backend: add getters

src/backend.rs

@@ -540,6 +540,9 @@ pub trait BackendDrmDevice {
     fn version(&self) -> Result<DrmVersion, DrmError>;
     fn set_direct_scanout_enabled(&self, enabled: bool);
     fn is_render_device(&self) -> bool;
+    fn direct_scanout_enabled(&self) -> bool {
+        false
+    }
     fn create_lease(
         self: Rc<Self>,
         lessee: Rc<dyn BackendDrmLessee>,
@@ -551,6 +554,10 @@ pub trait BackendDrmDevice {
     fn set_flip_margin(&self, margin: u64) {
         let _ = margin;
     }
+    #[expect(dead_code)]
+    fn flip_margin(&self) -> Option<u64> {
+        None
+    }
 }
 
 pub trait BackendDrmLease {

src/backends/metal/present.rs

@@ -1,6 +1,6 @@
 use {
     crate::{
-        backend::Connector,
+        backend::{BackendDrmDevice, Connector},
         backends::metal::{
             MetalError,
             allocator::{RenderBuffer, RenderBufferCopy},
@@ -814,13 +814,6 @@ impl MetalConnector {
         data
     }
 
-    fn direct_scanout_enabled(&self) -> bool {
-        self.dev
-            .direct_scanout_enabled
-            .get()
-            .unwrap_or(self.state.direct_scanout_enabled.get())
-    }
-
     fn prepare_present_fb(
         &self,
         cd: &Rc<ColorDescription>,
@@ -832,7 +825,7 @@ impl MetalConnector {
     ) -> Result<PresentFb, MetalError> {
         self.trim_scanout_cache();
         let try_direct_scanout = try_direct_scanout
-            && self.direct_scanout_enabled()
+            && self.dev.direct_scanout_enabled()
             // at least on AMD, using a FB on a different device for rendering will fail
             // and destroy the render context. it's possible to work around this by waiting
             // until the FB is no longer being scanned out, but if a notification pops up

src/backends/metal/video.rs

@@ -186,6 +186,12 @@ impl BackendDrmDevice for MetalDrmDevice {
         Some(self.id) == self.backend.ctx.get().map(|c| c.dev_id)
     }
 
+    fn direct_scanout_enabled(&self) -> bool {
+        self.direct_scanout_enabled
+            .get()
+            .unwrap_or(self.backend.state.direct_scanout_enabled.get())
+    }
+
     fn create_lease(
         self: Rc<Self>,
         lessee: Rc<dyn BackendDrmLessee>,
@@ -314,6 +320,10 @@ impl BackendDrmDevice for MetalDrmDevice {
             }
         }
     }
+
+    fn flip_margin(&self) -> Option<u64> {
+        Some(self.min_post_commit_margin.get())
+    }
 }
 
 pub struct HandleEvents {