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* [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting
@ 2017-04-09 13:56 Carlo Caione
  2017-04-09 13:56 ` [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state Carlo Caione
                   ` (2 more replies)
  0 siblings, 3 replies; 13+ messages in thread
From: Carlo Caione @ 2017-04-09 13:56 UTC (permalink / raw)
  To: dvhart, andy, platform-driver-x86, linux-kernel, linux; +Cc: Carlo Caione

From: Carlo Caione <carlo@endlessm.com>

Several HP laptops cannot be put to sleep using the LID since systemd complains
that the system is docked even though the laptop is not even dockable (see
[1]).

This is due to a bug in hp-wmi where the driver is failing to check for errors
before creating the input switches.

[1]: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1574120

Carlo Caione (2):
  hp-wmi: Fix error value for hp_wmi_tablet_state
  hp-wmi: Fix detection for dock and tablet mode

 drivers/platform/x86/hp-wmi.c | 42 ++++++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 14 deletions(-)

-- 
2.9.3

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state
  2017-04-09 13:56 [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
@ 2017-04-09 13:56 ` Carlo Caione
  2017-04-19 16:21   ` Andy Shevchenko
  2017-04-09 13:56 ` [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode Carlo Caione
  2017-04-13  6:28 ` [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
  2 siblings, 1 reply; 13+ messages in thread
From: Carlo Caione @ 2017-04-09 13:56 UTC (permalink / raw)
  To: dvhart, andy, platform-driver-x86, linux-kernel, linux; +Cc: Carlo Caione

From: Carlo Caione <carlo@endlessm.com>

hp_wmi_tablet_state() fails to return the correct error code when
hp_wmi_perform_query() returns the HP WMI query specific error code
that is a positive value.

Signed-off-by: Carlo Caione <carlo@endlessm.com>
---
 drivers/platform/x86/hp-wmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
index 96ffda4..13ba65c 100644
--- a/drivers/platform/x86/hp-wmi.c
+++ b/drivers/platform/x86/hp-wmi.c
@@ -290,7 +290,7 @@ static int hp_wmi_tablet_state(void)
 	int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, &state,
 				       sizeof(state), sizeof(state));
 	if (ret)
-		return ret;
+		return -EINVAL;
 
 	return (state & 0x4) ? 1 : 0;
 }
-- 
2.9.3

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode
  2017-04-09 13:56 [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
  2017-04-09 13:56 ` [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state Carlo Caione
@ 2017-04-09 13:56 ` Carlo Caione
  2017-04-13 18:21   ` Darren Hart
  2017-04-13  6:28 ` [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
  2 siblings, 1 reply; 13+ messages in thread
From: Carlo Caione @ 2017-04-09 13:56 UTC (permalink / raw)
  To: dvhart, andy, platform-driver-x86, linux-kernel, linux; +Cc: Carlo Caione

From: Carlo Caione <carlo@endlessm.com>

The current driver code is not checking for the error values returned by
'hp_wmi_dock_state()' and 'hp_wmi_tablet_state()' before passing the
returned values down to 'input_report_switch()'. This error code is
being translated to '1' in the input subsystem, reporting the wrong
status.

The biggest problem caused by this issue is that several laptops are
wrongly reported by the driver as docked, preventing them to be put to
sleep using the LID (and in most cases they are not even dockable).

With this patch we create the report switches only if we are able to
read the dock and tablet mode status correctly from ACPI.

Signed-off-by: Carlo Caione <carlo@endlessm.com>
---
 drivers/platform/x86/hp-wmi.c | 40 +++++++++++++++++++++++++++-------------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
index 13ba65c..2b721fd 100644
--- a/drivers/platform/x86/hp-wmi.c
+++ b/drivers/platform/x86/hp-wmi.c
@@ -572,10 +572,12 @@ static void hp_wmi_notify(u32 value, void *context)
 
