From 73ac09f173f878dbce6efc4c0234346ab734f466 Mon Sep 17 00:00:00 2001
From: Ian Douglas Scott <idscott@system76.com>
Date: Wed, 20 Mar 2024 12:26:37 -0700
Subject: [PATCH] Add `Device::syncobj_eventfd`

---
 drm-ffi/src/ioctl.rs   |  2 ++
 drm-ffi/src/syncobj.rs | 28 ++++++++++++++++++++++++++++
 src/control/mod.rs     | 12 ++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/drm-ffi/src/ioctl.rs b/drm-ffi/src/ioctl.rs
index 0f46801..c053ede 100644
--- a/drm-ffi/src/ioctl.rs
+++ b/drm-ffi/src/ioctl.rs
@@ -278,4 +278,6 @@ pub(crate) mod syncobj {
         0xCD,
         drm_syncobj_timeline_array
     );
+    /// Register an eventfd to be signalled by a syncobj.
+    ioctl_readwrite!(eventfd, DRM_IOCTL_BASE, 0xCF, drm_syncobj_eventfd);
 }
diff --git a/drm-ffi/src/syncobj.rs b/drm-ffi/src/syncobj.rs
index 6cb45a9..676e941 100644
--- a/drm-ffi/src/syncobj.rs
+++ b/drm-ffi/src/syncobj.rs
@@ -262,3 +262,31 @@ pub fn timeline_signal(
 
     Ok(args)
 }
+
+/// Register an eventfd to be signalled by a syncobj.
+pub fn eventfd(
+    fd: BorrowedFd<'_>,
+    handle: u32,
+    point: u64,
+    eventfd: BorrowedFd<'_>,
+    wait_available: bool,
+) -> io::Result<drm_syncobj_eventfd> {
+    let flags = if wait_available {
+        DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE
+    } else {
+        0
+    };
+    let mut args = drm_syncobj_eventfd {
+        handle,
+        point,
+        flags,
+        fd: eventfd.as_raw_fd(),
+        pad: 0,
+    };
+
+    unsafe {
+        ioctl::syncobj::eventfd(fd, &mut args)?;
+    }
+
+    Ok(args)
+}
diff --git a/src/control/mod.rs b/src/control/mod.rs
index 2b6f946..8520548 100644
--- a/src/control/mod.rs
+++ b/src/control/mod.rs
@@ -952,6 +952,18 @@ pub trait Device: super::Device {
         Ok(())
     }
 
+    /// Register an eventfd to be signalled by a syncobj.
+    fn syncobj_eventfd(
+        &self,
+        handle: syncobj::Handle,
+        point: u64,
+        eventfd: BorrowedFd<'_>,
+        wait_available: bool,
+    ) -> io::Result<()> {
+        ffi::syncobj::eventfd(self.as_fd(), handle.into(), point, eventfd, wait_available)?;
+        Ok(())
+    }
+
     /// Create a drm lease
     fn create_lease(
         &self,