[PATCH] platform/x86: Only activate tablet mode switch on 2-in-1's

[PATCH] platform/x86: Only activate tablet mode switch on 2-in-1's

[Mario Limonciello]

Some laptops such as the XPS 9360 support the intel-vbtn INT33D6
interface but don't initialize the bit that intel-vbtn uses to
represent switching tablet mode.

By running this only on real 2-in-1's it shouldn't cause false
positives.

Fixes: 30323fb6d5 ("Support tablet mode switch")
Reported-by: Jeremy Cline <jeremy@jcline.org>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
---
Note: I also moved the code for detecting tablet into it's own
function.  To keep things under 80 lines with if statements was
making the code very unreadable otherwise.

 drivers/platform/x86/intel-vbtn.c | 46 ++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 17 deletions(-)

diff --git a/drivers/platform/x86/intel-vbtn.c b/drivers/platform/x86/intel-vbtn.c
index b703d6f..8173307 100644
--- a/drivers/platform/x86/intel-vbtn.c
+++ b/drivers/platform/x86/intel-vbtn.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 #include <linux/input.h>
 #include <linux/input/sparse-keymap.h>
 #include <linux/kernel.h>
@@ -97,9 +98,35 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
 	dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
 }
 
-static int intel_vbtn_probe(struct platform_device *device)
+static void detect_tablet_mode(struct platform_device *device)
 {
+	const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
+	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
+	acpi_handle handle = ACPI_HANDLE(&device->dev);
 	struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	acpi_status status;
+	int m;
+
+	if (!(chassis_type && strcmp(chassis_type, "31") == 0))
+		goto out;
+
+	status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
+	if (ACPI_FAILURE(status))
+		goto out;
+
+	obj = vgbs_output.pointer;
+	if (!(obj && obj->type == ACPI_TYPE_INTEGER))
+		goto out;
+
+	m = !(obj->integer.value & TABLET_MODE_FLAG);
+	input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
+out:
+	kfree(vgbs_output.pointer);
+}
+
+static int intel_vbtn_probe(struct platform_device *device)
+{
 	acpi_handle handle = ACPI_HANDLE(&device->dev);
 	struct intel_vbtn_priv *priv;
 	acpi_status status;
@@ -122,22 +149,7 @@ static int intel_vbtn_probe(struct platform_device *device)
 		return err;
 	}
 
-	/*
-	 * VGBS being present and returning something means we have
-	 * a tablet mode switch.
-	 */
-	status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
-	if (ACPI_SUCCESS(status)) {
-		union acpi_object *obj = vgbs_output.pointer;
-
-		if (obj && obj->type == ACPI_TYPE_INTEGER) {
-			int m = !(obj->integer.value & TABLET_MODE_FLAG);
-
-			input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
-		}
-	}
-
-	kfree(vgbs_output.pointer);
+	detect_tablet_mode(device);
 
 	status = acpi_install_notify_handler(handle,
 					     ACPI_DEVICE_NOTIFY,
-- 
2.7.4

Re: [PATCH] platform/x86: Only activate tablet mode switch on 2-in-1's

[Jeremy Cline]

