From 88cfa76e2c7ffddbbe7d8173893a3529ff065570 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Thu, 6 Mar 2025 18:53:56 +0100
Subject: [PATCH] graphics: Merge set_scanout and flush_resource into
 update_plane

The old api was pretty virtio-gpu specific. The new api is closed to how
atomic mode setting on Linux works.
---
 graphics/driver-graphics/src/lib.rs |  9 ++++----
 graphics/vesad/src/scheme.rs        |  6 +----
 graphics/virtio-gpud/src/main.rs    |  2 +-
 graphics/virtio-gpud/src/scheme.rs  | 35 +++++++++++++++--------------
 4 files changed, 24 insertions(+), 28 deletions(-)

diff --git a/graphics/driver-graphics/src/lib.rs b/graphics/driver-graphics/src/lib.rs
index c35b88bcd8..3a9b503f54 100644
--- a/graphics/driver-graphics/src/lib.rs
+++ b/graphics/driver-graphics/src/lib.rs
@@ -17,8 +17,7 @@ pub trait GraphicsAdapter {
     fn create_resource(&mut self, width: u32, height: u32) -> Self::Resource;
     fn map_resource(&mut self, resource: &Self::Resource) -> *mut u8;
 
-    fn set_scanout(&mut self, display_id: usize, resource: &Self::Resource);
-    fn flush_resource(
+    fn update_plane(
         &mut self,
         display_id: usize,
         resource: &Self::Resource,
@@ -90,7 +89,7 @@ impl<T: GraphicsAdapter> GraphicsScheme<T> {
                             let (width, height) = self.adapter.display_size(display_id);
                             self.adapter.create_resource(width, height)
                         });
-                    self.adapter.set_scanout(display_id, resource);
+                    self.adapter.update_plane(display_id, resource, None);
 
                     self.active_vt = vt_event.vt;
                 }
@@ -196,7 +195,7 @@ impl<T: GraphicsAdapter> Scheme for GraphicsScheme<T> {
             return Ok(0);
         }
         let resource = &self.vts_res[vt][screen];
-        self.adapter.flush_resource(*screen, resource, None);
+        self.adapter.update_plane(*screen, resource, None);
         Ok(0)
     }
 
@@ -229,7 +228,7 @@ impl<T: GraphicsAdapter> Scheme for GraphicsScheme<T> {
             )
         };
 
-        self.adapter.flush_resource(*screen, resource, Some(damage));
+        self.adapter.update_plane(*screen, resource, Some(damage));
 
         Ok(buf.len())
     }
diff --git a/graphics/vesad/src/scheme.rs b/graphics/vesad/src/scheme.rs
index 48c3b0940a..47fde67e88 100644
--- a/graphics/vesad/src/scheme.rs
+++ b/graphics/vesad/src/scheme.rs
@@ -34,11 +34,7 @@ impl GraphicsAdapter for FbAdapter {
         resource.ptr.as_ptr().cast::<u8>()
     }
 
-    fn set_scanout(&mut self, display_id: usize, resource: &Self::Resource) {
-        self.flush_resource(display_id, resource, None);
-    }
-
-    fn flush_resource(
+    fn update_plane(
         &mut self,
         display_id: usize,
         resource: &Self::Resource,
diff --git a/graphics/virtio-gpud/src/main.rs b/graphics/virtio-gpud/src/main.rs
index 6b0b62f3fe..2313808470 100644
--- a/graphics/virtio-gpud/src/main.rs
+++ b/graphics/virtio-gpud/src/main.rs
@@ -192,7 +192,7 @@ impl Default for GetDisplayInfo {
 
 static RESOURCE_ALLOC: AtomicU32 = AtomicU32::new(1); // XXX: 0 is reserved for whatever that takes `resource_id`.
 
-#[derive(Debug, Copy, Clone)]
+#[derive(PartialEq, Eq, Debug, Copy, Clone)]
 #[repr(C)]
 pub struct ResourceId(u32);
 
diff --git a/graphics/virtio-gpud/src/scheme.rs b/graphics/virtio-gpud/src/scheme.rs
index d80f45bbb6..bc0c1c4f98 100644
--- a/graphics/virtio-gpud/src/scheme.rs
+++ b/graphics/virtio-gpud/src/scheme.rs
@@ -44,6 +44,7 @@ impl Resource for VirtGpuResource {
 pub struct Display {
     width: u32,
     height: u32,
+    active_resource: Option<ResourceId>,
 }
 
 pub struct VirtGpuAdapter<'a> {
@@ -164,24 +165,9 @@ impl GraphicsAdapter for VirtGpuAdapter<'_> {
         resource.sgl.as_ptr()
     }
 
-    fn set_scanout(&mut self, display_id: usize, resource: &Self::Resource) {
-        futures::executor::block_on(async {
-            let scanout_request = Dma::new(SetScanout::new(
-                display_id as u32,
-                resource.id,
-                GpuRect::new(0, 0, resource.width, resource.height),
-            ))
-            .unwrap();
-            let header = self.send_request(scanout_request).await.unwrap();
-            assert_eq!(header.ty, CommandTy::RespOkNodata);
-        });
-
-        self.flush_resource(display_id, resource, None);
-    }
-
-    fn flush_resource(
+    fn update_plane(
         &mut self,
-        _display_id: usize,
+        display_id: usize,
         resource: &Self::Resource,
         damage: Option<&[Damage]>,
     ) {
@@ -200,6 +186,19 @@ impl GraphicsAdapter for VirtGpuAdapter<'_> {
             let header = self.send_request(req).await.unwrap();
             assert_eq!(header.ty, CommandTy::RespOkNodata);
 
+            // FIXME once we support resizing we also need to check that the current and target size match
+            if self.displays[display_id].active_resource != Some(resource.id) {
+                let scanout_request = Dma::new(SetScanout::new(
+                    display_id as u32,
+                    resource.id,
+                    GpuRect::new(0, 0, resource.width, resource.height),
+                ))
+                .unwrap();
+                let header = self.send_request(scanout_request).await.unwrap();
+                assert_eq!(header.ty, CommandTy::RespOkNodata);
+                self.displays[display_id].active_resource = Some(resource.id);
+            }
+
             if let Some(damage) = damage {
                 for damage in damage {
                     self.flush_resource_inner(ResourceFlush::new(
@@ -261,11 +260,13 @@ impl<'a> GpuScheme {
                 adapter.displays.push(Display {
                     width: 640,
                     height: 480,
+                    active_resource: None,
                 });
             } else {
                 adapter.displays.push(Display {
                     width: info.rect.width,
                     height: info.rect.height,
+                    active_resource: None,
                 });
             }
         }