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 187CF23182D; Mon, 4 May 2026 17:41:51 +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=1777916513; cv=none; b=pli22Zn0OtKHeYD7VsFbDvYJvA7p5m7mOd2d0rhMubVEwyirUnqNDDIT6Dc1qqw5IlVRpMxRChN3dJPUr4FaUcoxj5vZ6HAdczT+E/tL8PJy4/dFKwVx+ZAUgy9zTExRTOg2h2OPiSuqWNDHsr2BQrCe0i0ePvH3HVnJuUCl50s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777916513; c=relaxed/simple; bh=6pq6bjfZyGoRsdQnszcih275UmRsgM0CIIy0h8hCQUA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BB4/7mGaLWZgAHqqpmtraRL6sKo9IxM2BPV/lDM3QzKuRaWwv3U9PnD0kN3mtBN5bRgRixdmSyBOav3AGMP1H0fipub3X5oc5JpC2/08dOQPWW9UM4SmJHR+VhMrv6wZ/BOndWNBmGPZq9ZLtK6MS5JMtY4BKeeAS6h9vB3Zy8E= 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=B7U08/8y; 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="B7U08/8y" 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 5F5E0175; Mon, 4 May 2026 19:41:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1777916507; bh=6pq6bjfZyGoRsdQnszcih275UmRsgM0CIIy0h8hCQUA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=B7U08/8yeNPtScPJQF+WdcZLHgn8xM54qa69zHz6Oad8R0BiSSc2Dm7FKavh4hwwT aY2T4JFV+f6KjmcjlaxY7QhdjwpvasWORe5iutSd249tXlfjZyp/z2BDnyQVGaBHfd 1I8ynU/XVZhy9at98yXSTbVBN0DYLXR3L0fpBVh0= Date: Mon, 4 May 2026 20:41:48 +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 16/20] drm/mode-config: Create drm_mode_config_create_initial_state() Message-ID: <20260504174148.GS1344263@killaraus.ideasonboard.com> References: <20260424-drm-mode-config-init-v3-0-8b68d9db0d8b@kernel.org> <20260424-drm-mode-config-init-v3-16-8b68d9db0d8b@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-v3-16-8b68d9db0d8b@kernel.org> On Fri, Apr 24, 2026 at 12:18:56PM +0200, Maxime Ripard wrote: > drm_mode_config_reset() can be used to create the initial state, but > also to return to the initial state, when doing a suspend/resume cycle > for example. > > It also affects both the software and the hardware, and drivers can > choose to reset the hardware as well. Most will just create an empty > state and the synchronisation between hardware and software states will > effectively be done when the first commit is done. > > That dual role can be harmful, since some objects do need to be > initialized but also need to be preserved across a suspend/resume cycle. > drm_private_obj are such objects for example. > > Thus, create another helper for drivers to call to initialize their > state when the driver is loaded, so we can make > drm_mode_config_reset() only about handling suspend/resume and similar. > > Reviewed-by: Dmitry Baryshkov > Signed-off-by: Maxime Ripard > --- > drivers/gpu/drm/drm_atomic.c | 12 +++++- > drivers/gpu/drm/drm_mode_config.c | 87 +++++++++++++++++++++++++++++++++++++++ > include/drm/drm_mode_config.h | 1 + > 3 files changed, 98 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c > index 253a00f450b0..f31b6147e682 100644 > --- a/drivers/gpu/drm/drm_atomic.c > +++ b/drivers/gpu/drm/drm_atomic.c > @@ -59,12 +59,20 @@ > * when preparing the update and kept alive as long as they are active > * in the device. > * > * Their respective lifetimes are: > * > - * - at reset time, the object reset implementation will allocate a new > - * default state and will store it in the object state pointer. > + * - at driver initialization time, the driver will allocate an initial, > + * pristine, state and will store it using > + * drm_mode_config_create_initial_state(). I think it's useful to keep documented where the state is stored. * - at driver initialization time, the driver will call * drm_mode_config_create_initial_state() to allocate an initial, pristine, * state and store in the object state pointer. > Historically, this was one > + * of drm_mode_config_reset() job, so one might still encounter it in > + * a driver. > + * > + * - at reset time, for example during suspend/resume, > + * drm_mode_config_reset() will reset the software and hardware state > + * to a known default and will store it in the object's