From d31f2a8dd0e199ef47546315ebf712c01fb9da22 Mon Sep 17 00:00:00 2001
From: komarukomaru <komarulaternson@gmail.com>
Date: Tue, 21 Apr 2026 13:03:03 +0600
Subject: [PATCH] backend/udev: disable drm syncobj on legacy DRM

---
 src/backend/udev.rs | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/backend/udev.rs b/src/backend/udev.rs
index 48da203..66cf523 100644
--- a/src/backend/udev.rs
+++ b/src/backend/udev.rs
@@ -300,10 +300,18 @@ pub fn init_udev(
             &default_feedback,
         );
     data.dmabuf_global = Some(dmabuf_global);
-    data.drm_syncobj_state = Some(smithay::wayland::drm_syncobj::DrmSyncobjState::new::<DriftWm>(
-        &data.display_handle,
-        device_fd.clone(),
-    ));
+    if drm.is_atomic() {
+        data.drm_syncobj_state =
+            Some(smithay::wayland::drm_syncobj::DrmSyncobjState::new::<DriftWm>(
+                &data.display_handle,
+                device_fd.clone(),
+            ));
+    } else {
+        tracing::info!(
+            "Legacy DRM active: disabling linux-drm-syncobj-v1 advertisement and falling back to implicit synchronization"
+        );
+        data.drm_syncobj_state = None;
+    }
 
     // 5. Set up libinput
     let libinput_session = LibinputSessionInterface::from(session.clone());