 	switch (event_id) {
 	case HPWMI_DOCK_EVENT:
-		input_report_switch(hp_wmi_input_dev, SW_DOCK,
-				    hp_wmi_dock_state());
-		input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
-				    hp_wmi_tablet_state());
+		if (test_bit(SW_DOCK, hp_wmi_input_dev->swbit))
+			input_report_switch(hp_wmi_input_dev, SW_DOCK,
+					    hp_wmi_dock_state());
+		if (test_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit))
+			input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
+					    hp_wmi_tablet_state());
 		input_sync(hp_wmi_input_dev);
 		break;
 	case HPWMI_PARK_HDD:
@@ -644,6 +646,7 @@ static int __init hp_wmi_input_setup(void)
 {
 	acpi_status status;
 	int err;
+	int val;
 
 	hp_wmi_input_dev = input_allocate_device();
 	if (!hp_wmi_input_dev)
@@ -654,17 +657,26 @@ static int __init hp_wmi_input_setup(void)
 	hp_wmi_input_dev->id.bustype = BUS_HOST;
 
 	__set_bit(EV_SW, hp_wmi_input_dev->evbit);
-	__set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
-	__set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
+
+	/* Dock */
+	val = hp_wmi_dock_state();
+	if (!(val < 0)) {
+		__set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
+		input_report_switch(hp_wmi_input_dev, SW_DOCK, val);
+	}
+
+	/* Tablet mode */
+	val = hp_wmi_tablet_state();
+	if (!(val < 0)) {
+		__set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
+		input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE, val);
+	}
 
 	err = sparse_keymap_setup(hp_wmi_input_dev, hp_wmi_keymap, NULL);
 	if (err)
 		goto err_free_dev;
 
 	/* Set initial hardware state */
-	input_report_switch(hp_wmi_input_dev, SW_DOCK, hp_wmi_dock_state());
-	input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
-			    hp_wmi_tablet_state());
 	input_sync(hp_wmi_input_dev);
 
 	if (!hp_wmi_bios_2009_later() && hp_wmi_bios_2008_later())
@@ -950,10 +962,12 @@ static int hp_wmi_resume_handler(struct device *device)
 	 * changed.
 	 */
 	if (hp_wmi_input_dev) {
-		input_report_switch(hp_wmi_input_dev, SW_DOCK,
-				    hp_wmi_dock_state());
-		input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
-				    hp_wmi_tablet_state());
+		if (test_bit(SW_DOCK, hp_wmi_input_dev->swbit))
+			input_report_switch(hp_wmi_input_dev, SW_DOCK,
+					    hp_wmi_dock_state());
+		if (test_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit))
+			input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
+					    hp_wmi_tablet_state());
 		input_sync(hp_wmi_input_dev);
 	}
 
-- 
2.9.3

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting
  2017-04-09 13:56 [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
  2017-04-09 13:56 ` [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state Carlo Caione
  2017-04-09 13:56 ` [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode Carlo Caione
@ 2017-04-13  6:28 ` Carlo Caione
  2017-04-13 17:23   ` Darren Hart
  2 siblings, 1 reply; 13+ messages in thread
From: Carlo Caione @ 2017-04-13  6:28 UTC (permalink / raw)
  To: Carlo Caione
  Cc: dvhart, andy, platform-driver-x86, linux-kernel, Linux Upstreaming Team

On Sun, Apr 9, 2017 at 3:56 PM, Carlo Caione <carlo@caione.org> wrote:
> From: Carlo Caione <carlo@endlessm.com>
>
> Several HP laptops cannot be put to sleep using the LID since systemd complains
> that the system is docked even though the laptop is not even dockable (see
> [1]).
>
> This is due to a bug in hp-wmi where the driver is failing to check for errors
> before creating the input switches.
>
> [1]: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1574120
>
> Carlo Caione (2):
>   hp-wmi: Fix error value for hp_wmi_tablet_state
>   hp-wmi: Fix detection for dock and tablet mode

Gentle ping.

