[PATCH libinput] touchpad: drop motion hysteresis

Hans de Goede hdegoede at redhat.com
Mon Feb 1 06:22:14 PST 2016


On 01-02-16 07:43, Peter Hutterer wrote:
> On Mon, Feb 01, 2016 at 12:38:13PM +1000, Peter Hutterer wrote:
>> Some older touchpad devices jitter a fair bit when a finger is resting on the
>> touchpad. That's why the hysteresis was introduced in the synaptics driver
>> back in 2011. However, the default value of the hysteresis in the synaptics
>> driver ended up being 0, even though the code looks like it's using a fraction
>> of the touchpad diagonal. When the hysteresis code was ported to libinput it
>> was eventually set to 0.5mm.
>> Turns out this is still too high and tiny finger motions are either
>> nonreactive or quite jumpy, making it hard to select small targets. Drop the
>> hysteresis by reducing its margin to 0. I'm leaving the code in place for now
>> because this will likely be needed for some devices.
>> https://bugs.freedesktop.org/show_bug.cgi?id=93503
>> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> patch is withdrawn, I just got recordings from a touchpad that needs it, so
> I'll combine this patch with the one that keeps the behaviour for that
> touchpad

I'm pretty sure that my alps semi-mt touchpad needs this too. Chances are
all semi-mt and single touch touchpads benefit from this ...



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