I want to use a Hanns-G HT225HPB 21.5" touch screen monitor with my Pi3B. This has a HDMI interface and a USB connection but says it is for 'Windows10'. The monitor works great but I can't get the touch to work at all. I have tried the USB connection to the Pi to no avail. Seems the HP L2105tm works OK but mine doesn't. At £180 it was a good buy and we want to use these for 'control panels' for a club model railway. It will use JAVA and JMRI. This works well on a Pi3 but only with a real mouse.
I can now answer my own question. The HANNS-G HT225HPB monitor works with my Pi3 (Jessie) without any extra drivers. It is a plug-and-play. However, I did need to install the xinput-calibrator.
sudo apt-get install xinput-calibrator
This now appears as an option in the preferences list and is a single point on the screen. Easy to use. The touch is now in the right place.
This is a really good monitor, at £180, and a good option if you want a large screen touch display instead of the 'official' but too small ones.
I had the same problem with Jessie & a Pi3. A firmware update of the monitor solved my problem. For the update you need a windows pc. After the update the touch (single click) works fine.
At the support website of Hannspree you can download the firmware: http://www.hannspree.eu/en/faq-touch-monitor#faqa3-2
I also used xinput-calibrator afterwards to fine tune the touch target detection.