• Pali Rohár's avatar
    Input: ALPS - do not mix trackstick and external PS/2 mouse data · 04aae283
    Pali Rohár authored
    Previously dev2 device was used for both external PS/2 mouse and internal
    trackstick device (if available). This change introduces dev3 device which
    is used for external PS/2 mouse data and dev2 is now used only for
    trackstick.
    
    In case that trackstick is not present dev2 is not created, so userspace
    does not see non existent device in system.
    
    Because laptops with ALPS devices often do not use i8042 active
    multiplexing all data (from touchpad, trackstick and external PS/2 mouse)
    come to one port.  So it is not possible to know if external PS/2 mouse is
    connected or not. In most cases external PS/2 mouse is not connected so
    driver will create dev3 input device after first bare PS/2 packet will be
    received. So there will not be "ghost" input device.
    
    This change also helps in identifying possible problems in future if driver
    decides to report 6-bytes trackstick packets as 3-bytes bare PS/2 (data
    will be reported to dev3 instead dev2).
    Signed-off-by: default avatarPali Rohár <pali.rohar@gmail.com>
    Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
    04aae283
alps.h 7.18 KB