hint what might be going on? I can understand a
> USB hub not working right, but it's much harder to understand
> how it could work right for pointing and wrong for scrolling.
>
> The mouse and keyboard are both elderly Dell take-offs from
> scrapped computers. The keyboard is model sk-8125, the mouse
> is model mo56uo.
>
> Thanks for reading, and insights appreciated.
>
> bob prohaska
>

You too ...

I had been chasing this fault in Debian on a desktop, where scrolling
the mousewheel upwards in a webpage sends the browser back to a previous
page, rather than to the top of the page!

It was driving me mad, so investigated with xev.

==========

My xev output,

adrian@desktop:~$ xev

ButtonPress event, serial 34, synthetic NO, window 0x4c00001,
     root 0x1cb, subw 0x4c00002, time 19590480, (42,57), root:(1032,373),
     state 0x0, button 8, same_screen YES

ButtonPress event, serial 34, synthetic NO, window 0x4c00001,
     root 0x1cb, subw 0x4c00002, time 19590480, (42,57), root:(1032,373),
     state 0x0, button 9, same_screen YES

Button 8/9 is normally for forward/backwards "horizontal" scrolling.

  Bug 443284 - mousewheel generating bogus button events
  https://bugzilla.redhat.com/show_bug.cgi?id=443284

has a workaround.

--
Adrian C

--- SoupGate-Win32 v1.05