-- 
Carlo Caione  |  +39.340.80.30.096  |  Endless

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting
  2017-04-13  6:28 ` [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
@ 2017-04-13 17:23   ` Darren Hart
  0 siblings, 0 replies; 13+ messages in thread
From: Darren Hart @ 2017-04-13 17:23 UTC (permalink / raw)
  To: Carlo Caione
  Cc: Carlo Caione, andy, platform-driver-x86, linux-kernel,
	Linux Upstreaming Team

On Thu, Apr 13, 2017 at 08:28:38AM +0200, Carlo Caione wrote:
> On Sun, Apr 9, 2017 at 3:56 PM, Carlo Caione <carlo@caione.org> wrote:
> > From: Carlo Caione <carlo@endlessm.com>
> >
> > Several HP laptops cannot be put to sleep using the LID since systemd complains
> > that the system is docked even though the laptop is not even dockable (see
> > [1]).
> >
> > This is due to a bug in hp-wmi where the driver is failing to check for errors
> > before creating the input switches.
> >
> > [1]: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1574120
> >
> > Carlo Caione (2):
> >   hp-wmi: Fix error value for hp_wmi_tablet_state
> >   hp-wmi: Fix detection for dock and tablet mode
> 
> Gentle ping.

Hi Carlo,

To set expectations. I try to get to patches within 48 hours, but depending on a
variety of things it can be as long as a week under normal circumstances. If you
do not hear a response within a week, please do ping. At 4 days, this is just a
little long, but not out of the norm. I'll get to these today.

-- 
Darren Hart
VMware Open Source Technology Center

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode
  2017-04-09 13:56 ` [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode Carlo Caione
@ 2017-04-13 18:21   ` Darren Hart
  2017-04-13 20:09     ` Carlo Caione
  0 siblings, 1 reply; 13+ messages in thread
From: Darren Hart @ 2017-04-13 18:21 UTC (permalink / raw)
  To: Carlo Caione; +Cc: andy, platform-driver-x86, linux-kernel, linux, Carlo Caione

On Sun, Apr 09, 2017 at 03:56:08PM +0200, Carlo Caione wrote:
> From: Carlo Caione <carlo@endlessm.com>
> 
> The current driver code is not checking for the error values returned by
> 'hp_wmi_dock_state()' and 'hp_wmi_tablet_state()' before passing the
> returned values down to 'input_report_switch()'. This error code is
> being translated to '1' in the input subsystem, reporting the wrong
> status.
> 
> The biggest problem caused by this issue is that several laptops are
> wrongly reported by the driver as docked, preventing them to be put to
> sleep using the LID (and in most cases they are not even dockable).
> 
> With this patch we create the report switches only if we are able to
> read the dock and tablet mode status correctly from ACPI.
> 
> Signed-off-by: Carlo Caione <carlo@endlessm.com>
> ---
>  drivers/platform/x86/hp-wmi.c | 40 +++++++++++++++++++++++++++-------------
>  1 file changed, 27 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
> index 13ba65c..2b721fd 100644
> --- a/drivers/platform/x86/hp-wmi.c
> +++ b/drivers/platform/x86/hp-wmi.c
> @@ -572,10 +572,12 @@ static void hp_wmi_notify(u32 value, void *context)
>  
>  	switch (event_id) {
>  	case HPWMI_DOCK_EVENT:
> -		input_report_switch(hp_wmi_input_dev, SW_DOCK,
> -				    hp_wmi_dock_state());
> -		input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
> -				    hp_wmi_tablet_state());
> +		if (test_bit(SW_DOCK, hp_wmi_input_dev->swbit))
> +			input_report_switch(hp_wmi_input_dev, SW_DOCK,
> +					    hp_wmi_dock_state());
> +		if (test_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit))
> +			input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
> +					    hp_wmi_tablet_state());
>  		input_sync(hp_wmi_input_dev);
>  		break;
>  	case HPWMI_PARK_HDD:
> @@ -644,6 +646,7 @@ static int __init hp_wmi_input_setup(void)
>  {
>  	acpi_status status;
>  	int err;
> +	int val;
>  
>  	hp_wmi_input_dev = input_allocate_device();
>  	if (!hp_wmi_input_dev)
> @@ -654,17 +657,26 @@ static int __init hp_wmi_input_setup(void)
>  	hp_wmi_input_dev->id.bustype = BUS_HOST;
>  
>  	__set_bit(EV_SW, hp_wmi_input_dev->evbit);
> -	__set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
> -	__set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
> +
> +	/* Dock */
> +	val = hp_wmi_dock_state();
> +	if (!(val < 0)) {
> +		__set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
> +		input_report_switch(hp_wmi_input_dev, SW_DOCK, val);
> +	}

In general, these are fine and can go in. I did want to get your opinion on one
thought though.

