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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 298A6C433EF for ; Tue, 15 Feb 2022 04:04:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233884AbiBOEEK (ORCPT ); Mon, 14 Feb 2022 23:04:10 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:38396 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231873AbiBOEED (ORCPT ); Mon, 14 Feb 2022 23:04:03 -0500 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADEA7F1AD4; Mon, 14 Feb 2022 20:03:45 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id A6AEC1F43572 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1644897824; bh=VG0gC/LlBYOoQhn5utxIdgmPSt7IfHbptUv0GV7NTBo=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=Ub6dmZitRz45cR9qIKXjTsVXU7KmUgK7H9oGw3VoIqMVy2lNgKyINSxJJ4Mxa9LeQ OSnaNgDQeenPnKVsHAu7FJW2ksmbmmFKxFZ9DhHBEOytGwf5+mTHiU3/rYyeYKZgAI 353erPgVFDlsdFJrWkpczRGLtWgrEDwEWidKsuTfjbzacs2ubqbjvCv53HpQkQgTDO sveWRuEs68cTQpVqRLx8QCaXWu0m6E77IzTClO5SoAIoZgIg7biB2Noa4C7YbpiD3/ +EhnyHcdKXZg/HDB7nczR4ihB2+cz0qN/2Cx4c4omJOGZErQyt9d55dDNGrym2WOmM PBwrKU+TudUGg== From: Gabriel Krisman Bertazi To: Hsin-Yi Wang Cc: dri-devel@lists.freedesktop.org, David Airlie , Daniel Vetter , amd-gfx@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, Chun-Kuang Hu , Sean Paul , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , linux-kernel@vger.kernel.org, Rob Herring , Matthias Brugger , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Simon Ser , Harry Wentland , Alex Deucher , Jani Nikula Subject: Re: [PATCH v8 1/3] gpu: drm: separate panel orientation property creating and value setting Organization: Collabora References: <20220208084234.1684930-1-hsinyi@chromium.org> <87leydhqt3.fsf@collabora.com> Date: Mon, 14 Feb 2022 23:03:39 -0500 In-Reply-To: (Hsin-Yi Wang's message of "Tue, 15 Feb 2022 11:15:02 +0800") Message-ID: <87czjoixno.fsf@collabora.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hsin-Yi Wang writes: > On Tue, Feb 15, 2022 at 9:17 AM Gabriel Krisman Bertazi > wrote: >> >> Hsin-Yi Wang writes: >> >> > drm_dev_register() sets connector->registration_state to >> > DRM_CONNECTOR_REGISTERED and dev->registered to true. If >> > drm_connector_set_panel_orientation() is first called after >> > drm_dev_register(), it will fail several checks and results in following >> > warning. >> >> Hi, >> >> I stumbled upon this when investigating the same WARN_ON on amdgpu. >> Thanks for the patch :) >> >> > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c >> > index a50c82bc2b2fec..572ead7ac10690 100644 >> > --- a/drivers/gpu/drm/drm_connector.c >> > +++ b/drivers/gpu/drm/drm_connector.c >> > @@ -1252,7 +1252,7 @@ static const struct drm_prop_enum_list dp_colorspaces[] = { >> > * INPUT_PROP_DIRECT) will still map 1:1 to the actual LCD panel >> > * coordinates, so if userspace rotates the picture to adjust for >> > * the orientation it must also apply the same transformation to the >> > - * touchscreen input coordinates. This property is initialized by calling >> > + * touchscreen input coordinates. This property value is set by calling >> > * drm_connector_set_panel_orientation() or >> > * drm_connector_set_panel_orientation_with_quirk() >> > * >> > @@ -2341,8 +2341,8 @@ EXPORT_SYMBOL(drm_connector_set_vrr_capable_property); >> > * @connector: connector for which to set the panel-orientation property. >> > * @panel_orientation: drm_panel_orientation value to set >> > * >> > - * This function sets the connector's panel_orientation and attaches >> > - * a "panel orientation" property to the connector. >> > + * This function sets the connector's panel_orientation value. If the property >> > + * doesn't exist, it will try to create one. >> > * >> > * Calling this function on a connector where the panel_orientation has >> > * already been set is a no-op (e.g. the orientation has been overridden with >> > @@ -2373,19 +2373,12 @@ int drm_connector_set_panel_orientation( >> > info->panel_orientation = panel_orientation; >> > >> > prop = dev->mode_config.panel_orientation_property; >> > - if (!prop) { >> > - prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE, >> > - "panel orientation", >> > - drm_panel_orientation_enum_list, >> > - ARRAY_SIZE(drm_panel_orientation_enum_list)); >> > - if (!prop) >> > - return -ENOMEM; >> > - >> > - dev->mode_config.panel_orientation_property = prop; >> > - } >> > + if (!prop && >> > + drm_connector_init_panel_orientation_property(connector) < 0) >> > + return -ENOMEM; >> > >> >> In the case where the property has not been created beforehand, you >> forgot to reinitialize prop here, after calling >> drm_connector_init_panel_orientation_property(). This means > hi Gabriel, > > drm_connector_init_panel_orientation_property() will create prop if > it's null. If prop fails to be created there, it will return -ENOMEM. Yes. But *after the property is successfully created*, the prop variable is still NULL. And then you call the following, using prop, which is still NULL: >> > + drm_object_property_set_value(&connector->base, prop, >> > + info->panel_orientation); This will do property->dev right on the first line of code, and dereference the null prop pointer. You must do prop = dev->mode_config.panel_orientation_property; again after drm_connector_init_panel_orientation_property successfully returns, or call drm_object_property_set_value using dev->mode_config.panel_orientation_property directly: drm_object_property_set_value(&connector->base, dev->mode_config.panel_orientation_property info->panel_orientation); -- Gabriel Krisman Bertazi