[PATCH v2 1/3] Fix SW_TABLET_MODE detection method

[Jorge Lopez <jorgealtxwork@gmail.com>]

The purpose of this patch is to introduce a fix and removal
of the current hack when determining tablet mode status.

Determining the tablet mode status requires reading Byte 0 bit 2 and 3
as reported by HPWMI_HARDWARE_QUERY.  The investigation identified the
failure was rooted in two areas; HPWMI_HARDWARE_QUERY failure (0x05)
and reading Byte 0, bit 2 only to determine the table mode status.
HPWMI_HARDWARE_QUERY WMI failure also rendered the dock state value invalid.

All changes were validated on a ZBook Workstation notebook.

Signed-off-by: Jorge Lopez <jorge.lopez2@hp.com>

---
Based on the latest platform-drivers-x86.git/for-next
---
 drivers/platform/x86/hp-wmi.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
index 48a46466f086..544fce906ce7 100644
--- a/drivers/platform/x86/hp-wmi.c
+++ b/drivers/platform/x86/hp-wmi.c
@@ -35,9 +35,6 @@ MODULE_LICENSE("GPL");
 MODULE_ALIAS("wmi:95F24279-4D7B-4334-9387-ACCDC67EF61C");
 MODULE_ALIAS("wmi:5FB7F034-2C63-45e9-BE91-3D44E2C707E4");
 
-static int enable_tablet_mode_sw = -1;
-module_param(enable_tablet_mode_sw, int, 0444);
-MODULE_PARM_DESC(enable_tablet_mode_sw, "Enable SW_TABLET_MODE reporting (-1=auto, 0=no, 1=yes)");
 
 #define HPWMI_EVENT_GUID "95F24279-4D7B-4334-9387-ACCDC67EF61C"
 #define HPWMI_BIOS_GUID "5FB7F034-2C63-45e9-BE91-3D44E2C707E4"
@@ -127,6 +124,7 @@ enum hp_wmi_command {
 enum hp_wmi_hardware_mask {
 	HPWMI_DOCK_MASK		= 0x01,
 	HPWMI_TABLET_MASK	= 0x04,
+	HPWMI_DETACHABLE_MASK	= 0x08,
 };
 
 struct bios_return {
@@ -347,12 +345,19 @@ static int hp_wmi_read_int(int query)
 
 static int hp_wmi_hw_state(int mask)
 {
-	int state = hp_wmi_read_int(HPWMI_HARDWARE_QUERY);
+	int state = 0, ret;
 
-	if (state < 0)
-		return state;
+	ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, HPWMI_READ, &state,
+				   0, sizeof(state));
 
-	return !!(state & mask);
+	if (ret)
+		return ret < 0 ? ret : -EINVAL;
+
+	/* determine if Detachable mode is enabled */
+	if (HPWMI_TABLET_MASK == mask)
+		state = (state & HPWMI_DETACHABLE_MASK );
+
+	return (state & mask);
 }
 
 static int omen_thermal_profile_set(int mode)
@@ -781,18 +786,16 @@ static int __init hp_wmi_input_setup(void)
 
 	/* Dock */
 	val = hp_wmi_hw_state(HPWMI_DOCK_MASK);
-	if (!(val < 0)) {
+	if (val > 0) {
 		__set_bit(SW_DOCK, hp_wmi_input_dev->swbit);
 		input_report_switch(hp_wmi_input_dev, SW_DOCK, val);
 	}
 
 	/* Tablet mode */
-	if (enable_tablet_mode_sw > 0) {
-		val = hp_wmi_hw_state(HPWMI_TABLET_MASK);
-		if (val >= 0) {
-			__set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
+	val = hp_wmi_hw_state(HPWMI_TABLET_MASK);
+	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);
-- 
2.25.1