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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2016-07-25 21:36:54 +0300 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2016-07-28 00:20:09 +0300 |
| commit | 4097461897df91041382ff6fcd2bfa7ee6b2448c (patch) | |
| tree | 9bdfe6f3e9375ec8c23e7fd67ac8590c4f55939d /drivers/input/serio/libps2.c | |
| parent | 887ec0bfbd146c08e34ccb65a8f4251dc110e52f (diff) | |
| download | linux-4097461897df91041382ff6fcd2bfa7ee6b2448c.tar.xz | |
Input: i8042 - break load dependency between atkbd/psmouse and i8042
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: Mark Laws <mdl@60hz.org>
Tested-by: Mark Laws <mdl@60hz.org>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers/input/serio/libps2.c')
| -rw-r--r-- | drivers/input/serio/libps2.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c index 316f2c897101..83e9c663aa67 100644 --- a/drivers/input/serio/libps2.c +++ b/drivers/input/serio/libps2.c @@ -56,19 +56,17 @@ EXPORT_SYMBOL(ps2_sendbyte); void ps2_begin_command(struct ps2dev *ps2dev) { - mutex_lock(&ps2dev->cmd_mutex); + struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex; - if (i8042_check_port_owner(ps2dev->serio)) - i8042_lock_chip(); + mutex_lock(m); } EXPORT_SYMBOL(ps2_begin_command); void ps2_end_command(struct ps2dev *ps2dev) { - if (i8042_check_port_owner(ps2dev->serio)) - i8042_unlock_chip(); + struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex; - mutex_unlock(&ps2dev->cmd_mutex); + mutex_unlock(m); } EXPORT_SYMBOL(ps2_end_command); |