topic Re: Touch screen loops on sending event in i.MX Processors

Touch screen loops on sending event

krzysztofsza_ac — Fri, 23 Jan 2015 06:41:26 GMT

Hello!

We're using touch screen controller with FT5206, while original var som mx6 board has FT5406. They belong to the same chip family and have the same kernel driver.

The problem is that for our touch controller, when I tap on screen it loops on sending signal, like it would still be touched. No matter where I tap, it behaves like Iwould tap on (0,0) and starts to drop down notification bar, see picture attached.

I've checked what's going on with getevent, and when I tap it keeps sending this:

root@android:/ # getevent /dev/input/event1

0003 0035 00000000

0003 0036 00000000

0000 0002 00000000

0000 0000 00000000

0003 0035 00000000

0003 0036 00000000

0000 0002 00000000

0000 0000 00000000

0003 0035 00000000

0003 0036 00000000

0000 0002 00000000

0000 0000 00000000

and so on...

The same in little better way:

root@android:/ # getevent -lt /dev/input/event1

[ 1462.463028] EV_ABS ABS_MT_POSITION_X 00000000

[ 1462.463031] EV_ABS ABS_MT_POSITION_Y 00000000

[ 1462.463033] EV_SYN SYN_MT_REPORT 00000000

[ 1462.463034] EV_SYN SYN_REPORT 00000000

Maybe this information will be also useful

root@android:/ # getevent -lp /dev/input/event1

add device 1: /dev/input/event1

name: "CTW6120 Touchscreen"

events:

ABS (0003): ABS_MT_POSITION_X : value 0, min 0, max 799, fuzz 0, flat 0, resolution 0

ABS_MT_POSITION_Y : value 0, min 0, max 479, fuzz 0, flat 0, resolution 0

input props:

<none>

This is for sure not problem of specific touchscreen, because when we changed to new one, problem still exists. Any ideas?

Re: Touch screen loops on sending event

CarlosCasillas — Tue, 27 Jan 2015 17:38:35 GMT

Hi,

Have you considered the differences between both controllers although being from the same family, or are you using the exact same driver with the other controller?

According with FT5x06 Datasheet, the FT5406 supports 28 TX and 16 RX Panel, while FT5206 supports 15 TX and 10 RX Panel, so, the differences may be the malfunction reasons if the driver is working properly with the FT5406 controller.

Hope this will be useful for you.
Best regards!
/Carlos

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Re: Touch screen loops on sending event

krzysztofsza_ac — Wed, 28 Jan 2015 07:10:33 GMT

Hello Carlos, yes - we know it. It should only affect precision of touch if FT5206 is connected with 7" touch panel. We can also suppose, that it's configured well to work with such panel, as we have it ordered as one device - touch panel with controller.

We suppose that problem is in driver or it's configuration. One thing is coordinate of (0,0) point and second is screen size in pixels. Is there any place in kernel that configuration on touch panel controller chip is done?