I have been sleuthing to try and figure out how this thing works in the device:
The screen and touchscreen are made together by DJN:
The kernel config has this:
CONFIG_TABLET_USB_KBTAB=y
CONFIG_INPUT_TOUCHSCREEN=y
CONFIG_TOUCHSCREEN_HIMAX_CHIPSET=y
CONFIG_TOUCHSCREEN_HIMAX_INCELL=y
CONFIG_TOUCHSCREEN_HIMAX_IC_HX83112=y
CONFIG_TOUCHSCREEN_HIMAX_INSPECT=y
CONFIG_TOUCHSCREEN_HIMAX_COMMON=y
CONFIG_TOUCHSCREEN_HIMAX_DEBUG=y
# CONFIG_TOUCHSCREEN_HIMAX_EMBEDDED_FIRMWARE=y
# CONFIG_SECURE_TOUCH_SYNAPTICS_DSX is not set
# CONFIG_TOUCHSCREEN_SYNAPTICS_TCM_REFLASH is not set
# CONFIG_TOUCHSCREEN_SYNAPTICS_TCM_RECOVERY is not set
# CONFIG_TOUCHSCREEN_FTS is not set
Touchscreen controller chip seems to be:
HX83112
Described as a:
In-cell Touch Display Integrated Controller (TDIC)
So the kernel is getting data from i2c. In the inspection.h file they do have dummy and notch keywords but they are not used elsewhere. I believe the HX83112 could have writable firmware.
Looking at a Motorola devices’ LCD document on scribd I can see that the chipset is connected via SPI and I2C buses. These are digital signals. In the case of I2C it uses a single data pin to communicate.
Possibilities:
Raw panel has strange output
HX83112 firmware/interpretation problem
Kernel driver issue
Android interpretation of HID data from driver
I think this makes it unlikely to have anything to do with the connector as it should be a i2c signal going to the mainboard. It would have to be the connector between the touchscreen and the display driver board located somewhere on the LCD panel under tape?