This adds some complexity to deal with what appears to be an unknown failure
mode (the query fails, we don't know why, so we don't set the bit on the input
dev for that feature). Since we don't know why it fails, can we be confident it
will always fail? Could it succeed at init here, but then fail later and leave
us in the same situation we are in now?

If so, have you considered just returning 0 on error and using a WARN_ONCE print
statement to report the error? This would simplify a lot of this logic that
you're adding in here to handle something we could just report and ignore.

That being said, your version avoids the input_report_switch() in the event of a
failure at init. In practice, I don't know if this is worth the added
complexity.

Your thoughts?

> +
> +	/* Tablet mode */
> +	val = hp_wmi_tablet_state();
> +	if (!(val < 0)) {
> +		__set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
> +		input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE, val);
> +	}
>  
>  	err = sparse_keymap_setup(hp_wmi_input_dev, hp_wmi_keymap, NULL);
>  	if (err)
>  		goto err_free_dev;
>  
>  	/* Set initial hardware state */
> -	input_report_switch(hp_wmi_input_dev, SW_DOCK, hp_wmi_dock_state());
> -	input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
> -			    hp_wmi_tablet_state());
>  	input_sync(hp_wmi_input_dev);
>  
>  	if (!hp_wmi_bios_2009_later() && hp_wmi_bios_2008_later())
> @@ -950,10 +962,12 @@ static int hp_wmi_resume_handler(struct device *device)
>  	 * changed.
>  	 */
>  	if (hp_wmi_input_dev) {
> -		input_report_switch(hp_wmi_input_dev, SW_DOCK,
> -				    hp_wmi_dock_state());
> -		input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
> -				    hp_wmi_tablet_state());
> +		if (test_bit(SW_DOCK, hp_wmi_input_dev->swbit))
> +			input_report_switch(hp_wmi_input_dev, SW_DOCK,
> +					    hp_wmi_dock_state());
> +		if (test_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit))
> +			input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
> +					    hp_wmi_tablet_state());
>  		input_sync(hp_wmi_input_dev);
>  	}
>  
> -- 
> 2.9.3
> 
> 

-- 
Darren Hart
VMware Open Source Technology Center

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode
  2017-04-13 18:21   ` Darren Hart
@ 2017-04-13 20:09     ` Carlo Caione
  2017-04-13 23:07       ` Darren Hart
  0 siblings, 1 reply; 13+ messages in thread
From: Carlo Caione @ 2017-04-13 20:09 UTC (permalink / raw)
  To: Darren Hart
  Cc: Carlo Caione, andy, platform-driver-x86, linux-kernel,
	Linux Upstreaming Team

On Thu, Apr 13, 2017 at 8:21 PM, Darren Hart <dvhart@infradead.org> wrote:
> On Sun, Apr 09, 2017 at 03:56:08PM +0200, Carlo Caione wrote:
>> From: Carlo Caione <carlo@endlessm.com>

/cut
>> @@ -644,6 +646,7 @@ static int __init hp_wmi_input_setup(void)
>>  {
>>       acpi_status status;
>>       int err;
>> +     int val;
>>
>>       hp_wmi_input_dev = input_allocate_device();
>>       if (!hp_wmi_input_dev)
>> @@ -654,17 +657,26 @@ static int __init hp_wmi_input_setup(void)
>>       hp_wmi_input_dev->id.bustype = BUS_HOST;
>>
>>       __set_bit(EV_SW, hp_wmi_input_dev->evbit);
>> -     __set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
>> -     __set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
>> +
>> +     /* Dock */
>> +     val = hp_wmi_dock_state();
>> +     if (!(val < 0)) {
>> +             __set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
>> +             input_report_switch(hp_wmi_input_dev, SW_DOCK, val);
>> +     }
>
> In general, these are fine and can go in. I did want to get your opinion on one
> thought though.
>
> This adds some complexity to deal with what appears to be an unknown failure
> mode (the query fails, we don't know why, so we don't set the bit on the input
> dev for that feature). Since we don't know why it fails, can we be confident it
> will always fail?

