Touchscreen mouse button emulation does not work on my system when kmsdrm backend is used. I noticed that finger motion events do come through, but the coordinates look strange. On my 1024x600 touchscreen coordinates of the bottom right corner of the screen are reported as: x = 15.98462 and y = 5.48409.
I tried the evtest utility and noticed that the max values are reported as 65535 instead of the device size:
Event type 3 (EV_ABS)
Event code 0 (ABS_X)
Value 512
Min 0
Max 65535
Event code 1 (ABS_Y)
Value 259
Min 0
Max 65535
Interestingly a little math gives us:
65535 / 1024 * 15.98462 = 1023.000
65535 / 600 * 5.48409 = 598.997
Should SDL handle this automatically? Is this a bug?