Chalkboard Electronics 7" touch screen: no touch

VinzC

Hi again.

I have a 7" open frame touch screen from Chalkboard Electronics that I need to use with Android 4.4. So far everything works but touching screen does only move the mouse pointer, just as described in a forum I found somewhere on the internet.

The touch screen is advertised on the invoice as capacitive mutli-touch. However it is detected by lsusb as 04D8:F723, which is the vendor:product ID of a *single* touch device. It should hence return 04D8:F724.

Here's what I've done:

• I have tried to upgrade the touch screen firmware to version 2.2, single touch, driverless. No change: touching the screen only moves the pointer, no activation of reactive areas.
• I have tried upgrading to firmware 2.2, multitouch but then touching the screen doesn't even move the pointer. I checked the system though and did find no hid-multitouch.ko kernel driver so I guess that's pretty normal. On the other hand lsusb expectedly detects the screen HID as 04D8:F724.
  

So in the end I don't have a clear idea what to do:

• I could go through patching and compiling the multitouch kernel driver but I need a matching toolchain, right? And then I don't even know what kernel config is used by the android 4.4 distribution that has been built for Orange Pi Mini...
• Or I could just use the single-touch feature but then I have no idea how to make touches work, that's the only thing that misses so far.
  

Facts:

• The touch screen works with Linux and kernel 3.18 at least, both ARM and x86.
• The touch screen works with Windows 7 at least.
• The touch screen works with android x86 versions 2.2 up to 4.0 but not with 4.4 and above.
  

Can anyone help?