That's not exactly true, at least for the firmware I have on the
laptop I'm working on.

For this hardware (can we assume for all the HP models?) when the WMI
calls returns the value of 0x04, that means that the query
(HPWMI_HARDWARE_QUERY in this case) is not implemented at all in the
SSDT.
In general reading the disassembled AML code when the WMI query fails
and returns a positive value this can be:
- 0x04: Query ID is unknown / not implemented but valid
- 0x02: Wrong signature
- 0x05: Wrong / invalid query number (?)

The problem here is that: (1) this is my personal interpretation of
the AML code obtained by disassembling the SSDT and (2) we cannot be
sure that this is the same on all the HP firmwares around.
For sure in general in all the cases I extracted from the SSDT table
on this hardware if the call failed the first time all the chances are
that it is going to fail also in the future.

In [1] is the SSDT table, the WMI method is WMAA if you want to check
my interpretation.

> Could it succeed at init here, but then fail later and leave
> us in the same situation we are in now?

I think that this is really unlikely

> If so, have you considered just returning 0 on error and using a WARN_ONCE print
> statement to report the error? This would simplify a lot of this logic that
> you're adding in here to handle something we could just report and ignore.

Yes, I thought to report just 0 but in that case we are advertising to
userspace fake capabilities for the hardware, like dockability or
laptop mode that in most cases are not even implemented on the
hardware (like on this laptop).

> That being said, your version avoids the input_report_switch() in the event of a
> failure at init. In practice, I don't know if this is worth the added
> complexity.
>
> Your thoughts?

AFAICT we can fail in hp_wmi_perform_query (as written in the comment
to the function):
1) with -EINVAL if the query was not successful or the output buffer
size exceeds buffersize. In this case I don't see how the next calls
could be successful.
2) with a positive error code returned from the WMI method. Given my
interpretation of this positive code reported before I don't see why
we should fail only on init and not on all the subsequent calls

So I'm still convinced that my implementation is correct and that
probably adding complexity on top is not really worth it. But of
course this is your call as maintainer :)

Thanks,

[1] https://paste.fedoraproject.org/paste/bBnqUlazz1tAjKsJKq7NHl5M1UNdIGYhyRLivL9gydE=

-- 
Carlo Caione  |  +39.340.80.30.096  |  Endless

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode
  2017-04-13 20:09     ` Carlo Caione
@ 2017-04-13 23:07       ` Darren Hart
  2017-04-19 16:23         ` Andy Shevchenko
  0 siblings, 1 reply; 13+ messages in thread
From: Darren Hart @ 2017-04-13 23:07 UTC (permalink / raw)
  To: Carlo Caione
  Cc: Carlo Caione, andy, platform-driver-x86, linux-kernel,
	Linux Upstreaming Team

