From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 65040258EE9; Mon, 4 May 2026 17:35:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777916114; cv=none; b=O44Hi6F8ASue54XvRITr0oZMLogZsLmLDYYvMOXhWhF2eAMVSJt77eowgBe2nFx07Gybeh2JtMnYnuiOFwx9XpGE9bmp7VQLgK/7CFb8+SMXfHsMO64kksDKoeLTaox7iWBOjJ2hfxkXodx9biMWfstK8Vl8lWWO5H43ePGil3Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777916114; c=relaxed/simple; bh=4uWECAxcPn2j8lm2dquwqliQA6WLP4/GhTLEzPXj/7I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ce39UN489VxoHhPbceuDxOn37i9HgQs6hTLprxZ4GoPWfFl9CYJmZzsb/IAr34BImFrGL7RTL4YoY7mQHn4LFh1fKXLxaL/dEtzpBLoe+BpuOUo/gLN0YU7kF9TnCSnLF0u8n5Qcwnp54NIUlEXIAZwGFqXy54EHebjMXO6gjd0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=mOlOY/Ju; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="mOlOY/Ju" Received: from killaraus.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 7354B175; Mon, 4 May 2026 19:35:07 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1777916107; bh=4uWECAxcPn2j8lm2dquwqliQA6WLP4/GhTLEzPXj/7I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mOlOY/JuCqXc1CY83W9gUwHSKOC0b68roGTUEFpHdsIAlm0S/ijzOs51FJpFuoboF 4wFZWCq0UJk0+jHcJHMtWrecpl115pIZDK+9ULWJkAGGkQuk3Y4JSYorXRe6W5lmk3 RjqqdiOIAdx8ZEyfU6gM46NRoVnZyGfdhBZXYbyY= Date: Mon, 4 May 2026 20:35:08 +0300 From: Laurent Pinchart To: Maxime Ripard Cc: Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , Jonathan Corbet , Shuah Khan , Dmitry Baryshkov , Jyri Sarha , Tomi Valkeinen , Andrzej Hajda , Neil Armstrong , Robert Foss , Jonas Karlman , Jernej Skrabec , Simon Ser , Harry Wentland , Melissa Wen , Sebastian Wick , Alex Hung , Jani Nikula , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , Chen-Yu Tsai , Samuel Holland , Dave Stevenson , =?utf-8?B?TWHDrXJh?= Canal , Raspberry Pi Kernel Maintenance , dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Daniel Stone , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev Subject: Re: [PATCH v3 15/20] drm/connector: Add new atomic_create_state callback Message-ID: <20260504173508.GR1344263@killaraus.ideasonboard.com> References: <20260424-drm-mode-config-init-v3-0-8b68d9db0d8b@kernel.org> <20260424-drm-mode-config-init-v3-15-8b68d9db0d8b@kernel.org> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260424-drm-mode-config-init-v3-15-8b68d9db0d8b@kernel.org> Hi Maxime, Thank you for the patch. On Fri, Apr 24, 2026 at 12:18:55PM +0200, Maxime Ripard wrote: > Commit 47b5ac7daa46 ("drm/atomic: Add new atomic_create_state callback > to drm_private_obj") introduced a new pattern for allocating drm object > states. > > Instead of relying on the reset() callback, it created a new > atomic_create_state hook. This is helpful because reset is a bit > overloaded: it's used to create the initial software state, reset it, > but also reset the hardware. > > It can also be used either at probe time, to create the initial state > and possibly reset the hardware to an expected default, but also during > suspend/resume. > > Both these cases come with different expectations too: during the > initialization, we want to initialize all states, but during > suspend/resume, drm_private_states for example are expected to be kept > around. > > reset() also isn't fallible, which makes it harder to handle > initialization errors properly. This is only really relevant for some > drivers though, since all the helpers for reset only create a new > state, and don't touch the hardware at all. > > It was thus decided to create a new hook that would allocate and > initialize a pristine state without any side effect: > atomic_create_state to untangle a bit some of it, and to separate the > initialization with the actual reset one might need during a > suspend/resume. > > Continue the transition to the new pattern with connectors. > > Reviewed-by: Dmitry Baryshkov > Signed-off-by: Maxime Ripard > --- > drivers/gpu/drm/drm_atomic_state_helper.c | 26 ++++++++++++++++++++++++++ > drivers/gpu/drm/drm_mode_config.c | 21 ++++++++++++++++++++- > include/drm/drm_atomic_state_helper.h | 2 ++ > include/drm/drm_connector.h | 16 ++++++++++++++++ > 4 files changed, 64 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c > index f67aacaa3b6e..6140926f4605 100644 > --- a/drivers/gpu/drm/drm_atomic_state_helper.c > +++ b/drivers/gpu/drm/drm_atomic_state_helper.c > @@ -554,10 +554,36 @@ void drm_atomic_helper_connector_reset(struct drm_connector *connector) > kfree(connector->state); > __drm_atomic_helper_connector_reset(connector, conn_state); > } > EXPORT_SYMBOL(drm_atomic_helper_connector_reset); > > +/** > + * drm_atomic_helper_connector_create_state - default &drm_connector_funcs.atomic_create_state