A binding for checking drm_device.num_crtcs. We'll need this in a moment
for vblank support, since setting it up requires knowing the number of
CRTCs that a driver has initialized.
Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
---
rust/kernel/drm/kms.rs | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/rust/kernel/drm/kms.rs b/rust/kernel/drm/kms.rs
index 3edd90bc0025a..d0745b44ba9b6 100644
--- a/rust/kernel/drm/kms.rs
+++ b/rust/kernel/drm/kms.rs
@@ -253,10 +253,27 @@ pub fn mode_config_lock(&self) -> ModeConfigGuard<'_, T> {
/// Return the number of registered [`Plane`](plane::Plane) objects on this [`Device`].
#[inline]
- pub fn num_plane(&self) -> i32 {
- // SAFETY: The only context which this could change is before registration, which must be
- // single-threaded anyway - so it's safe to just read this value
- unsafe { (*self.as_raw()).mode_config.num_total_plane }
+ pub fn num_plane(&self) -> u32 {
+ // SAFETY:
+ // * This can only be modified during the single-threaded context before registration, so
+ // this is safe
+ // * num_total_plane could be >= 0, but no less - so casting to u32 is fine (and better to
+ // prevent errors)
+ unsafe { (*self.as_raw()).mode_config.num_total_plane as u32 }
+ }
+
+ /// Return the number of registered CRTCs
+ /// TODO: while `num_crtc` is of i32, that type actually makes literally no sense here and just
+ /// causes problems and unecessary casts. Same for num_plane(). So, fix that at some point (we
+ /// will never get n < 0 anyway)
+ #[inline]
+ pub fn num_crtcs(&self) -> u32 {
+ // SAFETY:
+ // * This can only be modified during the single-threaded context before registration, so
+ // this is safe
+ // * num_crtc could be >= 0, but no less - so casting to u32 is fine (and better to prevent
+ // errors)
+ unsafe { (*self.as_raw()).mode_config.num_crtc as u32 }
}
}
--
2.46.1
