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Date:	Mon, 05 Jan 2015 21:18:29 +0100
From:	Gabriele Mazzotta <gabriele.mzt@...il.com>
To:	Benjamin Tissoires <benjamin.tissoires@...il.com>
Cc:	Peter Hutterer <peter.hutterer@...-t.net>,
	Hans de Goede <hdegoede@...hat.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Henrik Rydberg <rydberg@...omail.se>,
	linux-input <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Maxwell Anselm <silverhammermba@...il.com>
Subject: Re: [PATCH 1/2] input: synaptics - make image sensors report ABS_MT_TOUCH_MAJOR

On Monday 05 January 2015 21:13:09 Gabriele Mazzotta wrote:
> On Monday 05 January 2015 14:24:30 Benjamin Tissoires wrote:
> > Hi Gabriele,
> > 
> > [Adding Peter and Hans as this change will impact both
> > xf86-input-synaptics and libinput]
> > 
> > On Sat, Dec 27, 2014 at 6:31 AM, Gabriele Mazzotta
> > <gabriele.mzt@...il.com> wrote:
> > > Despite claiming to be able to report ABS_TOOL_WIDTH, image sensors
> > > were not doing it. Make them report widths and use ABS_MT_TOUCH_MAJOR
> > > instead ABS_TOOL_WIDTH.
> > 
> > It looks like the current xorg-synaptics code already handles
> > ABS_MT_TOUCH_MAJOR as finger_width. So I think we should be good in
> > replacing the ABS_TOOL_WIDTH event. However, I'd prefer having Peter
> > confirm this because xorg-synaptics still relies a lot on the single
> > touch emulation.
> 
> Yes, xorg-synaptics handles ABS_MT_TOUCH_MAJOR, I sent the patch for it.
> The width of the fingers is used only for the two fingers emulation and
> the palm detection, both of which are broken on image sensors as the
> width is never reported.
> 
> I'm normally using hid-rmi for my touchpad which never sends
> ABS_TOOL_WIDTH and everything seems to work correctly. Same for
> synaptics with this patch, although it seems that the pressure drops
> drastically when there are more than one finger, so this must be taken
> into account when defining the threshold values. I'll double check that
> everything is correct for 'z'.

It was wrong

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 808c8e3..b3aed2e 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -590,7 +590,7 @@ static void synaptics_parse_agm(const unsigned char buf[],
                          ((buf[5] & 0x01) << 2)) + 8;
                agm->x = (((buf[4] & 0x0f) << 8) | (buf[1] & 0xfe)) << 1;
                agm->y = (((buf[4] & 0xf0) << 4) | (buf[2] & 0xfe)) << 1;
-               agm->z = ((buf[3] & 0x30) | (buf[5] & 0x0e)) << 1;
+               agm->z = ((buf[3] & 0x30) | (buf[5] & 0x0e)) << 2;
                break;
 
        case 2:

