From patchwork Wed Mar 5 22:59:37 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lyude Paul X-Patchwork-Id: 14003647 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D2A67C19F32 for ; Wed, 5 Mar 2025 23:07:53 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 45D9D10E859; Wed, 5 Mar 2025 23:07:53 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="cGhLaVZE"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9021710E859 for ; Wed, 5 Mar 2025 23:07:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741216071; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=P8Wya8waZxf4PRUJ4SmPnCKJ5/8nzDdWThNqRlGolhE=; b=cGhLaVZE099ReiP/uX997zwgQjvRMj31nuVHhdvUUiJLWJtKmPVo3FEpxGbnfACuer8NY1 syvrvj2TAfq3Rb/+4pk8g4575yRMsbSh7W1vVAN6T6yd1tG1kP7HrCBPDUkZ5JhItOuT7u llzya6Z92F7ZaY+J/lnSvpJsfm3iiW8= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-113-fTF3WE_ONlOJowyS2fczRQ-1; Wed, 05 Mar 2025 18:07:43 -0500 X-MC-Unique: fTF3WE_ONlOJowyS2fczRQ-1 X-Mimecast-MFC-AGG-ID: fTF3WE_ONlOJowyS2fczRQ_1741216061 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6C3631800262; Wed, 5 Mar 2025 23:07:41 +0000 (UTC) Received: from chopper.redhat.com (unknown [10.22.88.81]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CAB83300019E; Wed, 5 Mar 2025 23:07:37 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org Cc: Danilo Krummrich , mcanal@igalia.com, Alice Ryhl , Maxime Ripard , Simona Vetter , Daniel Almeida , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?B?= =?utf-8?q?j=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Trevor Gross , linux-kernel@vger.kernel.org (open list) Subject: [RFC v3 21/33] rust: drm/kms: Add DriverPlane::atomic_check() Date: Wed, 5 Mar 2025 17:59:37 -0500 Message-ID: <20250305230406.567126-22-lyude@redhat.com> In-Reply-To: <20250305230406.567126-1-lyude@redhat.com> References: <20250305230406.567126-1-lyude@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Optional trait method for implementing a plane's atomic_check(). Signed-off-by: Lyude Paul --- V3: * Document ManuallyDrop uses better Signed-off-by: Lyude Paul --- 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::) + } else { + None + }, atomic_update: if Self::HAS_ATOMIC_UPDATE { Some(atomic_update_callback::) } 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, + _new_state: PlaneStateMutator<'_, PlaneState>, + _old_state: &PlaneState, + _state: &AtomicStateComposer, + ) -> Result { + build_error::build_error("This should not be reachable") + } } /// The generated C vtable for a [`DriverPlane`]. @@ -974,3 +993,31 @@ fn (PlaneStateMutator<'a, OpaquePlaneState>) -> Self T::atomic_update(plane, new_state, old_state, &state); } + +unsafe extern "C" fn atomic_check_callback( + plane: *mut bindings::drm_plane, + state: *mut bindings::drm_atomic_state, +) -> i32 { + // SAFETY: + // - We're guaranteed `plane` is of type `Plane` 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::::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)) +}