Re: [PATCH v4] i8042: Add debug_kbd option

Re: [PATCH v4] i8042: Add debug_kbd option

[Andreas Mohr]

Hi,

[no In-Reply-To header - lkml.org "headers" is broken ATM]

> +
> +static bool i8042_debug_kbd;
> +module_param_named(debug_kbd, i8042_debug_kbd, bool, 0600);
> +MODULE_PARM_DESC(i8042_kbd, "Turn i8042 kbd debugging output on or off
> (requires i8042.debug=1)");

seems inconsistent:
i8042_debug_kbd != debug_kbd != i8042_kbd
While the first two seem perfectly fine,
"i8042_kbd" sounds like a build error or similar to me, on the severity front.

(grepping kernel tree drivers/ on quick glance
does not seem to show any naming deviations in the MODULE_PARM_DESC area)


> "Turn i8042 kbd debugging output on or off (requires i8042.debug=1)"
should be improved to
  "Turn i8042 kbd debugging output on (requires i8042.debug=1)"
(it *is* default-off)
The point is that it
(at least now that it reached current implementation version?)
merely *enables* additional output,
it does *not* actively *disable* (veto)
something which may have been default-enabled elsewhere.


Also, since this is about "special" situations only
(many standard situations already have this output enabled),
it should be worded to somehow include this "special" enabling.

Also, I'd prefer to also see the *reason*
for it being default-disabled in modinfo output.

Also, "i8042" is useless (since completely scope-superfluous) information
(this *is* i8042 driver)

So perhaps wording in total could be something like
"Turn kbd debugging output unconditionally on (may reveal sensitive data)"
or possibly best
"Unconditional enable (may reveal sensitive data) of normally sanitize-filtered kbd data traffic log"

and in combination:
"[DESCRIPTION] (pre-condition: i8042.debug=1 enabled)"

"kbd debugging output"
could be shortened to
"kbd debug log"

So, a final suggestion might be:
"Unconditional enable (may reveal sensitive data) of normally sanitize-filtered kbd data traffic debug log [pre-condition: i8042.debug=1 enabled]"


And given that this description is now completely different,
one might choose to rename debug_kbd variable
to something more specific, too
("debug_full" / "debug_data" / "debug_traffic"?).


> +	i8042.debug_kbd [HW] Enable printing of interrupt data from the
> KBD port
> +			     (disabled by default, requires that
> i8042.debug=1
> +			     be enabled)
is not correct - code implementation definitely conveys
that it needs to be "*and* requires"
(especially since current wording strongly suggests that
*while it's default-disabled*,
i8042.debug_kbd will be implicitly enabled once i8042.debug=1 is available,
which is wrong).

Perhaps write it as something like
"and as pre-condition requires i8042.debug=1 to be enabled too".



Definitely very good to see this (quote) "big problem" corrected!

Thanks,

Andreas Mohr

[PATCH v5] i8042: Add unmask_kbd_data option

[cpaul]

From: Stephen Chandler Paul <cpaul@redhat.com>

A big problem with the current i8042 debugging option is that it outputs
data going to and from the keyboard by default. As a result, many dmesg
logs uploaded by users will unintentionally contain sensitive information
such as their password, as such it's probably a good idea not to output
data coming from the keyboard unless specifically enabled by the user.

Signed-off-by: Stephen Chandler Paul <cpaul@redhat.com>
---
				    Changes
* Fix incorrect option name in MODULE_PARM_DESC() (I have no idea how that
  happened in the first place)
* Replaced the description with one of the suggestions given by Andreas
* Rename debug_kbd to unmask_kbd_data
* Improve description in Documentation/kernel-parameters.txt

 Documentation/kernel-parameters.txt |  4 ++++
 drivers/input/serio/i8042.c         | 43 +++++++++++++++++++++++++++++++++----
 drivers/input/serio/i8042.h         | 13 +++++++++++
 drivers/input/serio/serio.c         |  4 +---
 include/linux/serio.h               |  2 ++
 5 files changed, 59 insertions(+), 7 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ae44749..352a5f1 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1304,6 +1304,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			     <bus_id>,<clkrate>
 
