• Dmitry Torokhov's avatar
    Input: i8042 - break load dependency between atkbd/psmouse and i8042 · 40974618
    Dmitry Torokhov authored
    As explained in 1407814240-4275-1-git-send-email-decui@microsoft.com we
    have a hard load dependency between i8042 and atkbd which prevents
    keyboard from working on Gen2 Hyper-V VMs.
    
    > hyperv_keyboard invokes serio_interrupt(), which needs a valid serio
    > driver like atkbd.c.  atkbd.c depends on libps2.c because it invokes
    > ps2_command().  libps2.c depends on i8042.c because it invokes
    > i8042_check_port_owner().  As a result, hyperv_keyboard actually
    > depends on i8042.c.
    >
    > For a Generation 2 Hyper-V VM (meaning no i8042 device emulated), if a
    > Linux VM (like Arch Linux) happens to configure CONFIG_SERIO_I8042=m
    > rather than =y, atkbd.ko can't load because i8042.ko can't load(due to
    > no i8042 device emulated) and finally hyperv_keyboard can't work and
    > the user can't input: https://bugs.archlinux.org/task/39820
    > (Ubuntu/RHEL/SUSE aren't affected since they use CONFIG_SERIO_I8042=y)
    
    To break the dependency we move away from using i8042_check_port_owner()
    and instead allow serio port owner specify a mutex that clients should use
    to serialize PS/2 command stream.
    Reported-by: default avatarMark Laws <mdl@60hz.org>
    Tested-by: default avatarMark Laws <mdl@60hz.org>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
    40974618
serio.h 4.38 KB