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Date: Wed, 7 Jan 2015 16:02:29 +1000
From: Peter Hutterer <peter.hutterer@...-t.net>
To: Benjamin Tissoires <benjamin.tissoires@...il.com>
Cc: Gabriele Mazzotta <gabriele.mzt@...il.com>,
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 Mon, Jan 05, 2015 at 02:24:30PM -0500, 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.
synaptics doesn't actually use TOUCH_MAJOR for finger width, we just forward
it as axis information (not that anyone uses it).
dropping TOOL_WIDTH would only affect palm detection which unreliable, off
by default and mostly broken. so this is fine with me.
Cheers,
Peter
>
> >
> > 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);
> + }
> +
> /* 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
> >
> > --
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