 	i8042.debug	[HW] Toggle i8042 debug mode
+	i8042.unmask_kbd_data
+			[HW] Enable printing of interrupt data from the KBD port
+			     (disabled by default, and as a pre-condition
+			     requires that i8042.debug=1 be enabled)
 	i8042.direct	[HW] Put keyboard port into non-translated mode
 	i8042.dumbkbd	[HW] Pretend that controller can only read data from
 			     keyboard and cannot control its state
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index cb5ece7..e6d1529 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -88,6 +88,10 @@ MODULE_PARM_DESC(nopnp, "Do not use PNP to detect controller settings");
 static bool i8042_debug;
 module_param_named(debug, i8042_debug, bool, 0600);
 MODULE_PARM_DESC(debug, "Turn i8042 debugging mode on and off");
+
+static bool i8042_unmask_kbd_data;
+module_param_named(unmask_kbd_data, i8042_unmask_kbd_data, bool, 0600);
+MODULE_PARM_DESC(unmask_kbd_data, "Unconditional enable (may reveal sensitive data) of normally sanitize-filtered kbd data traffic debug log [pre-condition: i8042.debug=1 enabled]");
 #endif
 
 static bool i8042_bypass_aux_irq_test;
@@ -116,6 +120,7 @@ struct i8042_port {
 	struct serio *serio;
 	int irq;
 	bool exists;
+	bool driver_bound;
 	signed char mux;
 };
 
@@ -133,6 +138,7 @@ static bool i8042_kbd_irq_registered;
 static bool i8042_aux_irq_registered;
 static unsigned char i8042_suppress_kbd_ack;
 static struct platform_device *i8042_platform_device;
+static struct notifier_block i8042_kbd_bind_notifier_block;
 
 static irqreturn_t i8042_interrupt(int irq, void *dev_id);
 static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
@@ -528,10 +534,10 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 	port = &i8042_ports[port_no];
 	serio = port->exists ? port->serio : NULL;
 
-	dbg("%02x <- i8042 (interrupt, %d, %d%s%s)\n",
-	    data, port_no, irq,
-	    dfl & SERIO_PARITY ? ", bad parity" : "",
-	    dfl & SERIO_TIMEOUT ? ", timeout" : "");
+	filter_dbg(port->driver_bound, data, "<- i8042 (interrupt, %d, %d%s%s)\n",
+		   port_no, irq,
+		   dfl & SERIO_PARITY ? ", bad parity" : "",
+		   dfl & SERIO_TIMEOUT ? ", timeout" : "");
 
 	filtered = i8042_filter(data, str, serio);
 
@@ -1438,6 +1444,29 @@ static int __init i8042_setup_kbd(void)
 	return error;
 }
 
+static int i8042_kbd_bind_notifier(struct notifier_block *nb,
+				   unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct serio *serio = to_serio_port(dev);
+	struct i8042_port *port = serio->port_data;
+
+	if (serio != i8042_ports[I8042_KBD_PORT_NO].serio)
+		return 0;
+
+	switch (action) {
+	case BUS_NOTIFY_BOUND_DRIVER:
+		port->driver_bound = true;
+		break;
+
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		port->driver_bound = false;
+		break;
+	}
+
+	return 0;
+}
+
 static int __init i8042_probe(struct platform_device *dev)
 {
 	int error;
@@ -1507,6 +1536,10 @@ static struct platform_driver i8042_driver = {
 	.shutdown	= i8042_shutdown,
 };
 
+static struct notifier_block i8042_kbd_bind_notifier_block = {
+	.notifier_call = i8042_kbd_bind_notifier,
+};
+
 static int __init i8042_init(void)
 {
 	struct platform_device *pdev;
@@ -1528,6 +1561,7 @@ static int __init i8042_init(void)
 		goto err_platform_exit;
 	}
 
+	bus_register_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
 	panic_blink = i8042_panic_blink;
 
 	return 0;
@@ -1543,6 +1577,7 @@ static void __exit i8042_exit(void)
 	platform_driver_unregister(&i8042_driver);
 	i8042_platform_exit();
 
