From patchwork Mon Sep 30 23:10:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lyude Paul X-Patchwork-Id: 13817274 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 5AD9CCEB2CD for ; Mon, 30 Sep 2024 23:40:16 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D0AF810E5A0; Mon, 30 Sep 2024 23:40:15 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="fbIk37o4"; 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 6E69710E5A0 for ; Mon, 30 Sep 2024 23:40:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727739613; 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=fXYRkES5IMRSEWy/SdffRUBHVVSOxpQy/XQZZbTshqY=; b=fbIk37o4uUCywcXOq95gDkAMzprMwGOxUD7ZMuTfDmbdZNMXtT5+5N9aeMHJWvB8qYmX8u Z+BQ68TQZJ1GuwtJXK/X6xNIcUlK601Es5BH0MF0rtMp0I1ozllXDW45mp7QZUEqJLbbbz qLEUqu8tUSpTJcV1dKSf+P+O0gPAjJQ= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-331-ZZjrKZJOO3uRfv2nR5MVhg-1; Mon, 30 Sep 2024 19:40:08 -0400 X-MC-Unique: ZZjrKZJOO3uRfv2nR5MVhg-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (unknown [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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 17FEF192DE39; Mon, 30 Sep 2024 23:40:06 +0000 (UTC) Received: from chopper.redhat.com (unknown [10.22.32.36]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 4928D3003E4D; Mon, 30 Sep 2024 23:40:02 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org Cc: Asahi Lina , Danilo Krummrich , mcanal@igalia.com, airlied@redhat.com, zhiw@nvidia.com, cjia@nvidia.com, jhubbard@nvidia.com, Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , linux-kernel@vger.kernel.org (open list) Subject: [WIP RFC v2 21/35] rust: drm/kms: Introduce DriverCrtc::atomic_check() Date: Mon, 30 Sep 2024 19:10:04 -0400 Message-ID: <20240930233257.1189730-22-lyude@redhat.com> In-Reply-To: <20240930233257.1189730-1-lyude@redhat.com> References: <20240930233257.1189730-1-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" An optional trait method for implementing a CRTC's atomic state check. Signed-off-by: Lyude Paul --- rust/kernel/drm/kms/crtc.rs | 46 +++++++++++++++++++++++++++++++++++-- 1 file changed, 44 insertions(+), 2 deletions(-) diff --git a/rust/kernel/drm/kms/crtc.rs b/rust/kernel/drm/kms/crtc.rs index 7864540705f76..43c7264402b07 100644 --- a/rust/kernel/drm/kms/crtc.rs +++ b/rust/kernel/drm/kms/crtc.rs @@ -27,7 +27,7 @@ marker::*, ptr::{NonNull, null, null_mut, addr_of_mut, self}, ops::{Deref, DerefMut}, - mem, + mem::{self, ManuallyDrop}, }; use macros::vtable; @@ -82,7 +82,7 @@ pub trait DriverCrtc: Send + Sync + Sized { helper_funcs: bindings::drm_crtc_helper_funcs { atomic_disable: None, atomic_enable: None, - atomic_check: None, + atomic_check: if Self::HAS_ATOMIC_CHECK { Some(atomic_check_callback::) } else { None }, dpms: None, commit: None, prepare: None, @@ -117,6 +117,21 @@ pub trait DriverCrtc: Send + Sync + Sized { /// /// Drivers may use this to instantiate their [`DriverCrtc`] object. fn new(device: &Device, args: &Self::Args) -> impl PinInit; + + /// The optional [`drm_crtc_helper_funcs.atomic_check`] hook for this crtc. + /// + /// Drivers may use this to customize the atomic check phase of their [`Crtc`] objects. The + /// result of this function determines whether the atomic check passed or failed. + /// + /// [`drm_crtc_helper_funcs.atomic_check`]: srctree/include/drm/drm_modeset_helper_vtables.h + fn atomic_check( + crtc: &Crtc, + old_state: &CrtcState, + new_state: BorrowedCrtcState<'_, CrtcState>, + state: &AtomicStateComposer + ) -> Result { + build_error::build_error("This should not be reachable") + } } /// The generated C vtable for a [`DriverCrtc`]. @@ -726,3 +741,30 @@ fn as_raw(&self) -> *mut bindings::drm_crtc_state { ) }; } + +unsafe extern "C" fn atomic_check_callback( + crtc: *mut bindings::drm_crtc, + state: *mut bindings::drm_atomic_state, +) -> i32 { + // SAFETY: + // * We're guaranteed `crtc` is of type `Crtc` via type invariants. + // * We're guaranteed by DRM that `crtc` is pointing to a valid initialized state. + let crtc = unsafe { Crtc::from_raw(crtc) }; + + // SAFETY: DRM guarantees `state` points to a valid `drm_atomic_state` + let state = unsafe { + ManuallyDrop::new(AtomicStateComposer::new(NonNull::new_unchecked(state))) + }; + + // SAFETY: Since we are in the atomic update callback, we're guaranteed by DRM that both the old + // and new atomic state are present within `state` + let (old_state, new_state) = unsafe {( + state.get_old_crtc_state(crtc).unwrap_unchecked(), + state.get_new_crtc_state(crtc).unwrap_unchecked(), + )}; + + from_result(|| { + T::atomic_check(crtc, old_state, new_state, &state)?; + Ok(0) + }) +}