How to enable Raspberry pi 7" inch touch screen?


I installed Ubuntu mate on Raaspberry pi 3+ which is connected to a 7" inch touch screen display. The mouse and keyboard work fine but the touch on the touch screen does not work. How do I enable touch function? I have the touch screen HDMI connected to raspberry pi HDMI output. Please let me know.

Could some one please tell me how to enable touch screen in ubuntu mate?

I have same problem with Ubuntu Mate 20.04 on Rpi4. Touch screen is not working but usb mouse and keyboard are working. Any updates here? @admins

Seems that after an an sudo apt-get update && sudo apt-get upgrade and a reboot the touch screen is working now