[PATCH] platform/x86: hp-wmi: Add periodic tablet mode poll

Greetings!

Some HP convertible laptops (e.g., ProBook x360 series) do not generate
ACPI events when switching between laptop and tablet mode, causing the
input subsystem to never receive SW_TABLET_MODE notifications.

Add a periodic delayed work that polls the tablet mode state every
second and reports changes via input_report_switch(). Track the last
known state to avoid sending duplicate events, and clean up the work
queue on module removal.

---
  drivers/platform/x86/hp/hp-wmi.c | 37 +++++++++++++++++++++++++++++---
  1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/hp/hp-wmi.c 
b/drivers/platform/x86/hp/hp-wmi.c
index 8ba286ed8721..4a4d57fa6d29 100644
--- a/drivers/platform/x86/hp/hp-wmi.c
+++ b/drivers/platform/x86/hp/hp-wmi.c
@@ -460,6 +460,8 @@ static struct notifier_block platform_power_source_nb;
  static enum platform_profile_option active_platform_profile;
  static bool platform_profile_support;
  static bool zero_insize_support;
+static int last_tablet_state = -1;
+static struct delayed_work tablet_mode_work;

  static struct rfkill *wifi_rfkill;
  static struct rfkill *bluetooth_rfkill;
@@ -1176,9 +1178,14 @@ static void hp_wmi_notify(union acpi_object *obj, 
void *context)
                 if (test_bit(SW_DOCK, hp_wmi_input_dev->swbit))
                         input_report_switch(hp_wmi_input_dev, SW_DOCK,
hp_wmi_get_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_get_tablet_mode());
+               if (test_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit)) {
+                       int tablet = hp_wmi_get_tablet_mode();
+                       if (tablet >= 0) {
+                               last_tablet_state = tablet;
+  input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE,
+                                           tablet);
+                       }
+               }
                 input_sync(hp_wmi_input_dev);
                 break;
         case HPWMI_PARK_HDD:
@@ -1271,6 +1278,24 @@ static void hp_wmi_notify(union acpi_object *obj, 
void *context)
         }
  }

+/*
+ * Periodically poll tablet mode state and send input events if changed.
+ * This works around missing ACPI events on some HP laptops.
+ */
+static void hp_wmi_tablet_mode_work_handler(struct work_struct *work)
+{
+       int cur = hp_wmi_get_tablet_mode();
+       if (cur >= 0 && cur != last_tablet_state) {
+               last_tablet_state = cur;
+               if (hp_wmi_input_dev && test_bit(SW_TABLET_MODE, 
hp_wmi_input_dev->swbit)) {
+                       input_report_switch(hp_wmi_input_dev, 
SW_TABLET_MODE, cur);
+                       input_sync(hp_wmi_input_dev);
+                       pr_debug("Tablet mode changed to %d\n", cur);
+               }
+       }
+       schedule_delayed_work(&tablet_mode_work, msecs_to_jiffies(1000));
+}
+
  static int __init hp_wmi_input_setup(void)
  {
         acpi_status status;
@@ -1298,6 +1323,10 @@ static int __init hp_wmi_input_setup(void)
         if (!(val < 0)) {
                 __set_bit(SW_TABLET_MODE, hp_wmi_input_dev->swbit);
                 input_report_switch(hp_wmi_input_dev, SW_TABLET_MODE, val);
+               last_tablet_state = val;
+               INIT_DELAYED_WORK(&tablet_mode_work,
+  hp_wmi_tablet_mode_work_handler);
+               schedule_delayed_work(&tablet_mode_work, 
msecs_to_jiffies(1000));
         }

         err = sparse_keymap_setup(hp_wmi_input_dev, hp_wmi_keymap, NULL);
@@ -1331,6 +1360,8 @@ static int __init hp_wmi_input_setup(void)

  static void hp_wmi_input_destroy(void)
  {
+       cancel_delayed_work_sync(&tablet_mode_work);
+       last_tablet_state = -1;
         wmi_remove_notify_handler(HPWMI_EVENT_GUID);
         input_unregister_device(hp_wmi_input_dev);
  }
-- 
2.50.1