hook for connectors Same comment as in 10/20. > + * @connector: connector object > + * > + * Initializes a pristine @drm_connector_state. "Allocate and initialize ..." > + * > + * This is useful for drivers that don't subclass @drm_connector_state. > + * > + * RETURNS: > + * Pointer to new connector state, or ERR_PTR on failure. > + */ > +struct drm_connector_state * > +drm_atomic_helper_connector_create_state(struct drm_connector *connector) > +{ > + struct drm_connector_state *state; > + > + state = kzalloc_obj(*state); > + if (!state) > + return ERR_PTR(-ENOMEM); > + > + __drm_atomic_helper_connector_state_init(state, connector); > + > + return state; > +} > +EXPORT_SYMBOL(drm_atomic_helper_connector_create_state); > + > /** > * drm_atomic_helper_connector_tv_margins_reset - Resets TV connector properties > * @connector: DRM connector > * > * Resets the TV-related properties attached to a connector. > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c > index 182d9a8104e7..92ff907f2485 100644 > --- a/drivers/gpu/drm/drm_mode_config.c > +++ b/drivers/gpu/drm/drm_mode_config.c > @@ -212,10 +212,26 @@ static int drm_mode_config_crtc_create_state(struct drm_crtc *crtc) > crtc->state = crtc_state; > > return 0; > } > > +static int drm_mode_config_connector_create_state(struct drm_connector *connector) > +{ > + struct drm_connector_state *conn_state; > + > + if (!connector->funcs->atomic_create_state) > + return 0; > + > + conn_state = connector->funcs->atomic_create_state(connector); > + if (IS_ERR(conn_state)) > + return PTR_ERR(conn_state); > + > + connector->state = conn_state; > + > + return 0; > +} > + > /** > * drm_mode_config_reset - call ->reset callbacks > * @dev: drm device > * > * This functions calls all the crtc's, encoder's and connector's ->reset > @@ -255,13 +271,16 @@ void drm_mode_config_reset(struct drm_device *dev) > drm_for_each_encoder(encoder, dev) > if (encoder->funcs && encoder->funcs->reset) > encoder->funcs->reset(encoder); > > drm_connector_list_iter_begin(dev, &conn_iter); > - drm_for_each_connector_iter(connector, &conn_iter) > + drm_for_each_connector_iter(connector, &conn_iter) { > if (connector->funcs->reset) > connector->funcs->reset(connector); > + else if (connector->funcs->atomic_create_state) > + drm_mode_config_connector_create_state(connector); > + } > drm_connector_list_iter_end(&conn_iter); > } > EXPORT_SYMBOL(drm_mode_config_reset); > > /* > diff --git a/include/drm/drm_atomic_state_helper.h b/include/drm/drm_atomic_state_helper.h > index e7c097e6dfe3..8576cd256737 100644 > --- a/include/drm/drm_atomic_state_helper.h > +++ b/include/drm/drm_atomic_state_helper.h > @@ -75,10 +75,12 @@ void drm_atomic_helper_plane_destroy_state(struct drm_plane *plane, > void __drm_atomic_helper_connector_state_init(struct drm_connector_state *conn_state, > struct drm_connector *connector); > void __drm_atomic_helper_connector_reset(struct drm_connector *connector, > struct drm_connector_state *conn_state); > void drm_atomic_helper_connector_reset(struct drm_connector *connector); > +struct drm_connector_state * > +drm_atomic_helper_connector_create_state(struct drm_connector *connector); > void drm_atomic_helper_connector_tv_reset(struct drm_connector *connector); > int drm_atomic_helper_connector_tv_check(struct drm_connector *connector, > struct drm_atomic_state *state); > void drm_atomic_helper_connector_tv_margins_reset(struct drm_connector *connector); > void > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > index 3e422a4f2e72..9fb794957d23 100644 > --- a/include/drm/drm_connector.h > +++ b/include/drm/drm_connector.h > @@ -1569,10 +1569,26 @@ struct drm_connector_funcs { > * when a connector is being hot-unplugged for drivers that support > * connector hotplugging (e.g. DisplayPort MST). > */ > void (*destroy)(struct drm_connector *connector); > > + /** > + * @atomic_create_state: > + * > + * Allocates a pristine, initialized, state for the connector object s/Allocates/Allocate/ > + * and returns it. This callback must have no side effects: in s/returns/return/ Reviewed-by: Laurent Pinchart > + * particular, the returned state must not be assigned to the > + * object's state pointer and it must not affect the hardware > + * state. > + * > + * RETURNS: > + * > + * A new, pristine, connector state instance or an error pointer > + * on failure. > + */ > + struct drm_connector_state *(*atomic_create_state)(struct drm_connector *connector); > + > /** > * @atomic_duplicate_state: > * > * Duplicate the current atomic state for this connector and return it. > * The core and helpers guarantee that any atomic state duplicated with -- Regards, Laurent Pinchart