commit_timeline: wait for implicit sync dmabufs

src/client.rs

@@ -168,7 +168,10 @@ impl Clients {
             last_xwayland_serial: Cell::new(0),
             surfaces_by_xwayland_serial: Default::default(),
             activation_tokens: Default::default(),
-            commit_timelines: Rc::new(CommitTimelines::new(&global.wait_for_sync_obj)),
+            commit_timelines: Rc::new(CommitTimelines::new(
+                &global.wait_for_sync_obj,
+                &global.ring,
+            )),
         });
         track!(data, data);
         let display = Rc::new(WlDisplay::new(&data));

src/ifs/wl_surface.rs

@@ -23,8 +23,8 @@ use {
         drm_feedback::DrmFeedback,
         fixed::Fixed,
         gfx_api::{
-            AcquireSync, AsyncShmGfxTexture, BufferResv, BufferResvUser, GfxError, ReleaseSync,
+            AsyncShmGfxTexture, BufferResv, BufferResvUser, GfxError, ReleaseSync, SampleRect,
-            SampleRect, SyncFile,
+            SyncFile,
         },
         ifs::{
             wl_buffer::WlBuffer,
@@ -190,7 +190,6 @@ struct SurfaceBufferExplicitRelease {
 pub struct SurfaceBuffer {
     pub buffer: Rc<WlBuffer>,
     sync_files: SmallMap<BufferResvUser, SyncFile, 1>,
-    pub sync: AcquireSync,
     pub release_sync: ReleaseSync,
     release: Option<SurfaceBufferExplicitRelease>,
 }
@@ -1093,9 +1092,9 @@ impl WlSurface {
                     self.reset_shm_textures();
                 }
                 buffer.update_texture_or_log(self, false);
-                let (sync, release_sync) = match pending.explicit_sync {
+                let release_sync = match pending.explicit_sync {
-                    false => (AcquireSync::Implicit, ReleaseSync::Implicit),
+                    false => ReleaseSync::Implicit,
-                    true => (AcquireSync::Unnecessary, ReleaseSync::Explicit),
+                    true => ReleaseSync::Explicit,
                 };
                 let release = pending
                     .release_point
@@ -1104,7 +1103,6 @@ impl WlSurface {
                 let surface_buffer = SurfaceBuffer {
                     buffer,
                     sync_files: Default::default(),
-                    sync,
                     release_sync,
                     release,
                 };

src/ifs/wl_surface/commit_timeline.rs

@@ -5,12 +5,14 @@ use {
             wl_buffer::WlBufferStorage,
             wl_surface::{PendingState, WlSurface, WlSurfaceError},
         },
+        io_uring::{IoUring, IoUringError, PendingPoll, PollCallback},
         utils::{
             clonecell::CloneCell,
             copyhashmap::CopyHashMap,
             hash_map_ext::HashMapExt,
             linkedlist::{LinkedList, LinkedNode, NodeRef},
             numcell::NumCell,
+            oserror::OsError,
         },
         video::drm::{
             sync_obj::{SyncObj, SyncObjPoint},
@@ -28,6 +30,7 @@ use {
         slice,
     },
     thiserror::Error,
+    uapi::{c::c_short, OwnedFd},
 };
 
 const MAX_TIMELINE_DEPTH: usize = 256;
@@ -37,6 +40,7 @@ linear_ids!(CommitTimelineIds, CommitTimelineId, u64);
 pub struct CommitTimelines {
     next_id: CommitTimelineIds,
     wfs: Rc<WaitForSyncObj>,
+    ring: Rc<IoUring>,
     depth: NumCell<usize>,
     gc: CopyHashMap<CommitTimelineId, LinkedList<Entry>>,
 }
@@ -83,15 +87,20 @@ pub enum CommitTimelineError {
     Depth,
     #[error("Could not upload a shm texture")]
     ShmUpload(#[source] GfxError),
+    #[error("Could not register an implicit-sync wait")]
+    RegisterImplicitPoll(#[source] IoUringError),
+    #[error("Could not wait for a dmabuf to become idle")]
+    PollDmabuf(#[source] OsError),
 }
 