On Thu, Feb 22, 2018 at 01:58:42PM -0600, Mario Limonciello wrote:
> Some laptops such as the XPS 9360 support the intel-vbtn INT33D6
> interface but don't initialize the bit that intel-vbtn uses to
> represent switching tablet mode.
> 
> By running this only on real 2-in-1's it shouldn't cause false
> positives.
> 
> Fixes: 30323fb6d5 ("Support tablet mode switch")
> Reported-by: Jeremy Cline <jeremy@jcline.org>
> Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> ---
> Note: I also moved the code for detecting tablet into it's own
> function.  To keep things under 80 lines with if statements was
> making the code very unreadable otherwise.
> 
>  drivers/platform/x86/intel-vbtn.c | 46 ++++++++++++++++++++++++---------------
>  1 file changed, 29 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel-vbtn.c b/drivers/platform/x86/intel-vbtn.c
> index b703d6f..8173307 100644
> --- a/drivers/platform/x86/intel-vbtn.c
> +++ b/drivers/platform/x86/intel-vbtn.c
> @@ -7,6 +7,7 @@
>   */
>  
>  #include <linux/acpi.h>
> +#include <linux/dmi.h>
>  #include <linux/input.h>
>  #include <linux/input/sparse-keymap.h>
>  #include <linux/kernel.h>
> @@ -97,9 +98,35 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
>  	dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
>  }
>  
> -static int intel_vbtn_probe(struct platform_device *device)
> +static void detect_tablet_mode(struct platform_device *device)
>  {
> +	const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
> +	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
> +	acpi_handle handle = ACPI_HANDLE(&device->dev);
>  	struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *obj;
> +	acpi_status status;
> +	int m;
> +
> +	if (!(chassis_type && strcmp(chassis_type, "31") == 0))
> +		goto out;
> +
> +	status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
> +	if (ACPI_FAILURE(status))
> +		goto out;
> +
> +	obj = vgbs_output.pointer;
> +	if (!(obj && obj->type == ACPI_TYPE_INTEGER))
> +		goto out;
> +
> +	m = !(obj->integer.value & TABLET_MODE_FLAG);
> +	input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
> +out:
> +	kfree(vgbs_output.pointer);
> +}
> +
> +static int intel_vbtn_probe(struct platform_device *device)
> +{
>  	acpi_handle handle = ACPI_HANDLE(&device->dev);
>  	struct intel_vbtn_priv *priv;
>  	acpi_status status;
> @@ -122,22 +149,7 @@ static int intel_vbtn_probe(struct platform_device *device)
>  		return err;
>  	}
>  
> -	/*
> -	 * VGBS being present and returning something means we have
> -	 * a tablet mode switch.
> -	 */
> -	status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
> -	if (ACPI_SUCCESS(status)) {
> -		union acpi_object *obj = vgbs_output.pointer;
> -
> -		if (obj && obj->type == ACPI_TYPE_INTEGER) {
> -			int m = !(obj->integer.value & TABLET_MODE_FLAG);
> -
> -			input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
> -		}
> -	}
> -
> -	kfree(vgbs_output.pointer);
> +	detect_tablet_mode(device);
>  
>  	status = acpi_install_notify_handler(handle,
>  					     ACPI_DEVICE_NOTIFY,
> -- 
> 2.7.4
> 

Tested-by: Jeremy Cline <jeremy@jcline.org>


Regards,
Jeremy

Re: [PATCH] platform/x86: Only activate tablet mode switch on 2-in-1's

[Darren Hart]

On Thu, Feb 22, 2018 at 08:15:51PM +0000, Jeremy Cline wrote:
> On Thu, Feb 22, 2018 at 01:58:42PM -0600, Mario Limonciello wrote:
> > Some laptops such as the XPS 9360 support the intel-vbtn INT33D6
> > interface but don't initialize the bit that intel-vbtn uses to
> > represent switching tablet mode.
> > 
> > By running this only on real 2-in-1's it shouldn't cause false
> > positives.
> > 
> > Fixes: 30323fb6d5 ("Support tablet mode switch")
> > Reported-by: Jeremy Cline <jeremy@jcline.org>
> > Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> > ---
> > Note: I also moved the code for detecting tablet into it's own
> > function.  To keep things under 80 lines with if statements was
> > making the code very unreadable otherwise.
> > 
...
> 
> Tested-by: Jeremy Cline <jeremy@jcline.org>

Wow, incredible turn around time Mario and Jeremy. Doing some
confirmation on my end, and will queue up to Fixes for 4.16 RC cycle.

-- 
Darren Hart
VMware Open Source Technology Center

Re: [PATCH] platform/x86: Only activate tablet mode switch on 2-in-1's

[Darren Hart]

On Thu, Feb 22, 2018 at 08:15:51PM +0000, Jeremy Cline wrote:
> On Thu, Feb 22, 2018 at 01:58:42PM -0600, Mario Limonciello wrote:
> > Some laptops such as the XPS 9360 support the intel-vbtn INT33D6
> > interface but don't initialize the bit that intel-vbtn uses to
> > represent switching tablet mode.
> > 
> > By running this only on real 2-in-1's it shouldn't cause false
> > positives.
> > 
> 
> Tested-by: Jeremy Cline <jeremy@jcline.org>

Problem verified, solution tested and also verified. Queuing patch.

-- 
Darren Hart
VMware Open Source Technology Center