On Thu, Apr 13, 2017 at 10:09:43PM +0200, Carlo Caione wrote:
> On Thu, Apr 13, 2017 at 8:21 PM, Darren Hart <dvhart@infradead.org> wrote:
> > On Sun, Apr 09, 2017 at 03:56:08PM +0200, Carlo Caione wrote:
> >> From: Carlo Caione <carlo@endlessm.com>
> 
> /cut
> >> @@ -644,6 +646,7 @@ static int __init hp_wmi_input_setup(void)
> >>  {
> >>       acpi_status status;
> >>       int err;
> >> +     int val;
> >>
> >>       hp_wmi_input_dev = input_allocate_device();
> >>       if (!hp_wmi_input_dev)
> >> @@ -654,17 +657,26 @@ static int __init hp_wmi_input_setup(void)
> >>       hp_wmi_input_dev->id.bustype = BUS_HOST;
> >>
> >>       __set_bit(EV_SW, hp_wmi_input_dev->evbit);
> >> -     __set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
> >> -     __set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
> >> +
> >> +     /* Dock */
> >> +     val = hp_wmi_dock_state();
> >> +     if (!(val < 0)) {
> >> +             __set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
> >> +             input_report_switch(hp_wmi_input_dev, SW_DOCK, val);
> >> +     }
> >
> > In general, these are fine and can go in. I did want to get your opinion on one
> > thought though.
> >
> > This adds some complexity to deal with what appears to be an unknown failure
> > mode (the query fails, we don't know why, so we don't set the bit on the input
> > dev for that feature). Since we don't know why it fails, can we be confident it
> > will always fail?
> 
> That's not exactly true, at least for the firmware I have on the
> laptop I'm working on.
> 
> For this hardware (can we assume for all the HP models?) when the WMI
> calls returns the value of 0x04, that means that the query
> (HPWMI_HARDWARE_QUERY in this case) is not implemented at all in the
> SSDT.
> In general reading the disassembled AML code when the WMI query fails
> and returns a positive value this can be:
> - 0x04: Query ID is unknown / not implemented but valid
> - 0x02: Wrong signature
> - 0x05: Wrong / invalid query number (?)
> 
> The problem here is that: (1) this is my personal interpretation of
> the AML code obtained by disassembling the SSDT and (2) we cannot be
> sure that this is the same on all the HP firmwares around.
> For sure in general in all the cases I extracted from the SSDT table
> on this hardware if the call failed the first time all the chances are
> that it is going to fail also in the future.
> 
> In [1] is the SSDT table, the WMI method is WMAA if you want to check
> my interpretation.
> 
> > Could it succeed at init here, but then fail later and leave
> > us in the same situation we are in now?
> 
> I think that this is really unlikely
> 
> > If so, have you considered just returning 0 on error and using a WARN_ONCE print
> > statement to report the error? This would simplify a lot of this logic that
> > you're adding in here to handle something we could just report and ignore.
> 
> Yes, I thought to report just 0 but in that case we are advertising to
> userspace fake capabilities for the hardware, like dockability or
> laptop mode that in most cases are not even implemented on the
> hardware (like on this laptop).

OK, I'm convinced that this approach is correct.

> 
> > That being said, your version avoids the input_report_switch() in the event of a
> > failure at init. In practice, I don't know if this is worth the added
> > complexity.
> >
> > Your thoughts?
> 
> AFAICT we can fail in hp_wmi_perform_query (as written in the comment
> to the function):
> 1) with -EINVAL if the query was not successful or the output buffer
> size exceeds buffersize. In this case I don't see how the next calls
> could be successful.


EINVAL is being used to broadly here. If the input values are incorrect, then
yes -EINVAL is the right response. However, if the query was unsuccessful, that
is more appropriately -EIO.

If the handle/method doesn't exist, that would be -ENXIO.

However, your changes make the driver self-consistent and I'll apply them as is
to testing.

You, me, or someone could prepare a follow up series to clean this driver up a
bit.

> 2) with a positive error code returned from the WMI method. Given my
> interpretation of this positive code reported before I don't see why
> we should fail only on init and not on all the subsequent calls
> 
> So I'm still convinced that my implementation is correct and that
> probably adding complexity on top is not really worth it. But of
> course this is your call as maintainer :)

Thanks for the additional context.

