mutter/mutter-fix-front-buffer-lock.patch

From 6fd0a273b669414aa1fcfd4cf193d8e6c9cd2773 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <mdaenzer@redhat.com>
Date: Wed, 27 Mar 2024 18:16:17 +0100
Subject: [PATCH] drm-buffer-gbm: Do not call ensure_fb_id from lock_front

When preparing a frame for scanout on a secondary GPU, calling
meta_drm_buffer_gbm_ensure_fb_id for the primary GPU device is
unnecessary and potentially harmful.

Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/3389
---
 src/backends/native/meta-drm-buffer-gbm.c  |  2 +-
 src/backends/native/meta-onscreen-native.c | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/backends/native/meta-drm-buffer-gbm.c b/src/backends/native/meta-drm-buffer-gbm.c
index 161d43957d4..4ca8fb0f462 100644
--- a/src/backends/native/meta-drm-buffer-gbm.c
+++ b/src/backends/native/meta-drm-buffer-gbm.c
@@ -186,7 +186,7 @@ lock_front_buffer (MetaDrmBufferGbm  *buffer_gbm,
       return FALSE;
     }
 
-  return meta_drm_buffer_gbm_ensure_fb_id (META_DRM_BUFFER (buffer_gbm), error);
+  return TRUE;
 }
 
 MetaDrmBufferGbm *
diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
index e40b03f3eaf..f2bae4f00d6 100644
--- a/src/backends/native/meta-onscreen-native.c
+++ b/src/backends/native/meta-onscreen-native.c
@@ -1373,6 +1373,17 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
 #endif
     }
 
+  if (!meta_drm_buffer_ensure_fb_id (onscreen_native->gbm.next_fb, &error))
+    {
+      g_warning ("Failed to ensure KMS FB ID on %s: %s",
+                 meta_device_file_get_path (render_device_file),
+                 error->message);
+
+      frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
+      meta_onscreen_native_notify_frame_complete (onscreen);
+      return;
+    }
+
   /*
    * If we changed EGL context, cogl will have the wrong idea about what is
    * current, making it fail to set it when it needs to. Avoid that by making
-- 
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