+	bus_unregister_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
 	panic_blink = NULL;
 }
 
diff --git a/drivers/input/serio/i8042.h b/drivers/input/serio/i8042.h
index fc080be..1db0a40 100644
--- a/drivers/input/serio/i8042.h
+++ b/drivers/input/serio/i8042.h
@@ -73,6 +73,17 @@ static unsigned long i8042_start_time;
 			printk(KERN_DEBUG KBUILD_MODNAME ": [%d] " format,	\
 			       (int) (jiffies - i8042_start_time), ##arg);	\
 	} while (0)
+
+#define filter_dbg(filter, data, format, args...)		\
+	do {							\
+		if (!i8042_debug)				\
+			break;					\
+								\
+		if (!filter || i8042_unmask_kbd_data)		\
+			dbg("%02x " format, data, ##args);	\
+		else						\
+			dbg("** " format, ##args);		\
+	} while (0)
 #else
 #define dbg_init() do { } while (0)
 #define dbg(format, arg...)							\
@@ -80,6 +91,8 @@ static unsigned long i8042_start_time;
 		if (0)								\
 			printk(KERN_DEBUG pr_fmt(format), ##arg);		\
 	} while (0)
+
+#define filter_dbg(filter, data, format, args...) do { } while (0)
 #endif
 
 #endif /* _I8042_H */
diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index a05a517..63422d2 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -49,8 +49,6 @@ static DEFINE_MUTEX(serio_mutex);
 
 static LIST_HEAD(serio_list);
 
-static struct bus_type serio_bus;
-
 static void serio_add_port(struct serio *serio);
 static int serio_reconnect_port(struct serio *serio);
 static void serio_disconnect_port(struct serio *serio);
@@ -1017,7 +1015,7 @@ irqreturn_t serio_interrupt(struct serio *serio,
 }
 EXPORT_SYMBOL(serio_interrupt);
 
-static struct bus_type serio_bus = {
+struct bus_type serio_bus = {
 	.name		= "serio",
 	.drv_groups	= serio_driver_groups,
 	.match		= serio_bus_match,
diff --git a/include/linux/serio.h b/include/linux/serio.h
index 9f779c7..df4ab5d 100644
--- a/include/linux/serio.h
+++ b/include/linux/serio.h
@@ -18,6 +18,8 @@
 #include <linux/mod_devicetable.h>
 #include <uapi/linux/serio.h>
 
+extern struct bus_type serio_bus;
+
 struct serio {
 	void *port_data;
 
-- 
2.4.3

Re: [PATCH v5] i8042: Add unmask_kbd_data option

[Andreas Mohr]

On Thu, Jul 02, 2015 at 11:46:48AM -0400, cpaul@redhat.com wrote:
> 				    Changes
> * Fix incorrect option name in MODULE_PARM_DESC() (I have no idea how that
>   happened in the first place)
> * Replaced the description with one of the suggestions given by Andreas
> * Rename debug_kbd to unmask_kbd_data
> * Improve description in Documentation/kernel-parameters.txt

Patch in its entirety seems fine to me, thanks!

Reviewed-by: Andreas Mohr <andim2@users.sf.net>

Re: [PATCH v5] i8042: Add unmask_kbd_data option

[Benjamin Tissoires]

On Jul 02 2015 or thereabouts, cpaul@redhat.com wrote:
> From: Stephen Chandler Paul <cpaul@redhat.com>
> 
> A big problem with the current i8042 debugging option is that it outputs
> data going to and from the keyboard by default. As a result, many dmesg
> logs uploaded by users will unintentionally contain sensitive information
> such as their password, as such it's probably a good idea not to output
> data coming from the keyboard unless specifically enabled by the user.
> 
> Signed-off-by: Stephen Chandler Paul <cpaul@redhat.com>
> ---

FWIW, in case you are missing my input Dmitry:
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Thanks everyone involved in this process!

