Hi Lyude,
> On 30 Sep 2024, at 20:10, Lyude Paul <lyude@xxxxxxxxxx> wrote:
>
> Add a binding for drm_atomic_helper_check_plane_state(). Since we want to
> make sure that the user is passing in the new state for a Crtc instead of
> an old state, we explicitly ask for a reference to a BorrowedCrtcState.
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
>
> ---
>
> TODO:
> * Add support for scaling options
Can / should this be a separate commit? This would allow this one to go in earlier.
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> ---
> rust/kernel/drm/kms/plane.rs | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/rust/kernel/drm/kms/plane.rs b/rust/kernel/drm/kms/plane.rs
> index 4d16d53179fca..cd5167e6441f1 100644
> --- a/rust/kernel/drm/kms/plane.rs
> +++ b/rust/kernel/drm/kms/plane.rs
> @@ -496,6 +496,31 @@ fn crtc<'a, 'b: 'a>(&'a self) -> Option<&'b OpaqueCrtc<<Self::Plane as ModeObjec
> // SAFETY: This cast is guaranteed safe by `OpaqueCrtc`s invariants.
> NonNull::new(self.as_raw().crtc).map(|c| unsafe { OpaqueCrtc::from_raw(c.as_ptr()) })
> }
> +
> + /// Run the atomic check helper for this plane and the given CRTC state
> + fn atomic_helper_check<S>(
> + &mut self,
> + crtc_state: &BorrowedCrtcState<'_, S>,
> + can_position: bool,
> + can_update_disabled: bool
> + ) -> Result
Some docs on the arguments would be nice IMHO. Things like `can_position` and `can_update_disabled`
seem a bit opaque.
> + where
> + S: FromRawCrtcState,
> + S::Crtc: AsRawCrtc<Driver = <Self::Plane as ModeObject>::Driver>
> + {
> + // SAFETY: We're passing the mutable reference from `self.as_raw_mut()` directly to DRM,
> + // which is safe.
> + to_result(unsafe {
> + bindings::drm_atomic_helper_check_plane_state(
> + self.as_raw_mut(),
> + crtc_state.as_raw(),
> + bindings::DRM_PLANE_NO_SCALING as _, // TODO: add parameters for scaling
> + bindings::DRM_PLANE_NO_SCALING as _,
No scaling means that you can only select the display’s highest resolution?
> + can_position,
> + can_update_disabled
> + )
> + })
> + }
> }
> impl<T: AsRawPlaneState + ?Sized> RawPlaneState for T {}
>
> --
> 2.46.1
>
Barring the comment above about the docs, this looks good.
— Daniel
