path: root/drivers/input/serio/libps2.c
diff options
authorDmitry Torokhov <dmitry.torokhov@gmail.com>2016-07-25 11:36:54 -0700
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2016-07-27 14:20:09 -0700
commit4097461897df91041382ff6fcd2bfa7ee6b2448c (patch)
tree9bdfe6f3e9375ec8c23e7fd67ac8590c4f55939d /drivers/input/serio/libps2.c
parentInput: synaptics-rmi4 - do not check for NULL when calling of_node_put() (diff)
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')
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);
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);