Cheers,
Benjamin

> 				    Changes
> * Fix incorrect option name in MODULE_PARM_DESC() (I have no idea how that
>   happened in the first place)
> * Replaced the description with one of the suggestions given by Andreas
> * Rename debug_kbd to unmask_kbd_data
> * Improve description in Documentation/kernel-parameters.txt
> 
>  Documentation/kernel-parameters.txt |  4 ++++
>  drivers/input/serio/i8042.c         | 43 +++++++++++++++++++++++++++++++++----
>  drivers/input/serio/i8042.h         | 13 +++++++++++
>  drivers/input/serio/serio.c         |  4 +---
>  include/linux/serio.h               |  2 ++
>  5 files changed, 59 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index ae44749..352a5f1 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1304,6 +1304,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>  			     <bus_id>,<clkrate>
>  
>  	i8042.debug	[HW] Toggle i8042 debug mode
> +	i8042.unmask_kbd_data
> +			[HW] Enable printing of interrupt data from the KBD port
> +			     (disabled by default, and as a pre-condition
> +			     requires that i8042.debug=1 be enabled)
>  	i8042.direct	[HW] Put keyboard port into non-translated mode
>  	i8042.dumbkbd	[HW] Pretend that controller can only read data from
>  			     keyboard and cannot control its state
> diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
> index cb5ece7..e6d1529 100644
> --- a/drivers/input/serio/i8042.c
> +++ b/drivers/input/serio/i8042.c
> @@ -88,6 +88,10 @@ MODULE_PARM_DESC(nopnp, "Do not use PNP to detect controller settings");
>  static bool i8042_debug;
>  module_param_named(debug, i8042_debug, bool, 0600);
>  MODULE_PARM_DESC(debug, "Turn i8042 debugging mode on and off");
> +
> +static bool i8042_unmask_kbd_data;
> +module_param_named(unmask_kbd_data, i8042_unmask_kbd_data, bool, 0600);
> +MODULE_PARM_DESC(unmask_kbd_data, "Unconditional enable (may reveal sensitive data) of normally sanitize-filtered kbd data traffic debug log [pre-condition: i8042.debug=1 enabled]");
>  #endif
>  
>  static bool i8042_bypass_aux_irq_test;
> @@ -116,6 +120,7 @@ struct i8042_port {
>  	struct serio *serio;
>  	int irq;
>  	bool exists;
> +	bool driver_bound;
>  	signed char mux;
>  };
>  
> @@ -133,6 +138,7 @@ static bool i8042_kbd_irq_registered;
>  static bool i8042_aux_irq_registered;
>  static unsigned char i8042_suppress_kbd_ack;
>  static struct platform_device *i8042_platform_device;
> +static struct notifier_block i8042_kbd_bind_notifier_block;
>  
>  static irqreturn_t i8042_interrupt(int irq, void *dev_id);
>  static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
> @@ -528,10 +534,10 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
>  	port = &i8042_ports[port_no];
>  	serio = port->exists ? port->serio : NULL;
>  
> -	dbg("%02x <- i8042 (interrupt, %d, %d%s%s)\n",
> -	    data, port_no, irq,
> -	    dfl & SERIO_PARITY ? ", bad parity" : "",
> -	    dfl & SERIO_TIMEOUT ? ", timeout" : "");
> +	filter_dbg(port->driver_bound, data, "<- i8042 (interrupt, %d, %d%s%s)\n",
> +		   port_no, irq,
> +		   dfl & SERIO_PARITY ? ", bad parity" : "",
> +		   dfl & SERIO_TIMEOUT ? ", timeout" : "");
>  
>  	filtered = i8042_filter(data, str, serio);
>  
> @@ -1438,6 +1444,29 @@ static int __init i8042_setup_kbd(void)
>  	return error;
>  }
>  
> +static int i8042_kbd_bind_notifier(struct notifier_block *nb,
> +				   unsigned long action, void *data)
> +{
