Int 2F Fn 530B  U - ??? (mousepwr.com, Others) - ???                       [p]

   AX = 530Bh
   BX = subfunction
       0003h ???
       0004h ???
   ???

Return: ???

Note:  it appears that subfunction 0003h reads or restores the current mouse
     settings (the MS Mouse driver hooks AX=530Bh), and 0004h might be
     the converse