From mboxrd@z Thu Jan 1 00:00:00 1970 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 C1E99CD6E54 for ; Sat, 30 May 2026 14:00:10 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2C6F010E355; Sat, 30 May 2026 14:00:10 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="AupyqGph"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id D915D10E355 for ; Sat, 30 May 2026 14:00:05 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id BEC6A4076D; Sat, 30 May 2026 14:00:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DAEA1F00898; Sat, 30 May 2026 14:00:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780149605; bh=DluBzgCs8mXvT0Xn5QB32A9r9aWWNOLoKeit24tlI5A=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=AupyqGphJ3z2s965ocPYI+5llnDRIhCctfs9k0fGC9WdUoawPCe50g1gljDmo6utf A0j/QXcyCex1aBmeQrAFNRWIqmUAuWzqFmd6VSF3F/yGcQxegXpkLwaunv6tq52/6k 7s6XTbAH2DLEaUsqWNUMk60qyRGOCzY89WSuu6tXuoZDZEgYpIxnKtyKeOyj/nkLR2 VBAgmNGTF/e9neOEMQ0hoIWh+HeP2IZQ80KloyYxVzw8pvsDxRK86M3yLLL9JT73yS mBEcEtN0oOs36ANwf1s5rMbeZJiBUzYv6Qo98/9Atfm5Ykqf4Vo1CeN8teo/KdwhAT UnGKfjYuwgOkQ== From: Maxime Ripard Date: Sat, 30 May 2026 15:59:09 +0200 Subject: [PATCH 04/76] drm/bridge: Add new atomic_create_state callback MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260530-drm-no-more-bridge-reset-v1-4-875d828d31bc@kernel.org> References: <20260530-drm-no-more-bridge-reset-v1-0-875d828d31bc@kernel.org> In-Reply-To: <20260530-drm-no-more-bridge-reset-v1-0-875d828d31bc@kernel.org> To: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter Cc: Dmitry Baryshkov , dri-devel@lists.freedesktop.org, Maxime Ripard X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=4765; i=mripard@kernel.org; h=from:subject:message-id; bh=yBHRsQmZbj5xT1ZIhn/9h711gXV45q7dolDADfjLuQg=; b=owGbwMvMwCmsHn9OcpHtvjLG02pJDFlSb83f+Gqz1ytcFeHp0OzPEvxUu2pdvTYrF4eyxJ+dR +bX7ZvXMZWFQZiTQVZMkeWJTNjp5e2LqxzsV/6AmcPKBDKEgYtTACbCvJGx3kFpzt15qzXsYnaI HWbkd9ENWv4pMEv/+69dHxK5H3EEdy1YHCdRL+kU8bntj/suWc0VjA1vdBrfHkx2+Xzpi9KF9xe vJMlfcogx4ZfjnbCrqyXsPOemgN+ruZ4wtOilBUXyTuwwZAIA X-Developer-Key: i=mripard@kernel.org; a=openpgp; fpr=BE5675C37E818C8B5764241C254BCFC56BF6CE8D 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" Commit 47b5ac7daa46 ("drm/atomic: Add new atomic_create_state callback to drm_private_obj") introduced a new pattern for allocating drm object states: atomic_create_state, a dedicated hook that allocates and initializes a pristine state without any side effect. The bridge atomic_reset callback is already fallible and in practice only allocates and initializes state without touching hardware. However, the reset name does not make this contract clear: callers and implementers cannot tell from the name alone whether the hardware will be affected or when the hook is safe to call. Add an atomic_create_state callback to drm_bridge_funcs to make the contract explicit: allocate a pristine state, initialize it, no side effects. The core calls it when available, falling back to atomic_reset otherwise. Signed-off-by: Maxime Ripard --- drivers/gpu/drm/drm_bridge.c | 8 ++++++-- include/drm/drm_bridge.h | 33 +++++++++++---------------------- 2 files changed, 17 insertions(+), 24 deletions(-) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 687b36eea0c7..ef06c1aa509a 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -498,11 +498,14 @@ static struct drm_private_state * drm_bridge_atomic_create_priv_state(struct drm_private_obj *obj) { struct drm_bridge *bridge = drm_priv_to_bridge(obj); struct drm_bridge_state *state; - state = bridge->funcs->atomic_reset(bridge); + if (bridge->funcs->atomic_create_state) + state = bridge->funcs->atomic_create_state(bridge); + else + state = bridge->funcs->atomic_reset(bridge); if (IS_ERR(state)) return ERR_CAST(state); return &state->base; } @@ -513,11 +516,12 @@ static const struct drm_private_state_funcs drm_bridge_priv_state_funcs = { .atomic_destroy_state = drm_bridge_atomic_destroy_priv_state, }; static bool drm_bridge_is_atomic(struct drm_bridge *bridge) { - return bridge->funcs->atomic_reset != NULL; + return (bridge->funcs->atomic_create_state || + bridge->funcs->atomic_reset); } /** * drm_bridge_attach - attach the bridge to an encoder's chain * diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 4ba3a5deef9a..a6c07d339afa 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -502,35 +502,24 @@ struct drm_bridge_funcs { struct drm_bridge_state *bridge_state, struct drm_crtc_state *crtc_state, struct drm_connector_state *conn_state); /** - * @atomic_reset: + * @atomic_create_state: * - * Reset the bridge to a predefined state (or retrieve its current - * state) and return a &drm_bridge_state object matching this state. - * This function is called at attach time. - * - * The atomic_reset hook is mandatory if the bridge implements any of - * the atomic hooks, and should be left unassigned otherwise. For - * bridges that don't subclass &drm_bridge_state, the - * drm_atomic_helper_bridge_reset() helper function shall be used to - * implement this hook. - * - * Note that the atomic_reset() semantics is not exactly matching the - * reset() semantics found on other components (connector, plane, ...). - * - * 1. The reset operation happens when the bridge is attached, not when - * drm_mode_config_reset() is called - * 2. It's meant to be used exclusively on bridges that have been - * converted to the ATOMIC API + * Allocate a pristine, initialized, state for the bridge + * object and return it. This callback must have no side + * effects: in particular, the returned state must not be + * assigned to the object's state pointer and it must not affect + * the hardware state. * * RETURNS: - * A valid drm_bridge_state object in case of success, an ERR_PTR() - * giving the reason of the failure otherwise. + * + * A new, pristine, bridge state instance or an error pointer + * on failure. */ - struct drm_bridge_state *(*atomic_reset)(struct drm_bridge *bridge); + struct drm_bridge_state *(*atomic_create_state)(struct drm_bridge *bridge); /** * @detect: * * Check if anything is attached to the bridge output. @@ -1369,11 +1358,11 @@ drm_bridge_get_current_state(struct drm_bridge *bridge) /* * Only atomic bridges will have bridge->base initialized by * drm_atomic_private_obj_init(), so we need to make sure we're * working with one before we try to use the lock. */ - if (!bridge->funcs || !bridge->funcs->atomic_reset) + if (!bridge->funcs || !bridge->funcs->atomic_create_state) return NULL; drm_modeset_lock_assert_held(&bridge->base.lock); if (!bridge->base.state) -- 2.54.0