> +	struct device *dev = data;
> +	struct serio *serio = to_serio_port(dev);
> +	struct i8042_port *port = serio->port_data;
> +
> +	if (serio != i8042_ports[I8042_KBD_PORT_NO].serio)
> +		return 0;
> +
> +	switch (action) {
> +	case BUS_NOTIFY_BOUND_DRIVER:
> +		port->driver_bound = true;
> +		break;
> +
> +	case BUS_NOTIFY_UNBOUND_DRIVER:
> +		port->driver_bound = false;
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
>  static int __init i8042_probe(struct platform_device *dev)
>  {
>  	int error;
> @@ -1507,6 +1536,10 @@ static struct platform_driver i8042_driver = {
>  	.shutdown	= i8042_shutdown,
>  };
>  
> +static struct notifier_block i8042_kbd_bind_notifier_block = {
> +	.notifier_call = i8042_kbd_bind_notifier,
> +};
> +
>  static int __init i8042_init(void)
>  {
>  	struct platform_device *pdev;
> @@ -1528,6 +1561,7 @@ static int __init i8042_init(void)
>  		goto err_platform_exit;
>  	}
>  
> +	bus_register_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
>  	panic_blink = i8042_panic_blink;
>  
>  	return 0;
> @@ -1543,6 +1577,7 @@ static void __exit i8042_exit(void)
>  	platform_driver_unregister(&i8042_driver);
>  	i8042_platform_exit();
>  
> +	bus_unregister_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
>  	panic_blink = NULL;
>  }
>  
> diff --git a/drivers/input/serio/i8042.h b/drivers/input/serio/i8042.h
> index fc080be..1db0a40 100644
> --- a/drivers/input/serio/i8042.h
> +++ b/drivers/input/serio/i8042.h
> @@ -73,6 +73,17 @@ static unsigned long i8042_start_time;
>  			printk(KERN_DEBUG KBUILD_MODNAME ": [%d] " format,	\
>  			       (int) (jiffies - i8042_start_time), ##arg);	\
>  	} while (0)
> +
> +#define filter_dbg(filter, data, format, args...)		\
> +	do {							\
> +		if (!i8042_debug)				\
> +			break;					\
> +								\
> +		if (!filter || i8042_unmask_kbd_data)		\
> +			dbg("%02x " format, data, ##args);	\
> +		else						\
> +			dbg("** " format, ##args);		\
> +	} while (0)
>  #else
>  #define dbg_init() do { } while (0)
>  #define dbg(format, arg...)							\
> @@ -80,6 +91,8 @@ static unsigned long i8042_start_time;
>  		if (0)								\
>  			printk(KERN_DEBUG pr_fmt(format), ##arg);		\
>  	} while (0)
> +
> +#define filter_dbg(filter, data, format, args...) do { } while (0)
>  #endif
>  
>  #endif /* _I8042_H */
> diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
> index a05a517..63422d2 100644
> --- a/drivers/input/serio/serio.c
> +++ b/drivers/input/serio/serio.c
> @@ -49,8 +49,6 @@ static DEFINE_MUTEX(serio_mutex);
>  
>  static LIST_HEAD(serio_list);
>  
> -static struct bus_type serio_bus;
> -
>  static void serio_add_port(struct serio *serio);
>  static int serio_reconnect_port(struct serio *serio);
>  static void serio_disconnect_port(struct serio *serio);
> @@ -1017,7 +1015,7 @@ irqreturn_t serio_interrupt(struct serio *serio,
>  }
>  EXPORT_SYMBOL(serio_interrupt);
>  
> -static struct bus_type serio_bus = {
> +struct bus_type serio_bus = {
>  	.name		= "serio",
>  	.drv_groups	= serio_driver_groups,
>  	.match		= serio_bus_match,
> diff --git a/include/linux/serio.h b/include/linux/serio.h
> index 9f779c7..df4ab5d 100644
> --- a/include/linux/serio.h
> +++ b/include/linux/serio.h
> @@ -18,6 +18,8 @@
>  #include <linux/mod_devicetable.h>
>  #include <uapi/linux/serio.h>
>  
> +extern struct bus_type serio_bus;
> +
>  struct serio {
>  	void *port_data;
>  
> -- 
> 2.4.3
> 

