Does absolute mouse work correctly when two systems have very different (total) resolution? For example, one is a laptop with a single screen, and another one is a desktop with three screens.
So if you report the max x/y as 32767, and the current x/y as 32767, the host will translate it to the corner, regardless of size of screen.
Absolute mouse HID report has a logical/physical min/max, not just delta. Regardless of size of screen, min/max correspond to the boundaries in absolute mode.
So it's just keeping track internally of the incremental relative accumulation of your mouse as you move it, and i assume, when you hit the min/max, swapping screens.
I assume it's reporting a high enough min/max resolution to make this not happen crappily.
The polling rate on mice is usually only 125hz (8ms), so it has plenty of time to handle the input.
Even "gaming" mice are usually only 1000hz (1ms).
I would guess, looking at it, that it takes a few microseconds to handle the mouse moves, max.
Despite the USB protocol overhead, it is plenty even for a gaming mouse. Pretty sure there's no point polling it at above 1 kilohertz or so.
Even with a non polling mouse there would be no point in reading the result more than a thousand times per second. If you move the mouse 3 inches per second (quite fast) and you only process 1000 reports a second you would still achieve a resolution of 0.003 inches.