linux-kernel - [PATCH V3] ACPI LID: increment wakeup count only when notified.

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Date:   Wed, 27 Jun 2018 10:55:02 -0700
From:   Ravi Chandra Sadineni <ravisadineni@...omium.org>
To:     rjw@...ysocki.net, lenb@...nel.org, ravisadineni@...omium.org,
        ravisadineni@...gle.com
Cc:     dmitry.torokhov@...il.com, tbroch@...gle.com,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        rajatja@...gle.com, bleung@...gle.com, furquan@...omium.org
Subject: [PATCH V3] ACPI LID: increment wakeup count only when notified.

Because acpi_lid_initialize_state() is called on every system
resume and it triggers acpi_lid_notify_state() which invokes
acpi_pm_wakeup_event() for the lid device, the lid's wakeup count is
incremented even if the lid was not the source of the event that woke up
the system. That behavior confuses user space deamons using
wakeup_count to identify the potential system wakeup source. To avoid
the confusion, only trigger acpi_pm_wakeup_event() in the
acpi_button_notify() path and don't do that in the
acpi_lid_initialize_state() path.

Signed-off-by: Ravi Chandra Sadineni <ravisadineni@...omium.org>
---
 v3:  Change is_notification to signal_wakeup
 V2: Increment the wakeup count only when the lid is open.

 drivers/acpi/button.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
index 2345a5ee2dbbc..40ed3ec9fc94c 100644
--- a/drivers/acpi/button.c
+++ b/drivers/acpi/button.c
@@ -235,9 +235,6 @@ static int acpi_lid_notify_state(struct acpi_device *device, int state)
 		button->last_time = ktime_get();
 	}
 
-	if (state)
-		acpi_pm_wakeup_event(&device->dev);
-
 	ret = blocking_notifier_call_chain(&acpi_lid_notifier, state, device);
 	if (ret == NOTIFY_DONE)
 		ret = blocking_notifier_call_chain(&acpi_lid_notifier, state,
@@ -366,7 +363,8 @@ int acpi_lid_open(void)
 }
 EXPORT_SYMBOL(acpi_lid_open);
 
-static int acpi_lid_update_state(struct acpi_device *device)
+static int acpi_lid_update_state(struct acpi_device *device,
+				 bool signal_wakeup)
 {
 	int state;
 
@@ -374,6 +372,9 @@ static int acpi_lid_update_state(struct acpi_device *device)
 	if (state < 0)
 		return state;
 
+	if (state && signal_wakeup)
+		acpi_pm_wakeup_event(&device->dev);
+
 	return acpi_lid_notify_state(device, state);
 }
 
@@ -384,7 +385,7 @@ static void acpi_lid_initialize_state(struct acpi_device *device)
 		(void)acpi_lid_notify_state(device, 1);
 		break;
 	case ACPI_BUTTON_LID_INIT_METHOD:
-		(void)acpi_lid_update_state(device);
+		(void)acpi_lid_update_state(device, false);
 		break;
 	case ACPI_BUTTON_LID_INIT_IGNORE:
 	default:
@@ -409,7 +410,7 @@ static void acpi_button_notify(struct acpi_device *device, u32 event)
 			users = button->input->users;
 			mutex_unlock(&button->input->mutex);
 			if (users)
-				acpi_lid_update_state(device);
+				acpi_lid_update_state(device, true);
 		} else {
 			int keycode;
 
-- 
2.18.0.rc2.346.g013aa6912e-goog