Bug 94755 - Middle button emulation on software buttons is unreliable
Summary: Middle button emulation on software buttons is unreliable
Alias: None
Product: Wayland
Classification: Unclassified
Component: libinput (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Wayland bug list
QA Contact:
Depends on:
Blocks: 94474
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Reported: 2016-03-30 06:15 UTC by Peter Hutterer
Modified: 2016-04-05 21:54 UTC (History)
3 users (show)

See Also:
i915 platform:
i915 features:


Description Peter Hutterer 2016-03-30 06:15:44 UTC
Out of 10 clicks with both fingers in the software button areas, I get 5-7 as middle-clicks at best, the rest is either left or right buttons. event-debug --verbose shows that the button state machine detects the right button areas but does not send the right button event then.
Comment 1 Peter Hutterer 2016-03-31 22:32:04 UTC
tested on a T450 and a T440 and it's pretty much the same effect on both. In most cases this isn't a libinput bug (all cases?) but the type of interaction we do with the middle button.

Primarily it's used for paste which is a single click immediately after putting the fingers down. It's very common to trigger the click before the sensor detected the second finger, resulting in a left or right click only. I don't think we can meaningfully put delays in without making actual button clicks sluggish, so I think that changing the software button code to include an actual middle button area is the only/best solution.
Comment 3 Peter Hutterer 2016-04-05 21:54:38 UTC
commit 886b5a2cd8c785e48ddf5ceb4a902cd1f518d2a9
Author: Peter Hutterer <peter.hutterer@who-t.net>
Date:   Mon Apr 4 10:06:36 2016 +1000

    touchpad: add a middle button software area

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