state pointer. > + * Not all objects are affected by drm_mode_config_reset() though. Does the reset implementation store a new state in the object's state pointer, or does it reset the contents of the already allocated state ? I read the documentation here as meaning the former, if it's actually the latter it should be reworded. Reviewed-by: Laurent Pinchart > * > * - whenever a new update is needed: > * > * + A new &struct drm_atomic_state is allocated using > * drm_atomic_state_alloc(). > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c > index 92ff907f2485..a43eb825671b 100644 > --- a/drivers/gpu/drm/drm_mode_config.c > +++ b/drivers/gpu/drm/drm_mode_config.c > @@ -21,10 +21,11 @@ > */ > > #include > #include > > +#include > #include > #include > #include > #include > #include > @@ -281,10 +282,96 @@ void drm_mode_config_reset(struct drm_device *dev) > } > drm_connector_list_iter_end(&conn_iter); > } > EXPORT_SYMBOL(drm_mode_config_reset); > > +/** > + * drm_mode_config_create_initial_state - Allocates the initial state s/Allocates/Allocate/ > + * @dev: drm device > + * > + * This functions creates the initial state for all the objects. Drivers > + * can use this in e.g. probe to initialize their software state. > + * > + * It has two main differences with drm_mode_config_reset(): the reset() > + * hooks aren't called and thus the hardware will be left untouched, but > + * also the &drm_private_obj structures will be initialized as opposed > + * to drm_mode_config_reset() that skips them. > + * > + * Returns: 0 on success, negative error value on failure. > + */ > +int drm_mode_config_create_initial_state(struct drm_device *dev) > +{ > + struct drm_crtc *crtc; > + struct drm_colorop *colorop; > + struct drm_plane *plane; > + struct drm_connector *connector; > + struct drm_connector_list_iter conn_iter; > + struct drm_private_obj *privobj; > + int ret; > + > + drm_for_each_privobj(privobj, dev) { > + struct drm_private_state *privobj_state; > + > + if (privobj->state) > + continue; > + > + if (!privobj->funcs->atomic_create_state) > + continue; > + > + privobj_state = privobj->funcs->atomic_create_state(privobj); > + if (IS_ERR(privobj_state)) > + return PTR_ERR(privobj_state); > + > + privobj->state = privobj_state; > + } > + > + drm_for_each_colorop(colorop, dev) { > + struct drm_colorop_state *colorop_state; > + > + if (colorop->state) > + continue; > + > + colorop_state = drm_atomic_helper_colorop_create_state(colorop); > + if (IS_ERR(colorop_state)) > + return PTR_ERR(colorop_state); > + > + colorop->state = colorop_state; > + } > + > + drm_for_each_plane(plane, dev) { > + if (plane->state) > + continue; > + > + ret = drm_mode_config_plane_create_state(plane); > + if (ret) > + return ret; > + } > + > + drm_for_each_crtc(crtc, dev) { > + if (crtc->state) > + continue; > + > + ret = drm_mode_config_crtc_create_state(crtc); > + if (ret) > + return ret; > + } > + > + drm_connector_list_iter_begin(dev, &conn_iter); > + drm_for_each_connector_iter(connector, &conn_iter) { > + if (connector->state) > + continue; > + > + ret = drm_mode_config_connector_create_state(connector); > + if (ret) > + return ret; > + } > + drm_connector_list_iter_end(&conn_iter); > + > + return 0; > +} > +EXPORT_SYMBOL(drm_mode_config_create_initial_state); > + > /* > * Global properties > */ > static const struct drm_prop_enum_list drm_plane_type_enum_list[] = { > { DRM_PLANE_TYPE_OVERLAY, "Overlay" }, > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > index 687c0ee163d2..00009250fde4 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -1005,9 +1005,10 @@ int __must_check drmm_mode_config_init(struct drm_device *dev); > static inline int drm_mode_config_init(struct drm_device *dev) > { > return drmm_mode_config_init(dev); > } > > +int drm_mode_config_create_initial_state(struct drm_device *dev); > void drm_mode_config_reset(struct drm_device *dev); > void drm_mode_config_cleanup(struct drm_device *dev); > > #endif > -- Regards, Laurent Pinchart