Input: libps2 - additional locking for i8042 ports
The serio ports on i8042 are not completely isolated; while we provide
enough locking to ensure proper serialization when accessing control
and data registers AUX and KBD ports can still have an effect on each
other on PS/2 protocol level. The most prominent effect is that
issuing a command for the device connected to one port may cause
abort of the command currently executing by the device connected to
another port.
Since i8042 nor serio subsystem are not aware of the details of the
PS/2 protocol (length of the commands and their replies and so on) the
locking should be done on libps2 level by adding special handling when
we see that we are dealing with serio port on i8042.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
index 3a95b50..769ba65 100644
--- a/drivers/input/serio/libps2.c
+++ b/drivers/input/serio/libps2.c
@@ -17,6 +17,7 @@
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/serio.h>
+#include <linux/i8042.h>
#include <linux/init.h>
#include <linux/libps2.h>
@@ -54,6 +55,24 @@
}
EXPORT_SYMBOL(ps2_sendbyte);
+void ps2_begin_command(struct ps2dev *ps2dev)
+{
+ mutex_lock(&ps2dev->cmd_mutex);
+
+ if (i8042_check_port_owner(ps2dev->serio))
+ i8042_lock_chip();
+}
+EXPORT_SYMBOL(ps2_begin_command);
+
+void ps2_end_command(struct ps2dev *ps2dev)
+{
+ if (i8042_check_port_owner(ps2dev->serio))
+ i8042_unlock_chip();
+
+ mutex_unlock(&ps2dev->cmd_mutex);
+}
+EXPORT_SYMBOL(ps2_end_command);
+
/*
* ps2_drain() waits for device to transmit requested number of bytes
* and discards them.
@@ -66,7 +85,7 @@
maxbytes = sizeof(ps2dev->cmdbuf);
}
- mutex_lock(&ps2dev->cmd_mutex);
+ ps2_begin_command(ps2dev);
serio_pause_rx(ps2dev->serio);
ps2dev->flags = PS2_FLAG_CMD;
@@ -76,7 +95,8 @@
wait_event_timeout(ps2dev->wait,
!(ps2dev->flags & PS2_FLAG_CMD),
msecs_to_jiffies(timeout));
- mutex_unlock(&ps2dev->cmd_mutex);
+
+ ps2_end_command(ps2dev);
}
EXPORT_SYMBOL(ps2_drain);
@@ -237,9 +257,9 @@
{
int rc;
- mutex_lock(&ps2dev->cmd_mutex);
+ ps2_begin_command(ps2dev);
rc = __ps2_command(ps2dev, param, command);
- mutex_unlock(&ps2dev->cmd_mutex);
+ ps2_end_command(ps2dev);
return rc;
}