From 02fbae62c2a09ce00f828223d602e9b186509daa Mon Sep 17 00:00:00 2001
From: Lyude Paul <lyude@redhat.com>
Date: Fri, 6 Sep 2024 13:09:42 -0400
Subject: [PATCH] rust: drm/kms: Add Device::num_crtcs()
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@redhat.com>
---
rust/kernel/drm/kms.rs | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/rust/kernel/drm/kms.rs b/rust/kernel/drm/kms.rs
index f6a808279d468..48ae8bc0f52ce 100644
--- a/rust/kernel/drm/kms.rs
+++ b/rust/kernel/drm/kms.rs
@@ -326,6 +326,20 @@ impl<T: KmsDriver> Device<T> {
// 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 }
+ }
}
/// A modesetting object in DRM.
--
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