 impl CommitTimelines {
-    pub fn new(wfs: &Rc<WaitForSyncObj>) -> Self {
+    pub fn new(wfs: &Rc<WaitForSyncObj>, ring: &Rc<IoUring>) -> Self {
         Self {
             next_id: Default::default(),
             depth: NumCell::new(0),
             wfs: wfs.clone(),
             gc: Default::default(),
+            ring: ring.clone(),
         }
     }
 
@@ -127,6 +136,7 @@ fn break_loops(list: &LinkedList<Entry>) {
         if let EntryKind::Commit(c) = &entry.kind {
             c.wait_handles.take();
             *c.shm_upload.borrow_mut() = ShmUploadState::None;
+            c.pending_polls.take();
         }
     }
 }
@@ -153,8 +163,15 @@ impl CommitTimeline {
     ) -> Result<(), CommitTimelineError> {
         let mut points = SmallVec::new();
         let mut pending_uploads = 0;
-        collect_commit_data(pending, &mut points, &mut pending_uploads);
+        let mut implicit_dmabufs = SmallVec::new();
-        let has_dependencies = points.is_not_empty() || pending_uploads > 0;
+        collect_commit_data(
+            pending,
+            &mut points,
+            &mut pending_uploads,
+            &mut implicit_dmabufs,
+        );
+        let has_dependencies =
+            points.is_not_empty() || pending_uploads > 0 || implicit_dmabufs.is_not_empty();
         if !has_dependencies && self.own_timeline.entries.is_empty() {
             return surface
                 .apply_state(pending)
@@ -174,6 +191,8 @@ impl CommitTimeline {
                 wait_handles: Cell::new(Default::default()),
                 pending_uploads: NumCell::new(pending_uploads),
                 shm_upload: RefCell::new(ShmUploadState::None),
+                num_pending_polls: NumCell::new(implicit_dmabufs.len()),
+                pending_polls: Cell::new(Default::default()),
             }),
         );
         let mut needs_flush = false;
@@ -198,6 +217,18 @@ impl CommitTimeline {
                 *commit.shm_upload.borrow_mut() = ShmUploadState::Todo(noderef.clone());
                 needs_flush = true;
             }
+            if implicit_dmabufs.is_not_empty() {
+                let mut pending_polls = SmallVec::new();
+                for fd in implicit_dmabufs {
+                    let handle = self
+                        .shared
+                        .ring
+                        .readable_external(&fd, noderef.clone())
+                        .map_err(CommitTimelineError::RegisterImplicitPoll)?;
+                    pending_polls.push(handle);
+                }
+                commit.pending_polls.set(pending_polls);
+            }
         }
         if needs_flush && noderef.prev().is_none() {
             flush_from(noderef.clone()).map_err(CommitTimelineError::DelayedCommit)?;
@@ -246,6 +277,23 @@ impl AsyncShmGfxTextureCallback for NodeRef<Entry> {
     }
 }
 
+impl PollCallback for NodeRef<Entry> {
+    fn completed(self: Rc<Self>, res: Result<c_short, OsError>) {
+        let EntryKind::Commit(commit) = &self.kind else {
+            unreachable!();
+        };
+        if let Err(e) = res {
+            commit
+                .surface
+                .client
+                .error(CommitTimelineError::PollDmabuf(e));
+            return;
+        }
+        commit.num_pending_polls.fetch_sub(1);
+        flush_commit(&self, commit);
+    }
+}
+
 struct Entry {
     link: Cell<Option<LinkedNode<Entry>>>,
     shared: Rc<CommitTimelines>,
@@ -272,6 +320,8 @@ struct Commit {
     wait_handles: Cell<SmallVec<[WaitForSyncObjHandle; 1]>>,
     pending_uploads: NumCell<usize>,
     shm_upload: RefCell<ShmUploadState>,
+    num_pending_polls: NumCell<usize>,
+    pending_polls: Cell<SmallVec<[PendingPoll; 1]>>,
 }
 
