It is important that the driver keeps a view of the system monitor layout so that it can direct the point of touch to the correct position within the system's monitor metrics. Given the driver process executes in a context where it might not have access to information about system monitor layouts this information is also held in the UPDD settings file tbupdd.ini in the setting monitorsetupmetrics
Example
monitorsetupmetrics=0:0:1079:1919:5760:0:1079:7679:0:0:1079:1919:3840:0:1079:5759:1920:0:1079:3839:0:0:1079:1919: repeated
Each group of 4 colon separated numbers gives the left , top, right, bottom co-ordinate of a monitor.
The first group is the primary monitor.
The second is the monitor 1 as seen by UPDD.
The third is monitor 2 as seen by UPDD.
And so forth.
In the example above it can be seen that Monitor 2 is set as the primary monitor.
For the positions that do not have an associated monitor (marked in green in the 4 monitor example above) the primary monitor values are recorded.
These value are set
1) On Windows during execution of the setup program.
2) During execution of the calibration program (All OS)
3) At system startup by aidaemom (All OS)
4) Optionally when a display setting changes by aidaemon. For this the dynamicmonitormetricssetting must be set which is by default on. If on (1) aidaemon recreates monitorsetupmetrics whenever a display change message is issued. Currently Windows only. This also caters for the relocation of the primary monitor.
This is a recent change in 5.1.1122 driver and hopefully will not cause any issues, especially when rotating in an extended desktop environment. In our tests all appears to work as expected.