Re: [PATCH] CHROMIUM: Input: synaptics - filter out the events with low z values

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Fri, Feb 24, 2012 at 10:08:35AM +0100, Henrik Rydberg wrote:
> > > The most striking effect is the ability to better retain a
> > > drag. Although the statement was made in light of possible
> > > (1-strong,1-weak) packets, it should help in the 2-weak case too.
> > 
> > The bigger question is why is this needed in kernel. The original
> > hysteresis with BTN_TOUCH was done for sole benefit of mousedev so that
> > we could allow somewhat better transition from standard PS/2 mode into
> > native Synaptics mode with absolute coordinates at time when barely
> > anyone had Synaptics X driver installed. This was, what, 10 years ago?
> 
> The semi-mt behavior is obviously a special case, where userspace
> relies on the reported number of fingers to transition between one
> touch and two touches. There is no pressure information sent to
> userspace in this case, so the situation is in fact quite similar to
> the ancient mousedev situation.

We still report ABS_PRESSURE but maybe we should report ABS_MT_PRESSURE
as well?

-- 
Dmitry