The current debouncing code monitors events and switches on when events are
too close together. From then on, any event can be delayed.
Vicente Bergas provided an algorithm that avoids most of these delays:
on a button state change we now forward the change without delay but start a
timer. If the button changes state during that timer, the changes are
ignored. On timer expiry, events are sent to match the hardware state
with the client's view of the device. This is only done if needed.
Thus, a press-release sequence of: PRP sends a single press event, a sequence of
PRPR sends press and then the release at the end of the timeout. The timeout
is short enough that the delay should not be noticeable.
This new mode is called the 'bounce' mode. The old mode is now referred to as
'spurious' mode and only covers the case of a button held down that loses
contact. It works as before, monitoring a button for these spurious contact
losses and switching on. When on, button release events are delayed as before.
The whole button debouncing moves to a state machine which makes debugging a
lot easier. See the accompanying SVG for the diagram.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit de994d135e)
This is via a simple search & replace. Later auditing is needed to switch
clicks that should not be debounced (e.g. touchpads) back to a non-debounced
version.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit 8cf6893f6d)
Some devices have worn-out switches or just cheap switches that trigger
multiple button events for each press. These can be identified by unfeasably
short time deltas between the release and the next press event. In the
recordings I've seen so far, that timeout is 8ms.
We have a two-stage behavior: by default, we do not delay any events but we
monitor timestamps. The first time a bouncing button is detected we switch to
debounce mode. From then on, release events are delayed slightly to check for
subsequent button events. If one occurs, the releas and press are filtered. If
none occurs, the release event is passed to the caller.
https://bugs.freedesktop.org/show_bug.cgi?id=100057
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
If the kernel sends us a button press for a button that is thought to be down
we have lost track of the state of the button. Ignore the button press event,
in the hope that the next release makes things right again.
A release event may be masked if another process grabs the device for some
period of time, e.g. libinput debug-events --grab.
https://bugs.freedesktop.org/show_bug.cgi?id=101796
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Switch to a pure factor with a max scaled after a function. The offset is just
0 now (will be removed eventually). Both are determined with a function based
on a linear/exponential regression of a sample set of data pairs.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Try to guess the default scroll buttons a bit better. Right now we default to
scroll button 0 (disabled) whenever a device doesn't have a middle button but
we might as well cast a wider net here as setting a scroll button only has a
direct effect when button scrolling is enabled.
Use the first extra button we find or fall back onto the right button if we
don't have any extra buttons.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This may be a feature for the future but for now be honest and don't claim
that button-based scrolling is available, it's not hooked up in the absolute
code path.
https://bugs.freedesktop.org/show_bug.cgi?id=99865
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Before, our states were idle, button down and scrolling. This adds a state
where the button is down and the timeout has expired (i.e. we're ready to send
scroll events) but we haven't actually sent any events anymore.
If the button is released in this state, we generate a normal click event.
https://bugs.freedesktop.org/show_bug.cgi?id=99666
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Device needs BTN_MIDDLE disabled, this way middle button emulation is present
by default.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
The button-scroll by default behavior is only true on devices with a middle
button.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
And disable middle button emulation for this test, it would mess with the test
results.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
This failed on devices without a middle button, we just didn't have a test
device to trigger this.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
We don't have the same libevdev context that libinput has so if libinput
disables/enables event codes we don't see that and may get unexpected
behavior in the test.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
We don't initialize click methods on devices with physical buttons. This model
is a special case, it's not a clickpad but it only has one button (because one
button is all you ever need and whatnot).
https://bugs.freedesktop.org/show_bug.cgi?id=99283
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Usually we reply INVALID before we reply UNSUPPORTED but that's only for those
values where the value is a programming error. But in this case it's a bit
more complicated. INVALID is only for the cases where the button doesn't exist
on the device, if we don't have button scrolling at all then we have
UNSUPPORTED for all.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
They weren't originally prefixed but the various tests were, but now that we
only have one test runner binary anyway, the prefix helps sorting the files
easily within e.g. gcov results.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
