I would be nice to have an automatic detection that hardware cursor is really drawed on screen, and then save it to a log file, or activate the software cursor, or warning the user that hardware cursor is not working.

Is very common that hardware cursor does not work. It really scares a newbie trapped on runlevel 5, checking if "ubuntu can replace windows".

How to detect if hardware cursor is really drawed, and where:
1- Calculate Fast Fourier Transform of cursor image -FFT(cursor)-
2- Put cursor on expected place.
3- Calculate Fast Fourier Transform of pixel screen drawed. -FFT(screen)-
4- Divide (is complex numbers task) FFT(screen) by FFT(cursor). You get FFT(peak)
5- calculate inverse Fast Fourier Transform of FFT(Peak), and get -Peak-
5- Check if Peak have a peak on expected place. If not, then, move cursor, and find new peak.

Distance betwen peak can tell if cursor is moving, how much, or if is drawed at all.
The fast fourier transform can detect even if the mouse cursor is someway distorted (like dimmed, or brighted, or noisy), but if is assumed that only for being drawed, is drawed exactly as expected, then can simply being searched along the screen. If many buggy cursors are being drawed, then moving cursor can tell where is the real cursor.

Came on, givme that:

function_Check_hardware_cursor_is_drawed(RGBAlpha_screen is array of [real, real, real, real]; RGBAlpha_Cursor is array of [real, real, real, real] ) {
}

I fill the code. I can return the position of cursor, or an error flag.

I have asked for this enhancement feature on gnome, but them told me that is a X guys issue.