Unfortunately a special kernel is needed (and no - DKMS is not enough) to make the touchscreen work.
This enables the touchscreen module and adds configuration for the touchscreen. During boot it will require additional firmware.
The firmware can be found here: https://github.com/m0ppers/gsl-firmware/tree/saphir-winpad-10-1/firmware/saphir/winpad_10_1
firmware.fw should be copied to /lib/firmware/silead/gsl1680-saphir-media-winpad-10.fw on the tablet.