 fn flush_from(mut point: NodeRef<Entry>) -> Result<(), WlSurfaceError> {
@@ -304,6 +354,9 @@ impl NodeRef<Entry> {
                         has_unmet_dependencies = true;
                     }
                 }
+                if c.num_pending_polls.get() > 0 {
+                    has_unmet_dependencies = true;
+                }
                 if has_unmet_dependencies {
                     return Ok(false);
                 }
@@ -417,18 +470,26 @@ fn collect_commit_data(
     pending: &mut PendingState,
     acquire_points: &mut SmallVec<[Point; 1]>,
     shm_uploads: &mut usize,
+    implicit_dmabufs: &mut SmallVec<[Rc<OwnedFd>; 1]>,
 ) {
     if let Some(Some(buffer)) = &pending.buffer {
         if buffer.is_shm() {
             *shm_uploads += 1;
         }
+        if !pending.explicit_sync {
+            if let Some(dmabuf) = &buffer.dmabuf {
+                for plane in &dmabuf.planes {
+                    implicit_dmabufs.push(plane.fd.clone());
+                }
+            }
+        }
     }
     if let Some(point) = pending.acquire_point.take() {
         acquire_points.push(point);
     }
     for ss in pending.subsurfaces.values_mut() {
         if let Some(state) = &mut ss.pending.state {
-            collect_commit_data(state, acquire_points, shm_uploads);
+            collect_commit_data(state, acquire_points, shm_uploads, implicit_dmabufs);
         }
     }
 }

src/io_uring.rs

@@ -1,11 +1,14 @@
-pub use ops::TaskResultExt;
+pub use ops::{
+    poll_external::{PendingPoll, PollCallback},
+    TaskResultExt,
+};
 use {
     crate::{
         async_engine::AsyncEngine,
         io_uring::{
             ops::{
                 accept::AcceptTask, async_cancel::AsyncCancelTask, connect::ConnectTask,
-                poll::PollTask, read_write::ReadWriteTask,
+                poll::PollTask, poll_external::PollExternalTask, read_write::ReadWriteTask,
                 read_write_no_cancel::ReadWriteNoCancelTask, recvmsg::RecvmsgTask,
                 sendmsg::SendmsgTask, timeout::TimeoutTask, timeout_link::TimeoutLinkTask,
             },
@@ -209,6 +212,7 @@ impl IoUring {
             cached_read_writes_no_cancel: Default::default(),
             cached_cancels: Default::default(),
             cached_polls: Default::default(),
+            cached_polls_external: Default::default(),
             cached_sendmsg: Default::default(),
             cached_recvmsg: Default::default(),
             cached_timeouts: Default::default(),
@@ -270,6 +274,7 @@ struct IoUringData {
     cached_read_writes_no_cancel: Stack<Box<ReadWriteNoCancelTask>>,
     cached_cancels: Stack<Box<AsyncCancelTask>>,
     cached_polls: Stack<Box<PollTask>>,
+    cached_polls_external: Stack<Box<PollExternalTask>>,
     cached_sendmsg: Stack<Box<SendmsgTask>>,
     cached_recvmsg: Stack<Box<RecvmsgTask>>,
     cached_timeouts: Stack<Box<TimeoutTask>>,

src/io_uring/ops.rs

@@ -4,6 +4,7 @@ pub mod accept;
 pub mod async_cancel;
 pub mod connect;
 pub mod poll;
+pub mod poll_external;
 pub mod read_write;
 pub mod read_write_no_cancel;
 pub mod recvmsg;

