Re: [PATCH] platform/x86: Only activate tablet mode switch on 2-in-1's
From: Jeremy Cline
Date: Thu Feb 22 2018 - 15:15:58 EST
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@xxxxxxxxxx>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
> ---
> 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@xxxxxxxxxx>
Regards,
Jeremy