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Message-ID: <AANLkTi=G3xYm5+Wqv0quGGUhDEd7x8r7WJhN-tb6G=TA@mail.gmail.com>
Date: Mon, 11 Oct 2010 12:46:40 -0500
From: Chris Bagwell <chris@...bagwell.com>
To: Takashi Iwai <tiwai@...e.de>
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
On Mon, Oct 11, 2010 at 12:10 PM, Takashi Iwai <tiwai@...e.de> wrote:
> 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.
>
True, but if I understand synaptic hardware MT behavior (sends
actively moving finger in higher resolution packet regardless of
original finger touch) then your patch will result in jumpy cursor on
X side and that side would need patches to attempt to guess invalid
data and discard. I've worked on a few similar patches to various
xf86-input-* and generally they've failed to detect difference between
invalid packets vs. fast user movements.
The main point of my 3 options was to address jumpy cursor in
xf86-input-* that are not MT aware. I think ABS_X/ABS_Y should only
allow its meaning to change at detectable time periods so user can
account for it and, specifically, that time period is best at
transition of BTN_TOOL_DOUBLETAP.
Assuming its easy enough to support exact rules for ABS_X/ABS_Y
changing meanings on kernel side (which I think it probably is pretty
easy), I think we should do it so that applications don't have to
become MT-aware as the official solution for jumpy cursors.
Chris
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