> 
> Thanks,
> 
> [1] https://paste.fedoraproject.org/paste/bBnqUlazz1tAjKsJKq7NHl5M1UNdIGYhyRLivL9gydE=
> 
> -- 
> Carlo Caione  |  +39.340.80.30.096  |  Endless
> 

-- 
Darren Hart
VMware Open Source Technology Center

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state
  2017-04-09 13:56 ` [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state Carlo Caione
@ 2017-04-19 16:21   ` Andy Shevchenko
  2017-04-19 16:24     ` Carlo Caione
  0 siblings, 1 reply; 13+ messages in thread
From: Andy Shevchenko @ 2017-04-19 16:21 UTC (permalink / raw)
  To: Carlo Caione
  Cc: dvhart, Andy Shevchenko, Platform Driver, linux-kernel, linux,
	Carlo Caione

On Sun, Apr 9, 2017 at 4:56 PM, Carlo Caione <carlo@caione.org> wrote:
> From: Carlo Caione <carlo@endlessm.com>
>
> hp_wmi_tablet_state() fails to return the correct error code when
> hp_wmi_perform_query() returns the HP WMI query specific error code
> that is a positive value.

>         int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, &state,
>                                        sizeof(state), sizeof(state));
>         if (ret)
> -               return ret;
> +               return -EINVAL;

Shouldn't be something like

if (ret)
 return ret < 0 ? ret : -EINVAL;

Looking into the code it looks like it may return all possible values:
0, negative, positive.

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode
  2017-04-13 23:07       ` Darren Hart
@ 2017-04-19 16:23         ` Andy Shevchenko
  2017-04-19 20:12           ` Darren Hart
  0 siblings, 1 reply; 13+ messages in thread
From: Andy Shevchenko @ 2017-04-19 16:23 UTC (permalink / raw)
  To: Darren Hart
  Cc: Carlo Caione, Carlo Caione, Andy Shevchenko, Platform Driver,
	linux-kernel, Linux Upstreaming Team

On Fri, Apr 14, 2017 at 2:07 AM, Darren Hart <dvhart@infradead.org> wrote:
> On Thu, Apr 13, 2017 at 10:09:43PM +0200, Carlo Caione wrote:
>> On Thu, Apr 13, 2017 at 8:21 PM, Darren Hart <dvhart@infradead.org> wrote:
>> > On Sun, Apr 09, 2017 at 03:56:08PM +0200, Carlo Caione wrote:

> EINVAL is being used to broadly here. If the input values are incorrect, then
> yes -EINVAL is the right response. However, if the query was unsuccessful, that
> is more appropriately -EIO.
>
> If the handle/method doesn't exist, that would be -ENXIO.
>
> However, your changes make the driver self-consistent and I'll apply them as is
> to testing.

Darren, if it's not yet in for-next, I would like Carlo to update his
patch 1. I think it's better if we not shadow negative error code from
the callee.

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state
  2017-04-19 16:21   ` Andy Shevchenko
@ 2017-04-19 16:24     ` Carlo Caione
  2017-04-19 16:26       ` Andy Shevchenko
  0 siblings, 1 reply; 13+ messages in thread
From: Carlo Caione @ 2017-04-19 16:24 UTC (permalink / raw)
  To: Andy Shevchenko
  Cc: Carlo Caione, dvhart, Andy Shevchenko, Platform Driver,
	linux-kernel, Linux Upstreaming Team

On Wed, Apr 19, 2017 at 6:21 PM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Sun, Apr 9, 2017 at 4:56 PM, Carlo Caione <carlo@caione.org> wrote:
>> From: Carlo Caione <carlo@endlessm.com>
>>
>> hp_wmi_tablet_state() fails to return the correct error code when
>> hp_wmi_perform_query() returns the HP WMI query specific error code
>> that is a positive value.
>
>>         int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, &state,
>>                                        sizeof(state), sizeof(state));
>>         if (ret)
>> -               return ret;
>> +               return -EINVAL;
>
> Shouldn't be something like
>
> if (ret)
>  return ret < 0 ? ret : -EINVAL;
>
> Looking into the code it looks like it may return all possible values:
> 0, negative, positive.

When the HP WMI query returns a positive value something went wrong.
hp_wmi_perform_query() returns 0 on success.

