linux-kernel - Re: [PATCH 3/3] Input: synaptics - remove touches over button click area

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Date:	Mon, 11 Oct 2010 19:10:33 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Chris Bagwell <chris@...bagwell.com>
Cc:	Chase Douglas <chase.douglas@...onical.com>,
	linux-input@...r.kernel.org, xorg-devel@...ts.x.org,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Andy Whitcroft <apw@...onical.com>,
	Henrik Rydberg <rydberg@...omail.se>,
	linux-kernel@...r.kernel.org,
	Peter Hutterer <peter.hutterer@...-t.net>,
	Duncan McGreggor <duncan.mcgreggor@...onical.com>
Subject: Re: [PATCH 3/3] Input: synaptics - remove touches over button click area

At Mon, 11 Oct 2010 11:24:04 -0500,
Chris Bagwell wrote:
> 
> On Fri, Oct 8, 2010 at 9:58 AM, Chase Douglas
> <chase.douglas@...onical.com> wrote:
> > Now that we have proper multitouch support, we can handle integrated
> > buttons better. If we know the top of the buttons on the touchpad, we
> > can ignore any touches that occur within the touchpad area while a
> > button is clicked. It may be possible to get the button area by querying
> > the device, but for now allow the user to manually set it.
> >
> > A note on why this works: the Synaptics touchpads have pseudo touch
> > tracking. When two touches are on the touchpad, an MT touch packet with
> > just the X, Y, and pressure values is sent before a normal Synaptics
> > touch packet. When one touch is obviously in motion and the other is
> > stationary, the touchpad controller sends the touch in motion in the
> > normal packet and the stationary touch in the MT packet. Single touch
> > emulation is provided by the normal packet, so an action like clicking
> > a button and dragging with another finger still works as expected.
> >
> > Tested on a Dell Mini 1012 with synaptics_multitouch=1 and
> > synaptics_button_thresh=4100.
> >
> > Signed-off-by: Chase Douglas <chase.douglas@...onical.com>
> > ---
> >  drivers/input/mouse/synaptics.c |   16 +++++++++++++++-
> >  1 files changed, 15 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> > index 7289d88..e67778d 100644
> > --- a/drivers/input/mouse/synaptics.c
> > +++ b/drivers/input/mouse/synaptics.c
> > @@ -49,6 +49,12 @@ module_param(synaptics_multitouch, bool, 0644);
> >  MODULE_PARM_DESC(synaptics_multitouch,
> >                 "Enable multitouch mode on Synaptics devices");
> >
> > +static int synaptics_button_thresh = YMIN_NOMINAL + YMAX_NOMINAL;
> > +module_param(synaptics_button_thresh, int, 0644);
> > +MODULE_PARM_DESC(synaptics_button_thres,
> > +                "Y coordinate threshold of integrated buttons on Synaptics "
> > +                "devices");
> > +
> >  /*****************************************************************************
> >  *     Stuff we need even when we do not want native Synaptics support
> >  ****************************************************************************/
> > @@ -463,6 +469,10 @@ static void synaptics_parse_hw_state(unsigned char buf[], struct synaptics_data
> >        }
> >  }
> >
> > +#define TOUCH_OVER_BUTTON(hw) (((hw).left || (hw).middle || (hw).right) && \
> > +                              (YMAX_NOMINAL + YMIN_NOMINAL - (hw).y > \
> > +                               synaptics_button_thresh))
> > +
> >  /*
> >  *  called for each full received packet from the touchpad
> >  */
> > @@ -477,7 +487,7 @@ static void synaptics_process_packet(struct psmouse *psmouse)
> >        synaptics_parse_hw_state(psmouse->packet, priv, &hw);
> >
> >        if (SYN_MULTITOUCH(priv, &hw)) {
> > -               if (hw.z > 0) {
> > +               if (hw.z > 0 && !TOUCH_OVER_BUTTON(hw)) {
> >                        input_report_abs(dev, ABS_MT_POSITION_X, hw.x);
> >                        input_report_abs(dev, ABS_MT_POSITION_Y,
> >                                         YMAX_NOMINAL + YMIN_NOMINAL - hw.y);
> > @@ -509,6 +519,10 @@ static void synaptics_process_packet(struct psmouse *psmouse)
> >                return;
> >        }
> >
> > +       /* If touch occurs over depressed button, ignore it */
> > +       if (TOUCH_OVER_BUTTON(hw))
> > +               hw.z = 0;
> > +
> >        if (hw.z > 0) {
> >                priv->num_fingers++;
> >                finger_width = 5;
> > --
> > 1.7.1
> >
> >
> 
> I'm convinced now that clickpad style touchpads can't work without
> multi-touch and something like logic in xf86-input-multitouch.

Actually Clickpad works without multi-touch patch.  With my patches to
synaptics, it worked in some level.  There are many restrictions (e.g.
pushing the button first then drag), though.


Takashi
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