Migrate DRM outputs to Smithay DrmCompositor

compositor/src/backends/direct/planes.rs

@@ -0,0 +1,39 @@
+use smithay::backend::drm::compositor::FrameFlags;
+
+pub(super) fn frame_flags(fullscreen: bool, animating: bool, locked: bool) -> FrameFlags {
+    let mut flags = FrameFlags::ALLOW_CURSOR_PLANE_SCANOUT;
+
+    if fullscreen && !animating && !locked {
+        flags |= FrameFlags::ALLOW_PRIMARY_PLANE_SCANOUT;
+    }
+
+    // Overlay planes stay disabled until their effects and capture behavior
+    // have been validated on hardware independently of fullscreen scanout.
+    flags
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn only_settled_unlocked_fullscreen_frames_allow_primary_scanout() {
+        for fullscreen in [false, true] {
+            for animating in [false, true] {
+                for locked in [false, true] {
+                    let flags = frame_flags(fullscreen, animating, locked);
+                    assert_eq!(
+                        flags.contains(FrameFlags::ALLOW_PRIMARY_PLANE_SCANOUT),
+                        fullscreen && !animating && !locked,
+                    );
+                    assert!(flags.contains(FrameFlags::ALLOW_CURSOR_PLANE_SCANOUT));
+                    assert!(!flags.intersects(
+                        FrameFlags::ALLOW_PRIMARY_PLANE_SCANOUT_ANY
+                            | FrameFlags::ALLOW_OVERLAY_PLANE_SCANOUT
+                            | FrameFlags::SKIP_CURSOR_ONLY_UPDATES
+                    ));
+                }
+            }
+        }
+    }
+}