Touchscreen, wrong finger motion coordinates when using kmsdrm backend

[jalih]

I noticed there is a problem with touchscreen finger motion coordinates on my system when using the kmsdrm backend. I have a touchscreen using 1024x600 resolution, SDL3 currently reports touchscreen max coordinates as:

x: 15.98462, y: 5.48409

I noticed evtest utility reports my touchscreen max values as:

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

A little bit of math gives us:

65535 / 1024 * 15.98462 = 1023.000
65535 / 600 * 5.48409 = 598.997

Should SDL3 do this normalization or mapping of coordinates to the actual screen resolution?