From 560c53d87dedf7df8185eb370cfbf3575826e85c Mon Sep 17 00:00:00 2001
From: Vaxry <vaxry@vaxry.net>
Date: Mon, 27 Oct 2025 13:34:08 +0000
Subject: [PATCH] monitor/dpms: fix possible invalid state

If dpms gets immediately re-enabled, a commit could fail, not schedule any frames anymore, and the monitor would be stuck off. Fix this by adding a timer to retry if commit fails.

ref #12045
---
 src/helpers/Monitor.cpp | 27 +++++++++++++++++++++++++--
 src/helpers/Monitor.hpp |  3 +++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/helpers/Monitor.cpp b/src/helpers/Monitor.cpp
index ac9c065f..e12a4bff 100644
--- a/src/helpers/Monitor.cpp
+++ b/src/helpers/Monitor.cpp
@@ -1882,13 +1882,14 @@ void CMonitor::setDPMS(bool on) {
 
     if (on) {
         // enable the monitor. Wait for the frame to be presented, then begin animation
-        m_dpmsBlackOpacity->setValueAndWarp(1.F);
         m_dpmsBlackOpacity->setCallbackOnEnd(nullptr);
+        m_dpmsBlackOpacity->setValueAndWarp(1.F);
         m_pendingDpmsAnimation        = true;
         m_pendingDpmsAnimationCounter = 0;
         commitDPMSState(true);
     } else {
         // disable the monitor. Begin the animation, then do dpms on its end.
+        m_dpmsBlackOpacity->setCallbackOnEnd(nullptr);
         m_dpmsBlackOpacity->setValueAndWarp(0.F);
         *m_dpmsBlackOpacity = 1.F;
         m_dpmsBlackOpacity->setCallbackOnEnd(
@@ -1908,7 +1909,29 @@ void CMonitor::commitDPMSState(bool state) {
     m_output->state->setEnabled(state);
 
     if (!m_state.commit()) {
-        Debug::log(ERR, "Couldn't commit output {} for DPMS = {}", m_name, state);
+        Debug::log(ERR, "Couldn't commit output {} for DPMS = {}, will retry.", m_name, state);
+
+        // retry in 2 frames. This could happen when the DRM backend rejects our commit
+        // because disable + enable were sent almost instantly
+
+        m_dpmsRetryTimer = makeShared<CEventLoopTimer>(
+            std::chrono::milliseconds(2000 / sc<int>(m_refreshRate)),
+            [this, self = m_self](SP<CEventLoopTimer> s, void* d) {
+                if (!self)
+                    return;
+
+                m_output->state->resetExplicitFences();
+                m_output->state->setEnabled(m_dpmsStatus);
+                if (!m_state.commit()) {
+                    Debug::log(ERR, "Couldn't retry committing output {} for DPMS = {}", m_name, m_dpmsStatus);
+                    return;
+                }
+
+                m_dpmsRetryTimer.reset();
+            },
+            nullptr);
+        g_pEventLoopManager->addTimer(m_dpmsRetryTimer);
+
         return;
     }
 
diff --git a/src/helpers/Monitor.hpp b/src/helpers/Monitor.hpp
index 687fc049..ff697725 100644
--- a/src/helpers/Monitor.hpp
+++ b/src/helpers/Monitor.hpp
@@ -68,6 +68,7 @@ struct SMonitorRule {
 class CMonitor;
 class CSyncTimeline;
 class CEGLSync;
+class CEventLoopTimer;
 
 class CMonitorState {
   public:
@@ -138,6 +139,8 @@ class CMonitor {
     bool                        m_createdByUser    = false;
     bool                        m_isUnsafeFallback = false;
 
+    SP<CEventLoopTimer>         m_dpmsRetryTimer;
+
     bool                        m_pendingFrame    = false; // if we schedule a frame during rendering, reschedule it after
     bool                        m_renderingActive = false;