@chaithubk
Are you reading from your device

continously
or just reading from it when device notifies you that data has arrived

In the scenario 1 device will misbehave like you have mentioned

@SGaist said:

Very interesting and detailed explanation, thanks !

I wonder wether Qt should automatically detect or not your multiple devices… That's a question you should bring to either the interest mailing list or the #qt IRC channel. You'll find there Qt's developers/maintainers (this forum is more user oriented)

Ah, thanks for the info! I will check out the mailing list and the IRC channel!

For my purposes, auto-detect is probably not necessary, but I am unsure about "the general case". Anyway, it would be interesting to get the developers input on why there is a difference in auto-detect behavior depending on driver capabilities, and whether that is intentional or a bug.

Thanks!

Cheers,

/johan

Driver was the the right way to go, thanks for pointing this out.

It turns out that the driver had a calibration method built in, but the transform matrix was not set to change the coordinates. I calculated the new matrix values based on the max coordinates displayed by evtest and the actual coordinates of the framebuffer, plugged them in to the driver code, compiled and ... it works!. Evtest displays correct coordinates and Qt works correctly with no tslib.
I don't like the fact that calibration matrix is hardcoded into the driver, but I consider fixing this an extracredit activity to be done sometime in the future.