White ring round a touch point in Android on i.MX6

[YongJunChang]

Hello all,

We are working on porting JB4.3 onto our i.MX6-based customized board. The board is desinged being based on a i.MX6 SABRE.

We've done a lot so that almost everything is working except touchscreen. When the device is boot-up, a white circle shows on a screen.

This is different from what we can enable in 'Settings-Developer options-Show touches'. In order to click something, first I have to move this circle by dragging it.

Then have to double click the circle to make 'single-touch'. This is very wierd and never have seen before when I developed using i.MX5 and GB.

Do you have any idea what this feature is?

[EricNelson]

Hello Yong Chang,

You need to create an input descriptor file (/system/usr/idc/MYTOUCHSCREENDEV.idc)

that tells Android that the particular input driver is a touch screen. What you're seing

now is Android interpreting the device as a mouse (of sorts).

You can normally just copy the file HannStar_P1003_Touchscreen.idc to a file

named MYTOUCHSCREENDEV.idc, where "MYTOUCHSCREENDEV" is

the name of your touch screen as reported in the "Name" field in /proc/bus/input/devices.

I think the actual filename appears in the output of 'adb logcat "V:*"' (verbose logcat).