From 84d45bd13acce0b16c8f86e83144f22b18d9398e Mon Sep 17 00:00:00 2001
From: fazzi <18248986+fxzzi@users.noreply.github.com>
Date: Sun, 26 Apr 2026 19:21:13 +0100
Subject: [PATCH] monitor: set format back after failing DS activation (#14168)

we do run m_lastScanout.reset(), but m_lastScanout might sometimes not
be set. cache format from before attempting DS, and set back to it on
activation failure.
---
 src/helpers/Monitor.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/helpers/Monitor.cpp b/src/helpers/Monitor.cpp
index 44e067659..37606d4f6 100644
--- a/src/helpers/Monitor.cpp
+++ b/src/helpers/Monitor.cpp
@@ -1991,7 +1991,8 @@ bool CMonitor::attemptDirectScanout() {
     if (m_lastScanout.expired())
         m_prevDrmFormat = m_drmFormat;
 
-    const bool NEEDS_TEST = !m_lastScanout || m_drmFormat != params.format; // do not retest while it's active
+    const auto PREV_FORMAT = m_drmFormat;
+    const bool NEEDS_TEST  = !m_lastScanout || m_drmFormat != params.format; // do not retest while it's active
     if (m_drmFormat != params.format) {
         m_output->state->setFormat(params.format);
         m_drmFormat = params.format;
@@ -2004,6 +2005,10 @@ bool CMonitor::attemptDirectScanout() {
 
     if (NEEDS_TEST && !m_state.test()) {
         Log::logger->log(Log::TRACE, "attemptDirectScanout: failed basic test");
+        if (m_drmFormat != PREV_FORMAT) {
+            m_output->state->setFormat(PREV_FORMAT);
+            m_drmFormat = PREV_FORMAT;
+        }
         return false;
     }
 
@@ -2029,6 +2034,10 @@ bool CMonitor::attemptDirectScanout() {
 
     if (!ok) {
         Log::logger->log(Log::TRACE, "attemptDirectScanout: failed to scanout surface");
+        if (m_drmFormat != PREV_FORMAT) {
+            m_output->state->setFormat(PREV_FORMAT);
+            m_drmFormat = PREV_FORMAT;
+        }
         m_lastScanout.reset();
         return false;
     }