Re: [PATCH v5] i8042: Add unmask_kbd_data option

[Dmitry Torokhov]

Hi Stephen,

On Thu, Jul 02, 2015 at 11:46:48AM -0400, cpaul@redhat.com wrote:
> +static int i8042_kbd_bind_notifier(struct notifier_block *nb,
> +				   unsigned long action, void *data)
> +{
> +	struct device *dev = data;
> +	struct serio *serio = to_serio_port(dev);
> +	struct i8042_port *port = serio->port_data;
> +
> +	if (serio != i8042_ports[I8042_KBD_PORT_NO].serio)
> +		return 0;
> +
> +	switch (action) {
> +	case BUS_NOTIFY_BOUND_DRIVER:
> +		port->driver_bound = true;
> +		break;
> +
> +	case BUS_NOTIFY_UNBOUND_DRIVER:

I think it should be BUS_NOTIFY_UNBIND_DRIVER so that we see the KBD
data as it goes through driver cleanup. Yell if you disagree, or I'll
change it locally.

Thanks.

-- 
Dmitry

Re: [PATCH v5] i8042: Add unmask_kbd_data option

[Stephen Chandler Paul]

On Wed, 2015-07-15 at 09:59 -0700, Dmitry Torokhov wrote:
> Hi Stephen,
> 
> On Thu, Jul 02, 2015 at 11:46:48AM -0400, cpaul@redhat.com wrote:
> > +static int i8042_kbd_bind_notifier(struct notifier_block *nb,
> > +				   unsigned long action, void 
> > *data)
> > +{
> > +	struct device *dev = data;
> > +	struct serio *serio = to_serio_port(dev);
> > +	struct i8042_port *port = serio->port_data;
> > +
> > +	if (serio != i8042_ports[I8042_KBD_PORT_NO].serio)
> > +		return 0;
> > +
> > +	switch (action) {
> > +	case BUS_NOTIFY_BOUND_DRIVER:
> > +		port->driver_bound = true;
> > +		break;
> > +
> > +	case BUS_NOTIFY_UNBOUND_DRIVER:
> 
> I think it should be BUS_NOTIFY_UNBIND_DRIVER so that we see the KBD
> data as it goes through driver cleanup. Yell if you disagree, or I'll
> change it locally.
Sounds good to me

Cheers,
	Stephen Chandler Paul

> 
> Thanks.
> 

[PATCH v4] i8042: Add debug_kbd option

[cpaul]

From: Stephen Chandler Paul <cpaul@redhat.com>

A big problem with the current i8042 debugging option is that it outputs
data going to and from the keyboard by default. As a result, many dmesg
logs uploaded by users will unintentionally contain sensitive information
such as their password, as such it's probably a good idea not to output
data coming from the keyboard unless specifically enabled by the user.

Signed-off-by: Stephen Chandler Paul <cpaul@redhat.com>
---
				    Changes
* Remove #ifdefs around notifier code
* Rename i8042_port.filter_dbg to i8042.driver_bound
* Instead of checking the parent of the current device, compare serio against
  i8042_ports[I8042_KBD_PORT_NO].serio
* Use a switch case instead of an if-else when checking the action in the bus
  notifier
* Export serio_bus into serio.h, register the bus notifiers at module load time
  as opposed to port registration time

 Documentation/kernel-parameters.txt |  3 +++
 drivers/input/serio/i8042.c         | 43 +++++++++++++++++++++++++++++++++----
 drivers/input/serio/i8042.h         | 13 +++++++++++
 drivers/input/serio/serio.c         |  4 +---
 include/linux/serio.h               |  2 ++
 5 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ae44749..a9d2b19 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1304,6 +1304,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			     <bus_id>,<clkrate>
 
 	i8042.debug	[HW] Toggle i8042 debug mode
+	i8042.debug_kbd [HW] Enable printing of interrupt data from the KBD port
+			     (disabled by default, requires that i8042.debug=1
+			     be enabled)
 	i8042.direct	[HW] Put keyboard port into non-translated mode
 	i8042.dumbkbd	[HW] Pretend that controller can only read data from
 			     keyboard and cannot control its state
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index cb5ece7..e29d6a4 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -88,6 +88,10 @@ MODULE_PARM_DESC(nopnp, "Do not use PNP to detect controller settings");
 static bool i8042_debug;
 module_param_named(debug, i8042_debug, bool, 0600);
 MODULE_PARM_DESC(debug, "Turn i8042 debugging mode on and off");
+
+static bool i8042_debug_kbd;
+module_param_named(debug_kbd, i8042_debug_kbd, bool, 0600);
+MODULE_PARM_DESC(i8042_kbd, "Turn i8042 kbd debugging output on or off (requires i8042.debug=1)");
 #endif
 
 static bool i8042_bypass_aux_irq_test;
@@ -116,6 +120,7 @@ struct i8042_port {
 	struct serio *serio;
 	int irq;
 	bool exists;
+	bool driver_bound;
 	signed char mux;
 };
 
@@ -133,6 +138,7 @@ static bool i8042_kbd_irq_registered;
 static bool i8042_aux_irq_registered;
 static unsigned char i8042_suppress_kbd_ack;
 static struct platform_device *i8042_platform_device;
+static struct notifier_block i8042_kbd_bind_notifier_block;
 
 static irqreturn_t i8042_interrupt(int irq, void *dev_id);
 static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
@@ -528,10 +534,10 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 	port = &i8042_ports[port_no];
 	serio = port->exists ? port->serio : NULL;
 
