platform/x86: intel-vbtn: Update tablet mode switch at end of probe

ACER Vivobook Flip (TP401NAS) virtual intel switch is implemented as
follow:

   Device (VGBI)
   {
       Name (_HID, EisaId ("INT33D6") ...
       Name (VBDS, Zero)
       Method (_STA, 0, Serialized)  // _STA: Status ...
       Method (VBDL, 0, Serialized)
       {
           PB1E |= 0x20
           VBDS |= 0x40
       }
       Method (VGBS, 0, Serialized)
       {
           Return (VBDS) /* \_SB_.PCI0.SBRG.EC0_.VGBI.VBDS */
       }
       ...
    }

By default VBDS is set to 0. At boot it is set to clamshell (bit 6 set)
only after method VBDL is executed.

Since VBDL is now evaluated in the probe routine later, after the device
is registered, the retrieved value of VBDS was still 0 ("tablet mode")
when setting up the virtual switch.

Make sure to evaluate VGBS after VBDL, to ensure the
convertible boots in clamshell mode, the expected default.

Fixes: 2617317 ("platform/x86: intel-vbtn: Eval VBDL after registering our notifier")
Signed-off-by: Gwendal Grignou <[email protected]>
Reviewed-by: Kuppuswamy Sathyanarayanan <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Ilpo Järvinen <[email protected]>
Signed-off-by: Ilpo Järvinen <[email protected]>

Author: gwendalcr

drivers/platform/x86/intel/vbtn.c

@@ -136,8 +136,6 @@ static int intel_vbtn_input_setup(struct platform_device *device)
 	priv->switches_dev->id.bustype = BUS_HOST;
 
 	if (priv->has_switches) {
-		detect_tablet_mode(&device->dev);
-
 		ret = input_register_device(priv->switches_dev);
 		if (ret)
 			return ret;
@@ -312,6 +310,9 @@ static int intel_vbtn_probe(struct platform_device *device)
 		if (ACPI_FAILURE(status))
 			dev_err(&device->dev, "Error VBDL failed with ACPI status %d\n", status);
 	}
+	// Check switches after buttons since VBDL may have side effects.
+	if (has_switches)
+		detect_tablet_mode(&device->dev);
 
 	device_init_wakeup(&device->dev, true);
 	/*