From 575b6611bc2e6c82c267b9e6e48af66875dc4f46 Mon Sep 17 00:00:00 2001
From: Ian Douglas Scott <idscott@system76.com>
Date: Wed, 26 Jun 2024 14:39:03 -0700
Subject: [PATCH] Add `linux-drm-syncobj-v1` protocol

---
 src/backend/kms/mod.rs              | 27 ++++++++++++++++++++++++++-
 src/wayland/handlers/compositor.rs  | 27 +++++++++++++++++++++++++++
 src/wayland/handlers/drm_syncobj.rs | 19 +++++++++++++++++++
 src/wayland/handlers/mod.rs         |  1 +
 4 files changed, 73 insertions(+), 1 deletion(-)
 create mode 100644 src/wayland/handlers/drm_syncobj.rs

diff --git a/src/backend/kms/mod.rs b/src/backend/kms/mod.rs
index 7073b88b..0ceb1247 100644
--- a/src/backend/kms/mod.rs
+++ b/src/backend/kms/mod.rs
@@ -27,7 +27,11 @@ use smithay::{
         wayland_server::{Client, DisplayHandle},
     },
     utils::{DevPath, Size},
-    wayland::{dmabuf::DmabufGlobal, relative_pointer::RelativePointerManagerState},
+    wayland::{
+        dmabuf::DmabufGlobal,
+        drm_syncobj::{supports_syncobj_eventfd, DrmSyncobjState},
+        relative_pointer::RelativePointerManagerState,
+    },
 };
 use tracing::{error, info, trace, warn};
 
@@ -60,6 +64,8 @@ pub struct KmsState {
 
     session: LibSeatSession,
     libinput: Libinput,
+
+    pub syncobj_state: Option<DrmSyncobjState>,
 }
 
 pub fn init_backend(
@@ -126,6 +132,8 @@ pub fn init_backend(
 
         session,
         libinput: libinput_context,
+
+        syncobj_state: None,
     });
 
     // start x11
@@ -138,6 +146,23 @@ pub fn init_backend(
         }
     }
 
+    let kms = match &mut state.backend {
+        BackendData::Kms(kms) => kms,
+        _ => unreachable!(),
+    };
+    if let Some(primary_node) = kms
+        .primary_node
+        .and_then(|node| node.node_with_type(NodeType::Primary).and_then(|x| x.ok()))
+    {
+        if let Some(device) = kms.drm_devices.get(&primary_node) {
+            let import_device = device.drm.device_fd().clone();
+            if supports_syncobj_eventfd(&import_device) {
+                let syncobj_state = DrmSyncobjState::new::<State>(&dh, import_device);
+                kms.syncobj_state = Some(syncobj_state);
+            }
+        }
+    }
+
     Ok(())
 }
 
diff --git a/src/wayland/handlers/compositor.rs b/src/wayland/handlers/compositor.rs
index 1c43d3c3..03bb6c8c 100644
--- a/src/wayland/handlers/compositor.rs
+++ b/src/wayland/handlers/compositor.rs
@@ -14,6 +14,7 @@ use smithay::{
             CompositorHandler, CompositorState, SurfaceAttributes,
         },
         dmabuf::get_dmabuf,
+        drm_syncobj::DrmSyncobjCachedState,
         seat::WaylandFocus,
         shell::{
             wlr_layer::LayerSurfaceAttributes,
@@ -100,7 +101,14 @@ impl CompositorHandler for State {
 
     fn new_surface(&mut self, surface: &WlSurface) {
         add_pre_commit_hook::<Self, _>(surface, move |state, _dh, surface| {
+            let mut acquire_point = None;
             let maybe_dmabuf = with_states(surface, |surface_data| {
+                acquire_point = surface_data
+                    .cached_state
+                    .get::<DrmSyncobjCachedState>()
+                    .pending()
+                    .acquire_point
+                    .clone();
                 surface_data
                     .cached_state
                     .get::<SurfaceAttributes>()
@@ -113,6 +121,25 @@ impl CompositorHandler for State {
                     })
             });
             if let Some(dmabuf) = maybe_dmabuf {
+                if let Some(acquire_point) = acquire_point {
+                    if let Ok((blocker, source)) = acquire_point.generate_blocker() {
+                        let client = surface.client().unwrap();
+                        let res = state.common.event_loop_handle.insert_source(
+                            source,
+                            move |_, _, state| {
+                                let dh = state.common.display_handle.clone();
+                                state
+                                    .client_compositor_state(&client)
+                                    .blocker_cleared(state, &dh);
+                                Ok(())
+                            },
+                        );
+                        if res.is_ok() {
+                            add_blocker(surface, blocker);
+                            return;
+                        }
+                    }
+                }
                 if let Ok((blocker, source)) = dmabuf.generate_blocker(Interest::READ) {
                     let client = surface.client().unwrap();
                     let res =
diff --git a/src/wayland/handlers/drm_syncobj.rs b/src/wayland/handlers/drm_syncobj.rs
new file mode 100644
index 00000000..50939c12
--- /dev/null
+++ b/src/wayland/handlers/drm_syncobj.rs
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-3.0-only
+
+use crate::state::{BackendData, State};
+use smithay::{
+    delegate_drm_syncobj,
+    wayland::drm_syncobj::{DrmSyncobjHandler, DrmSyncobjState},
+};
+
+impl DrmSyncobjHandler for State {
+    fn drm_syncobj_state(&mut self) -> &mut DrmSyncobjState {
+        let kms = match &mut self.backend {
+            BackendData::Kms(kms) => kms,
+            _ => unreachable!(),
+        };
+        kms.syncobj_state.as_mut().unwrap()
+    }
+}
+
+delegate_drm_syncobj!(State);
diff --git a/src/wayland/handlers/mod.rs b/src/wayland/handlers/mod.rs
index 82415aa4..a10ea5b7 100644
--- a/src/wayland/handlers/mod.rs
+++ b/src/wayland/handlers/mod.rs
@@ -9,6 +9,7 @@ pub mod decoration;
 pub mod dmabuf;
 pub mod drm;
 pub mod drm_lease;
+pub mod drm_syncobj;
 pub mod foreign_toplevel_list;
 pub mod fractional_scale;
 pub mod idle_inhibit;