-	dbg("%02x <- i8042 (interrupt, %d, %d%s%s)\n",
-	    data, port_no, irq,
-	    dfl & SERIO_PARITY ? ", bad parity" : "",
-	    dfl & SERIO_TIMEOUT ? ", timeout" : "");
+	filter_dbg(port->driver_bound, data, "<- i8042 (interrupt, %d, %d%s%s)\n",
+		   port_no, irq,
+		   dfl & SERIO_PARITY ? ", bad parity" : "",
+		   dfl & SERIO_TIMEOUT ? ", timeout" : "");
 
 	filtered = i8042_filter(data, str, serio);
 
@@ -1438,6 +1444,29 @@ static int __init i8042_setup_kbd(void)
 	return error;
 }
 
+static int i8042_kbd_bind_notifier(struct notifier_block *nb,
+				   unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct serio *serio = to_serio_port(dev);
+	struct i8042_port *port = serio->port_data;
+
+	if (serio != i8042_ports[I8042_KBD_PORT_NO].serio)
+		return 0;
+
+	switch (action) {
+	case BUS_NOTIFY_BOUND_DRIVER:
+		port->driver_bound = true;
+		break;
+
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		port->driver_bound = false;
+		break;
+	}
+
+	return 0;
+}
+
 static int __init i8042_probe(struct platform_device *dev)
 {
 	int error;
@@ -1507,6 +1536,10 @@ static struct platform_driver i8042_driver = {
 	.shutdown	= i8042_shutdown,
 };
 
+static struct notifier_block i8042_kbd_bind_notifier_block = {
+	.notifier_call = i8042_kbd_bind_notifier,
+};
+
 static int __init i8042_init(void)
 {
 	struct platform_device *pdev;
@@ -1528,6 +1561,7 @@ static int __init i8042_init(void)
 		goto err_platform_exit;
 	}
 
+	bus_register_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
 	panic_blink = i8042_panic_blink;
 
 	return 0;
@@ -1543,6 +1577,7 @@ static void __exit i8042_exit(void)
 	platform_driver_unregister(&i8042_driver);
 	i8042_platform_exit();
 
+	bus_unregister_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
 	panic_blink = NULL;
 }
 
diff --git a/drivers/input/serio/i8042.h b/drivers/input/serio/i8042.h
index fc080be..a198f0d 100644
--- a/drivers/input/serio/i8042.h
+++ b/drivers/input/serio/i8042.h
@@ -73,6 +73,17 @@ static unsigned long i8042_start_time;
 			printk(KERN_DEBUG KBUILD_MODNAME ": [%d] " format,	\
 			       (int) (jiffies - i8042_start_time), ##arg);	\
 	} while (0)
+
+#define filter_dbg(filter, data, format, args...)		\
+	do {							\
+		if (!i8042_debug)				\
+			break;					\
+								\
+		if (!filter || i8042_debug_kbd)			\
+			dbg("%02x " format, data, ##args);	\
+		else						\
+			dbg("** " format, ##args);		\
+	} while (0)
 #else
 #define dbg_init() do { } while (0)
 #define dbg(format, arg...)							\
@@ -80,6 +91,8 @@ static unsigned long i8042_start_time;
 		if (0)								\
 			printk(KERN_DEBUG pr_fmt(format), ##arg);		\
 	} while (0)
+
+#define filter_dbg(filter, data, format, args...) do { } while (0)
 #endif
 
 #endif /* _I8042_H */
diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index a05a517..63422d2 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -49,8 +49,6 @@ static DEFINE_MUTEX(serio_mutex);
 
 static LIST_HEAD(serio_list);
 
-static struct bus_type serio_bus;
-
 static void serio_add_port(struct serio *serio);
 static int serio_reconnect_port(struct serio *serio);
 static void serio_disconnect_port(struct serio *serio);
@@ -1017,7 +1015,7 @@ irqreturn_t serio_interrupt(struct serio *serio,
 }
 EXPORT_SYMBOL(serio_interrupt);
 
-static struct bus_type serio_bus = {
+struct bus_type serio_bus = {
 	.name		= "serio",
 	.drv_groups	= serio_driver_groups,
 	.match		= serio_bus_match,
diff --git a/include/linux/serio.h b/include/linux/serio.h
index 9f779c7..df4ab5d 100644
--- a/include/linux/serio.h
+++ b/include/linux/serio.h
@@ -18,6 +18,8 @@
 #include <linux/mod_devicetable.h>
 #include <uapi/linux/serio.h>
 
+extern struct bus_type serio_bus;
+
 struct serio {
 	void *port_data;
 
-- 
2.4.3