Optional trait method for implementing a plane's atomic_check().
Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
---
V3:
* Document ManuallyDrop uses better
Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
---
rust/kernel/drm/kms/plane.rs | 53 ++++++++++++++++++++++++++++++++++--
1 file changed, 50 insertions(+), 3 deletions(-)
diff --git a/rust/kernel/drm/kms/plane.rs b/rust/kernel/drm/kms/plane.rs
index b090aebc35649..f3adc30c17489 100644
--- a/rust/kernel/drm/kms/plane.rs
+++ b/rust/kernel/drm/kms/plane.rs
@@ -11,7 +11,7 @@
alloc::KBox,
bindings,
drm::{device::Device, fourcc::*},
- error::{to_result, Error},
+ error::{from_result, to_result, Error},
init::Zeroable,
prelude::*,
private::Sealed,
@@ -20,7 +20,7 @@
use core::{
cell::Cell,
marker::*,
- mem,
+ mem::{self, ManuallyDrop},
ops::*,
pin::Pin,
ptr::{addr_of_mut, null, null_mut, NonNull},
@@ -69,7 +69,11 @@ pub trait DriverPlane: Send + Sync + Sized {
cleanup_fb: None,
begin_fb_access: None,
end_fb_access: None,
- atomic_check: None,
+ atomic_check: if Self::HAS_ATOMIC_CHECK {
+ Some(atomic_check_callback::<Self>)
+ } else {
+ None
+ },
atomic_update: if Self::HAS_ATOMIC_UPDATE {
Some(atomic_update_callback::<Self>)
} else {
@@ -117,6 +121,21 @@ fn atomic_update(
) {
build_error::build_error("This should not be reachable")
}
+
+ /// The optional [`drm_plane_helper_funcs.atomic_check`] hook for this plane.
+ ///
+ /// Drivers may use this to customize the atomic check phase of their [`Plane`] objects. The
+ /// result of this function determines whether the atomic check passed or failed.
+ ///
+ /// [`drm_plane_helper_funcs.atomic_check`]: srctree/include/drm/drm_modeset_helper_vtables.h
+ fn atomic_check(
+ _plane: &Plane<Self>,
+ _new_state: PlaneStateMutator<'_, PlaneState<Self::State>>,
+ _old_state: &PlaneState<Self::State>,
+ _state: &AtomicStateComposer<Self::Driver>,
+ ) -> Result {
+ build_error::build_error("This should not be reachable")
+ }
}
/// The generated C vtable for a [`DriverPlane`].
@@ -974,3 +993,31 @@ fn <D, P>(PlaneStateMutator<'a, OpaquePlaneState<D>>) -> Self
T::atomic_update(plane, new_state, old_state, &state);
}
+
+unsafe extern "C" fn atomic_check_callback<T: DriverPlane>(
+ plane: *mut bindings::drm_plane,
+ state: *mut bindings::drm_atomic_state,
+) -> i32 {
+ // SAFETY:
+ // - We're guaranteed `plane` is of type `Plane<T>` via type invariants.
+ // - We're guaranteed by DRM that `plane` is pointing to a valid initialized state.
+ let plane = unsafe { Plane::from_raw(plane) };
+
+ // SAFETY: We're guaranteed by DRM that `state` points to a valid instance of `drm_atomic_state`
+ // We use ManuallyDrop here since AtomicStateComposer would otherwise drop a owned reference to
+ // the atomic state upon finishing this callback.
+ let state = ManuallyDrop::new(unsafe {
+ AtomicStateComposer::<T::Driver>::new(NonNull::new_unchecked(state))
+ });
+
+ // SAFETY: We're guaranteed by DRM that both the old and new atomic state are present within
+ // this `drm_atomic_state`
+ let (old_state, new_state) = unsafe {
+ (
+ state.get_old_plane_state(plane).unwrap_unchecked(),
+ state.get_new_plane_state(plane).unwrap_unchecked(),
+ )
+ };
+
+ from_result(|| T::atomic_check(plane, new_state, old_state, &state).map(|_| 0))
+}
--
2.48.1
