From 03bbe07937bbd7c784b663b90f27f735bed9bba0 Mon Sep 17 00:00:00 2001
From: lx-s <lx-s@users.noreply.github.com>
Date: Tue, 18 Aug 2026 12:12:57 +0200
Subject: [PATCH] Fixed display standby detection.

---
 Dist/bin/changelog.txt |  9 ++++++---
 WinMute/WinMute.cpp    | 46 ++++++++++++++++++++++++++++++++++++------
 WinMute/WinMute.h      |  4 ++++
 3 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/Dist/bin/changelog.txt b/Dist/bin/changelog.txt
index a2fc056..845bdd3 100644
--- a/Dist/bin/changelog.txt
+++ b/Dist/bin/changelog.txt
@@ -5,9 +5,12 @@ Version 2.6.0 (2026-08-18)
  * Added "Mute on Laptop Lid Close"
  * Added: New translations
  * Added: Program is now build with control-flow enforcement (CET)
- * Fixed some possible race conditions
- * Fixed memory leak in wifi detector
- * Fixed possible security issues in update checker
+ * Fixed: Display stand-by detection
+ * Fixed: 60 second cadence time to mute/unmute devices that take a few
+    seconds to wake up and register as "plugged in" again.
+ * Fixed: Possible race conditions
+ * Fixed: Memory leak in wifi detector
+ * Fixed: Hardened update checker
  * Fixed: No longer immediately exiting if the workstation-lock notification
    can not be registered. WinMute will retry registering with TermService
    for about half a minute and disable mute-on-lock if the service does not
diff --git a/WinMute/WinMute.cpp b/WinMute/WinMute.cpp
index fa38afc..64e8476 100644
--- a/WinMute/WinMute.cpp
+++ b/WinMute/WinMute.cpp
@@ -337,13 +337,31 @@ bool WinMute::Init()
         return false;
     }
 
+    // GUID_CONSOLE_DISPLAY_STATE is documented for kernel-mode/session 0
+    // consumers; interactive applications are supposed to use
+    // GUID_SESSION_DISPLAY_STATUS. Register for both, since neither is
+    // guaranteed to be delivered on every Windows version.
+    hSessionDisplayNotify_ = RegisterPowerSettingNotification(
+        hWnd_, &GUID_SESSION_DISPLAY_STATUS, DEVICE_NOTIFY_WINDOW_HANDLE);
+    if (hSessionDisplayNotify_ == nullptr) {
+        const DWORD lastError = GetLastError();
+        ShowWindowsError(L"RegisterPowerSettingNotification", lastError);
+        log.LogWinError(L"RegisterPowerSettingNotification", lastError);
+        UnregisterPowerSettingNotification(hPowerNotify_);
+        hPowerNotify_ = nullptr;
+        return false;
+    }
+
     hLidCloseNotify_ = RegisterPowerSettingNotification(
         hWnd_, &GUID_LIDSWITCH_STATE_CHANGE, DEVICE_NOTIFY_WINDOW_HANDLE);
     if (hLidCloseNotify_ == nullptr) {
         const DWORD lastError = GetLastError();
         ShowWindowsError(L"RegisterPowerSettingNotification", lastError);
         log.LogWinError(L"RegisterPowerSettingNotification", lastError);
+        UnregisterPowerSettingNotification(hSessionDisplayNotify_);
+        hSessionDisplayNotify_ = nullptr;
         UnregisterPowerSettingNotification(hPowerNotify_);
+        hPowerNotify_ = nullptr;
         return false;
     }
 
@@ -880,13 +898,25 @@ LRESULT WinMute::OnPowerBroadcast(HWND, WPARAM wParam, LPARAM lParam)
     } else if (wParam == PBT_POWERSETTINGCHANGE) {
         const PPOWERBROADCAST_SETTING bs =
             reinterpret_cast<PPOWERBROADCAST_SETTING>(lParam);
-        if (IsEqualGUID(bs->PowerSetting, GUID_CONSOLE_DISPLAY_STATE)) {
+        if (IsEqualGUID(bs->PowerSetting, GUID_CONSOLE_DISPLAY_STATE) ||
+            IsEqualGUID(bs->PowerSetting, GUID_SESSION_DISPLAY_STATUS))
+        {
             const DWORD state = bs->Data[0];
-            if (state == 0x0) {  // Display standby
-                muteCtrl_.NotifyDisplayStandby(true);
-            } else if (state == 0x1) {  // Display on
-                muteCtrl_.NotifyDisplayStandby(false);
-            } else if (state == 0x2) {  // Display dimmed
+            const bool isSession =
+                IsEqualGUID(bs->PowerSetting, GUID_SESSION_DISPLAY_STATUS);
+            WMLog::GetInstance().LogDebug(
+                L"Power event: {} display state {}",
+                isSession ? L"session" : L"console", state);
+            // Both notifications describe the same display, so ignore the
+            // duplicate that arrives for the second registration.
+            if (state != lastDisplayState_) {
+                lastDisplayState_ = state;
+                if (state == 0x0) {  // Display standby
+                    muteCtrl_.NotifyDisplayStandby(true);
+                } else if (state == 0x1) {  // Display on
+                    muteCtrl_.NotifyDisplayStandby(false);
+                } else if (state == 0x2) {  // Display dimmed
+                }
             }
         } else if (IsEqualGUID(bs->PowerSetting, GUID_LIDSWITCH_STATE_CHANGE)) {
             const DWORD state = bs->Data[0];
@@ -1058,6 +1088,10 @@ void WinMute::Unload() noexcept
         UnregisterPowerSettingNotification(hPowerNotify_);
         hPowerNotify_ = nullptr;
     }
+    if (hSessionDisplayNotify_ != nullptr) {
+        UnregisterPowerSettingNotification(hSessionDisplayNotify_);
+        hSessionDisplayNotify_ = nullptr;
+    }
     if (hLidCloseNotify_ != nullptr) {
         UnregisterPowerSettingNotification(hLidCloseNotify_);
         hLidCloseNotify_ = nullptr;
diff --git a/WinMute/WinMute.h b/WinMute/WinMute.h
index 680f199..81a159a 100644
--- a/WinMute/WinMute.h
+++ b/WinMute/WinMute.h
@@ -76,7 +76,11 @@ class WinMute {
     UINT_PTR wtsRetryTimerId_ = 0;
     int wtsRetryAttempts_ = 0;
     HPOWERNOTIFY hPowerNotify_ = nullptr;
+    HPOWERNOTIFY hSessionDisplayNotify_ = nullptr;
     HPOWERNOTIFY hLidCloseNotify_ = nullptr;
+    // Console and session display notifications can both fire for the same
+    // transition. 0xFFFFFFFF means "no state seen yet".
+    DWORD lastDisplayState_ = 0xFFFFFFFF;
 
     TrayIcon wmTray_;
     TrayIcon updateTray_;
-- 
2.43.0