src/io_uring/ops/poll_external.rs

@@ -0,0 +1,116 @@
+use {
+    crate::{
+        io_uring::{
+            sys::{io_uring_sqe, IORING_OP_POLL_ADD},
+            IoUring, IoUringData, IoUringError, IoUringTaskId, Task,
+        },
+        utils::oserror::OsError,
+    },
+    std::{cell::Cell, rc::Rc},
+    uapi::{c, OwnedFd},
+};
+
+pub trait PollCallback {
+    fn completed(self: Rc<Self>, res: Result<c::c_short, OsError>);
+}
+
+pub struct PendingPoll {
+    data: Rc<IoUringData>,
+    shared: Rc<PollExternalTaskShared>,
+    id: IoUringTaskId,
+}
+
+impl Drop for PendingPoll {
+    fn drop(&mut self) {
+        if self.shared.id.get() != self.id {
+            return;
+        }
+        self.shared.callback.take();
+        self.data.cancel_task(self.id);
+    }
+}
+
+impl IoUring {
+    pub fn poll_external(
+        &self,
+        fd: &Rc<OwnedFd>,
+        events: c::c_short,
+        callback: Rc<dyn PollCallback>,
+    ) -> Result<PendingPoll, IoUringError> {
+        self.ring.check_destroyed()?;
+        let mut pw = self.ring.cached_polls_external.pop().unwrap_or_default();
+        pw.shared.id.set(self.ring.id_raw());
+        pw.shared.callback.set(Some(callback));
+        pw.fd = fd.raw() as _;
+        pw.events = events as _;
+        pw.data = Some(Data { _fd: fd.clone() });
+        let pending = PendingPoll {
+            data: self.ring.clone(),
+            shared: pw.shared.clone(),
+            id: pw.shared.id.get(),
+        };
+        self.ring.schedule(pw);
+        Ok(pending)
+    }
+
+    pub fn readable_external(
+        &self,
+        fd: &Rc<OwnedFd>,
+        callback: Rc<dyn PollCallback>,
+    ) -> Result<PendingPoll, IoUringError> {
+        self.poll_external(fd, c::POLLIN, callback)
+    }
+
+    #[expect(dead_code)]
+    pub fn writable_external(
+        &self,
+        fd: &Rc<OwnedFd>,
+        callback: Rc<dyn PollCallback>,
+    ) -> Result<PendingPoll, IoUringError> {
+        self.poll_external(fd, c::POLLOUT, callback)
+    }
+}
+
+struct Data {
+    _fd: Rc<OwnedFd>,
+}
+
+#[derive(Default)]
+struct PollExternalTaskShared {
+    id: Cell<IoUringTaskId>,
+    callback: Cell<Option<Rc<dyn PollCallback>>>,
+}
+
+#[derive(Default)]
+pub struct PollExternalTask {
+    shared: Rc<PollExternalTaskShared>,
+    events: u16,
+    fd: i32,
+    data: Option<Data>,
+}
+
+unsafe impl Task for PollExternalTask {
+    fn id(&self) -> IoUringTaskId {
+        self.shared.id.get()
+    }
+
+    fn complete(mut self: Box<Self>, ring: &IoUringData, res: i32) {
+        self.data.take();
+        self.shared.id.set(Default::default());
+        if let Some(cb) = self.shared.callback.take() {
+            let res = if res < 0 {
+                Err(OsError::from(-res as c::c_int))
+            } else {
+                Ok(res as _)
+            };
+            cb.completed(res)
+        }
+        ring.cached_polls_external.push(self);
+    }
+
+    fn encode(&self, sqe: &mut io_uring_sqe) {
+        sqe.opcode = IORING_OP_POLL_ADD;
+        sqe.fd = self.fd;
+        sqe.u3.poll_events = self.events;
+    }
+}

src/renderer.rs

@@ -472,7 +472,7 @@ impl Renderer<'_> {
                 self.base.scale,
                 bounds,
                 Some(buffer.clone()),
-                buffer.sync.clone(),
+                AcquireSync::Unnecessary,
                 buffer.release_sync,
             );
         } else if let Some(color) = &buffer.buffer.color {