• Cameron Gutman's avatar
    Input: xpad - prevent spurious input from wired Xbox 360 controllers · 7013f7ca
    Cameron Gutman authored
    [ Upstream commit 1ff5fa3c ]
    After initially connecting a wired Xbox 360 controller or sending it
    a command to change LEDs, a status/response packet is interpreted as
    controller input. This causes the state of buttons represented in
    byte 2 of the controller data packet to be incorrect until the next
    valid input packet. Wireless Xbox 360 controllers are not affected.
    Writing a new value to the LED device while holding the Start button
    and running jstest is sufficient to reproduce this bug. An event will
    come through with the Start button released.
    Xboxdrv also won't attempt to read controller input from a packet
    where byte 0 is non-zero. It also checks that byte 1 is 0x14, but
    that value differs between wired and wireless controllers and this
    code is shared by both. I think just checking byte 0 is enough to
    eliminate unwanted packets.
    The following are some examples of 3-byte status packets I saw:
    01 03 02
    02 03 00
    03 03 03
    08 03 00
    Signed-off-by: default avatarCameron Gutman <aicommander@gmail.com>
    Signed-off-by: default avatarPavel Rojtberg <rojtberg@gmail.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
xpad.c 48 KB