[Interest] QT Touch handling bug

Fri Nov 17 09:11:55 CET 2017

Hello!

I am not sure how to contact you in the correct way or if I need to subscribe/join
to your organization, before asking questions about QT...

But I have the same problem with the qevdevtouch-handler, as described below.
I found this post, when googling the Net for info on the problem!

My question is, have anyone looked at this and is there a recommended
solution/work-around to solve this issue?

We are currently using the Qt version 5.6.2 and 5.7.1, but have not got around
to test this on the 5.7 version.
We have customers using the 5.6 version and they have the touch-problem...

Any information would be helpful!

The following was found at:
http://lists.qt-project.org/pipermail/development/2016-August/026786.html

Regards
Per

Per Görling

Field Application Engineer
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FROM: Rob Martens
Mon Aug 8 16:04:10 CEST 2016

I'm relatively sure this problem exposes a bug in qevdevtouchhandler.cpp. I

sometimes get a 0 reported from a touch event when I know the locations

from the driver never included a 0. I hope someone with experience

in QEvdevTouchScreenData::processInputEvent would look at it and see if

this isn't the case.

Thanks,

Rob

Problem Summary

Driver:

FocalTech ft5x06 TouchScreen driver.

ft5x06_ts.c

QT Code:

qevdevtouchhandler.cpp, within libQt5EglDeviceIntegration.so.5.5.0

Configuration:

type A processing (or not B type)

single touch is true

Description of problem:

When QEvdevTouchScreenData::processInputEvent gets the following (see

below) set of events an invalid touch location (always zero) is reported to

the qt Window. You can see below the full output trace (no other events

occurred).  When QT is processing the input events the second touch up

reports the y as 0, which is wrong.

The patterns seems to be the following. When QT doesn't get a ABS_Y

location after the last BTN_TOUCH Down, it reports y as 0 which is

incorrect. This always happens when y or x does not change between touches.

So if a user happens to touch in the same spot (like on a button) the

second click may not register.

Is this a problem with QT not keeping the previous Y or X location and

using that or is it a problem with the driver not reporting the X or Y

location after the touch down event? This is an annoying problem because it

means that on screens button presses are randomly missed.

QEvdevTouchScreenData::processInputEvent EV_KEY, BTN_TOUCH, 1 DOWN ******

QEvdevTouchScreenData::processInputEvent EV_ABS, ABS_X, 334

QEvdevTouchScreenData::processInputEvent EV_ABS, ABS_Y, 174

QEvdevTouchScreenData::processInputEvent EV_ABS, ABS_PRESSURE, 100

QEvdevTouchScreenData::processInputEvent EV_SYN, SYN_REPORT, 0

QEvdevTouchScreenData::addTouchPoint tp.rawPositions.append(QPointF(334,

174));

QEvdevTouchScreenData::processInputEvent reportPoints()

QWindowSystemInterface::handleTouchEvent m_touchPoints.count()=1 1

x=0.695833 y=0.639706

QEvdevTouchScreenData::processInputEvent EV_KEY, BTN_TOUCH, 0   UP

QEvdevTouchScreenData::processInputEvent EV_ABS, ABS_PRESSURE, 0

QEvdevTouchScreenData::processInputEvent EV_SYN, SYN_REPORT, 0

QEvdevTouchScreenData::addTouchPoint tp.rawPositions.append(QPointF(334,

174));

QEvdevTouchScreenData::processInputEvent reportPoints()

QWindowSystemInterface::handleTouchEvent m_touchPoints.count()=1 1

x=0.695833 y=0.639706

QEvdevTouchScreenData::processInputEvent EV_KEY, BTN_TOUCH, 1 DOWN

***************

QEvdevTouchScreenData::processInputEvent EV_ABS, ABS_X, 336

>>>>>>>>>>>>>>>>>>>>>>>>>> NOTICE Y not reported because it is the same

location as before

QEvdevTouchScreenData::processInputEvent EV_ABS, ABS_PRESSURE, 100

QEvdevTouchScreenData::processInputEvent EV_SYN, SYN_REPORT, 0

QEvdevTouchScreenData::addTouchPoint tp.rawPositions.append(QPointF(336, 0

));

QEvdevTouchScreenData::processInputEvent reportPoints()

QWindowSystemInterface::handleTouchEvent m_touchPoints.count()=1 1 0.700000

0.000000

QEvdevTouchScreenData::processInputEvent EV_KEY, BTN_TOUCH, 0   UP

QEvdevTouchScreenData::processInputEvent EV_ABS, ABS_PRESSURE, 0

QEvdevTouchScreenData::processInputEvent EV_SYN, SYN_REPORT, 0

QEvdevTouchScreenData::addTouchPoint  tp.rawPositions.append(QPointF(336, 0

));

QWindowSystemInterface::handleTouchEvent m_touchPoints.count()=1 1

x=0.700000 y=0.000000

DTS for ft5x06

dts

  ft5x06_ts at 38<http://lists.qt-project.org/mailman/listinfo/development> {

   compatible = "focaltech,5x06";

   reg = <0x38>;

   focaltech,family-id = <0x55>;

   pinctrl-names = "default";

   pinctrl-0 = <&ctw6120_pins>;

   interrupt-parent = <&gpio0>;

   interrupts = <3 IRQ_TYPE_EDGE_FALLING>;

   vdd-supply = <&touch_3v3_regulator>;

   vcc_i2c-supply = <&touch_3v3_regulator>;

   focaltech,irq-gpio = <&gpio0 3 0x00>;

   focaltech,display-coords = <0 0 480 272>;

   focaltech,name = "ft6x06";

   focaltech,no-force-update;

   focaltech,group-id = <1>;

   focaltech,hard-reset-delay-ms = <20>;

   focaltech,soft-reset-delay-ms = <150>;

   focaltech,num-max-touches = <1>;

   focaltech,fw-name = "ft_8610_qrd_fw.bin";

   focaltech,fw-delay-aa-ms = <100>;

   focaltech,fw-delay-55-ms = <30>;

   focaltech,fw-upgrade-id1 = <0x79>;

   focaltech,fw-upgrade-id2 = <0x08>;

   focaltech,fw-delay-readid-ms = <10>;

   focaltech,fw-delay-era-flsh-ms = <2000>;

   focaltech,fw-auto-cal;

   //focaltech,mirror_h;

   //focaltech,mirror_v;

   };

--

Rob Martens

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