-- 
Carlo Caione  |  +39.340.80.30.096  |  Endless

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state
  2017-04-19 16:24     ` Carlo Caione
@ 2017-04-19 16:26       ` Andy Shevchenko
  0 siblings, 0 replies; 13+ messages in thread
From: Andy Shevchenko @ 2017-04-19 16:26 UTC (permalink / raw)
  To: Carlo Caione
  Cc: Carlo Caione, dvhart, Andy Shevchenko, Platform Driver,
	linux-kernel, Linux Upstreaming Team

On Wed, Apr 19, 2017 at 7:24 PM, Carlo Caione <carlo@endlessm.com> wrote:
> On Wed, Apr 19, 2017 at 6:21 PM, Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
>> On Sun, Apr 9, 2017 at 4:56 PM, Carlo Caione <carlo@caione.org> wrote:
>>> From: Carlo Caione <carlo@endlessm.com>
>>>
>>> hp_wmi_tablet_state() fails to return the correct error code when
>>> hp_wmi_perform_query() returns the HP WMI query specific error code
>>> that is a positive value.
>>
>>>         int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, &state,
>>>                                        sizeof(state), sizeof(state));
>>>         if (ret)
>>> -               return ret;
>>> +               return -EINVAL;
>>
>> Shouldn't be something like
>>
>> if (ret)
>>  return ret < 0 ? ret : -EINVAL;
>>
>> Looking into the code it looks like it may return all possible values:
>> 0, negative, positive.
>
> When the HP WMI query returns a positive value something went wrong.
> hp_wmi_perform_query() returns 0 on success.

Yes, that's what I didn't object anyhow. My point is not to shadow
negative errors if any.

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode
  2017-04-19 16:23         ` Andy Shevchenko
@ 2017-04-19 20:12           ` Darren Hart
  0 siblings, 0 replies; 13+ messages in thread
From: Darren Hart @ 2017-04-19 20:12 UTC (permalink / raw)
  To: Andy Shevchenko
  Cc: Carlo Caione, Carlo Caione, Andy Shevchenko, Platform Driver,
	linux-kernel, Linux Upstreaming Team

On Wed, Apr 19, 2017 at 07:23:39PM +0300, Andy Shevchenko wrote:
> On Fri, Apr 14, 2017 at 2:07 AM, Darren Hart <dvhart@infradead.org> wrote:
> > On Thu, Apr 13, 2017 at 10:09:43PM +0200, Carlo Caione wrote:
> >> On Thu, Apr 13, 2017 at 8:21 PM, Darren Hart <dvhart@infradead.org> wrote:
> >> > On Sun, Apr 09, 2017 at 03:56:08PM +0200, Carlo Caione wrote:
> 
> > EINVAL is being used to broadly here. If the input values are incorrect, then
> > yes -EINVAL is the right response. However, if the query was unsuccessful, that
> > is more appropriately -EIO.
> >
> > If the handle/method doesn't exist, that would be -ENXIO.
> >
> > However, your changes make the driver self-consistent and I'll apply them as is
> > to testing.
> 
> Darren, if it's not yet in for-next, I would like Carlo to update his
> patch 1. I think it's better if we not shadow negative error code from
> the callee.

See my response in the V2 Carlo submitted.

-- 
Darren Hart
VMware Open Source Technology Center

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2017-04-19 20:12 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-04-09 13:56 [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
2017-04-09 13:56 ` [PATCH 1/2] hp-wmi: Fix error value for hp_wmi_tablet_state Carlo Caione
2017-04-19 16:21   ` Andy Shevchenko
2017-04-19 16:24     ` Carlo Caione
2017-04-19 16:26       ` Andy Shevchenko
2017-04-09 13:56 ` [PATCH 2/2] hp-wmi: Fix detection for dock and tablet mode Carlo Caione
2017-04-13 18:21   ` Darren Hart
2017-04-13 20:09     ` Carlo Caione
2017-04-13 23:07       ` Darren Hart
2017-04-19 16:23         ` Andy Shevchenko
2017-04-19 20:12           ` Darren Hart
2017-04-13  6:28 ` [PATCH 0/2] hp-wmi: Fix dock status and tablet mode reporting Carlo Caione
2017-04-13 17:23   ` Darren Hart

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