> > >
> > > Since the 'w' slot is used to report the finger count when two or more
> > > fingers are on the touchpad, make sure that only meaningful values are
> > > emitted, i.e. values greater than or equal to 4, and assign the correct
> > > range to ABS_MT_TOUCH_MAJOR.
> > >
> > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=77161
> > > Signed-off-by: Gabriele Mazzotta <gabriele.mzt@...il.com>
> > > ---
> > >  drivers/input/mouse/synaptics.c | 11 +++++++++--
> > >  1 file changed, 9 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> > > index f947292..ea0563e 100644
> > > --- a/drivers/input/mouse/synaptics.c
> > > +++ b/drivers/input/mouse/synaptics.c
> > > @@ -814,6 +814,8 @@ static void synaptics_report_slot(struct input_dev *dev, int slot,
> > 
> > Just FYI, this does not apply anymore on top of Dmitry's tree.
> > synaptics_report_slot() has been removed, and you should now report
> > the slot state in synaptics_report_mt_data().
> > 
> > >         input_report_abs(dev, ABS_MT_POSITION_X, hw->x);
> > >         input_report_abs(dev, ABS_MT_POSITION_Y, synaptics_invert_y(hw->y));
> > >         input_report_abs(dev, ABS_MT_PRESSURE, hw->z);
> > > +       if (hw->w >= 4)
> > 
> > That I don't like. IMO, at this point, .w should only contain the
> > finger width, unconditionally.
> > Also, with 2/2, .w is computed accurately for the second finger, but
> > not for the first.
> > 
> > I tried to figure out a way to properly extract the actual width
> > information from the sgm packet when the w is 0 or 1, and the only way
> > I found was to do the fix in synaptics_image_sensor_process(). I would
> > have preferred dealing with that in synaptics_parse_hw_state()
> > directly, but I think the final code would be more and more ugly.
> > Dealing with the true finger width in synaptics_image_sensor_process()
> > is not a problem for cr48 sensors, because they will not have the
> > ABS_MT_TOUCH_MAJOR event exported.
> > 
> > Anyway, something like that "should" work (sorry for the tab/space,
> > gmail in use), of course, this is untested when I send the mail :) :
> > 
> > diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> > index 95c15451..caf7ccd 100644
> > --- a/drivers/input/mouse/synaptics.c
> > +++ b/drivers/input/mouse/synaptics.c
> > @@ -852,6 +852,17 @@ static void synaptics_image_sensor_process(struct
> > psmouse *psmouse,
> >         else
> >                 num_fingers = 4;
> > 
> > +       /* When multiple fingers are on the TouchPad, the width is encoded in
> > +        * X, Y and Z */
> > +       if (sgm->w == 0 || sgm->w == 1) {
> > +               sgm->w = ((sgm->x & BIT(1)) >> 1) |
> > +                         (sgm->y & BIT(1)) |
> > +                        ((sgm->z & BIT(0)) << 1);
> > +               sgm->x &= ~BIT(1);
> > +               sgm->y &= ~BIT(1);
> > +               sgm->z &= ~BIT(0);
> > +       }
> > +
> 
> It works perfectly with some adjustments:
> 
> 	/* When multiple fingers are on the TouchPad, the width is encoded in
> 	 * X, Y and Z */
> 	if (sgm->w == 0 || sgm->w == 1) {
> 		sgm->w = (((sgm->x & BIT(1)) >> 1) |
> 			  (sgm->y & BIT(1)) |
> 			  ((sgm->z & BIT(0)) << 2)) + 8;
> 		sgm->x &= ~BIT(1);
> 		sgm->y &= ~BIT(1);
> 		sgm->z &= ~BIT(0);
> 	}
> 
> >         /* Send resulting input events to user space */
> >         synaptics_report_mt_data(psmouse, sgm, num_fingers);
> >  }
> > 
> > 
> > > +               input_report_abs(dev, ABS_MT_TOUCH_MAJOR, hw->w);
> > >  }
> > >
> > >  static void synaptics_report_mt_data(struct psmouse *psmouse,
> > > @@ -1462,8 +1464,13 @@ static void set_input_params(struct psmouse *psmouse,
> > >                                         INPUT_MT_TRACK : INPUT_MT_SEMI_MT));
> > >         }
> > >
> > > -       if (SYN_CAP_PALMDETECT(priv->capabilities))
> > > -               input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0);
> > > +       if (SYN_CAP_PALMDETECT(priv->capabilities)) {
> > > +               if (SYN_CAP_IMAGE_SENSOR(priv->ext_cap_0c))
> > > +                       input_set_abs_params(dev,
> > > +                                            ABS_MT_TOUCH_MAJOR, 4, 15, 0, 0);
> > > +               else
> > > +                       input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0);
> > > +       }
> > 
> > Again, I'd prefer having Peter's point of view here.
> > 
> > If we really need both, we will need to change input-mt to also
> > emulate ABS_TOOL_WIDTH from ABS_MT_TOUCH_MAJOR like we do between
> > ABS_MT_POSITION_X|Y and ABS_X|Y.
> > 
> > Cheers,
> > Benjamin
> > 
> > >
> > >         __set_bit(BTN_TOUCH, dev->keybit);
> > >         __set_bit(BTN_TOOL_FINGER, dev->keybit);
> > > --
> > > 2.1.4
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-input" in
> > > the body of a message to majordomo@...r.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html

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